CALIFORNIA AGRICULTURAL EXTENSION SERVICE r CIRCULAR 125 Revised JUNE, 1 949 IRRIGATED PASTURES IN CALIFORNIA BURLE J. JONES and J. B. BROWN Revised by MILTON D. MILLER and L. J. BOOHER COLL I VERS I T Y AN IRRIGATED PASTURE • . . can help you diversify and balance your farm operations — and conserve your soil. IRRIGATED PASTURES pro- vide an important part of the forage for Califor- nia's meat and dairy herds. California does not raise enough livestock to meet the needs of its rap- idly expanding popula- tion. In 1948, we im- ported 80 per cent of our pork requirements, 50 per cent of our beef needs, 35 per cent of our lamb and mutton, and nearly all of our butter. Some California farm crops are already in over- production. More proba- bly will be. Some of this "surplus" acreage might be profitably converted to irrigated pastures and the production of more livestock. Under Good Management, an Irrigated Pasture Provides: 1 . Conservation and improvement of soil resources. 2. Cheaper, more nutritious feed for livestock. 3. Low harvest costs, because livestock harvest their own feed. 4. Some saving in protein feed supplements. 5. Better gains in young stock. 6. Higher production in a breeding herd. 7. More economical gains in market animals. 8. A more evenly distributed farm labor load over the year. When Planning an Irrigated Pasture, The Grazier Must Consider: l.SOIL AND CLIMATE. The site must lend itself to irrigation and to one of the mixtures of species suitable for pasturage. 2. THE SIZE OF THE FARM. Unless only part-time use of the pasture is possible, there must be enough acreage for rotation grazing. A balance of year-round feed supplies of hay, concentrates, and pasture should be maintained. 3. THE KIND AND QUANTITY OF LIVESTOCK. Irrigated pastures may be desirable for special uses only, such as for a breeding herd or flock, or to fatten for market. 4. THE COSTS, WHICH INCLUDE: (1) installation of the irrigation system, which will vary with type of soil and natuial topography of the land; (2) irrigation water needed, the amount depending upon soil, climate, and length of irrigation season; (3) labor costs for irrigation, which depend on the type of system in- stalled. (A full discussion of average costs will be found on page 41.) 5. PRODUCTION. An irrigated pasture should yield as large a tonnage of feed per acre as alfalfa, but should be more economical in harvesting and feeding costs- in terms of livestock gains, 400 to 500 pounds per acre per year. The Goals of Good Pasture Management Are: 1 . To produce as much meat or milk per acre as possible. 2. To obtain and continue the highest possible grazing capacity of animal units per acre. 3. To use the feed at its highest possible nutritive value. 4. To maintain an adequate stand and balance of legumes and grasses throughout the pasture season. These Goals May be Achieved by: 1 . Wise use of available irrigation water. 2. Rotation grazing so that plants are eaten when their nutritive con- tent is highest — and will have a chance to recover after grazing. 3. Mowing pastures during the spring months when there is a surplus of forage. This adds to hay supplies, helps reduce weeds, and con- trols the coarse growth which has sprung up around cattle drop- pings. 4. Harrowing, to scatter manure droppings. 5. Fertilizing. 6. Weed control. Recent Studies Show That . . . irrigated pastures may not provide enough dry matter, and there- fore dry roughage supplements may be necessary to keep down bloat hazard in cattle and sheep and to promote satisfactory gains. . . . the supplemental grain fattening of beef cattle on irrigated pasture looks like a good proposition under certain situations. . . . forage from irrigated pastures is usually more expensive than that from natural range, but is a cheaper source of nutrients than most other livestock feeds. Dairying particularly could be made more profitable by using more irrigated pastures. . . . California ranges are being improved by the shifting of part of their summer burden to irrigated pastures. Interested in a special phase of Irrigated pastures? SEE TABLE OF CONTENTS ON PAGES 58 AND 59. The authors wish to thank Professors B. A. Madson and M. L. Peterson, of the Division of Agronomy, Professor F. J. Veihmeyer, of the Division of Ir- rigation, and Mr. Ruben Albaugh, of the Monterey County Agricultural Extension Service, who reviewed the manuscript and made helpful sug- gestions. The Authors: Mr. Jones is Assistant Professor of Agricultural Extension, Emeritus, Davis. Mr. Brown was Associate in the Experiment Station, Division of Irriga- tion, Davis. (Deceased.) Mr. Miller is Extension Specialist in Agronomy, Davis. Mr. Booher is Extension Specialist in Irrigation, Davis. IRRIGATED PASTURES IN CALIFORNIA BURLE J. JONES and J. B. BROWN Revised by MILTON D. MILLER and L. J. BOOHER An irrigated pasture is an irrigated area on which is growing a satisfactory stand of seeded forage plants suitable for grazing by livestock. It may occasionally be mowed for hay, or to reduce weeds or coarse clumps about the droppings of cattle. Such pastures are usually made up of a mixture of long-lived grasses and legumes. Sometimes a legume, such as Ladino clover or alfalfa, is seeded alone; occasionally only a grass, such as Dallis, is seeded. But a mixture of legume and grass species is usually recommended for cattle, sheep, and horses. Hogs thrive best on a pasture comprised only of legumes. Irrigated pastures came into use in California in the early 1930's. An unoffi- cial survey by competent authorities placed the acreage in the state, as of November, 1948, at about 575,000 acres. This included only pasture acreage popu- larly recognized as "irrigated pasture" (Ladino clover, Ladino clover-alfalfa- grass mixtures) . It did not include irri- gated mountain meadows, sudangrass, or alfalfa stands which are pastured. Because the plants generally used have a shallow root system, irrigated pastures are being extensively used in areas of heavy or shallow soil which is frequently underlain with hardpan or tight subsoil clay layers. In such areas, pastures are proving profitable where no other culti- vated crop has been permanently success- ful. On many farms, however, deep fertile soils have been seeded to pasture to bal- ance livestock operations economically between winter and summer feed require- ments. Annual feed costs are reduced by allowing livestock to harvest their own feed during the growing season. Increasingly, California farmers are considering irrigated pastures as a crop in the rotation system. It has been esti- mated that 8,000 acres of rice land are in a rotation system with irrigated pasture. Irrigated pastures are now common in the highly productive and high-priced lands supplying some of our larger milk sheds. Plantings in Orange, Riverside, and Los Angeles counties have shown that where water seepage losses are not too high, such pastures provide cheaper feed than green (clipped) alfalfa, or al- falfa hay, and concentrates. Santa Clara, Alameda, and Contra Costa counties, as part of the San Francisco milk shed, use them extensively. Successful irrigated pastures depend on soil and climate, over-all farm program, costs, production, and kind of stock Probably the first consideration should be the adaptation of the site to a particu- lar mixture of species. Some mixture can be assembled that will grow on almost any soil where enough irrigation water is [5 available to meet requirements of grow- ing plants during the dry summer. Very shallow soils may be used, for although roots of many grasses strike deeper, most can grow in as little soil as 9 inches. Adaptability to farm program. The general farm program must be con- sidered in planning an irrigated pasture. This includes the size of the farm, kind of livestock, and the proper balance of year-round feed supplies. On most farms, it probably will be necessary to purchase supplementary feeds, such as hay, silage, and concentrates, or to produce them on other cultivated land. It is not possible to balance stock numbers exactly with the seasonal availability of pasture feeds. The spring flush of pasture growth will prob- ably exceed requirements. The short- production winter months (see page 24) will require considerable stock feeding from sources other than pasture. Unless only part-time use of the pasture is pos- sible, there must be sufficient pasture acreage to allow for rotation grazing. Many range stockmen are now operat- ing irrigated pastures in connection with their ranges. Their cattle or sheep are moved onto the green irrigated pastures during the summer months after the feed has dried up on the range. At the end of the irrigated pasture season, the stock then return to the range. Such a pro- gram, if properly used, can assist in im- proving California rangelands principally by reducing overgrazing and by assisting desirable resident perennial range species to become reestablished. Stockmen are also using irrigated pastures for special purposes, such as to provide good feed for weaner calves or lambs, or to fatten stock for market. Farmers are planting fields to irrigated pasture which until recently produced a cash specialty crop. As surpluses develop in the postwar period, ranchers are con- verting land used for surplus crops to pasture. This provides a better balanced farming program. Pasture can be used to produce needed livestock products for California's rapidly expanding popula- tion. The greater use of pasture is also sound from the standpoint of maintaining the fertility of California farms. Costs. In figuring costs of feed pro- duced by irrigated pastures, soil prepa- ration, overhead, and maintenance must Fig. 1 .— Even utilization of Ladino clover and grass pasture by dairy cattle. Cattle and sheep pasture should be about 45 per cent legumes, 55 per cent grasses. [6] Fig. 2.— Hogs do best on a pure legume pasture, but grass-legume pastures (above) are often used. Growing pigs do especially well on pasture. Pasturing hogs should receive a grain sup- plement. be considered. Alfalfa is a good standard measure by which to figure probable ex- pense and future returns. If soil, topog- raphy, water facilities, and climate are suitable for alfalfa (on the basis of aver- age returns) , it is likely that an irrigated pasture crop would also be profitable. Actual expenditures for preparation, seeding, and maintenance vary, depend- ing on topography, water costs, taxes, and upkeep of irrigation structures. (See fig- ures on page 43.) Production. Alfalfa is also a good yardstick for measuring feed production. An irrigated pasture should yield as large a tonnage of feed per acre as alfalfa, using no more irrigation water or labor, and should be more economical because the livestock harvest their own feed. In general, this is a fair comparison, al- though there may be a few exceptions. Where an irrigated pasture is grown on soil too shallow for alfalfa, the com- parison still holds— production should equal a fair yield of alfalfa. Pasture production should be judged by average returns for several years, not by returns for one season only. Alfalfa producers, for example, are able to make a frequent check during irrigation and harvesting operations, and the harvest itself gives a fairly accurate record of annual yields. Pasture operators, on the other hand, do not have occasion to make such check-ups, since there are no bales or sacks to weigh. However, progressive stockmen now own livestock scales with which they weigh stock on and off their irrigated pastures. Valuable records of gain in weight are thus being obtained and the graziers concerned know where they stand. Weeds may creep in, compo- sition of the mixture may change, and total yield may decline without the oper- ator's knowledge if no in and out weights are obtained. [7] Production in terms of animal units per acre varies widely, depending on cer-. tain fixed soil, climatic, and irrigation limitations beyond the control of a pros- pective operator. These should all be considered in determining whether an irrigated pasture is economically sound. Once the pasture is established, manage- ment practices should be regulated to maintain high production. Few Califor- nia pastures show a lower carrying capac- ity than one animal unit (1 mature cow) per acre for the grazing season (8 to 11 months) . Some pastures carry as high as two or even three units per acre per season. Under proper management, most of the pastures in this state should sup- port two animal units per acre, if the mix- ture and stand are adequate. Improvement in livestock and in- come* Livestock improvement should begin with a well-planned and properly conducted feed production program. Next in importance is a sound breeding program. For the dairyman, a good irri- gated pasture, grazed at the right stage of growth for maximum nutritive values, has been shown to produce more milk than does hay, or even hay and concen- trates. And the saving in the cost of harvesting and feeding often means the difference between profit and loss. With irrigated pastures, the range op- Fig. 3. — Sheep on contour-basin irrigated pasture. They do well on grass-legume type used for cattle. erator may increase both the quantity and the quality of his output, through better gains in young stock, a higher production in the breeding herd, and more economi- cal gains in market animals. While he may appear to be substituting higher- priced feeds for range forage, he will be effecting a saving in protein and grain supplements. He can be improving the productivity of his range if he properly coordinates the grazing program on the range with his irrigated pastures. land Preparation and Irrigation Types of irrigation vary, depending upon differences in the soil, land contours, and the amount of water that is available The purpose of land preparation is to provide for the most economic and uniform application of irrigation water. Pastures require a greater number of ir- rigations each season than do other crops. For this reason, it is particularly impor- tant that the land be properly prepared so that a minimum amount of labor will be required for irrigation. Once the land has been planted, very little can be done to improve the irrigation system without destroying the stand, releveling, and re- seeding. Pastures are irrigated by strip checks, contour checks, wild flooding, and sprin- kling. Each method is discussed sepa- rately in this section. The method chosen will depend upon the type of soil, the available water supply, and the lay of the land. [8] Type of Soil. Fine-textured soils, or those underlain with a hardpan or clay layer, are preferred for irrigated pas- tures because water can be applied more efficiently, and because these soils hold more water near the surface where it is needed. Many large areas of heavy, shal- low soils in California, which were once considered of no value for irrigated farm- ing, are now used for irrigated pastures. The amount of water which a soil can store for use by plants depends largely upon the size of the soil particles. The amount of readily available water which can be retained in a one-foot depth of soil, following an irrigation, is equivalent to about 1 inch of water in a sandy soil, 1% to 2 inches in a loam soil, and 2 to 3 inches in most clay soils. These amounts can be taken only as a rough guide since some sandy soils can store more water for use by plants than can some clay soils. It is necessary to apply only enough water, at each irrigation, to wet the soil to the depth of rooting. Most of the clovers and pasture grasses will root to a depth of only about 2 feet. Birdsfoot tre- foil will root to a depth of 4 to 6 feet, alfalfa, to 6 feet or more. It is desirable to have alfalfa or other deep-rooted plants in the pasture mixture on porous soils to permit a more efficient use of the irrigation water. Water does not penetrate into all types of soils at the same rate. Fine-textured soils (such as clays) and soils that are puddled take water slowly. Coarse- textured soils (such as sands) generally take water rapidly. It is difficult to irri- gate sandy soils efficiently by surface irrigation methods because the water pen- etrates too deeply near the point of ap- plication. Available Water Supply. When selecting a system of irrigation and when preparing the land, the farmer must con- sider the rate at which he will receive his water. Irrigation water is supplied from canals or wells. Where the supply is from canals, the farmer may receive his water as a continuous flow, on demand, or on a rotation basis. If the farmer owns his own pump, he can operate it to suit his needs. The size of the stream of water which the farmer can obtain for irrigating his «m 'M#**' v-'i'Z 14&J9 Z. Fig*>4.