UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA STATIONARY SPRAY PLANTS IN CALIFORNIA (A Progress Report) B. D. MOSES and W. P. DURUZ In co-operation with T. A. WOOD, of the California Committee on the Relation of Electricity to Agriculture BULLETIN 406 October, 1926 UNIVERSITY OF CALIFORNIA PRINTING OFFICE BERKELEY, CALIFORNIA 1926 FOREWORD This bulletin is a contribution of the Divisions of Agricultural Engineering and Pomology and the Stationary Spraying Sub-Com- mittee of the California Committee on the Relation of Electricity to Agriculture. It is the first of a series planned to report the results of investigations conducted jointly by the Agricultural Experiment Station, College of Agriculture, University of California, and the California Committee on the Relation of Electricity to Agriculture. This committee represents the agricultural and electrical industries in California that are working together for the purpose of making available reliable information concerning the use of electricity on the farm, and cooperating with similar committees in other states.* E. D. Merrill, Director, California Agricultural Experiment Station. The personnel of this committee for 1925-26 is : L. J. Fletcher, College of Agriculture, Chairman. N. E. Sutherland, Pacific Gas and Electric Company, Treasurer. B. D. Moses, College of Agriculture, Executive Secretary. E. H. Alvord, General Electric Company. H. M. Crawford, Pacific Gas and Electric Company. J. J. Deuel, California Farm Bureau Federation. A. M. Frost, San Joaquin Light and Power Corporation. Alex. Johnson, California Farm Bureau Federation. B. M. Maddox, Southern California Edison Company. C. A. Utley, Pelton Water Wheel Company. STATIONARY SPRAY PLANTS IN CALIFORNIA 1 B. D. M0SES2 and W. P. DUEUZ,3 m cooperation with T. A. WOOD* A stationary spray plant, as the name would imply, is an outfit that remains in a fixed place. The plant consists essentially of a power unit and pump of sufficient capacity to force spray liquids through underground pipes to all parts of the orchard. At convenient points lengths of hose are attached to the pipes and the spray material is applied to the trees in the usual way through spray rods or spray guns. The prevailing method of spraying orchards has been, and still is, by means of movable sprayers. The common type consists of a tank, gasoline engine and pump mounted on wheels and drawn through the orchard by a team or tractor. A smaller outfit operated by man power may be hauled on a sled or wagon, and a still smaller unit may be operated by hand while the operator carries the load on his back. Nowhere, perhaps, has the combating of diseases and insects affect- ing fruit trees been a more serious problem than in California, where the mild climate favors the overwintering of many pests. The wholesale planting of orchards during the last two decades, in many instances by persons unfamiliar with known cultural practices, has tended to aggravate the situation. New insects and new diseases have been introduced from other states and countries. Methods of com- bating pests in one locality or district have been found inapplicable to other districts with different climatic conditions. The earlier deciduous orchards were planted along the coast and in coastal valleys. Later plantings followed the rivers farther inland. As an industry, fruit growing soon spread into the interior valleys and the adjacent foothills or wherever water was available for i The writers are indebted to the following fruit growers who have generously cooperated and permitted the study and testing of their stationary spray plants: Alfred G. Brown, Santa Clara; E. A. Gammon, Hood; L. B. Landsborough, with the A. B. Humphrey Kanch, Mayhews; W. W. Monroe, Sebastopol; Hayward Eeed, Broderick; Howard Reed, Marysville, and Adrian C. Wilcox, Santa Clara. 2 Division of Agricultural Engineering. 3 Division of Pomology. 4 California Committee on the Relation of Electricity to Agriculture. 