UNIVERSITY OF CALIFORNIA AGRICULTURAL EXPERIMENT STATION COLLEGE OF AGRICULTURE BENJ ' DE WHEELER ' '»■•>"«« THOMAS FORSYTH HUNT, DEAN AN D DlR ECTOR BERKELEY H. E. VAN NORMAN, vice-Director and Dean University Farm School CIRCULAR No. 87 (Be vised October, 1917) ALFALFA By WAREEN T. CLARKE This wonderful forage plant was introduced into this state some time between the years 1851 and 1854, and has not only become, in the time that has elapsed since its introduction, the standard forage plant in California, but it has also become known and appreciated far beyond the boundaries of the state. The annual value of the crop in California approximates some thirty-five millions of dollars now, and the acreage devoted to its culture is constantly being in- creased. In view of these facts, and recognizing the fact that concise information is demanded by both old and new planters, the following summary of practices is presented. SOIL EEQUIEEMENTS Alfalfa is a deep feeding plant, sending its long tap roots far down into the soil for nutriment. It has been known to penetrate to the depth of twelve feet in a single season, and the roots of exceptionally deep rooted plants have been traced to the depth of sixty-five feet. This deep feeding character of the plant should be noted, and, so far as possible, the fact should be taken into consideration by the intending planter. The soils in which free water is found close to the surface should be avoided. Under these conditions the deep root is likely to decay, and the plant will suffer, if it does not die. A deep, well-drained, moderately heavy loam soil, free from hard pan, with no standing water closer than fifteen or twenty feet, is to be preferred to all others. Our best alfalfa fields are on such soils as these. While the alfalfa plant prefers a deep, well drained, moderately heavy soil, it readily adapts itself to a great variety of soils, and some very profitable alfalfa fields are to be found on practically all types of California soils. However, it will not remain profitable as long upon the shallow soils as it will upon the deeper soils. On soils that are underlaid with hardpan or have a water-table at a depth of about three feet, alfalfa will not remain profitable more than about five years, whereas, if given proper care, it will last from twenty to thirty years upon deep, well-drained soil. In general, it may be said that the deeper the soil, the longer the alfalfa will remain in good condition. CLIMATIC KEQUIBEMENTS The first alfalfa seed brought into California came, no doubt, from Chili. Planted in the great inland valleys of the state, its production here was begun under climatic conditions very similar to those of the plant's native habitat. Soon, however, it was found to be adaptable to conditions very different from those found in the great valleys, and it is now a staple crop throughout the entire state. Alfalfa, however, seems to do best away from the immediate influence of coast conditions. For its growth and production, a long, hot growing season is desirable, and the longer this growing season is, if other conditions are favorable, the greater will be the number of crops per year, and the greater will be the yield. This optimum of climatic conditions then should be sought by the intending grower. Entirely satisfactory plantations of certain varieties of alfalfa are to be found, nevertheless, in regions of this state in which the growing season is short. We are therefore justified in saying that the adaptability of the plant allows of its use under a great variety of climatic conditions. WATEE BEQUIBEMENTS Under California conditions of climate and soil, the intending planter of alfalfa should have irrigation water at his command. In general, this command of water may be considered as an essential for success. It is true that many alfalfa fields are to be found in this state where no facilities for irrigation exist, yet good crops are harvested. Still, the success of these non-irrigated fields is not so great as it would be were water available when needed. Both pocket gophers and squirrels are a pest in alfalfa fields, and the most effective way to destroy them is by drowning. If the general soil conditions do not seem to demand the use of irrigation water for the success of the crop, the possibility of drowning out these pests must be considered. PREPARATION OF THE LAND Most of the land that is being seeded to alfalfa in this state, has been used previously either for pasture or grain growing purposes. In either case, but more especially in the latter, the physical condition of the soil is bad. Almost invariably we find in this land, at a depth of a few inches, what is commonly known as ''plow sole" or "culti- vation hard pan. ' ' This is in no wise to be considered as a true hard pan, but is, more correctly speaking, a compaction of the finer particles from the upper stratum of the soil into a very firm, impervious layer of soil just beneath the cultivated surface. This subsoil must be broken up before the air, water, and plant roots can penetrate to the deeper portions of the soil. The first move, then, in preparing land for alfalfa, is to plow it deeply, so as to fully break up the subsoil. This deep plowing should be done before the land is leveled, otherwise in the process of leveling, the hard subsoil in the lower places of the field will be covered so deeply that it will be impossible to break it up later. In many cases that we have studied the plowing has been done after