— Strip-checked land ready for seeding (Oakdale District, Stanislaus County). Note rolling nature of country and direction of strips. Checks are about 1 3 feet wide. [9] fields varies in different localities. It de- pends upon the source of supply, or upon the method of distribution in case the water is obtained from a canal. Lay of the Land. Before the land is prepared for irrigation, it is desirable to have a topographic survey made of the field. A contour map, based on the survey, will show the direction and amount of slope, and the location of high and low spots in the field. The amount of earth to be moved in preparing the land for irrigation can also be determined from the survey. This amount will vary on different farms, de- pending upon the unevenness of the ground surface. If there is only a shallow depth of topsoil, the depths of cuts should be kept at a minimum. Final grades should be selected so that there will be a balance of cuts with fills. An allowance for shrinkage, generally about 10 per cent, is made when exca- vated soil is placed in fills. An engineer or surveyor is usually hired to make the survey, to do the neces- sary computations for earth moving, and to select and lay out the irrigation system. The charge for this service is generally about $2 to $4 per acre. Strip checks are the best method for smooth, gently sloping land and finer-textured soils; this method requires much land preparation For the strip-check method of irriga- tion, low levees or borders are con- structed at intervals across the field to guide the water as it moves down the slope (fig. 4, p. 9). This method has proved most successful on gently sloping lands which have a fine-textured soil that does not permit the water to penetrate too rapidly. The width and length of the checks and the desired slope to use will depend upon the shape of the field, the topography, the amount of water available, and the type of soil. All of these factors must be prop- erly balanced for each field. On sandy soils with steep slopes, or on clay soils with only small flows of water available, it is sometimes desirable to have the checks as narrow as 8 feet. On heavy soils, where large flows of water are available and the land is nearly flat, the checks may be as wide as 30 to 40 feet. In a number of areas, farmers prefer to have the checks about 13 feet wide. It is common practice to have the di- rection of the runs made so that the water moves down the steepest slope. This re- duces the amount of cross-leveling that is required. If the field has a water penetra- tion problem, this practice may not be desirable. Water penetration is generally increased when the slope is reduced. This can be accomplished by further land level- ing or by altering the direction of the runs. If the land has considerable side fall, the strips should be made narrow. The difference in elevation between any two adjacent checks should not be over 0.2 foot. The length of the strips will depend upon the shape of the field and the rate at which water penetrates the soil. In sandy soil, a great deal of water may be wasted by deep percolation at the upper ends of the runs if the strips are too long. This difficulty can sometimes be partly over- come by increasing the amount of water turned into each check. Table 1 gives the recommended lengths of runs for checks of different widths and for various rates of flow. If the slopes are steep, strips longer than 800 feet should be limited in width to 15 feet or less. This table applies only to clay and clay loam soils. For porous loams and sandy loams, increase delivery rates for the sizes of checks given in the table from 2 to 5 times, or use shorter checks. This will permit the water to cover the ground quickly without too much being applied 10] Table 1 SIZES OF STRIP CHECKS FOR CLAY LOAM AND CLAY SOILS Length of check for various widths of strip Flow delivered to each strip 10 feet wide 15 feet wide 20 feet wide 25 feet wide cu. ft. per sec. 0.2 gals, per min. 90 135 feet 440 660 880 880 1,320 1,320 feet 440 660 660 880 880 1,320 1,320 feet 440 660 660 880 880 1,320 1,320 feet 0.3 0.4 180. . 0.5 .. . 225 270 315 440 0.6 0.7 0.8 360 405 450 540 675 660 0.9 660 1.0. . . 880 880 1.2 1.5. . . 1,320 at any single irrigation. However, the velocity of the water should be kept suffi- ciently low to prevent erosion. Strip checks require grade in only one direction— that in which the water flows down the check. This grade may or may not be uniform. Grades of 0.2 to 0.5 foot per 100 feet are desirable for covering the ground quickly. Steeper slopes are used in some districts where the soil re- sists erosion and where it would be in- advisable to level the fields. Some farmers prefer to have the first 10 feet of the checks perfectly level so that the water will be uniformly distrib- uted between the levees before it moves down the checks. To insure uniform coverage over the full width of the checks, the land between the borders must be carefully cross-leveled. The unit head, which is the rate of delivery of water into each check, may vary from 0.2 to 1.0 cubic foot per second (90 to 450 gallons per minute) . The unit head can be regulated by changing the number of checks irrigated at one time. The farmer has more control over this one factor than any of the other factors which make up his irrigation system. By experience, he will learn the size of stream to use to obtain the most efficient and uniform application of water. Land Preparation. More land level- ing is required for strip checks than for any other type of flood irrigation. The cost of a good job of land preparation is generally repaid, in future years, with dividends in reduced irrigation labor costs, savings on the amount of water used, and higher crop yields. The first step in preparing the land for the strip-check method of irrigation is to do the necessary earth moving. The land should then be plowed or disked and the whole field smoothed with a float or land plane before the border levees are built (fig. 5). In land planing, it is best to level diagonally across the field first, then lengthwise across the field. Next, apply a special irrigation to settle the fills. After this, it is sometimes desirable to plow or disk and plane the field a second time. Various types of equipment are used for constructing levees. Power machines, such as road graders or special, custom- built attachments for tractors which build the borders and level the ground between them in one operation, are used in some areas (fig. 6). Disk ridgers, crowders, or alfalfa checkers are also used, but with [ii] -k'S=^. ' U^~k «\ Fig. 5.— Land planing is done after field has been rough-leveled, to insure that minor irregularities are eliminated. Careful leveling permits efficient use of irrigation water. these, it is necessary to work the strip checks a second time to cross-level the land between the borders. The size and the shape of the levees are important. They should have a base width of about 2 feet and a settled height of about 6 inches. Levees of this size will be covered with a growth of legumes and grasses, so that the entire field can be used for producing feed. When the levees are first constructed, they are composed of loose earth and are irregular in shape. Before being seeded, they should be com- pacted and smoothed. This can be done with some type of ringroller (fig. 10, p. 21) while the entire field is being rolled. The lower ends of the border should be left open to drain off any excess water. Ponding at the lower ends of the runs drowns useful vegetation and encourages growth of undesirable, water loving types of weeds, such as curly dock and the sedges. Adequate drainage ditches should be built for collecting and removing sur- plus water from the low end of the field. In some districts, this surplus water is used to irrigate other fields; in other dis- tricts, it is dumped into main drainage ditches. 1 948 Cost of Preparing Land. The total cost of preparing land for irrigation by the strip-check method will vary de- pending upon the amount of earth mov- ing required. Rough leveling work can be done for 8 to 12 cents per cubic yard of earth moved. Leveling which requires that the land be left with a finished surface within 0.1 foot of the desired elevation will cost 14 to 20 cents per cubic yard. The cost for leveling the land may be as little as $20 or as much as $80 per acre. One large operator in Yolo County found that, during 1948, it cost about $30 per acre to level his land. After the earth moving work, the soil is usually plowed and sometimes chiseled. The cost of chiseling will be about $1.50 per acre ; plowing will cost slightly more. The cost for land planing depends on how many times the machine has to go over the land (fig. 5) . For once over, the cost will be between 50 cents and $1 per acre, depending upon the width of the blade and the efficiency of the operator. Most farmers plane their land two to four times. Levees can be constructed for about $4 per acre. Harrowing and rolling the field after levee construction will cost about [12 *#£ Fig. 6.— Checking attachment for tractor. This machine builds the borders and levels the ground between them in one operation. Machine is equipped with leveling gauge. $1 per acre. The cost of constructing head ditches will average between $1 and $1.25 per acre. As of 1948, the total cost of preparing land for the strip-check method of irri- gation, including the cost of the survey, varied from $30 to $130 per acre. If the land is fairly level, an average cost of about $50 per acre can be used for esti- mating purposes. If concrete pipe lines are used instead of open ditches, this cost will be increased by $60 to $150 per acre, depending upon the amount of water to be carried and the length of the irriga- tion runs. Labor Costs. For irrigation by strip checks, labor costs per season vary with the total number of irrigations, the size of the stream to be distributed, and the length of time water is allowed to run at a single setting. Where water is furnished by an irrigation company or district, de- livery is usually on a 24-hour basis and provision must be made for night irri- gation. When water is supplied by private pump, lands are usually irrigated only in daylight hours. With a large stream of water divided between a few checks of small area, water changes occur at frequent intervals, and close attention is required. Under such conditions, the irrigator must give his en- tire time to water deliveries. When small amounts of water are delivered to each strip, and the checks are large, the water is sometimes allowed to run for a long time and the irrigator may not devote all his time to water deliveries. The average cost of irrigation labor on 24 farms in 1947, as shown by table 3, page 43, was $7.04 per acre for the season. Turnout Structures. Gates for con- trolling the delivery of water from open ditches to the checks must be easy to operate and yet give close regulation of the water. The turnout gates are generally placed in the ditch bank at the center of each check. Wooden field gates, such as are used in alfalfa irrigation, are sometimes used where the checks are large and big heads of water are necessary. For small, narrow checks, some form of slide gate attached to pipes passing through the ditch bank is generally used (fig. 7) . Concrete pipe lines are most useful where the topography is rough or where seepage loss from earth ditches is exces- sive. Pipe lines allow close control of the flow of water with a minimum amount of labor. Risers, in which orchard or alfalfa valves are installed, are placed at the head 13 Fig. 7.— Types of turnout struc- tures. These are placed in the ir- rigation supply ditch bank at the center of each check. Water flows through them from the ditch to irrigate the checks. The gates may be adjusted to regulate the flow of water. ■;...:,;, . ■r ;V .-...; # . of the levee beteen two checks. There should only be half as many risers as there are checks. Short sections of porta- ble pipe are attached to irrigation hy- drants placed over the risers during irrigation (fig. 8). The hydrants contain slide gates for regulating the distribution of water between the two checks. Most erosion encountered with the strip-check method starts at the head of the checks because the water enters the check too fast. To cut down this fast mov- ing water, the outlets should be placed slightly lower than the ground surface. The water will then be discharged into a pool. The outlets should never be placed so high that they permit the water to fall onto the ground surface. Contour checks are good for flat lands. They cost less to prepare, and they have the lowest irrigation labor costs Contour checks are irregular basins formed by small levees or ridges similar to those used in the irrigation of rice. This method is only suitable on heavy soils where the land is nearly flat or gently sloping. The contour-check method can be used to better advantage than can the strip-check method, on irregular- shaped fields. Large heads of water must be available so that the basins can be filled in a short time. Flows of 6 to 10 cubic feet per second are desirable. If the land has previously been irri- gated, the only land preparation required is to go over the field several times with a land plane. If new land is to be irrigated by the contour-check method, some rough land leveling may be needed. Location of the contours is determined by use of the engineer's level and rod. Each levee is constructed on a contour, or line of equal elevation. The vertical inter- val between the bases of adjacent ridges is usually 0.2 foot. Where the land is so flat that very large areas would be en- closed by levees located on a 0.2-foot in- terval, the basins may be divided by cross levees or the vertical interval may be reduced. For irrigated pastures, it is not desirable to have more than 1 acre of land within each basin, although basins up to 4% or 5 acres have been successfully irrigated. If the pasture is to be harvested for a seed crop, the levees should be at least 20 to 30 feet apart at their narrowest point. [14] The levees used in the contour-check method serve as a dam for the water. They must, therefore, be larger than those used for the strip-check method. A desira- ble size for the levees is a base width of 30 to 36 inches, and a height of 14 inches when new. The settled height should be at least 12 inches. A broad, shallow ditch should be con- structed down the slope through the ap- proximate center of each check. Control gates are installed where the ditch passes through the levees. The ditch is used for rapidly draining the basins after they have been irrigated, and for carrying the water from the source of supply to the lower basins. In addition to the control gate on the ditch, ordinary stop gates are sometimes installed through the levee near both ends of the basin. The gates serve both as a check and as a spillway to keep the water from overtopping the levee. The fields are irrigated from basin to basin, water being drained from the upper to lower basins, successively. Ex- cess water from the last check is dis- charged to lower lands or to wasteways. Labor costs for irrigation by contour checks are lower than for any other sys- tem of irrigation, probably not exceeding $3 per acre per year. The cost of leveling the land for con- tour irrigation will vary from practically nothing to as much as $50 per acre where considerable earth moving is required. Chiseling and planing the field will cost about $8 per acre. The cost of having the contours located by a surveyor, and of constructing the levees, will be between $2.50 and $4 per acre. Installing the gates in the levees will cost between $2.50 and $5 per acre. In general, the average cost of preparing land for contour irrigation will be about $30 per acre. This is about per acre less than for strip-checks. Fig. 8.— Irrigating two checks from single alfalfa-type valve with irrigation hydrant attached. [15] Wild flooding is used to a great extent in the Sierra foothills. It requires little earthwork, but it needs the irrigator's constant attention The common method of irrigating pas- tures in the Sierra Nevada foothills is by spilling from ditches on flat grades, lo- cated on ridges and along the sides of the hills (fig. 9). The water is distributed from the ditches at selected points. It moves down the side of the hill to the next distribution ditch, spreading out over the area between on its journey downward. The irrigator must have considerable ex- perience in irrigating a particular field by this method before he can apply the water evenly over the pasture. Very little leveling work can be done because of the slopes and the shallow soils. Ditches, which are located on grades of l 1 /^ to 2 inches per hundred feet, are built with a plow or with hand tools. Distances between ditches vary from 50 to 300 feet, depending upon topography. Delivery heads are small— from V2 to 1 cubic foot per second (20 to 40 California miner's inches). The few structures used are of simple design and easily built. The water is generally purchased from canal companies in units of miner's inches, for the season, or for a 24-hour period. Two to four acres are irrigated from each seasonal miner's inch bought. The amount of labor involved per acre in using this method of irrigation is greater than for the two methods pre- viously described. Practically continuous attention is required by the irrigator while the water is running. Water is raised in the distribution ditch by build- ing a dirt dam at the downstream edge of a section to be irrigated. The ditch bank is then opened at a number of places above the temporary stop. When the first section is watered, the operations are re- peated for other sections along the ditch. An irrigator can water about 4 acres per day by this method. W- ., .<*# mi^P^x ■:.#,- Fig. 9.— Wild flooded irrigated pasture (Nevada County). Area in foreground is dry range. The ditch, plowed nearly on the contour, is broken at intervals to permit the water to seep down across the field to the next lower ditch. 