4 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION irrigation. Soon many new problems in spraying had to be met and all existing knowledge of older districts in the eastern states and even in European countries was drawn upon, but in the end our experi- menters had to work out their own spraying programs, often embrac- ing new methods, new equipment, and even new materials. The development of spraying equipment has gone forward slowly and conservatively. Eastern manufacturers, in the main, have kept step with the western manufacturers of spraying equipment, par- ticularly as regards the portable gasoline power outfits. However, it remained for the western coast to devise and put into operation a new idea in spraying, namely, the stationary spray plant. Users of portable sprayers have often had some difficulty in spraying at exactly the proper time on account of muddy ground in the orchard. The ordinary portable spraying outfit, loaded with 200 gallons of liquid, weighs at least a ton. Obviously, such a load cannot be easily transported through an orchard just after a heavy rain or after a thaw. A still greater difficulty in spraying arose in certain California orchards in the lowlands adjacent to the Sacramento River, which at certain times in the winter and early spring were apt to be inundated. Prune and pear orchards along the river were sometimes submerged to a depth of several feet for a week at a time. Owing to the sandy nature of the subsoil, no damage resulted to the trees themselves from the submergence, but while the water was on the ground and for several days afterward, it was impossible to spray. Unfortunately, one of the most vital spray applications for pears was necessary at a time when it was utterly impossible to enter the orchard with any sort of movable outfit. One orchard owner, Mr. Hayward Reed, 5 tried the plan of mounting a sprayer on a barge. He later used very long lengths of hose and even pipe-lines in order to spray considerable 5 "The year 1906 was a disastrous one for me," writes Mr. Keed. "The scab infection was so bad that 98 per cent of the crop were No. 2 and No. 3 pears. Improper spraying was the cause. The following year, 1907, was my most success- ful season. High grade pears with other favorable conditions made this possible. As the time neared for scab spraying, a great flood came (fig. 1). I sprayed in boats while I could, but when the water receded some, this could not be done. Wagons also were of no avail. In a quandary I told Honda (my foreman) to couple the hose lengths together and spray as far as possible. We kept on until a thousand feet were used. At that time I conceived the idea of using pipes. Knowing how much cheaper and stronger they were, I felt they could carry the spray material long distances, and that hose attached at different intervals would operate successfully. The following year, 1908, I installed the underground pipe system at Rose Orchard, using %-inch pipe for main and laterals. Since then I have enlarged the system, using 1^-inch for main and %-inch for laterals. The year 1909 proved the value of the pipe system. Another great flood came. Our spraying was done on time by men working in gum boots. Later I installed the system in the New England, Folsom, and Gridley orchards." Bul. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA areas from high ground. This finally gave him the idea of establish- ing a central pumping plant and carrying pipes underground from it to all parts of the orchard. At intervals there were risers located close to the trees so they would be out of the way, where spray hoses could be attached. After much experimenting, the number of trees Fig. 1. — Flood scenes in 1906 in the Hayward Eeed orchard. possible to be sprayed economically from one point was found. Many other details, such as size of pipes for mains and laterals, and the required capacity of the pump were worked out. Mr. Reed's system proved so satisfactory that other fruit growers have installed similar plants. A survey made in 1925 revealed at least 6 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION ten stationary plants in successful operation in California. The state of Washington 6 has several hundred plants. Most of these are located in the Wenatchee and Yakima districts. In that state conditions making it difficult to spray at the right times by old methods have brought about this extensive use of the stationary outfits. TH5 o~T/)T/ONAPY SPPAY/HG SYSTEM ^\ r^h r~\ r\ r^MPf lime* d/aopam O U U U O KJ Uf ^f'Laterate Q O O O ooooooo 4 Pisers a service cocks tor hose connections ( " "gate i5 £" ^^ 0? mo ins O O G O G G ( £&> OOOOOQQ U> U> u* U>' L-i \J U G Q Q O O Q O ~\ /-"^ JQCJC G G C J' o a o a n d n PLAN 4 risers a service cocks for hose connections Pumping I4 'mains jf* ' iateny/s, Station J-fCT/O/V THPU A -A to risers Fig. 2. — Diagram of stationary spraying system. s Morris, O. M., Stationary spray plants, Wash. Agr. Exp. Sta. Popular Bui. 125:1-20. 