leveling, and, as a consequence, the lower places were filled in with earth from the high places, and the subsoil was not broken up. The result has been that in a short time — a year or two — the field presented a spotted appearance and the alfalfa failed to produce in the places where the hard subsoil had not been broken. The land should be well leveled so that it can be irrigated in the most economical way, and so that the water can be distributed uni- formly over the field. To do this the services of a surveyor should be secured to determine the levels. If the square check system of irrigation is to be used, the checks should be of such a size as will permit of the high point being covered with water to a depth of three inches at least, with a levee system of not more than sixteen inches high at its highest point. The levees should be made broad and low, so that the various implements, mowing machines, rakes, wagons, etc., may be used over the field as a whole, without reference to the levees. When the levees are not at right angle or parallel with the lay of the field they are more difficult to mow and. rake over, hence contour, irregular levees should be avoided so far as possible. Occasionally the slope of the land may be such that contour lines will have to be used. If this is the case and the land is rather heaw so that it will not wash readily, the water can be turned directly from one check to the other through the border without constructing lateral ditches. This permits of a very cheap system of leveling and checking. If the soil is sandy it will not stand the washing, and lateral ditches for carrying the water must be constructed as with other systems of check- ing. In the very heavy soils where the water percolates downward very slowly, the contour system is to be recommended, for with this system it is possible to hold the water within every given check long enough to force deep percolation. It may then be drained into the next lower check before it has stood long enough to kill the alfalfa. In certain cases " it may be desirable to use the strip system of checking. This system can be used to advantage where the soil is moderately heavj^ and where the slope is not too abrupt. If this system of checking is used on the sandier soils, the slope should be as great as possible and yet not great enough to allow excessive wash- ing. The strips should range from thirty to seventy-five feet in width, and on the heavier soils should range from one-eighth to one- fourth of a mile in length ; on the sandier soils the length should range from one-eighth to one-sixteenth of a mile. Regardless of the system of checking, the land should always be plowed and irrigated and then re-leveled with a scraper before seeding. Each particular piece of land presents its own problem regarding the best system of checking and it is well for the inexperienced planter to call upon his farm advisor or upon the agricultural department of the University of California, Berkeley, for detailed advice regarding the system best adapted to his soil and water conditions before spending much money in checking his land. While deep plowing is essential in the proper preparation of land for alfalfa planting, it should be remembered that the alfalfa seed demands a firm seed bed for its best success. Therefore, after the land has been deeply plowed, leveled and checked and then replowed, it should be gone over carefully with some sort of compacter. An ordinary roller followed by a light harrow may be used. The disk cultivator, heavily weighted, with the bar set straight has been suc- cessfully used as a sub-surface packer. Any implement that will compact the subsurface somewhat and still leave the surface fairly loose may be used. SEEDING AND VAEIETIES The first question that will probably arise in the mind of the intending planter when it comes to the choice of seed, will be as to the best variety of alfalfa to plant. Studies of this question indicate that for the general conditions found in California, the Chilian alfalfa is the most satisfactory and for ordinary plantings in our "great valleys" throughout the north and south where irrigation is to be practiced, this variety will probably give the best results. In localities where irrigation is impossible, the Turkestan variety will be the most satisfactory. This is a very hardy variety and will stand cold weather conditions better and also produce a crop on less water than will the Chilian variety. The Turkestan alfalfa stays dormant much later in the spring and also goes dormant earlier in the fall than most other varieties. The hay of the Turkestan alfalfa as produced in California is not as fine and clean as the hay of the Chilian alfalfa and it is not to be recommended for irrigated lands in the large interior valleys. Another variety of alfalfa known as the Arabian is desirable for certain special purposes. It is a "short life" perennial and is not recommended except in short rotation or for interplantings in orchards where the stand is only desired for two or three years. Another variety which has met with considerable favor during the past few years is the Peruvian. It is a rather tall, rank growing variety which will, under most conditions, produce a heavier yield than the common Chilian. It has an erect habit of growth and starts growing earlier in the spring and continues later in the fall than most varieties. It has a tendency to become a little coarse and produce an inferior quality of hay, but this can be mostly overcome by planting it rather thickly and exercising care not to allow it to stand too long- before cutting. The Grimm alfalfa is another variety that is grown to advantage in some localities. It has a branching root system which makes it better adapted than other varieties to wet, shallow soils. It is also very hardy and this, together with its branching root system makes it well adapted to some of the mountainous valleys of this state which have a water-table comparatively near the surface. Many other varieties of alfalfa have been tested in California, but so far the choice seems to be between the above-named varieties. 