16 Sprinkling is expensive, but it is good where the water costs are high and the land is hard to prepare for other methods of irrigation Sprinkling is one of the newer methods of irrigating pastures. Even distribution and the possibility of controlling the amounts of water applied at each irriga- tion favor the use of this method for sec- tions of high water cost, for pastures located on coarse-textured, easily pene- trated soil, and for locations difficult or impossible to level. There are three general types of sprinkler systems: 1. Underground main and lateral lines with rotating sprinklers in fixed locations. This system requires a large investment per acre. To reduce pipe costs, lateral lines should be as widely spaced as operating pressures will allow. With wide spacing, operating pressures must be high— usually from 40 to 50 pounds per square inch at the pump. Al- though first cost and power costs are high for this type of system, labor charges are very low. 2. Underground or portable main lines with portable lateral lines equipped with rotating sprinklers. First cost is lower for this type of system than for ( 1 ) ; operating pressures are the same; but labor charges for moving the laterals add considerably to the total cost of operation. Time out for moving the lines reduces the percentage of total time the sprinklers can be operated. In irrigat- ing other crops, studies showed that twenty-five systems using two distributing lines operated 85 per cent of the time, while thirteen single-line systems oper- ated only 67 per cent of total irrigation time. 3. Portable surface-pipa main lines with the end sections perfor- ated for spray irrigation. This system is cheaper in first cost than either ( 1 ) or (2) , and will operate on pressures as low as 8 to 10 pounds per square inch. A strip from 30 to 35 feet wide and as long as the perforated section of the pipe is wetted at each setting. Rates of application by this method are high, the lowest rate being about 1 inch in depth per hour for the area covered. For an application of 2 inches in depth the line would have to be moved every 2 hours. Power costs are low for this system, but labor charges are high. In general, the high cost limits sprin- kling to small areas which cannot be irrigated by other methods. (California Experiment Station Circular 388 dis- cusses sprinkler irrigation in detail.) Main costs are for water and labor. Water used depends on temperature, length of season, depth of wetting, plant types, system, and layout How fo figure amounts of water. As a means of checking up on irrigation practices, the depth of water applied to any field in a given time by a given flow may be easily figured by using the fol- lowing approximate formulas: 1. Flow in cubic feet per second x hours run r, i 1 : — -. — rn = Inches depth applied Number of acres irrigated Example: Area, 40 acres Flow, 8 cubic feet per second Time to irrigate, 15 hours 8x15 120 40 40 = 3 inches deep [17] 2. Flow in gallons per minute x hours run 450 x number of acres irrigated Inches depth applied Example: Area, 25 acres Flow, 900 gallons per minute Time to irrigate, 40 hours 900x40 2x8 450 x 25 ~ ~5~ 3.2 inches deep With these formulas, the irrigator can find out the efficiency of any particular layout. Such calculations may show a need for changes in operation or layout. Use of water. The total amount of water used will depend on temperature, length of growing season, frequency of application, depth of wetting, and to some extent on plant types, irrigation method, and layout. In northern counties the short growing season limits total use, while in coastal regions the lower tem- peratures reduce the rate at which plants give off water. The high summer tempera- tures and long growing season of the in- terior valleys require greater use of water. Water applied at each irrigation is always more than that given off by plants, and under some conditions this excess is considerable. Each time the pasture is ir- rigated, a portion of the water applied is lost by surface evaporation— the more frequent the applications, the more water lost. The amount of water applied and the soil texture determine the depth of wetting. Coarse texture tends to increase water application both at a single irriga- tion and for the season. Difficulty in wet- ting soils evenly to the depth of the roots results in the application of too much water. In some cases runoff water is dis- charged to wasteways. On coarse-textured soils in the interior valleys, it is often necessary to irrigate everv week. Observations show that the number of irrigations during the season may range from 15 to more than 20, with a total use of 6 to 10 acre-feet. On deep, porous loams and silt loams at the Uni- versity Farm at Davis, irrigations were at 10-day intervals and the water use for the season was 5 to 6 acre-feet. Actual measurements of water on pastures on shallow clay loams in the Sierra foothills of Nevada County showed a total annual use of 2% to 3 acre-feet applied in 12 irrigations. The length of the irrigation season was 6 months. On heavy Madera clays in Merced County, approximately 3 acre-feet of water was used during the season, applications being at 12-day in- tervals. While it is difficult to estimate before- hand the total water use of pasture crops and the frequency of application, it would appear that a total use of 5 acre-feet ap- plied in 15 irrigations is a satisfactory basis for planning the enterprise. Cost of wafer. The principal cash costs of irrigated pastures are for water and for irrigation labor. Labor costs are discussed under the various methods of irrigation. Water is supplied by irrigation enter- prises and by private pumping. The vari- ous enterprises usually deliver gravity water and the cost varies considerably. While in some sections the cost may be less than $2 per acre per year, the annual charge for the majority varies from $3 to $5, with higher costs of $8 to $10 in other areas. Under most of the gravity systems, water costs are on an acreage basis and water is not measured carefully. Certain systems may not be able to furnish late- season water, in which case private pump- ing is required. The cost of pumping varies with the tvpe of power used, the total pumping head, over-all efficiency, and total use of the plant. The costs indicated below are for electric power alone, the overhead be- [18] Table 2 COST OF ELECTRIC POWER Lift from well Lift above ground and pipe friction Total pumping head Use per acre per year Acre-feet X pumping head Power costs per acre feet 60 60 60 60 60 60 feet 30 30 30 feet 60 90 60 90 60 90 acre-feet 3 3 5 5 7 7 acre-feet-feet 180 270 300 450 420 630 dollars 3.60 5.40 6.00 9.00 8.40 12.60 ing considered as part of the general over- head expenses of the farm enterprise. With an over-all plant efficiency of 60 per cent, an estimated use of 5 acre-feet per acre per season, and a pumping ca- pacity of 1 cubic foot per second for 40 or more acres, power costs, under commercial rates, will approximate 2 cents per acre-foot per foot of lift. If over- head costs on pumping are considered separately, an additional allowance of 1.8 cents per acre-foot per foot of lift should be made. Table 2 shows the cost of electric power for various pumping heads and various amounts of water. An average cost of water of $8 per acre per year is a fair figure for use in plan- ning an irrigated-pasture enterprise. Seedbed Preparation and Planting Seedbeds should be firm — usually preirrigated. Seed may be broadcast or sown by drill. Planting should be done in fall or early winter. A seedbed satisfactory for seeding alfalfa is adequate for an irrigated pas- ture. Such a seedbed has a firm, moist bottom covered by 2 to 3 inches of moist, well-worked soil free from big clods and large air pockets. A loose, cloddy seedbed filled with air pockets may result in a patchy, poor stand. Wetting the soil be- fore planting is important because: (1) it settles the fills and reveals potholes and other irregularities that can be corrected before seeding; (2) it firms the soil for seeding; (3) it provides an even and de- pendable moisture supply for germinat- ing the seed. It is not always essential to preirrigate, however, if there has been enough rainfall just before seeding. After the irrigation or rain, the field should be replaned (see page 12) if irregular set- tling has occurred. Levees will then have to be rebuilt (where strip-check or con- tour-basin irrigation is to be used). A final harrowing should be given the field just before it is seeded. If the soil is still loose and open after the planing and har- rowing, the field should be rolled with a ringroller to firm it. Time of seeding recommendations do not vary greatly in the counties. Fall seeding is most common. In northern counties at higher elevations, spring seed- ing is used to some extent. In Shasta County, October 1 to November 15 seed- ing is recommended ; in Riverside County, October, November, or February; in Ma- dera County, December to February; and [19] in Orange County, early December or early March. All of the varieties com- monly used in an irrigated-pasture mix- ture will germinate and grow in the fall, except Dallisgrass and Rhodesgrass, and these will usually remain dormant for a spring germination to a sufficient stand. Fall and winter temperatures and mois- ture conditions are generally more favor- able for continuous and adequate soil moisture until the young plants are so well established that irrigation can be applied without danger of washing. Soils with a tendency to form a surface crust are less likely to do so in the fall. Winter temperatures, however, are likely to be fatal to sprouting plants in the northern and colder parts of the state, hence the practice of spring seeding in those areas. Seeding in the heat of summer rarely gives best results. Seeding methods by ground equipment vary widely in different parts of the state and among individual producers. Some plant the grass and clo- ver seeds separately, others mix and sow them together. The claim that clover seeds settle to the bottom in a mixture is not generally true when the seeding is done by hand. If a mechanical broadcast seeder or drill is used, the grass and clover seeds should be planted separately since they will not distribute evenly through ordi- nary seeding equipment. Any method that will give an even distribution of all species is satisfactory. Three types of ground equipment are being used for mechanical seeding of pastures: (1) an endgate broadcast-seeder mounted on the bed of a truck or wagon; (2) grain drills with special grass seeding attachments; (3) a new type combination broadcast-seeder and ringroller (fig. 10) . Airplane seeding appears to be in- creasing, especially in areas where the size of the fields is large enough to justify this method. As with ground equipment, it is usually necessary to seed the legumes separately from the grasses. Special seed- ing attachments for airplanes are neces- sary to handle the small-seeded legume species, such as Ladino clover and alfalfa. The seeding rate of the legumes, with standard grain seeders, will probably be much too high. Present costs of plane seeding vary between $1 and $2 per acre (including two times over). The cost of ground-rig seeding (which also usually requires two times over) in some in- stances is less than this. On a calm day, a careful flyer can uniformly distribute seed on 300-500 acres. In seeding the legumes separately, he must be particu- larly careful to lap the seedings, otherwise the field will be strip-seeded to legumes. Some plane operators are now seeding both the legumes and grasses in a com- plete mixture in a single flight. Whether the seeding can be done in one flight only depends upon the operator and his equip- ment. The best plan is to secure an experi- enced operator and let him apply the seed as he wishes. The pasture owner should make it clear to the operator that he re- quires a uniform seeding of both legumes and grasses. Since the costs per acre for ground and plane seedings are fairly close, the principal advantage to plane seeding seems to be the speed with which the job can be accomplished. The pasture owner can get the seed on while the seed- bed is in prime shape. If seeding should be delayed by rains after the field has been prepared, a plane can be used when ground equipment cannot get into the wet field. Seed shallow, not over % inch deep in most soils if a grain drill is used to plant. Subsequent operations should not bury the seed deeper. Ringrolling or harrowing should immediately follow seeding, whether the seedings are by the broadcast or drill method. Experience has shown that ring- rolling (fig. 10) presses sufficient soil over and about the seed to insure good germination. It further insures the firm seedbed required by germinating grass and legume plants. If only harrowing is used, it should be light. [20 Fig. 10.— New type commercial pasture seeder— actually a ringroller with a seeding attachment. A ringroller firms seedbeds and presses the soil about the seeds after planting. Seeding rates vary rather markedly in the various counties (pages 50-57) . In general, heavier rates of seeding prevail in the southern part of the state for rea- sons shown (page 23) . Lesser fluctuations among adjoining counties are doubtless due to differences in prevailing methods of land preparation and in methods of seeding. If a seedbed is in prime condition and moisture is adequate, experience has shown that 12 pounds of seed per acre will eventually produce as good a stand of plants as will 24 pounds. With the "standard" mixture given on page 22, the 14 pounds of seed, if evenly distributed over an acre of land, would give the following number of seeds per square foot: Ladino, 49; annual ryegrass, 10; perennial ryegrass, 15; orchardgrass, 40; tall fescue, 21; a total of 135. A good stand will be obtained if less than 10 per cent of these develop strong plants on a square foot of soil. Liberal allowances should be made for wastage and loss, but it is uneconomic to use seed extrava- gantly. Proportionate amounts of the rye- grasses have been reduced markedly in recommendations and in current practice since this circular was first issued. Experi- ence has shown that these quick-starting grasses tend to shade out the seedlings of other perennials that start more slowly. The population of ryegrasses can be in- creased at any time in the life of a pasture by oversowing in the winter or early spring. Seed costs (unless excessive amounts per acre are used) represent a small part of the investment in pasture development, and every grower can and should use the best available. Low-cost seed isn't always the most economical seed. Irrigated pas- tures are primarily a long-time crop, and [21] it is important that all of the seeds in the mixture be of top quality, even if the cost per pound is somewhat high. The use of certified seed, when avail- able, will assure the grower that he is getting the best, with maximum purity and freedom from weed seeds. Further, he is assured of getting the exact strains and varieties he wishes to use. This is particularly important with new strains and varieties of forage plants coming on to the market. Common seed is usually a mixture of common and less productive strains. Certified seed of the improved varieties is carefully produced and in- spected to insure that it is true to type, free of disease, and free of noxious weed seeds. General- and Special- Purpose Mixtures The two main types of legume and grass mixtures are general-purpose, and those which are used for special soil conditions Beginning on page 50 is a list, by coun- some areas of the state, including the San ties, of general-purpose and special-pur- Joaquin Valley. Recent research by the pose mixtures recommended by local farm University of California has shown that advisors. These recommendations are the disease is caused by an excessive based on extensive local observations and amount of molybdenum in the pasture results secured in local tests. The special plants. Certain districts of Fresno, Kings, mixtures are suggested for particular cli- Kern, Santa Barbara, and Riverside coun- matic, soil, and topographic conditions. ties are involved. Sheep are, reportedly, The following mixture, however, might rarely affected; horses and hogs have be considered as standard, in terms of never been reported as being affected. In pounds of seed per acre, in any area to these special areas, research has shown which all are adapted. (Alfalfa, birdsfoot that the legumes, such as birdsfoot trefoil trefoil, and Dallisgrass, optional.) and Ladino clover, are usually much higher in molybdenum content than are J 3 mo . ' the grasses. However, among the legumes, Domestic ryegrass 2 u i> . 4 , , . . i {f j n . i n alialia is the lowest in molybdenum. Perennial ryegrass 2 ■ . i . . P J . , . Orchardarass g Acting on this lniormation, local tarm Tall fescue 4 advisors have recommended pasture mix- tures which avoid legumes known to take Total 14 up large amounts of molybdenum. For example, the Kern County farm advisor For assistance on situations not in- recommends no legumes at all in the pas- eluded in the list (pages 50-57), consult ture mixture where the problem is acute, your local farm advisor. These agricul- In Kern County areas moderately affected, tural specialists have developed pasture alfalfa is the only legume recommended mixtures especially compounded to fit in the mixture, as follows : Alfalfa, 2 lbs. ; local situations— for example, areas af- Dallisgrass, 3 lbs.; annual ryegrass, 2 f ected by the molybdenum problem. lbs. ; perennial ryegrass, 2 lbs. ; Rhodes- Molybdenum toxicity in cattle, grass, 2 lbs. ; tall fescue, 8 lbs. ; total, 20 Since about 1869, a cattle disease charac- lbs. per acre. terized by diarrhea, breeding difficulties, Although the right kind of pasture mix- and change of coat color has occurred in ture will help in reducing molybdenum f 22 1 injury, other pasture and livestock man- agement factors can also be used. For example, during the first season, the ini- tial two or three crops on an irrigated pasture should be cut for hay rather than being grazed. Heavy and less frequent irrigations have assisted in some districts. Rotational grazing, so as to graze only older growth, has generally aided. Feed- ing of straw or access to range feed will tend to relieve the severe diarrhea symp- toms. For more complete information on this problem, the grazier should consult his local farm advisor. Investigations are proceeding which will undoubtedly yield more information on methods of prevent- ing molybdenum poisoning on irrigated pastures. In case difficulty develops with stock, consult your local veterinarian. Recommendations in the list show several interesting trends: 1. In the southern part of the state, a larger poundage of seed and a greater number of species are used. This is prob- ably because more species are needed to produce growth through the longer pas- ture season in that area. 2. Bur clover or black medic is gen- erally included in the mixture for the southern counties because these plants grow during the winter months and pro- vide a legume at that time. 3. A light seeding of alfalfa is generally advised in the San Joaquin Valley and, to a lesser degree, in other warm areas. This is to provide a legume during the hotter months when there is a sag in the growth of Ladino clover. 