1924. Bul. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA GENERAL DESCRIPTION Figure 2 shows diagrammatically the general arrangement of the underground pipes in a stationary spray system. The location of the pumping station is governed by the size of the orchard, water supply, power lines, roads, ranch buildings, and the topography of the land. It is usually near the center of the orchard. The equipment of the pumping station consists of a heavy duty spray pump driven by an Fig. 3. — Pumping station of the two- story type. The lower floor is used for the service tank, pump, and motor, while the upper floor is for mixing the materials. The auxiliary water tank is a recommended accessory in order to insure plenty of water when needed. electric motor or a gas engine and provided with mixing and service tanks. The equipment used on portable rigs may be employed in the stationary plant, but provision must be made for any increase in pressure or discharge. A main line is laid from the pump through the center or along one side of the orchard with laterals leading off from it. Outlets are systematically provided on laterals so that hose may be attached for spraying the trees. All permanent piping is laid about eighteen inches below the surface of the ground so as not to interfere with tillage. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION DESCRIPTION OF SEPARATE UNITS Housing. — The pumping equipment should be housed in a suitable building, the type depending upon whether it is to be used solely for housing spray machinery and materials or for other purposes as well. Figure 3 shows a type of building which is used for spraying only; figure 4, the interior of a building used for spraying, for storage, and for housing an irrigation pump, and figure 5, a building which is used as a farm shop as well as for storage. The main essential is to have the building so arranged as to facilitate the handling of spray materials. Power Unit. — The power unit consists of either an electric motor or a gas engine and the power is transmitted to the pump by belt, gears, or chain (fig. 6). Any standard electric motor may be used, ranging from 5 to 15 horsepower, according to the size of the pump and the pressure to be maintained. If a belt drive is used, the motor should be connected to the pump with a belt of correct length to prevent "belt slap," using pulleys of proper sizes to obtain the speed specified for the pump. For an electric installation, the line from the transformer to the motor should not be excessively long and wire of the proper size should be used to avoid excessive voltage drop. The motor base, starter box, and switch box should, of course, be grounded. This precaution is especially important since the floor of the pump house is usually wet. If a gas engine is used, it should be equipped with a reliable governor in order to avoid damage from excessive engine speeds. Pump. — A heavy duty pump is necessary to develop high pressures at the nozzles. In long lines of pipe, where several nozzles are used and velocities through the pipe are relatively high, pump pressures as great as 400 pounds to the square inch are necessary. In short lines of pipe, pump pressures vary from 250 to 300 pounds to the square inch. Because of the heavy duty performed by it, the pump must be placed on a solid base, preferably concrete. Tanks. — Two round-bottomed wooden tanks, similar to those on portable rigs, are commonly used, both for mixing the liquid and serv- ing the pump. Such tanks range in size from 200 to 1000 gallons each. Two systems of arrangement are followed : in one, a small mixing tank is on a higher level than the larger service tank, and in the other, both tanks are of the same size and on the same level. In the first arrange- ment the service tank is replenished from the mixing tank (figs. 3 and 4), while in the second the tanks are alternately used for mixing and service by transferring the suction hose or by operating a two-way valve on the pump suction (fig. 7). Bul. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA 9 Each tank is fitted with its own agitator driven from the pump shaft. In some instances the agitator of the mixing tank is horizontal and is driven from the tail-end of the agitator shaft of the service tank. In other cases the agitator is vertical and is driven by a shaft Fig. 4. — Interior of pumping station. a. Shows service tank with vertical agitator. T). Shows mixing tank, service tank, and pump. Belts connect with a 35-h.p. electric motor which is also used for pumping water for irrigation. 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Fig. 5. — A well-planned pumping station which has many conveniences. The mixing of spray materials is facilitated by a vat in the ground, into which the lime-sulfur is poured from the barrels and then pumped by means of a hand pump to the mixing tank. The brick furnace is used in heating water for oil emulsions. The far end of this building is used as a farm shop and for storage. The photograph shows an auxiliary portable sprayer being filled from the same mixing tank that is used for the stationary system. Fig. 6. — A typical installation showing mixing tank, pump, and power unit. A 10-hp. electric motor is used for driving the pump. BUL. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA 11 and gears from the power unit. Vertical agitators in flat-bottomed tanks (fig. 4) require special attention because of the tendency of the mixture, as a whole, to whirl, causing heavy materials in suspension to settle along the sides and bottom. This objection is not found with horizontal agitators in the round-bottomed tanks. An adequate supply of water should be piped to the tanks, either from a reservoir, tank, or pump, as shown in figures 3 and 5. Pipe Lines. — After a careful study of the orchard topography and tree spacing, a piping diagram should be drawn and the trenches dug accordingly (fig. 8). Galvanized iron pipe with screw fittings should Fig. 7. — This illustrates two tanks on the same level. Each in turn serves as a mixing tank and a service tank. be selected to stand the pressure under which it is to operate (see table 1). The pipe lines consist of mains, 1 to 1% inches in diameter, and laterals % to 1 inch in diameter, with gate valves between the pump and the mains and at the head of each lateral (fig. 9). This arrangement facilitates flushing the line and also aids in preventing the settling of spray material in laterals not being used. Frequent use of unions is recommended so as to simplif}^ future repairs or altera- tions in the line. Because of the high pressures to be maintained, good pipe-compound must be used in making connections, and the pipe and fittings must be screwed tight. Abrupt turns in the line should be avoided wherever possible. Long radius bends are better than ordinary short elbows. All pipe should be carefully reamed so as to eliminate constrictions from cutting or threading. These precautions will reduce friction losses and permit high nozzle pressures. Table 2 gives the friction loss per thousand feet for ordinary and for old iron pipe. r f tt ft 6 Fig. 8. a. Connecting pipe before lowering into the trench. b. Laying the pipe to an even grade by means of a level before covering. Bul. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA 13 It is a customary practice to place a lateral at every eighth row of trees and a riser or service connection at every fifth tree in the row. This may be modified for different orchards, according to the planting distance, but in any case the risers should be not more than 150 or 160 feet apart to avoid hose lengths of more than 100 feet. Figure 10 shows the location of risers in different orchards. If they are permanent, the risers should be protected by posts or should be located near trees; temporary risers should be removed after each spraying period, the fittings for the connection being located at the Fig. 9. — Gate valves on the main and lateral should be provided. TABLE 1 Strength of New Butt-welded Wrought Steel Pipe in Pounds per Square Inch* Standard Extra strong Double extra strong Size, inches Bursting pressure, Barlow's formula Working pressure Bursting pressure, Barlow's formula Working pressure Bursting pressure, Barlow's formula Working pressure l A 10,384 1298 14,000 1750 28,000 3,500 % 8,608 1076 11,728 1716 23,464 2,933 l 8,088 1011 10,888 1611 21,776 2,722 Vi 6,744 843 9,200 1150 18,408 2,301 VA 6,104 763 8,416 1052 16,840 2,105 2 5,184 648 7,336 917 14,680 1,835 VA 5,648 706 7,680 960 15,360 1,920 3 4,936 617 6,856 857 13,714 1,714 * Note. — After Crane Company Catalogue 50 : 626. 