6 Good, clean, vigorous seed of anj T variety is necessary to secure a good stand. The source of this seed, that is; the locality where grown, should be known by the planter so that its desirability may be, in part at least, determined. The intending planter can have his seed tested as to purity and germination, by sending a four-ounce sample to the Experiment* Station, Berkeley, California. This service is done gratis and every grower should take advantage of it so that he may be sure of using seed that will grow, and be free from dodder and other noxious weeds. The amount of seed used per acre varies a great deal with different planters, but careful studies of the question indi- cate that if a clean, vigorous seed is put into a good seed bed, from 12!/2 to 15 pounds per acre is ample. Using more of such seed under such conditions would mean waste. This seed should, for best results, be drilled into a well-prepared seed-bed and under most conditions no nurse crop used. Some planters use a nurse crop of some cereal, but usually the crop does more harm to the young alfalfa plants by robbing them of moisture, than it does good in fancied protection. The nurse crop is recom- mended only when fall seeding is practiced under conditions where weed growth is bad, or where the land is sand} r and subject to blowing. In the former case it will help keep down the weeds and in the latter it will help hold the sand. The time of planting will depend altogether upon the frost con- ditions in the locality where the planting is to be done. The fact should be noted, that the alfalfa plant, when in the seed leaf stage, is easily killed by frost. After it has passed the seed leaf stage, it is much more resistant to frost. If, then, frosts are likel} T to occur in the regions where the plantings are being made in the fall, seeding should be postponed until spring, when danger of cold weather is over. In general, the best results will probably be secured by sowing as early as possible in the spring to avoid frosts. INOCULATION It is a well recognized fact that, for full success in growing alfalfa^ the plants must be supplied with nitrogen gathering bacteria. These minute organisms, so essential to the proper growth of this plant, are usually present in our California soils, and as a general thing artificial inoculation is not necessary except where new plantings are at some distance from older fields. Pure cultures of bacteria may be obtained on the market for the purpose, and under some conditions it may be desirable to use these. Generally, however, a perfect inoculation can be obtained by broadcasting one or two hundred pounds of soil, from some well-growing' alfalfa field, over each acre of the new field. This inoculated soil should be well harrowed into the land before seeding. The process is not difficult and requires no technical skill. Inoculation can also be satisfactorily accomplished by what is known as the "soil suspension" method. A quantity of soil is taken from some field where the alfalfa is growing well, and the soil con- tains the desired bacteria. This is indicated by the nodules which can be found upon the roots of the growing plant. To a given volume of soil add two or three volumes of water. This is stirred vigorously several times during one day, and then the earth is allowed to settle. The alfalfa seed is then dipped in this water, which now carries the bacteria, after which it is placed in the shade and dried enough so that it separates readily, then planted immediately. This method has the advantage of being cheap, easy and effective. It is the part of wisdom for the planter of alfalfa to insure the presence of the necessary bacteria. IKEIGATION It has been previously pointed out that no definite rule can be laid down regarding the amount of water to use in growing alfalfa. In general, however, experience indicates that frequent shallow irriga- tions are to be preferred to occasional heavy floodings. In the writer's experience and observation an irrigation of four or five acre inches, ten days before cutting, brings the best results on most soils. Irrigating at this time has a tendency to overcome leaf shedding, and it should be remembered that 60 per cent of the value of the alfalfa is in the leafage. It will also cause new growth to start up from the crown as soon as the crop is cut, and in this way the new crop will be growing while the previous crop is being harvested. On heavy soils irrigation before cutting will also have a tendency to keep the soil in better physical condition as it prevents the sun from shining directly upon the wet earth, thus reducing the tendency to bake and crack. It is very much to the growers' advantage to keep his alfalfa growing steadily throughout the growing season, and to do this it may be necessary on some soils to irrigate lightly twice between cuttings. «C U CO o ti <$ S3 < Q V h