4. Recommended mixtures usually have a number of different species in them to take advantage of their seasonal differ- ence in growth habit. While most of the perennial grasses may be kept green throughout much of the grazing season by pasturing and irrigation, they do have a preferred season for growth and ripen- ing. Annual ryegrass is the earliest we now have in growth and natural maturity. It tends to become semidormant, even under irrigation, by midsummer. Peren- nial ryegrass is somewhat later and more persistent in growth habit. Orchardgrass, meadow fescue, and Dallisgrass are mid- season grasses, while redtop and timothy are late. Tall fescue is a midseason grass which grows well into the fall. Harding is the latest of all and, in the warmer sec- tions, is practically winter-growing. 5. Seed mixtures are based not only upon climatic and soil conditions, but also upon kind of livestock which will use the pastures. Cattle and sheep require a dif- ferent type of pasturage from hogs. Horses do best on still another kind. With cattle and sheep, bloat hazard must be considered as well as grazing preferences. When the mixture is mostly grasses, the animals tend to crop the leg- umes closely. When the pasture is largely legumes, they search for grasses and the coarser material. From 40 to 50 per cent legumes has been found to meet the graz- ing preference of cattle and sheep with a minimum of bloat hazard. For hog pasture alone, legumes, such as Ladino clover or alfalfa, are best. Hogs will eat a limited amount of succulent grasses, but their needs are best met by legume forage. Grasses in the mixture will be neglected, become coarse and woody, and the grazing capacity of the pasture will be lowered. A legume pasture should only be used for hogs, since the bloat hazard on a straight legume pasture is very high for cattle and sheep. Horses, on the other hand, prefer rather coarse, stemmy grasses for most of their grazing ration. From 10 to 20 per cent legumes meets their requirements, although such a low percentage will hardly maintain maximum forage yields unless heavy applications of nitrogen fer- tilizers are made. Goafs which are grazed do best on the type of pasture discussed above for cattle and sheep. Feeding management of milking goats on pasture is very similar to that for dairy cattle. [23] Pasture Management Pasture management includes: getting the best feed value; grazing rotation; supplemental feeding; clipping; harrowing; fertilizing; weed control The three chief objectives of a pasture operator should be (1) to maintain an adequate stand and balance of desired species throughout the pasture season, (2) to obtain and continue the highest possible grazing capacity, and (3) to use the pasture plants when they are most nutritious. It will not generally be possible for a grazier to determine the full success of his seeding or the average composition of his stand during the first year after seeding. Most of the perennial grasses used do not develop fully until the second or third year. Some of the seeds may lie dormant for a considerable time awaiting favorable soil temperature or moisture conditions. Ladino clover usually con- tains a rather high percentage of hard seeds, which will not germinate until the seed coat has been softened by long con- tact with moisture. Many seedings that have appeared as failures the first year have developed into satisfactory stands and good mixtures. One of the reasons for using some rye- grass is that it germinates and grows rapidly and provides much of the forage during the first pasture season. A new pasture may be grazed without injury to it when the ryegrass in the mixture is 6 to 8 inches high. However, the stock should be on it only while actually graz- ing; it should not be pastured too close; and no stock should be on the field while the soil is wet. The efficient use of irrigation water and proper grazing rotation contribute more to successful pasture operations than any other items. Irrigation facilities, layouts, and practices are discussed in an earlier section (page 8). Since water is gener- ally the most expensive single item, its proper use without waste is doubly impor- tant in economic pasture practices. Obtaining the best feed value from a pasture. The following tabula- tion shows the variation in the protein content of some plants at different stages of maturity : Digestible protein, on PLANT AND STAGE the basis of 15 per cent moisture Alfalfa: Immature 17.0 After bloom 5.4 Kentucky bluegress: Before heading 15.0 After bloom 2.7 Orchardgrass: Before heading 13.0 After heading 4.9 Timothy: Pasture stage 13.9 In seed 2.2 Mixed grasses: Immature 10.3 At haying stage 4.7 Mixed grasses and clover (closely pastured) 13.0 [24] rwjff/n^m WATER SUPPLY AND SALT LICK GATE Fig. 11.— A good layout for rotation grazing. Under this system, water and salt are accessible to any one paddock from a single small corral. Gates are used to close off pastures not being grazed. Above: (1) pasture now being grazed (note cattle in corral for water); (2) and (3) pastures recovering from recent grazing; (4) pasture nearly ready for grazing. From this tabulation it is evident that animals on a good pasture of immature grasses and clover receive a liberal supply of protein, which is usually the most costly part of livestock ration. Immature pastur- age also provides a better supply of vita- mins, particularly carotene, from which vitamin A is made in the animal body. With dairy stock, this results in a higher vitamin-A content in milk. In addition, such pasture is usually about twice as rich in phosphates as mature, freshly cured grass. While it is true that livestock derive the most feed value from plants before the seed has matured, it must also be re- membered that plants cannot survive in full vigor unless allowed to mature enough to nourish themselves. There is no exact rule that can be applied to all plants at the same time, with regard to when the best feed value can be obtained. In general, when a plant starts to flower, it will have stored enough nourishment so that its top may be grazed or clipped without reducing its vitality. Grazing rotation. Rotation of live- stock should be timed to fit in with irri- gations. A pasture should not be grazed while wet. This causes permanent dam- age to soil and plants by compaction and trampling. Irrigations are from 7 to 12 days apart, in the interior valleys. During the spring and summer, it takes from 10 to 21 days for a Ladino clover-grass pas- ture to recover from a close grazing— considerably longer in the fall months (page 24). The number of pasture sub- divisions or paddocks required will de- pend upon the individual setup. From 3 to 8 subdivisions are commonly used. With a pasture divided into 3 sections, each paddock could be grazed for 7 days with a 14-day resting period between grazings. During this recovery period, 2 or 3 irrigations could easily be applied. Objections to certain grasses have arisen through faulty grazing manage- ment. Dallisgrass, for example, starts rather late in the spring, but is a rapid and persistent grower throughout the summer and develops seed heads in rather short intervals after grazing. Once it has formed seeds, the stock avoid it; thus in some pastures there are many matured plants of Dallis, while the other species [25] .,,.,.... ,,-'..; .-u..L^.., &:*, s ,^,.> «„.,..., , • ^,.^^ : S^^OSHA* «Sg <*4 Fig. 1 2.— Electric fences are an economical means of subdividing pastures for rotation grazing. have been grazed more closely and evenly. In fields where Dallis (or any other spe- cies) takes the lead at some time during the season, the rotation period should be shortened so that the pasturage is cropped when it is most nutritious and palatable. It may also need heavier stocking or mow- ing. In some pastures, orchardgrass is not looked upon with favor because it tends to form coarse tufts or tussocks. An even mixture of any of these bunch grasses with Ladino clover or trefoil can only be insured by a rotation planned to keep them from getting too mature. And any rotation that is adequate must be flexible so that it can be adjusted to meet the growth habits of all the plants in the mix- ture. In general, rather close and prolonged cropping tends to increase the clovers at the expense of grasses, while infrequent and insufficient grazing tends to produce more grasses than clover. A good rule-of- thumb which seems to be reasonably sat- isfactory is to put livestock on a pasture when the Ladino clover begins to show considerable bloom. But no definite rule can be given to cover all pasture plants, all sites, and all seasons. Maximum feed values and carrying capacity will usually be obtained when enough animals are turned in to crop the growth moderately close and evenly in a rather short time (3 to 6 days). Where high -producing dairy cows are concerned, it may be ad- visable to give the last part of each rota- tion over to young or dry cows. Wise pasture management is necessary throughout the growing season. If soil, climate, and moisture are favorable, a plant's ability to compete with others in the mixture will depend on its height and the thickness of its foliage at maturity. By these standards, orchardgrass is more aggressive than annual ryegrass, and much more so than perennial ryegrass and Ladino clover. Thus if the early spe- cies in the mixture are allowed to reach full maturity— or even full height— they tend to weaken and choke out the species which normally come on later. Some plants with runners or rhizomes, such as Kentucky bluegrass and Bermudagrass, have creeping habits which help them form a sod and thus resist crowding by other species. Proper pasture manage- ment, therefore, depends upon keeping down the more aggressive species when their growth is strongest, by grazing or mowing. This will maintain a good mix- ture and a long pasture season. [26] ' :-*" *■*•■ *-*■: Fig. 13.— Creep feeding beef calves on pasture. Fencing excludes cows, but openings are large enough for calves to get into area where self feeders are located. A set rotation scheme eliminates fluc- tuations in the quality of feed. A moder- ately mature paddock should be pastured off in 3 to 6 days and the stock moved on to the next one. It has been repeatedly shown that the very young leaves of plants are more succulent, or watery, and less nourishing than those which are more mature. On immature pastures, grazing animals tend to overgraze to satisfy their needs. Where the pasturage is more ma- ture and nutritious, however, the animals' needs are better satisfied without such close grazing. To insure even and ade- quate nutrition, therefore, the operator should adjust irrigation and grazing rota- tions so that livestock will be on as nearly uniform feed as possible. Overgrazing reduces profits because it lowers feed production and tends to accentuate livestock parasite difficulties. At the end of a rotation grazing period, there should be from 4 to 6 inches of even plant growth over the pasture. During the growing season, this reserve makes pos- sible a very rapid recovery after grazing. If pasture is eaten into the ground con- tinuously, recovery is slower and total production of forage and livestock prod- ucts is very much lower. A Tehama County Extension Service cooperator nearly doubled his pounds of gain of lamb by converting from a continuously close cropping program to a rotation sys- tem. Now he never crops his pasture closer than about 6 inches, and he follows a set rotation scheme. Recent research at the College of Agri- culture has shown that the bulk of live- stock internal parasites living in pastures is near the ground level. It has been found that the plant growth 6 to 8 inches high and higher is comparatively free of these parasites. Therefore, a grazier can reduce his parasite-control problem by not graz- ing his pastures too closely. Supplemental Feeding of Meat Animals. 1 Extensive observations and a number of tests with cattle and sheep have clearly established the advisability of having dry roughage always available to stock on irrigated pasture. Preferably, it should be fed in bunkers or racks, but some graziers feed it loose on the ground. Any kind of dry hay can be used, and ordinary grain straw will meet this re- quirement very well. It should be chopped 1 This section was contributed by Horace T. Strong, Extension Specialist in Animal Hus- bandry, Berkeley. [27] 'itcfaiiliif •,-,,i--'ir*/ -t^'v :.":..• ■ Wmmm?%&£^ Fig. 14.— Feeding corral and calf creep feeder on irrigated pasture. Stock work back and forth at will from pasture to corral for supplemental grain and hay. for sheep. Mature beef and dairy cattle on irrigated pasture will consume from 1,000 to 2,000 pounds of dry roughage per head during a pasture season of nine months. Dry roughage provided in this way reduces the danger of bloat (see page 29), adds variety to the ration, and also supplies additional dry matter to meet the daily nutritive requirements of the pas- turing animals. Succulent green forage from irrigated pastures alone is often too low in percentage of dry matter for proper nutrition. Only a limited number of field trials have been conducted in this state on the supplemental feeding of grain and other concentrates to meat animals on irrigated pasture. The practice of finishing beef cattle on irrigated pastures is spreading. Lambs appear to make satisfactory gains on good irrigated pasture with no other supplement than dry roughage. Records recently kept by the Agricul- tural Extension Service on two ranches in Monterey County indicate that two-year- old steers can be economically finished on irrigated pasture when supplemented with about three pounds of rolled barley and four pounds of grain hay per head, per day. Gains from pasture and supple- ments totaled 640 pounds of beef per acre of pasture fed. One of the ranches with a large group of cows and calves produced 869 pounds of gain per acre of pasture per season when the pasturing stock was supplemented with barley and barley hay. The extent to which grain may profita- bly be fed to cattle on pasture will depend to a large measure upon the individual ranch setup and current price relation- ships. The quality and class of cattle avail- able, age of cattle and market demand, as well as the quality of the pasture itself, are factors which necessarily must be con- sidered. The farmer has a choice of four possible methods in fattening cattle for market: (1) finish on pasture with no supplemental feed other than a minimum of dry roughage; (2) give supplemental full feed of grain and hay during entire pasture feeding period, finishing on pas- ture; (3) give supplemental full feed of grain and hay for the last 60 to 90 days on pasture; (4) finish cattle on full feed in the dry lot following the pasture feeding period. There is need for additional trials which will provide growers with more ex- perience and information on this subject. [28] There appears to be considerable oppor- tunity in this general field. Numerous tests have shown that hogs make the most economical gains when self-fed grain on pasture. In most cases, the pasturage provided is nearly 100 per cent legumes, such as Ladino or alfalfa. Reducing the Bloat Hazard. 2 Bloat is a hazard when cattle and sheep are grazed on pastures high in legumes, such as clovers or immature alfalfa. Birdsfoot trefoil is not troublesome in this regard. The accumulation of gas in the first two stomachs of ruminants occurs, not be- cause of excessive gas formation, but rather because there is an interference with the normal mechanism of gas elimi- nation when ruminant animals eat clover or immature alfalfa exclusively. Belching, the usual means of getting rid of gas in cattle and sheep, appears to depend upon the presence of coarse, irritating rough- age in the first stomach. The leaves of grasses have barbed edges, and the stems, harsh fibers which stimulate belching. Leaves of legumes, such as alfalfa and Ladino, are smooth and do not stimulate belching. There are several methods of prevent- ing bloat: 1. Mix grasses with legumes. Practical experience indicates that bloat rarely occurs if grasses make up at least 50 per cent of the mixture. One must bear in mind that the proportion of grasses to legumes may vary with the season. In alfalfa mixtures, the percentage of grasses may decline in the summer to the point where it will be imperative to supplement the pasture with dry roughage to prevent serious bloat losses. A similar situation may prevail in Ladino mixtures in the early spring. 2. Feed dry roughage. Dry hay or straw may be fed in drylot, but pref- erably it should be fed in the pasture. Experience with milking dairy cows has shown that bloat may be completely pre- vented on alfalfa pasture by feeding cows all the Sudan hay they will consume over- night and then turning them onto alfalfa during the day. Feeding of dry Sudan hay in the pasture has likewise proved effec- tive. Alfalfa hay or barley straw is less effective, but still of definite value. Oat or barley hay should be fully as effective as alfalfa hay. 3. Alternate Sudan and legume pasture. It has been found that if milking cows are pastured on green Sudangrass overnight, bloat is usually prevented when they are placed on alfalfa pasture the following day. Pure Sudan pasture is very palatable, and the writer believes that its use in conjunction with alfalfa and Ladino pastures should be encouraged. It is likely that in addition to preventing bloat, such an alternate sys- tem of pasturing may actually improve the nutrition and productivity of the animals involved. Moreover, with more pasture operators practicing crop rota- tion, Sudangrass can be nicely fitted into the crop rotation scheme. 