1917. The safe working pressure varies from 617 pounds per square inch in the three-inch pipe to 1298 pounds per square inch in the J^-inch pipe, all of which are higher than the pressures likely to be obtained at any time in the piping systems. Since standard fittings and valves do not carry quite as high pressures as the standard pipe, it may be better to use heavy valves, especially in the larger sizes. 14 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION intersection of diagonals between trees. Each riser is fitted with a service cock and a hose coupling. Hose. — The best quality high pressure rubber hose must be used in order to withstand the heavy pressure and hard service to which it is subjected when dragged through the orchard. The size is usually % 6 -inch and the length should not be over 100 feet (fig. 11). 3 -A^ **• •■■ -"*.* Fig. 10. — Four types of risers. a. Double gate valve. c. Garden valve. fc. Service cock. d. Gate valve. Fig. 11. — Spraying by means of the stationary system. a. Using spray rod with 200 feet of hose. A helper is necessary to assist in moving the hose about. T). Using the spray gun with 74 feet of hose. One man can handle this length satisfactorily. 16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION TABLE 2 Friction Drop in Pipes for Various Bates of Discharge* }4 in. Wrought iron pipe, actual inside diameter .623 in. % in. Wrought iron pipe, actual inside diameter .824 in. 1 in. Wrought iron pipe, actual inside diameter 1.048 in. Dis- charge gal. Velocity in ft. per sec. Pressure drop per 1000 ft. of pipe in lbs. Velocity in ft. per sec. Pressure drop per 1000 ft. of pipe in lbs. Velocity in ft. per sec. Pressure drop per 1000 ft. of pipe in lbs. per min. Ordinary iron Old iron Ordinary iron Old iron Ordinary iron Old iron 1 1.05 2.10 3.16 4.21 5.26 6.31 7.37 8.42 9.47 10.52 9.1 32.2 68.5 117.3 177.8 247.2 329.5 425.0 525.0 637.5 13.45 48.6 104.2 177.8 268.8 377.3 498.5 642. 793.5 967.0 2 1.20 1.80 2.41 3.01 3.61 8.24 17.78 30.35 46.05 63.7 12.58 26.45 46.05 68.9 97.1 3 4 5 6 7 1.12 1.49 1.86 2.23 5.47 9.28 14.09 19.73 8.24 14.01 21.29 29.92 8 9 4.81 108.4 164.8 2.98 33.82 50.7 10 12 6.02 7.22 164.8 229.8 253.0 343.5 3.72 4.46 5.20 50.7 71.1 95.4 76.8 108.4 14 143.2 15 9.02 343.5 529.0 16 5.95 6.69 7.44 121.4 151.8 182.2 182.2 18 225.5 20 12.03 589.5 893.0 277.5 22 24 25 9.30 277.5 416.3 26 28 30 11.15 13.02 14.88 385.8 516. 659. 585. 35 781. 40 998. 45 50 * Adapted from Williams and Hazen, Hydraulic Tables, 3rd edition, pp. 26-29, 1920. Publisher- John Wiley & Sons, Inc., New York. Bitl. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA 17 TABLE 2— (Concluded) Friction" Drop in Pipes for Various Bates of Discharge* \\i in. Wrought iron pipe, actual inside diameter 1.380 in. \ X A. in. Wrought iron pipe, actual inside diameter 1.611 in. 2 in. Pipe or hose, actual inside diameter 2.00 in. Dis- charge gal. per Velocity in ft. per sec. Pressure drop per 1000 ft. of pipe in lbs. Velocity in ft. per sec. Pressure drop per 1000 ft. of pipe in lbs. Velocity in ft. per sec. Pressure drop per 1000 ft. of pipe or hose in lbs. min. Ordinary iron Old iron Ordinary iron Old iron Ordinary Old 1 2 3 4 .86 1.07 1.29 1.50 1.72 2.47 3.64 5.20 6.90 8.81 3.73 5.51 7.89 10.41 13.45 .63 .79 .94 1.10 1.26 1.42 1.57 1.89 2.20 1.137 1.726 2.428 3.208 4.12 5.12 6.20 8.72 11.62 1.735 2.602 3.642 4.355 6.20 7.76 9.41 13.18 17.56 5 6 7 .61 .868 1.258 8 9 .82 1.432 2.168 10 12 14 15 2.14 2.57 3.00 13.23 18.65 24.72 19.95 28.2 37.7 1.02 1.23 1.43 2.168 3.035 4.075 3.295 4.64 6.16 16 18 20 22 3.43 3.86 4.29 31.65 39.45 48.3 48.3 59.4 72.9 2.52 2.83 3.15 3.46 3.78 14.78 18.39 22.55 26.88 31.65 22.54 27.74 33.82 40.32 46.82 1.63 1.84 2.04 5.204 6.46 7.89 7.89 9.84 11.93 24 25 5.36 72.0 108.8 2.55 11.84 18.04 26 4.09 4.41 4.72 5.51 6.30 7.08 7.87 36.42 42.06 47.68 63.75 81.5 100.6 123.2 55.07 63.3 71.98 95.4 121.8 151.8 185.6 28 30 35 40 45 6.43 7.51 8.58 101.8 135.3 173.5 155.2 207.5 264.5 3.06 3.57 4.08 4.60 5.11 16.65 22.12 28.62 35.55 42.92 25.15 33.82 42.92 53.3 50 10.72 260.1 398.8 65.05 * Adapted from Williams and Hazen, Hydraulic Tables, 3rd edition, pp. 26-29, 1920. John Wiley & Sons, Inc., New York. Publisher- 18 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION o o o to iO i-i CM CM CO <=/§> 2 CO o ® "O Oi ;h iO P-l ^h CO CO cj v o i-i »o i-h r-H T3 W\ "^ o^ CM i-H co rH © ^ m Ph 2? © CM , £ ^ 2 o © ^ o © S ^ S| N co CD V* CM © Oi 00 H 00 el ™ O M fS "=> 2 o 2 ^\ g CO CO O ^ CO §2 N to cd v cm o io i>- h -r! m\ o) oo h oo 2 -< « CO CO o CD O o iO 0) V* CM O iO b- T3 M\C5 O0 H 00 »h\o gcocoioocDoT; £ g 2 o ^ ^ ^ £ 5 U ^ co \N ,-H O rH\ CD „ 00 O O O i-l T5 °<3 CM 00 00 © co v ^ e© % © ^ 53 o i^ _§ oa o \* © ,—> © ^8oo2| N ^s sg ° ^ cm £ © ^ 5 ^ CO O "£ CO £ ^ 2 § T^t © "^ CI CM 53 © ^ *3 a 2 o 5 a O fl o © Pi £ _§ S . *" a & O « ^ o 2 £ S5 I £ i. 8 § : 3 £ 2 * "S §1 8 § - fl-O M ^ I -a J : a ^ 1^ hH CQ CQ O BUL. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA 19 FIELD OBSERVATIONS In order to obtain first-hand knowledge of the stationary spray systems as they are operated in California, the writers made a per- sonal canvas of the state, locating six such installations and securing the cooperation of the owners. Three different methods for securing information were used: (1) field observations, (2) questionnaires to owners, and (3) field tests. The results of this investigation are given in tabular form. Table 3 gives a physical description of the six orchards upon which ten separate tests were run. Table 4 gives the conditions under which the tests were run and the results obtained. Tables 5 and 6 have been compiled from the information furnished by the owners and from data secured during the tests. Operation of the System. — At the beginning of the spraying period the pump and power unit are inspected, risers installed, if they are not already in place, and hose couplings attached. The foreman directs his men according to the plan of spraying to be followed. Helpers become necessary when long lengths of hose are used. Where risers are fitted with double service cocks, one helper can take care of two or more hose (fig. 10a). It is a good plan to distribute the hose throughout the orchard, using different laterals and thereby maintaining satisfactory nozzle pressures. The pump is started and all lines are filled with water to prevent the subsequent filling of unused pipes with spray liquid. All valves are then closed including the cut-off cock at the pump. The spray mixture is prepared and the service tank filled (fig. 12). Meanwhile the men in the orchard have connected their hose and opened the proper service cocks. When the mixture in the tank has been thoroughly agitated and sufficient pressure developed, the cut-off cock at the pump is opened, thus applying pressure to the piping system. As soon as the clear water has been expelled, spraying begins. In the spraying operation each man with a hose adopts a definite system to prevent missing trees or portions of trees and to avoid winding the hose around trees already sprayed. Figure 13 shows a good system to follow. As spraying progresses, new laterals are turned on and the old ones shut off. At the end of the day that part of the system which has been used is flushed out by pumping clear water through this part of the pipe- 20 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Fig. 12. -Showing methods by which concentrated lime-sulfur is conveyed to the mixing tank. a. Dipping the concentrated solution from an underground reservoir and carry- ing it in buckets to the mixing tank. b. Using suction pump to lift solution from an underground reservoir to the mixing tank. c. A suction hose withdrawing the liquid directly from a barrel of the concentrated solution, d. Lifting a full barrel to the mixing platform. Bul. 406] STATIONARY SPRAY PLANTS IN CALIFORNIA 21 line. Flushing is accomplished by changing the suction from the service tank to the water supply by means of cross valves, or by filling the service tank itself with water. Men on the last lateral continue spraying until clear water appears. The foreman determines when to turn in clear water in order to finish spraying before quitting time; flushing is thus completed soon after spraying is finished. Thorough flushing is especially important after spraying with materials such as arsenate of lead or Bordeaux mixture. Laterals - rf^-Q/ser o — — o — -o-Jj °)( ° ) C ° )| °~~ "° — *-°— t— o — >-o — »-c f j — Pbth taken by nozz/emon. — ^—- — — Path taken by he/per changing t?ose from one riser to another. Fig. 13. — A plan for routing nozzle-man so that no trees will be missed. The diagram is simply suggestive, the purpose being to illustrate how the nozzle-man can be routed so as not to miss any trees, and so as to prevent twisting and tangling of the hose. Three blocks are shown, the detail path for the last three trees only is shown in the upper left-hand block, to illustrate how the connection may be transferred from one riser to another. The first route in the lower right-hand block is shown in detail, to illustrate the method of transferring from one riser to another at the end of the lateral. 22 UNIVERSITY OP CALIFORNIA EXPERIMENT STATION GO J CS,I "~ I CMCMOCOOS© ^ O O) (N CM CO < < . r XLOLOO*tfG001> c oc iT. PC 10 5C LO c CM LO O uo GO £ CP ~ CP 53 £ ft '- cp Td 3 fl c a a s 9-s 8. ft= S _■ ,2 -e §1 i | , CP CP CP o d cj oj ^ - cu ft£ o o 3 a 3 ft? 5 !° s, Q C72 > > > 02 d o o CO ~ ._ tf Pu ft