4. Pasture alfalfa in the bloom stage. Under most conditions, bloat is not troublesome if alfalfa is allowed to reach the early bloom stage (10 to 25 per cent bloom) before pasturing. If, under this condition, there is still difficulty with bloat, cutting strips of the pasture as illustrated in figure 16 is advised. (Note that the animals are concentrated in the cut strips.) Just why animals prefer mown alfalfa to standing alfalfa we do not know. But because they do, they automatically prevent or reduce bloat by consuming the coarse stems with the succulent tips. Dairymen have recognized for many years that if green alfalfa is cut and fed in drylot, bloat rarely occurs. Allowing the cows to eat the cut alfalfa in the field, as is suggested, will save labor. Further- more, clipping the pastures is helpful in weed control. 2 This section was contributed by Dr. H. H. Cole of the Division of Animal Husbandry, Davis. [29 Mowing, If the livestock numbers on any given farm are properly balanced with year-round feed supplies, there will probably be an excess of pasture during the spring months of flushest growth. At this time hay supplies may be consider- ably increased by so adjusting the rota- tion that each paddock may be mowed at least once (fig. 11, p. 25). This practice also has other benefits. It is one means of controlling the growth of weedy plants and of reducing the coarse growth that has accumulated around cattle drop- pings (fig. 15). Even in fields that are being pastured, occasional mowing is a beneficial practice in reducing weeds and promoting even cropping and full utili- zation. If the hay is not needed, it may be placed in windrows on the levees. Stock will subsequently clean it up with great relish as they pasture the green feed. Harrowing, Harrowing of pasture to spread the droppings of cattle has long been a regular practice in most foreign countries. Authorities have calculated Fig. 15. — Coarse, ungrazed clumps around cattle droppings. These can be reduced by mowing and harrowing. that the droppings of a herd of 30 cows, if fully utilized, have the following annual fertilizer values : 9 tons of sulfate of am- monia, 2^4 tons of superphosphate, 4% tons of potassium. On the other hand, un- scattered droppings of 30 cows would mean a loss in potential grazing areas in and around the droppings equal to 4% acres a year. Plans for making the flexible loose-ring harrow shown in figure 18, are obtainable from any farm advisor. This is listed as B 502-1 on the University's list of farm-building plans. A flexible type harrow (fig. 18, p. 33) does a better job of breaking up and spreading cattle droppings than does the rigid type. Some graziers are using sec- tions of war-surplus steel matting (for temporary air strips) as pasture harrows. Harrowing is especially effective after a rain or irrigation, when the droppings may be easily broken up and spread. Fertilizing. It is too frequently as- sumed that pasturing livestock return enough manurial material to the soil to [30] * '•* >mt ' '""■ *■ WmtlwgFim Fig. 16.— Pasture mowing helps control bloat and weeds, and aids in developing a uniform stand. Note cattle seeking dry feed on mown strip. maintain maximum yields. This is not true. Much of the soil fertility is con- verted into milk, meat, or wool, and thus is permanently removed. Because Ladino clover and some of the grasses used with it are shallow-rooted, a high percentage of their food is taken from the first foot of soil. This puts a heavy drain on soil resources, and may eventually result in decreased plant vigor. In some California soils, this has not oc- curred in fifteen or more years of pas- ture use. In others, however, it may occur in a much shorter interval, while still others always require fertilizers for maxi- mum production. Need of fertilizer can best be deter- mined by plot tests to show plant re- sponses on each site, and such tests should always be made in any system of ade- quate pasture management. Fertilizer practices should be based on results of these tests. It is difficult to measure plant responses on an area that is being pastured. Some experience also shows that on some soils, repeated fertilizer applications are essen- tial to produce significant results. Where first responses are uncertain, it may be good practice to apply the same fertilizer element to identical small test areas each year for a period of three to five years before attempting to reach conclusions. Some soils fail to respond to any known element of plant food. This may mean that no fertilizer is needed. If, however, such soil is not producing properly, it would be well to continue a fertilizer test- ing program. Nitrogen, phosphorus, potassium, lime, sulfur, or some micronutrient element (an element necessary to plant growth, but in very small amounts) may be deficient when production is not adequate or be- gins to decline at some time in the life of the stand. Plot tests are useful in finding out these facts. On many soils, legumes respond to phosphorus, and grasses to nitrogen (fig. 17). On some soils a good growth of Ladino cannot be economically attained, apparently because of inade- quate supplies of phosphorus; and added phosphorus may be fixed in these soils so rapidly that it is not available to the plants. In addition to maintaining general pro- duction, fertilization may be a valuable aid in maintaining the balance of legumes and grasses. Thus if the legume is defi- cient, it may be stimulated by the addition [31] ,?i«i^#$3§§ , 1 Fig. 17.— Foreground, fertilized with phos- phate—stimulates clover; background, fertilized with nitrogen— stimulates grasses. of phosphorus (or sulfur or some other element to which it has shown a response). If the grasses are low, they can almost always be stimulated by the addition of nitrogen. There is perhaps no fixed time to apply fertilizers. Usually applications in the spring (January to March) seem to pro- duce the best results. In the older pasture districts, it has generally been found that annual top-dressings in amounts known to be adequate for plant needs for the season are preferable to larger amounts applied at two- to five-year intervals. A recent survey showed that some graziers are applying fertilizers twice a year, in February or March and in July or August. This tends to prolong the season of pas- turage and to promote plant growth in midsummer and fall as well as in the spring. California dairymen are rapidly in- stalling liquid manure pits and pumps so that corral and barn manure can be re- turned to the pastures. In some cases, it is being returned in liquid form through the irrigation system. Pastures respond remarkably well to application of animal manure. Control of weeds. Besides the weedy species already discussed, there are many other undesirable species that are invad- ing irrigated pastures to such an extent as to greatly reduce the carrying capacity. The presence of certain sedges and swamp grasses is usually a sign of faulty land preparation and irrigation practice, since these species thrive in lands too wet for ideal pasture-plant responses. Such plants as dock should be promptly at- tacked as soon as they appear, and should be removed by pulling or grubbing be- fore the seed heads mature. This is doubtless the cheapest and most effective method if done in time, but persistence is essential. Various species of plantain may also gain too much headway. Sheep will keep most of these in check, but they are not relished by cattle. Recent research by the College of Agri- culture has shown that it may ultimately be possible to use certain chemicals in controlling some of the weedy species, such as dock, plantain, and yellow star thistle. In preliminary tests, 2,4-D, at the rate of about % pound of acid equivalent per acre, has controlled these weeds in Ladino clover-grass pastures without any apparent permanent damage either to the clover or grasses. In some of the trials, the clover was temporarily set back, but recovered in two to three weeks. Alfalfa was seriously damaged. Until more is learned about the long-time effect of 2,4-D upon pasture plants, this chemical should be used only on a field-trial basis, and for spot treatment of very weedy areas. The judicious use of a mower before the weeds get too large and go to seed is still the safest recommendation. Pasture crop rotation. Pastures should be regarded as a crop, and land devoted to pasture should be included in a well-balanced farm program of crop ro- tation. It should not remain in pasture indefinitely. Weeds can be more effec- tively controlled by growing a cultivated annual crop on pasture land for a year or two, once every five to seven years. Crop rotation also results in better than normal [32 1 Fig. 18.— A flexible, loose-ring harrow built by the Division of Agricultural Engineering of the University of California. yields of the annual type feed crops, such as Sudangrass (page 29). Usually a grazier will want to grow feed type crops during this rotation period, to meet his requirements for supplementary feeds. Irrigated pastures in orchards not advisable. In a few areas, notably Lake, Placer, and El Dorado counties, ir- rigated pastures have been established in orchards. However, if the pasture is prop- erly irrigated, the trees are usually dam- aged from overirrigation. Moreover, if arsenical dusts are used for pest control in the orchards, a toxic residue harmful to stock may accumulate on the forage beneath the trees. In addition to grazing on the pasture, the stock also browse on the trees, frequently causing serious dam- age. Because of these disadvantages, it is probably inadvisable to grow irrigated pastures in orchards. Ergot poisoning of stock. This poi- soning is fairly rare in California, but when it does occur, it results in rather severe damage to stock. A rotational grazing and pasture clipping program which prevents grasses from seeding in late spring and early fall will practically eliminate the condition. Ergot is a fungus disease which attacks the grasses— principally perennial rye- grass and occasionally Dallisgrass— when they are flowering and making seed. The initial plant symptoms appear at flower- ing time when a sticky exudate called honeydew covers the seed heads. The ex- udate attracts flies and insects which spread the disease in the grass plants of the field. As the disease progresses, black, horny bodies called sclerotia develop in- side the seeds and destroy them. When these sclerotia are mature, they may either fall to the ground or stay in the seed. In either case, they carry the fungus over winter to reinfect succeeding grass crops. Stock pasturing ergotized fields are usually covered about their heads and bodies with the sticky, black exudate. In heavily ergotized fields, stock may de- velop varying degrees of nervousness to the point of spasms. In case nervous symptoms develop in grazing stock, they should be moved immediately to other types of pasturage, such as range or stub- ble, if possible. No clear-cut evidence has yet been obtained to show that, under California conditions, ergotized grass has caused abortion in livestock. [33] Adding Species to established Stands Both Ladino clover and narrowleaf trefoil ma/ be added to established pastures or to stands of Bermuda- or Johnsongrass Adding legumes to Bermuda- or Johnsongrass stands. Many producers who have dense resident stands of Ber- mudagrass have been interested in some legume as an associate with it to enrich the feed and increase the carrying capac- ity. In a number of counties, methods of accomplishing this with Ladino clover have been worked out very satisfactorily. In most cases, the stand of Bermuda has been reduced to a satisfactory ratio, and in a few instances it has been practically eliminated, but this is not a general oc- currence. In seeding Ladino clover in Bermuda- grass, it should be remembered that this grass is a summer grower and dormant in late fall and winter. One method is to disk Bermuda thoroughly in the fall and re- duce it to as good a seedbed as possible before sowing the clover. Probably the best way to reduce Bermudagrass is to turn it over with a moldboard plow in August, with the soil as dry as possible. Most of the roots are in the top 6 to 8 inches of the soil, and this will expose them to the killing effect of the sun. After 30 to 40 days, the soil is again plowed to expose the other side of the sod to sun- light. Such treatment will kill a high per- centage of the plants and their roots. The Ladino will start in the fall and will usually be ready to compete with the Bermuda by the time the latter becomes active in the spring. Bermudagrass will endure more drought than Ladino clover. It is essential to irrigate frequently, es- pecially on the light soils where Bermuda is most likely to thrive, if a satisfactory association is to be achieved. Success is also more likely to follow where the irri- gation slope is nearly flat than where there is a considerable grade. It has frequently been shown that 150 to 200 pounds of superphosphate per acre, applied annu- ally, will stimulate the clover and aid in crowding out the grass. Bermuda frequently thrives in land that is too alkaline for the best growth of Ladino. In such areas, narrowleaf tre- foil has been found to be a good legume. This is especially true in seepage areas next to canals or ditches where the trefoil can secure underground moisture. The methods of seeding and management are similar to those given above for Ladino clover and grass mixtures. Numerous tests in many parts of the state have shown that Ladino clover will also associate with Johnsongrass. Since the growing season of Johnsongrass is similar to that of Bermuda, the seeding practice should be similar. After that, irrigation and management become the deciding factors. Livestock will consume liberal amounts of Johnsongrass in combination with clover as a natural method of balancing their own ration. But since Johnson is a tall-growing grass, it may soon become too tall and coarse to be relished and will then begin to shade and crowd out the clover. The pasture should then be mowed to reduce the grass competition and pro- mote new and more palatable growth. Johnsongrass will be greatly weakened and may eventually be eliminated if the top growth is kept down, since this gradu- ally saps the plant vitality. Adding grasses to pure legume pastures. Perennial grasses, such as tall fescue or orchardgrass, cannot be success- fully introduced into established stands of pure perennial legumes, such as Ladino clover, by simply broadcasting them into the pasture. The legume stand should be [34] heavily reduced in the autumn, by disking or harrowing, and ringrolling before the grass seed is sown. If this is carefully done, enough legumes will be left to make reseeding of them unnecessary. The grass should then be seeded and the pasture again ringrolled. Unless some seedbed work is done, the perennial grasses will not be able to compete with the heavy established stand of legumes. Thirty pounds per acre of nitrogen (as commer- cial fertilizer), applied a few weeks after seeding, has helped stimulate grasses. A farmer interested in an irrigated pas- ture primarily from a grazing standpoint should probably make an initial planting of a grass and legume mixture (except for swine alone). If he decides to grow La- dino for seed, he may do so. Seedsmen can separate most types of grass seed from Ladino clover seed with modern seed cleaning equipment. Seed yields per acre may be somewhat lower under this sys- tem, but economic livestock gains and minimum bloat trouble are usually the primary interest of the grazier, not seed production. Adding legumes to "grassy" pas- tures. Both Ladino clover and birdsfoot trefoil have been successfully reintro- duced into pastures which have become predominantly grass. Seed of either or both legumes at the rate of 1 to 2 lbs. per acre of each, is simply broadcast into the pasture in the fall. Some farmers pre- fer to harrow it in. Subsequent manage- ment is important if the endeavor is to succeed. Irrigations should be timed to favor the legumes. A fertilizer (generally phosphorus) which will stimulate only the legumes may also be used. Alfalfa can rarely be introduced in this manner, since it requires a well disked and harrowed seedbed. legume and Crass Species Used in irrigated Pastures Several species of legumes and grasses are suitable for irrigated pastures. All have their own growth habits, special uses, and limitations The species recommended for general- and special-purpose mixtures in the var- ious counties are shown in the section on mixtures (pages 50-57). It may be useful, however, to discuss their growth habits, special uses, and limitations. It has been said that most bunch grasses are too coarse and tufty to make an ideal mixture with Ladino clover. A sod-forming or colony grass, with root- stocks, such as Kentucky bluegrass, would seem better suited to an ideal as- sociation with most legumes. No such grasses are now available that are gen- erally adapted to California conditions. At present, it is well to remember that where irrigation water must be applied at frequent intervals, and where other op- erating and overhead costs are high— as in this state— high production in terms of grazing capacity is a vital consideration. In meeting this requirement, the bunch grasses have no equal among those that are now available. Pasture operators should therefore select those of good feed value that will