Hazen. 1920. Hydraulic tables (3rd ed.), 26-29. STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION No. 253. Irrigation and Soil Conditions in the Sierra Nevada Foothills, California. 261. Melaxuma of the Walnut, "Juglans regia." 262. Citrus Diseases of Florida and Cuba Compared with Those of California. 263. Size Grades for Ripe Olives. 268. Growing and Grafting Olive Seedlings. 273. Preliminary Report on Kearney Vine- yard Experimental Drain. 275. The Cultivation of Belladonna in California. 276. The Pomegranate. 277. Sudan Grass. 278. Grain Sorghums. 279. Irrigation of Rice in California. 283. The Olive Insects of California. 294. Bean Culture in California. 304. A Study of the Effects of Freezes on Citrus in California. 310. Plum Pollination. 312. Mariout Barley. 313. Pruning Young Deciduous Fruit Trees. 319. Caprifigs and Caprification. 324. Storage of Perishable Fruit at Freez- ing Temperatures. 325. Rice Irrigation Measurements and Experiments in Sacramento Valley, 1914-1919. 328. Prune Growing in California. 331. Phylloxera-Resistant Stocks. 335. Cocoanut Meal as a Feed for Dairy Cows and Other Livestock. 339. The Relative Cost of Making Logs from Small and Large Timber. 340. Control of the Pocket Gopher in California. 343. Cheese Pests and Their Control. 344. Cold Storage as an Aid to the Mar- keting of Plums. 346. Almond Pollination. 347. The Control of Red Spiders in Decid- uous Orchards. 348. Pruning Young Olive Trees. 349. A Study of Sidedraft and Tractor Hitches. 350. Agriculture in Cut-over Redwood Lands. 352. Further Experiments in Plum Pollina- tion. 353. Bovine Infectious Abortion. 354. Results of Rice Experiments in 1922. 357. A Self-mixing Dusting Machine for Applying Dry Insecticides and Fungicides. 358. Black Measles, Water Berries, and Related Vine Troubles. 361. Preliminary Yield Tables for Second Growth Redwood. 362. Dust and the Tractor Engine. 363. The Pruning of Citrus Trees in Cali- fornia. 364. Fungicidal Dusts for the Control of Bunt. 365. Avocado Culture in California. BULLETINS No. 366. 367. 368. 369. 370. 371. 372. 373. 374. 375. 376. 377. 379. 380. 381. 382. 383. 385. 386. 387. 388. 389. 390. 391. 392. 393. 394. 395. 396. 397. 398. 399. 400. 401. 402. 403. 404. 405. 406. Turkish Tobacco Culture, Curing and Marketing. Methods of Harvesting and Irrigation in Relation of Mouldy Walnuts. Bacterial Decomposition of Olives dur- ing Pickling. Comparison of Woods for Butter Boxes. Browning of Yellow Newtown Apples. The Relative Cost of Yarding Small and Large Timber. The Cost of Producing Market Milk and Butterfat on 246 California Dairies. Pear Pollination. A Survey of Orchard Practices in the Citrus Industry of Southern Cali- fornia. Results of Rice Experiments at Cor- tena, 1923. Sun-Drying and Dehydration of Wal- nuts. The Cold Storage of Pears. Walnut Culture in California. Growth of Eucalyptus in California Plantations. Growing and Handling Asparagus Crowns. Pumping for Drainage in the San Joaquin Valley, California. Monilia Blossom Blight (Brown Rot) of Apricot. Pollination of the Sweet Cherry. Pruning Bearing Deciduous Fruit Trees. Fig Smut. The Principles and Practice of Sun- drying Fruit. Berseem or Egyptian Clover. Harvesting and Packing Grapes in California. Machines for Coating Seed Wheat with Copper Carbonate Dust. Fruit Juice Concentrates. Crop Sequences at Davis. Cereal Hay Production in California. Feeding Trials with Cereal Hay. Bark Diseases of Citrus Trees. The Mat Bean (Phaseolus aconilifo- lius). Manufacture of Roquefort Type Cheese from Goat's Milk. Orchard Heating in California. The Blackberry Mite, the Cause of Redberry Disease of the Himalaya Blackberry, and its Control. The Utilization of Surplus Plums. Cost of Work Horses on California The Codling Moth in Walnuts. Farm-Accounting Associations. The Dehydration of Prunes. Citrus Culture in Central California. Stationary Spray Plants in California. CIRCULARS No. 87. Alfalfa. 