yield the most pasturage and then adjust management to make the best possible use of them. Alkali tolerance of species. Irri- gated pastures are being used profitably in the San Joaquin Valley and elsewhere in the state to reclaim soils too saline to grow other crops. Through selection of an appropriate combination of saline- [35] tolerant forage species for the seed mix- ture, satisfactory production is being achieved on some very difficult sites. The growing grasses and legumes help to speed the reclamation and improvement of the soil. The frequent irrigations re- quired greatly aid in leaching the salts down through the soils. In Monterey County, some very satisfactory pasturage has been developed by using narrowleaf trefoil and grasses to reclaim saline coastal tidelands. Recently, the U. S. Regional Salinity Laboratory at Riverside, California, pub- lished the following list 5 which shows the comparative salinity tolerance of forage species. The list is divided into three groups. The plants in each group are listed in the order of their saline toler- ance—those at the top are most toler- ant; those at the bottom, least tolerant. Although some of the species are not used in irrigated pastures, all have been in- cluded, to show their relative rating. I. GOOD SALT TOLERANCE Alkali sacaton Saltgrass Nuttall alkaligrass Bermudagrass Rhodesgrass Rescuegrass Canada wild rye Beardless wild rye Western wheatgrass II. MODERATE SALT TOLERANCE White sweet clover Yellow sweet clover Perennial ryegrass Mountain bromegrass Barley (cereal) Birdsfoot trefoil (narrowleaf) Strawberry clover Dallisgrass Sudangrass Hubam clover Alfalfa (Calif. Common) Tall fescue Rye (cereal) Wheat (cereal) Oats (cereal) Orchardgrass Blue grama Meadow fescue Reed canarygrass Big trefoil Smooth bromegrass Tall meadow oatgrass Cicer milk vetch Sour clover Sickle milk vetch ill. POOR SALT TOLERANCE White Dutch clover Meadow foxtail Alsike clover Red clover Ladino clover Burnet In addition to differences in salt tolerance among plant species, there are significant differences in strains and varieties. Inves- tigation on this point is continuing. Ladino clover: A perennial, presumed to be a large form of white Dutch clover. Top and root length varies from 6 inches to over 2 feet, depending on depth, poros- ity, and fertility of soil. Main stems creep close to the ground, and are rather coarse, with short joints. With favorable mois- ture, stems lengthen and take root at the joints, so that even a sparse stand soon thickens and becomes dense. (Unlike Dutch clover, Ladino seldom forms new independent plants by this method.) It recovers rapidly after grazing or mowing (often in 2 weeks), and is mostly leafy, not stemmy. It has a growing season as long as that of other available legumes; is winter-dormant in most parts of the state; and undergoes a slight sag during midsummer in warmer parts of the main valleys. The dormant period depends upon severity of the winter. Very sandy soils do not favor Ladino, for moisture in the top foot may be depleted too rapidly to allow economic pasture production. Ladino does not thrive in the high sum- mer temperatures of the Imperial and Palo Verde valleys. Elsewhere in the state, 3 Mimeograph. Diagnosis and Improvement of Saline and Alkali Soils. L. A. Richards, editor. July, 1947. [36 it appears to be well adapted when used on appropriate sites. Alfalfa: California Common, or Chil- ean alfalfa is generally used. Baltic, Grimm, or Ladak are sometimes seeded where winters are severe. Africa is now being used to some extent in southern California where it makes moderate growth during winter months when most other varieties are dormant. It is not so long-lived as California Common, and will freeze out at colder, higher eleva- tions. Alfalfa is chiefly used on soils too porous for Ladino, but is sometimes used with Ladino to maintain a pasture's le- gume content during the hottest months. Alfalfa is also used instead of Ladino to seed borders or strips when they have to be made so high that there is not enough moisture for Ladino. Alsike clover: A perennial chiefly used in the northern counties (Lassen, Modoc, Siskiyou, and eastern Shasta). Farther south (notably the northern Sac- ramento Valley) , it is used in the mixture for heavy soils and for sites where seep- age or irrigation water collect in too great amounts for Ladino. It is able to withstand wet, cold, heavy soils better than many other legumes. Bur clover: A winter annual, in com- mon use in all but the colder sections of California, it is entirely dependent upon seed for reproduction. It does not require seeding, however, except where natural stands have been eliminated or reduced by close pasturing or other farm prac- tices. It is not popular for irrigated pas- tures north of San Francisco because it is semidormant in winter and does not start much earlier in spring than Ladino. Bur clover grows well in winter in the southern part of the state, and fills the need for a legume to extend the pasture season. A close relative, black medic (Medicago lupulina) , is used occasion- ally in southern California for this purpose. Subterranean clover: An annual with climatic preferences and growth season similar to bur clover. The plant is creeping, soft, and woolly, all parts being covered by fairly long, soft hair. Each leaf is formed of three heart-shaped, faintly toothed leaflets, and is carried on a long stalk. After seeds form, the stems bend down and grow until the seed head is pushed into the soil. This habit of bury- ing its own seed makes the plant equiva- lent to a perennial. It does well in really acid soils if enough phosphorus is avail- able. General use of this clover is not now recommended although it has proved adaptable in a considerable part of the state. It might well be tested both where bur clover is recommended, and in acid or granitic soils where bur clover does not thrive. The Mt. Barker strain (midseason) is generally used although Late Tallarook (late season) is also doing well on the north coast. Strawberry clover: A perennial, low-growing plant that spreads by creep- ing stems that root at the joints. Flower heads are round, pinkish to white in color, and resemble an immature straw- berry. It is used in some northern areas of the state, particularly the Tule Lake basin and the coastal plains of Humboldt County. Elsewhere it is chiefly used on soils that are too salty or swampy for Ladino. With ample irrigation, it has sur- vived in the Sacramento and San Joaquin valleys, but is not yet widely used in any of the warmer sections. In those parts, it is at best a low undercover plant that pro- duces some feed and probably contributes some nitrogen to improve soil conditions. Further experience is necessary before its range and usefulness in irrigated pastures in this state can be determined. Seed of the Palestine strain of straw- berry clover is now available on the market. This is a taller form which seems to have more of a winter-growing habit than the common strain. Limited experi- ence indicates that it may become a useful legume in irrigated pastures under con- ditions to which strawberry clover is adapted. 37 Narrowleaf or prostrate birds- foot trefoil: A perennial legume which, in some respects, resembles a fine- stemmed, fine-leaved alfalfa. Stems vary in habit of growth but usually are creep- ing or spreading, seldom erect. New shoots develop from a crown similar to alfalfa but they are much more branch- ing. Leaves are arranged in groups of five leaflets, three at the end of a short branch, or petiole, and two on opposite sides at the base of the petiole or at the point of attachment with the main branch or stem. Flowers are arranged in rather showy clusters of four to six. They range in color from deep orange to a pale lemon- yellow. Seed pods are straight, cylindri- cal, usually about 1 inch long and one- eighth inch in diameter. Pods vary in color from green to brown (when ripe). These snap open when ripe and scatter the seed. The two halves of the pod twist into spirals. The clusters of ripened seed pods resemble a bird's foot, hence the common name, birdsfoot trefoil. This species is very tolerant of alkali conditions and makes a very satisfactory growth where Ladino clover will fail. It is being used with excellent results in the reclamation of alkali soils in the San Joaquin Valley and along coastal tide- lands. This species may also find greater use in areas where irrigation water can- not be applied often enough for Ladino clover. Trefoil grows more slowly than Ladino clover, where the latter is adapted, and probably will not replace Ladino for general use. Some authorities consider the narrow- leaf type as a variety of the erect, or broadleaf, type, and have so designated it as var. tenuifolius. Research work of recent date shows that narrowleaf trefoil is probably sufficiently distinct to be des- ignated a separate species. It is now being designated by some researchers as Lotus tenuis. Broadleaf or erect birdsfoot tre- foil: The species is extremely variable but, in general, shows a more erect type of growth than the narrowleaf type. Authorities designate it as Lotus cor- niculatus. As indicated by the common name, broadleaf trefoil has wider leaflets which may also be shorter than those of narrowleaf trefoil. Flowers of the broad- leaf type may also be somewhat larger. In regions of cold winters, broadleaf tre- foil may survive where the narrowleaf type is severely damaged or entirely killed. Until more is known regarding the comparative adaptation of these species, only general recommendations can be made. It appears that the narrowleaf type should be used under very alkaline con- ditions; the adaptation of broadleaf tre- foil to alkali is unknown. At higher elevations, in the absence of alkali, the broadleaf type may be used. Under all other situations requiring trefoil, a mix- ture of the two types may be advisable. Annual ryegrass: So much breeding and selection work has been done on the ryegrasses and so many local and trade names have been attached to them that a word of general explanation is needed. Practically all the cultivated ryegrasses originate in two species: Lolium multi- florum, most commonly called "Italian ryegrass" or "annual ryegrass," and L. perenne, generally called "perennial rye- grass," or "English ryegrass." Some call them both short-lived grass, usually per- ennial. Various selections of Italian rye- grass are known as "Western-grown," "Oregon-grown," "Domestic," "Wim- mera," and "Westerwold." Commercial seed now marketed here is most com- monly known as either Western-grown or Domestic ryegrass, and it seems fairly certain that this contains a considerable percentage of hybrids with perennial rye- grass. In any event, parent plants have been known to survive in California for three or four years. Paceys ryegrass, Clunes ryegrass, and many other selec- tions of perennial ryegrass have no out- standing merit above that of the parent. All strains of annual ryegrass can be dis- [38 tinguished from perennial ryegrass by their emerging leaves, which are rolled, while in the perennial they are folded. Generally there are short bristles on Ital- ian ryegrass seeds and not on perennial, but this characteristic varies widely. Annual ryegrass is more stemmy and less leafy than perennial. It is popular as an irrigated pasture plant in California because it is very palatable, makes excel- lent growth, has high production, and early-spring growing habits. The latter quality makes it valuable as early feed and as a moderately good competitor with the flush spring growth of Ladino— hence a valuable bloat preventive. No other grass we now have can compete with it in these respects. It does tend to become dormant in late summer and should be mixed with other grasses to take its place at that season. Perennial ryegrass: Perennial, or English ryegrass is fully as palatable as Domestic, bears more basal leafage, but does not produce so high a yield. Desir- able because it grows later in the summer. In pastures to be used largely for sheep, it is probably better than Domestic. Per- ennial ryegrass is no longer used in some areas (notably the central coast) because of rust injury, but it is hoped that a rust- resistant strain may eventually become available. Ryegrass 12: This ryegrass is just coming on the market. It is made up of strains selected by the California College of Agriculture from foundation seed stocks obtained from New Zealand. It is presumably a sister strain of short rota- tion ryegrass. The original seed, received at Davis, represented selections from an artificial hybrid between annual and per- ennial ryegrass made by the New Zealand Plant Research Bureau. Ryegrass 12 is morphologically about intermediate be- tween the parents. It produces early fall growth, recovers more rapidly after pas- turing or clipping than does either annual or perennial ryegrass, and remains green and grows much longer than annual rye- grass. More uniform, longer-lived strains are being developed. Present strains should be used with the full knowledge that they are variable and may be short- lived. Since it is impossible to distinguish Ryegrass 12 seed from the other types of ryegrass, growers should use only certi- fied seed to be assured of getting the variety ordered. Orchardgrass: A perennial, readily distinguished by its large, circular bunches, folded leaf blades, and flattened sheaths (especially at the base of the stems) . The shape of the flower head has suggested the English name of "cocks- foot." It is coarse and tufty, but has re- mained popular in pasture mixtures here because it is hardy, persistent, aggressive, and, in the earlier stages, is relished by all classes of livestock including sheep. The latter tend to avoid the main stems and heads, often allowing the plant to become too mature and woody. The coarse, tussocky bunches which result have led to some complaint about this valuable grass. Careful management is essential. Grass should be mowed when- ever necessary to keep it from getting beyond the stage of greatest usefulness. Meadow foxtail: A long-lived, per- ennial grass. The underground branches are short, so that the grass is in loose tufts. The flowering stems are erect and usually about 3 feet high, and the head is much like that of timothy. It starts growth early in the season, being very tolerant of cold. It is a lover of wet land, but does not thrive in stagnant, saline sites. It is being used to some extent on wetter sites in northern counties and occasionally else- where in the state. Tall fescue: A perennial selection of meadow fescue, but more drought- tolerant. It is thriftier in growth than the parent, with more basal leaves. This se- lection of meadow fescue has now prac- tically replaced the parent in use for irrigated pastures in California from Im- perial to Siskiyou counties. Its long sea- son of growth, high production of forage, 39] and high degree of palatability for all livestock have resulted in its extensive use and wide popularity. It is now included in pasture mixtures in all counties where it has been given a representative test. Hardinggrass: A perennial which grows in large, dense, leafy tufts. Once established, it is very persistent. High seed prices and low germination have hindered fullest use of this plant. It is one of the few perennials to make good growth in winter when most other plants are dormant, but will not survive the cold winters of northeastern California. It pre- fers heavy, black soils and deep volcanic loams, but will produce well on lighter soils underlaid by heavier strata. Though tall and rather coarse, its abundant leaves are relished by all classes of livestock. Only a light seeding (2 to 3 pounds per acre) is recommended to prolong the pasture season in the more temperate parts of the state. Dallisgrass: A perennial which nor- mally has a deep, strong root system and grows in clumps which tend to die out in the center and enlarge around the edge as the plant ages. Ladino clover plants in association with it are often found oc- cupying the centers of these old clumps. After nearly twenty years of experience, this combination is classed as ideal by graziers who like Dallisgrass. Leaves are numerous near the ground but few on the stems, which are usually drooping or angled. In most of the state (except the colder portions where it will not survive the winters), it starts rather late in the spring and becomes dormant in the fall. But during the summer it recovers more rapidly after grazing than any other grass we have. This factor is disliked by some operators because, like other grasses, it is not so palatable as it gets older. Some irrigation districts oppose the use of this grass because its light, oily seeds float on the water and the plants become estab- lished along the ditch banks. Smooth brome: A perennial, tall- growing, leafy grass that spreads by underground creeping rootstocks which tend to become sod-bound in a few years so that renovation is necessary for best results. Although popular as a hay and pasture plant in northeastern California, it has never found a place in any part of the state where winters are mild and sum- mer temperatures high. General use, therefore, is not recommended. Kentucky bluegrass: A perennial, true creeping, or colony, grass. While mainly adapted to colder parts of the state, it is not generally recommended there for pasture mixtures. Objections are that it produces too dense a sod and that growth is not luxuriant enough to provide adequate livestock-carrying capacity. In recent years it has been used in parts of the San Joaquin and Sacramento valleys. Some producers believe it has a place there in association with Ladino, espe- cially for sheep. Observations in several counties show that it is crowding out the clover and that it does not yield so much forage as the stronger-growing plants available. This may be partly due to lack of adaptation in those areas. Prospective planters should make observations on local experience, when possible, before planting bluegrass in irrigated pastures. Rhodesgrass: A perennial, fine- stemmed, leafy grass growing to an aver- age height of nearly 3 feet under favorable conditions. It spreads by running branches which root and produce a tuft at every joint. It will not withstand winter temper- atures below 18° F. It is popular in pas- ture mixtures in the Palo Verde and Imperial valleys, where it is quite at home. Farther north, within its climatic limitations, it is not generally used except in areas that are too alkaline for most other species. It probably has a real place on such sites. Through its ability to ab- sorb alkali salts, however, it may become so saline as to have a scouring effect on livestock. When this is true, the stock should be rotated to less purgative feeds. Bermudagrass: A perennial which spreads by both surface runners and [40] underground stems. It is usually consid- ered a pest in California, and the most common demand is for a mixture that will live with Bermuda rather than for seed of this grass for its own value (see page 34) . In some interior valleys of San Ber- nardino County and the Palo Verde and Imperial valleys, it is far more luxuriant than farther north, and has a longer growing season. For this reason, and be- cause it has high feed values, graziers in those areas are not generally opposed to it. Redtopgrass: A native perennial with a creeping habit of growth which makes a coarse, loose tuft. It is a wet-land type of grass, but will withstand consid- able drought. Although primarily adapted to mountain meadows and pastures, it may have a place as a sod-former in seep- age areas where it will furnish late feed. Its normal maturity dates are similar to those of timothy. Timothy: A perennial, and, like red- topgrass, a northern species. It is fre- quently used as a hay and pasture plant in areas of cold winter and moderate sum- mer temperatures, but has never been durable when used in a mixed pasture in the lower elevations of the state. Burnet: This herb of the rose family has been widely overadvertised as a for- age plant in recent years. It is of excellent forage value, but it is a low yielder. It recovers very slowly after mowing or grazing. A tap-rooted perennial, it tends to rosette near the ground. This crowding habit affords it protection against over- grazing and competition of other plants. It is not recommended for irrigated pas- ture use. Cost Studies to irrigated Pastures Costs of establishing irrigated pastures depend on land preparation required, seed mixture, seed prices, and wage rates. Irrigation is the main annual cost item — 400-500 pounds of lamb or beef per acre Irrigated pasture costs are shown by records obtained by the Agricultural Ex- tension Service in conducting pasture- management studies. Such studies have been carried on at different times in var- ious counties throughout the state since 1936. Recent ones were conducted in Butte, Colusa, Sacramento, San Joaquin, and Yolo counties. Combined averages of all records in these studies are shown in table 3. Since the main purpose of the studies was to develop local information on good management practices as related to production costs, the figures in the tables are not intended to be representa- tive of averages of all pastures in the counties concerned. Wide variations in costs and the amounts of pasturage ob- tained per acre were found to exist among individual records because of differences in management practices, soil types, kinds of plants in stands, and source of water. Pasturage in the studies was measured in terms of animal-unit months. An animal-unit month was considered to be equivalent to the average amount of total feed which would be consumed per month by a mature beef animal or a dairy cow producing 200 pounds of milk fat per year. This unit was also considered to be equal to approximately 400 pounds of total digestible nutrients or the equiva- lent of 0.4 ton of hay. All livestock using 4 This section was contributed by B. B. Bur- lingame, Extension Specialist in Farm Manage- ment, Berkeley. [41] pastures were converted to this basis, de- pending upon their probable total feed consumption. For example, dairy cows giving 400 pounds of milk fat per year were rated at 1.33 animal units, yearling dairy heifers at 0.66 animal unit, lambs (70 to 90 pounds) at 0.15 animal unit, and mature sheep at 0.20 animal unit. Other feed given to animals while they were on pasture was deducted from total feed requirements in calculating the net animal-unit months from pasturage. Any hay harvested was converted to animal- unit months and added to pasturage, but the costs, aside from mowing, were not included. Pastures in the study ranged in age from 1 to 15 years. The cost of establish- ing these stands depended largely upon the amount of land preparation required, the seed mixture used, wage rates, and seed prices at time of planting. Original costs varied from a few dollars, where seed was sown in old alfalfa stands, to $30 an acre. Depreciation on most stands was calculated at 10 per cent. Interest on investment charges was computed at 5 per cent of average value of stands, fences, irrigation, and other facilities. Average values for the life of these items were figured at one-half the original cost. Land values used in computing interest costs were based upon normal agricul- tural values which were somewhat lower than market values during the four years indicated. Total annual costs on individual pas- tures in the studies ranged from about $16 to over $50 per year. Pasturage ob- tained was from 5 to over 20 animal-unit months per acre per year. These wide variations in costs and use resulted in some pastures having a cost per animal- unit month as low as $1 while others ran as high as $7 or more. All records in the four years of the studies averaged $3.14 per animal-unit month. The average cost per 100 pounds of total digestible nutri- ents supplied by the pastures was one- fourth of this figure, or 79 cents. Hay averaging 50 per cent total digestible nu- trients could cost only $7.90 per ton to be equally cheap. Irrigation was the most important an- nual cost item in the studies. On the average, a little over 60 per cent of the total cash and labor cost was for water and irrigation labor. Water costs ranged from approximately $2 per acre on land in certain irrigation districts to over $20 where pumping was done from consider- able depth. The labor cost of irrigating varied from less than $3 per acre to more than $17 per acre, due to differences in the method of irrigation, size of head, and efficiency of the irrigation system. Over 90 per cent of the pasturage in the studies was obtained by cooperators during the eight months, March through October, as shown in table 3. Total animal-unit months of pasturage for the four years of the studies averaged 10. Under favorable conditions, well-managed irrigated pastures in the Central Valley of California should produce at least 12 animal-unit months of feed at a total cost not over $30 per acre (as of 1948) , which would result in a cost per animal-unit month of $2.50 or less. Although most pastures in the studies were used by dairy cattle, a few records were obtained on gains in weights of lambs and steers. These indicated that a gross gain, excluding mortality, of be- tween 400 and 500 pounds of lamb or beef is commonly produced from an acre of irrigated pasture after allowances for any supplemental feeds. Several cooperators in the Colusa County study harvested Ladino clover seed from a portion of their acreage. This is a relatively new practice which paid quite well for some growers during war- time high seed prices. However, it appears that seed production will become a spe- cialized business in itself, not combined with a balanced livestock program, since seed production results in about 2% to 3 months loss of feed during the middle of the pasture season. [42 Table 3 SUMMARY OF IRRIGATED PASTURE MANAGEMENT STUDY RECORDS IN NORTHERN CALIFORNIA COUNTIES* 1944, 1945, 1946, and 1947: MATURE STANDS 1944 1945 1946 1947 Total number of records in studies Total acres covered by records Animal-unit months of pasturage per acre January February March April May June July August September October November December Total for year 26 1,472 0.1 0.2 0.5 0.8 1.4 1.5 1.4 1.3 1.3 1.0 0.3 0.2 10.0 22 919 0.2 0.2 0.5 0.8 1.4 1.5 1.5 1.5 1.4 1.2 0.6 0.1 10.9 25 1,068 0.1 0.2 0.5 1.0 1.5 1.5 1.2 1.1 1.1 1.0 0.4 0.2 24 1,188 0.1 0.1 0.6 1.0 1.3 1.3 1.2 1.2 1.1 0.9 0.4 0.2 9.8 9.4 COSTS Cost per acre: Irrigation labor Other labor (fence work, fertilizing, clipping, etc.) Water cost or power for pumping Other materials (seed, fertilizer, etc.) .... County taxes General expense and other cash costs .... Depreciation on stand Depreciation, irrigation system, fences, etc. Total cash and depreciation costs .... Interest on average value of stands, 5 per cent Interest on average value of facilities. . . . Interest on normal land values Total cost of production Total cost per animal-unit month Cost per 100 pounds total digestible nutrients! Equivalent value of alfalfa hay per ton at above cost of total digestible nutrients .... $ 6.16 $ 7.88 $ 8.69 1.88 2.69 2.65 5.03 5.07 3.68 2.07 4.80 2.14 1.30 1.24 1.44 0.99 1.13 1.03 1.74 1.57 1.79 2.25 1.92 2.01 $21.42 $26.30 $23.43 $ 0.43 $ 0.42 $ 0.41 0.98 0.91 0.92 6.28 5.89 5.48 $29.11 $33.52 $30.24 $ 2.92 $ 3.09 $ 3.09 $ 0.73 $ 0.77 $ 0.77 $ 7.30 $ 7.70 $ 7.70 $ 7.04 1.63 5.34 1.56 2.62 0.80 2.32 2.56 $23.87 $ 0.50 1.72 7.03 $32.62 $ 3.48 $ 0.87 $ 8.70 * Includes records from studies conducted by Agricultural Extension Service in Butte, Colusa, Sacramento, San Joaquin, and Yolo counties. t Based on one animal unit = 400 pounds total digestible nutrients. Control of livestock Parasites on irrigated Pastures 5 Irrigated pastures favor development of certain livestock parasites, but this disadvantage may be overcome by routine preventive measures There are certain internal parasites which infect sheep and cattle. In their mature stages, they inhabit the animal body, where they reproduce. The young, undeveloped parasites are then excreted by the animal, and find conditions in irri- gated pastures well suited to their devel- opment. Irrigated pastures are especially good breeding grounds for para- sites because: (1) they provide moist conditions and even temperatures at the base of plants (conditions under which parasites thrive) ; (2) they protect the immature parasites from the drying ef- fects of direct sunlight; (3) they carry more animals per acre than do nonirri- gated lands, so that parasite population is higher; (4) they are commonly used for young animals, which are more sus- ceptible to parasites than older ones, and consequently are greater carriers. In spite of these dangers, irrigated pas- tures can be used to advantage if the op- erator will take certain routine measures to suppress parasites and prevent in- fection. Coccidiosis, This disease is produced in sheep and cattle when the wall of the intestine is invaded by small, one-celled parasites belonging to the genus Eimeria. The infective stages are found in soil and vegetation as a result of being excreted by an infected animal. At this immature stage, considerable moisture is required for rapid growth and development. Be- cause irrigated pastures provide this moisture requirement, coccidiosis of sheep and, particularly, cattle appears to be increasing in California, especially in sections where irrigated pastures are common, and there is an increased con- centration of stock. The most constant symptom of coccidi- osis is "bloody scours." Although certain other conditions may produce similar symptoms, whenever such scours occur, coccidiosis should be suspected and a def- inite diagnosis should be made by a com- petent person. Treatment. Experience has shown that placing infected animals on dry feed, particularly nonleguminous hay, usually stops the scouring fairly readily. This treatment may, however, merely relieve the symptoms without necessarily curing the infection. There is no chemical defi- nitely known to be satisfactory in the treatment of coccidiosis in stock. Limited studies on treatment of calves with sulfa- guanidine in daily doses of about 5 grams per calf, at the first appearance of symp- toms, indicate that this chemical may cure the disease. Comparable results have not been obtained in the treatment of coc- cidiosis in lambs. Preventive measures. Coccidiosis may best be prevented by determining, as far as possible, that animals purchased come from "clean" ranches, and when this is not possible, by quarantining new animals, especially young ones, for ap- proximately 2 weeks before they are placed on pastures with other stock. It has been found that, under feed-yard con- ditions, infections in lambs may be ef- fectively prevented by mixing ground crude sulfur (approximately 150 mesh) with the feed in such quantities that the 5 This section was contributed by M. A. Stew- art, Professor of Parasitology, and Entomologist in the Experiment Station, Berkeley. [44] final mixture contains from 0.5 to 1.5 per cent sulfur. Concentrations of sulfur in excess of 1.5 per cent produce objection- able laxative effects. The sulfur-feed mix- ture has been fed for as long as 72 days without ill effects. If the infection has already broken out in the flock, lambs given daily doses of 1 to 3 grams of sulfa- guanidine can be protected. Two-tenths per cent by weight of sulfaguanidine in the feed will result in a daily intake in lambs of approximately 3 grams of the drug. Its high cost usually prohibits its use as a preventive measure. Stomach worms. There are three main types of stomach worm: the large (Ostertagia) , the small, or microscopic (Trichostrongylus) , and the twisted wire- worm, or eastern stomach worm (Haemon- chus contortus) . The latter is ordinarily of little importance in California. These worms invade the fourth stomach and small intestine of the animal. The eggs are excreted by the infected animal, hatch, pass through a free-living state (outside the animal) , then become infec- tive and crawl up on plants, where they are eaten by the animal. In their free- living stage, the worms require moisture and protection from direct sunlight and drying. Animals infected with stomach worms, in acute cases, scour, lose weight, and become weak and anemic. The diarrheic feces are typically blackish and of par- ticularly foul odor. Infections with these parasites are espe- cially common and severe in the fall, winter, and spring months. Infections decrease during the summer, as shown by Furman, 6 because of higher tempera- tures, and because the immature parasites dry up on the plants. Furman has also shown that in summer more infective worms are found on the upper leaves of Ladino clover than on alfalfa, and more on alfalfa than on Domestic ryegrass. This is probably because the dense shade provided by Ladino gives more protection against drying and high temperatures than do alfalfa and ryegrass. Further- more, the angles formed by the leaves and stem of Ladino do not keep the im- mature worms from crawling directly to the higher leaves which are easily reached by the grazing animals. The leaf angles in alfalfa, however, act as a partial block, and those of ryegrasses form an even more effective barrier. The moisture on the surface of the various plants is suffi- cient during the other months of the year, however, so that there is not much differ- ence in the number of worms in the higher leaves on the three types of plants. The conclusion is that Ladino clover is a more favorable breeding ground for stomach- worm infection during summer months than is alfalfa or western ryegrass. Mois- ture and temperature conditions, how- ever, are such that even on Ladino, serious infections may be expected only during fall, winter, and spring months, and at that time there is enough moisture on all pasture plants so that there is little difference between numbers of parasites on Ladino and on alfalfa or ryegrass. Treatment. Stomach- worm infections in sheep and cattle may be successfully treated with cunic mixture, which is made up in the following way: 1. Make a stock solution of 2 pounds of copper sulfate in 1 gallon of water in a wooden or earthenware container. 2. To 1 pint of the above solution, add ll 1 /^ quarts of water to make 3 gallons. 3. To this 3 gallons of copper sulfate solution add 4 fluid ounces of 40 per cent nicotine sulfate (Black Leaf 40) . 4. Steps 2 and 3 may be repeated as needed. This is better than mixing all the amount at once as the completed mixture deteriorates on standing. The dosage for a full-grown ewe is 4 fluid ounces, graduated to 2 ounces for lambs 3 months old. Since cattle have a 6 Furman, Deane P. Effects of environment upon the free-living stages of Ostertagia circum- cincta (Stadelmann) Trichostrongylidae: I. Laboratory experiments. Amer. Jour. Vet. Res. 5:79-86. 1944. II. Field experiments. Amer. Jour. Vet. Res. 5:147-53. 