117. The Selection and Cost of a Small Pumping Plant. 127. House Fumigation. 129. The Control of Citrus Insects. 136. Melilotus indica as a Green-Manure Crop for California. 144. Oidium or Powdery Mildew of the Vine. No. 157. Control of the Pear Scab. 160. Lettuce Growing in California. 164. Small Fruit Culture in California. 166. The County Farm Bureau. 170. Fertilizing California Soils for the 1918 Crop. 173. The Construction of the Wood-Hoop Silo. 178. The Packing of Apples in California. CIRCULARS— (Continued) No. No. 179. Factors of Importance in Producing 265. Milk of Low Bacterial Count. 266. 190. Agriculture Clubs in California. 199. Onion Growing in California. 267. 202. County Organizations for Rural Fire Control. 269. 203. Peat as a Manure Substitute. 270. 209. The Function of the FaTm Bureau. 272. 210. Suggestions to the Settler in California. 212. Salvaging Rain-Damaged Prunes. 273. 215. Feeding Dairy Cows in California. 274. 217. Methods for Marketing Vegetables in California. 276. 220. Unfermented Fruit Juices. 277. 228. Vineyard Irrigation in Arid Climates. 230. Testing Milk, Cream, and Skim Milk 278. for Butterfat. 231. The Home Vineyard. 279. 232. Harvesting and Handling California Cherries for Eastern Shipment. 281. 234. Winter Injury to Young Walnut Trees during 1921-22. 235. Soil Analysis and Soil and Plant 282. Inter-relations. 236. The Common Hawks and Owls of 283. California from the Standpoint of 284. the Rancher. 285. 237. Directions for the Tanning and Dress- 286. ing of Furs. 287. 238. The Apricot in California. 288. 239. Harvesting and Handling Apricots 289. and Plums for Eastern Shipment. 290. 240. Harvesting and Handling Pears for 291. Eastern Shipment. 241. Harvesting and Handling Peaches for 292. Eastern Shipment. 293. 243. Marmalade Juice and Jelly Juice from 294. Citrus Fruits. 295. 244. Central Wire Bracing for Fruit Trees. 245. Vine Pruning Systems. 296. 247. Colonization and Rural Development. 248. Some Common Errors in Vine Prun- 298. ing and Their Remedies. 249. Replacing Missing Vines. 299. 250. Measurement of Irrigation Water on 300. the Farm. 301, 252. Supports for Vines. 302. 253. Vineyard Plans. 303. 254. The Use of Artificial Light to Increase Winter Egg Production. 304, 255. Leguminous Plants as Organic Fertil- 305, izer in California Agriculture. 306. 256. The Control of Wild Morning Glory. 257. The Small-Seeded Horse Bean. 307. 258. Thinning Deciduous Fruits. 259. Pear By-products. 261. Sewing Grain Sacks. 262. Cabbage Growing in California. 263. Tomato Production in California. 264. Preliminary Essentials to Bovine Tuberculosis Control. Plant Disease and Pest Control. Analyzing the Citrus Orchard by Means of Simple Tree Records. The Tendency of Tractors to Rise in Front; Causes and Remedies. An Orchard Brush Burner. A Farm Septic Tank. California Farm Tenancy and Methods of Leasing. Saving the Gophered Citrus Tree. Fusarium Wilt of Tomato and its Con- trol by Means of Resistant Varieties. Home Canning. Head, Cane, and Cordon Pruning of Vines. Olive Pickling in Mediterranean Coun- tries. The Preparation and Refining of Olive Oil in Southern Europe. The Results of a Survey to Determine the Cost of Producing Beef in Cali- fornia. Prevention of Insect Attack on Stored Grain. Fertilizing Citrus Trees in California. The Almond in California. Sweet Potato Production in California. Milk Houses for California Dairies. Potato Production in California. Phylloxera Resistant Vineyards. Oak Fungus in Orchard Trees. The Tangier Pea. Blackhead and Other Causes of Loss of Turkeys in California. Alkali Soils. The Basis of Grape Standardization. Propagation of Deciduous Fruits. The Growing and Handling of Head Lettuce in California. Control of the California Ground Squirrel. The Possibilities and Limitations of Cooperative Marketing. Poultry Breeding Records. Coccidiosis of Chickens. Buckeye Poisoning of the Honey Bee. The Sugar Beet in California. A Promising Remedy for Black Measles of the Vine. Drainage on the Farm. Liming the Soil. A General Purpose Soil Auger and its Use on the Farm. American Foulbrood and its Control. The publications listed above may be had by addressing College of Agriculture, University of California, Berkeley, California. 10m-10,'26