1944. [45] lower tolerance for nicotine, the dosage is 3% ounces for animals weighing more than 150 pounds. The drug is adminis- tered with a drenching syringe. It is rec- ommended that the animals be kept off food and water for 12 hours before treat- ment and be starved for another 2 hours after treatment. It is usually most practi- cal to drench in the morning. If cunic mixture is given in too large doses, fatal poisoning may result. Animals which have been shipped some distance and starved en route should be fed the night before treatment to prevent their absorbing too much of the drug. Care must be taken during drenching to make sure that none of the solution gets into the lungs. Phenothiazine is practically 100 per cent effective in the treatment of twisted wire-worm infections. It is less efficient, but still good, against Trichostrongylus axei, Ostertagia circumcincta, and O. tri- furcata. All these nematodes occur in the fourth stomach. This drug is not satisfac- tory in the elimination of the so-called "stomach worms" that localize in the small intestine. Phenothiazine may be given as a bolus, in gelatin capsules, or as a drench. It is given at a dosage rate of 25 grams for sheep and 15 grams for lambs weighing up to 60 pounds. Cattle are given from 50 to 80 grams and calves from 24 to 40 grams. This drug should not be given to animals that are markedly anemic, weakened, and emaciated, nor to constipated animals, since such animals cannot tolerate it and consequently may be severely poisoned. Most animals will accept phenothiazine in the feed, but group feeding of the drug may be dangerous since some animals, particularly those in a thriving condition, may eat considerably more than their share of the material. Group feeding is unreliable so far as dosage rate is con- cerned. However, the administration of phenothiazine mixed in feed may be con- sidered suitable for animals fed indi- vidually or where the drug is given for preventive rather than curative purposes. Preventive measures. Stomach- worm infections on irrigated pastures can be prevented to a large extent by treating all new animals with cunic mixture before they are placed on the pasture and, in heavily infected areas, by treating the ani- mals every 3 weeks from the time they are 3 weeks old. Phenothiazine-salt mixtures in concen- trations of not more than 1 part pheno- thiazine to 9 parts salt or less than 1 part phenothiazine to 14 parts salt are of some value, at least, as a means of preventing clinical infections with the nematodes against which the drug is effective. Also, it is claimed that under such circum- stances, sufficient phenothiazine is elim- inated by the animal to prevent the development of infective larvae in the feces and thus heavy "seeding" of pas- tures with infective larvae is avoided. This method of prevention of clinical infection is effective only at those seasons of the year (late fall, winter, and early spring, in California) when heavy infections are acquired. These mixtures are not of cura- tive value after infections producing acute symptoms have been acquired. Furman (see footnote 6, p. 45) has shown that stomach-worm larvae will remain alive on irrigated pastures sown to Ladino clover or alfalfa for at least 200 days, including the summer months, and also that the larvae will migrate up- ward through 12 inches of plowed soil. Plowing followed by rotation might be of some value in controlling pasture in- festations. Nodular worms. Another group of parasites known as "nodular worms" (Oesophagostomum) cause a disease which produces symptoms similar to those caused by stomach worms, but in acute cases they may be more serious than the latter. Generally these worms become a serious problem only in those regions where summer rains occur, but it is possible that moisture conditions in irrigated pastures may increase the prob- lem in California. [46] Treatment. Phenothiazine is the only drug known to be effective in the treat- ment of nodular-worm infections. The dosage rates are the same as those recom- mended for the treatment of stomach- worm infections. The same preventive measures also apply. Liver flukes. The liver fluke (Fasciola hepatica) is a small, brownish-gray, somewhat leaf-shaped organism about 1 inch long. The severity of the disease caused by the fluke itself is determined by the general condition of the infected animal and by the number of flukes it is harboring. In sheep, animals that are only moderately infected fail to gain weight properly, are poor mothers, and are easy prey to such diseases as pneumonia, hem- orrhagic septicemia, and lungworm infec- tions; heavier infections may result (in addition to extensive liver damage) in rupture of the liver capsule and hemor- rhage into the abdominal cavity. In very acute infections in sheep, which are rare, the animal dies suddenly with bleeding from the nostrils and anus, suggesting anthrax. In more typical cases, the sheep shows an elevated temperature and is off color. This is followed by an anemia with "bottle-jaw" and marked muscular weak- ness. The skin becomes dry and the wool is dry and brittle. There may occasionally be diarrhea or constipation. Such animals may either die or recover. Liver flukes in sheep are involved in the occurrence of the serious bacterial infection, black disease. The flukes carry the black disease bacteria on their bodies, from the intestine to the liver. The young flukes destroy the liver tissue, thus aiding the bacterial growth. The clinical picture of liver-fluke infec- tion in cattle is somewhat different from that in sheep. Constipation is marked and the feces are hard and brittle. Diarrhea occurs only in the extreme stages. Emaci- ation occurs rapidly and the animals, especially calves, are soon prostrated. Heavier infections are necessary to pro- duce clinical symptoms in cattle than in sheep. Many times cattle are infected heavily enough for their livers to be con- demned in the slaughterhouse but not sufficiently to produce obvious symptoms. The life history of the liver fluke is more complicated than that of the other parasites discussed. Adult flukes which are located in the bile ducts of the liver deposit tremendous numbers of eggs which are carried into the small intestine with the bile, and voided with the feces of the infected animals. The eggs hatch in the presence of water. The eggs do not develop at temperatures below 50° F, but will remain alive for several months. The young fluke (miracidium) , when hatched from the egg, swims about in search of an appropriate species of water snail, which will act as an intermediate host. Only certain species of snails are suitable for this purpose. After the miracidium invades the snail host, it develops and multiplies until it reaches the cercaria stage. Each miracidium which enters the snail produces about 300 cercariae. These escape from the body of the snail, swim about in the water, and eventually work their way up on various meadow and swamp grasses and water plants. Here they glue themselves to the plants in the form of small white cysts, just below the water level. When these infested plants are eaten by the animal, the young flukes escape from the cysts into the small in- testine and burrow through the intestinal wall. After this, they wander about in the body cavity for a time— sometimes occur- ring in tremendous numbers— and finally reach the liver. There they penetrate the capsule and burrow through the liver tis- sue for a month or more, finally reaching the minute bile tubes down which they pass to the bile ducts, where they reach maturity. The cysts may remain alive on vegeta- tion for a considerable time, even over winter. They can successfully resist mild drying and low temperatures, but high temperatures are rapidly fatal. They are able to exist on dry hay for a few weeks, 47 and if it is not properly dried, the cysts may remain infective on it for a year or more. Treatment. Liver-fluke infections in sheep may be treated successfully by the administration of carbon tetrachloride or tetrachloroethylene in 1-cc. doses. If the sheep have not had access to pasturage or feed containing legumes, or other sources of calcium, they either should be placed on such a feed for a few weeks before treatment with either of these drugs, or a few animals should be given a preliminary treatment under the ob- servation of a veterinarian, to determine the effect of the drug. Treatment should not be given soon after a change of feed. Carbon tetrachloride or tetrachloroethy- lene should not, in general, be given if the animal is unusually fat, if it is on a high protein and fat diet, or during lacta- tion. Cattle have a low tolerance for both carbon tetrachloride and tetrachloroethy- lene. Therefore, these drugs should not be used for the treatment of bovine infec- tions with liver flukes. Hexachloroethane is the most satisfactory drug known for the treatment of liver-fluke infections in cattle. It is given in capsules at a dosage rate of 3 ounces for adult animals. Younger animals are given proportion- ately smaller doses. Preventive measures. Several sur- veys have been made by the author to determine whether or not liver-fluke in- fections were being acquired on irrigated pastures in California, and in no instance has such been found to be true. These investigations have shown so far that when cases of fluke infections were pres- ent in animals on irrigated pastures they were actually acquired elsewhere. It has been stated, however, that liver-fluke in- fections have been acquired on irrigated pastures in Mendocino County. It is true that appropriate intermediate snail hosts may occur on such pastures and it is pos- sible that liver-fluke infections may result. The chief danger lies in the possibility that a snail-host population may build up in the irrigation ditches and that the im- mature flukes, escaping from the snails, may be transported to the plants during irrigation. Effective snail control is the only prac- tical means of controlling liver-fluke in- fections in irrigated pastures. Copper sulfate (bluestone) is the most efficient chemical known for this purpose, but care must be taken not to apply it to streams or other bodies of water in which there are fish because it is more toxic to them than to snails. It should not be applied to irrigated pastures in large quantities over long periods of time since it is pos- sible that the copper content of the soil may be built up to such an extent as to slow down, or possibly prevent the growth of forage plants. The strength of the copper sulfate solu- tion used depends upon the amount of decomposing organic matter in the water. In California, it is usually used in stand- ing water at the rate of 1 part copper sulfate to 1,000,000 parts water (1 ounce to 7,800 gallons), and is repeated at the end of a month to kill those snails that were in the egg stage at the time of the first treatment. In the treatment of flowing streams, select a uniform section of stream. Meas- ure the average width and depth. Find the speed at which the water travels (feet per second) by finding how many seconds it takes a small piece of wood to float a measured distance. Next, multiply the width times depth times speed times 6. This will give the amount of copper sul- fate, at a dilution of 1 part per 1,000,000 parts of water, needed to treat each mile of stream. If there is a considerable amount of decomposing vegetation in the water, the amount of chemical used should be correspondingly increased. Remember, these concentrations of copper sulfate will kill fish. Place the necessary amount of copper sulfate crystals in a burlap sack and suspend a sack in the stream at inter- vals of 1 mile. [48 Snails in or on the mud of the banks of the stream, above the water level, will not be killed. These banks, therefore, should be treated in the same way as swamps and marshes. Marshes and sim- ilar moist places may be treated by mixing thoroughly 1 part granulated copper sul- fate with from 4 to 8 parts sand or road dust and broadcasting or dusting the mix- ture at the rate of from 10 to 30 pounds per acre. The amount of copper sulfate in the mixture and the rate at which the mixture is applied are determined by the amount of surface water present. Greater areas of surface water require stronger mixtures and larger quantities of the mix- ture. Attention is again drawn to the possible danger of ruining the soil by applying too much copper sulfate over too long a period of time. It is necessary to make a second appli- cation one month after the first, in all of the methods described above. Three or four days after the first treatment, the area should be searched for live snails, to determine the effectiveness of the treat- ment; if it has been ineffective, probably too weak a concentration of copper sulfate was used. This treament is not effective in controlling snails in cold weather since they burrow into the mud during winter. After the second application, inspec- tions should be made approximately every 3 months during the spring, sum- mer, and fall, to determine whether or not reinfestations are occurring. On the following pages, you will find both general- and special-purpose mixtures recommended for each county in California, and for special soil conditions within those counties. The space provided below is for your convenience in keeping a record of the mix- ture particularly suited to your own irrigated pasture. It is suggested that you fill out this blank and keep it on hand for reference. MY PASTURE MIX SEEDING DATE LEGUMES Lbs./Acre Total lbs. required GRASSES Lbs./Acre Total lbs. required [49] MIXTURES RECOMMENDED BY COUNTY FARM ADVISORS COUNTY GENERAL-PURPOSE MIXTURE (species and lbs. per acre) SPECIAL-PURPOSE MIXTURE (species and lbs. per acre) ALAMEDA Ladino clover, 3; annual ryegrass, 1; perennial ryegrass, 2; orchard- grass, 3; tall fescue grass, 4; total, 13; occasionally added or substi- tuted: alfalfa, 2; narrowleaf trefoil, 1. On marshy or slightly alkali land: Ladino clover, 1; narrowleaf trefoil, 2; yellow sweet clover, 2; annual ryegrass, 2; perennial ryegrass, 2; tall fescue grass, 4; total, 13; oc- casionally added or substituted: al- falfa, 2. BUTTE Ladino clover, 3; annual ryegrass, 2; perennial ryegrass, 2; orchard- grass, 3; tall fescue grass, 4; total, 14; occasionally added or substi- tuted: alfalfa, 2; narrowleaf trefoil, 2; Dallisgrass, 3. * COLUSA Ladino clover, 4; Ryegrass 12, 4; tall fescue grass, 3; total, 11; occasionally added or substituted: narrowleaf trefoil, 2; orchardgrass, 3; Dallisgrass, 3. On alkali land: Ladino clover, 3; narrowleaf trefoil, 3; Dallisgrass, 4; tall fescue grass, 3; *ota/, 13. On riverbottom land: Alfalfa, 3; Ryegrass 12, 3; tall fescue grass, 4; total, 10. CONTRA COSTA Ladino clover, 3; annual ryegrass, 2; perennial ryegrass, 2; orchard- grass, 3; tall fescue grass, 4; total, 14. On moderately alkali land: Ladino clover, 1; narrowleaf trefoil, 2; annual ryegrass, 2; perennial rye- grass, 2; orchardgrass, 1; Dallis- grass, 2; tall fescue grass, 4; /ota/, 14. On very alkali land: Narrowleaf trefoil, 2; yellow sweet clover, 2; annual ryegrass, 2; per- ennial ryegrass, 1; Dallisgrass, 2; tall fescue grass, 2; Rhodesgrass, 3; total, 14. EL DORADO Ladino clover, 3; annual ryegrass, 2; perennial ryegrass, 2; orchard- grass, 3; tall fescue grass, 4; total, 14. FRESNO Ladino clover, 2; alfalfa, 2; bur clover, 2; perennial ryegrass, 2; orchardgrass, 2; Dallisgrass, 2; tall fescue grass, 2; /©/#/, 24. On light, sandy land: Alfalfa, 4; bur clover, 2; perennial ryegrass, 2; orchardgrass, 2; Dallis- grass, 2; tall fescue grass, 2; /o/^/, 14. On molybdenum problem land: Alfalfa, 6; perennial ryegrass, 2; orchardgrass, 2; Dallisgrass, 2; tall fescue grass, 2; /©/#/ 14. (In severe molybdenum districts omit all le- gumes from mixture.) [50] MIXTURES RECOMMENDED BY COUNTY FARM ADVISORS — Continued COUNTY GENERAL-PURPOSE MIXTURE (species and lbs, per acre) SPECIAL-PURPOSE MIXTURE (species and lbs. per acre) HUMBOLDT Ladino clover, 5; annual ryegrass, 7 1 /i; perennial ryegrass, l x /i\ total, 20; occasionally added or substi- tuted: alfalfa, 20; alsike clover, 10. IMPERIAL Alfalfa, 8; bur clover, tyr, Dallis- grass, 8; tall fescue grass, 8; total, 25V2. KERN Ladino clover, 2; alfalfa, 1; annual ryegrass, 2; perennial ryegrass, 4; orchardgrass, 2; Dallisgrass, 2; tall fescue grass, 7; total, 20. On valley sandy land: Alfalfa, 2; yellow sweet clover, 1; annual ryegrass, 3; perennial rye- grass, 3; orchardgrass, 2; tall fescue grass, 7; Rhodesgrass, 2; total, 20. On mountain valley land: Ladino clover, 1; alfalfa, 1; broad- leaf trefoil, 1; strawberry clover, 1; annual ryegrass, 2; perennial rye- grass, 3; orchardgrass, 2; tall fescue grass, 6; tall oatgrass, 3; total, 20. On molybdenum problem land: Annual ryegrass, 2; perennial rye- grass, 3; Dallisgrass, 3; tall fescue grass, 8; Rhodesgrass, 2; total, 18; occasionally added or substituted: alfalfa, 2. KINGS Ladino clover, 2; alfalfa, 2; bur clover, 2; annual ryegrass, 2; per- ennial ryegrass, 2; orchardgrass, 3; tall fescue grass, 3; total, 16. LAKE Ladino clover, 3; annual ryegrass, 2; perennial ryegrass, 2; Dallisgrass, 3; tall fescue grass, 4; total, 14; oc- casionally added or substituted: al- falfa, 1. On marshy or subirrigated land: Narrowleaf trefoil, 1; alsike clover, 3; annual ryegrass, 5; orchardgrass, 2; Hardinggrass, 1; total, 12. LASSEN Alfalfa, 2; perennial ryegrass, 2; orchardgrass, 3; smooth brome- grass, 3; tall oatgrass, 3; crested wheatgrass, 2; total, 15; occasionally added or substituted: alsike clover, 1; yellow sweet clover, 2. LOS ANGELES (except Antelope Valley) Ladino clover, 3; bur clover, 2; an- nual ryegrass, 3; perennial ryegrass, 3; orchardgrass, 3; Dallisgrass, 3; tall fescue grass, 3; total, 20; oc- casionally added or substituted: al- falfa, 3; barley, 10. [51] MIXTURES RECOMMENDED BY COUNTY FARM ADVISORS — Continued COUNTY GENERAL-PURPOSE MIXTURE (species and lbs, per acre) SPECIAL-PURPOSE MIXTURE (species and lbs. per acre) MADERA Ladino clover, 2; alfalfa, 2; narrow- leaf trefoil, 1; bur clover, 2; annual ryegrass, 2; orchardgrass, 2; Dallis- grass, 2; tall fescue grass, 2; total, 15. On moderately alkali land: Alfalfa, 2; narrowleaf trefoil, 1; strawberry clover, 1; alsike clover, 2; yellow sweet clover, 2; annual ryegrass, 2; orchardgrass, 2; Dallis- grass, 2; tall fescue grass, 2; Rhodes- grass, 1; total, 17. On strongly alkali land: Narrowleaf trefoil, 2; strawberry clover, 2; alsike clover, 2; yellow sweet clover, 2; white sweet clover, 2; tall fescue grass, 3; Rhodesgrass, 2; total, 15. On very sandy land: Alfalfa, 3; bur clover, 2; yellow sweet clover, 2; orchardgrass, 3; Dallisgrass, 2; tall fescue grass, 3; /