1273 
 
 Issued June 30,1910. 
 
 U. S. DEPARTMENT OF AGRICULTURE. 
 
 FARMERS’ BULLETIN 404 
 
 IRRIGATION OF ORCHARDS. 
 
 BY 
 
 SAMUEL FORTIER, 
 
 Chief of Irrigation Investigations , 
 Office of Experiment Stations. 
 
 WASHINGTON: 
 
 GOVERNMENT PRINTING OFFICE. 
 
 1910 . 
 
LETTER OF TRANSMITTAL. 
 
 U. S. Department of Agriculture, 
 
 Office of Experiment Stations, 
 Washington , D. O., Aril 25, 1910. 
 
 Sir: I have the honor to transmit herewith material for a bulletin 
 on the irrigation of orchards, prepared by Samuel Fortier, chief of 
 irrigation investigations of this Office. This material is based on 
 the best irrigation practices of the arid region, and is intended pri¬ 
 marily for the use of settlers in that region. It is therefore recom¬ 
 mended that it be published as a Farmers’ Bulletin. 
 
 Doctor Fortier desires to acknowledge the receipt of notes on the 
 irrigation of orchards from state agents of this Office and special 
 agents appointed temporarily for this and other purposes. 
 
 Respectfully, 
 
 A. C. True, 
 
 Director. 
 
 Hon. James Wilson, 
 
 Secretary of Agriculture. 
 
 404 
 
 2 
 
6 
 
 C 0 N T E NTS. 
 
 Tage. 
 
 Selection of lands for orchards. 5 
 
 Typical water supplies for orchards. 6 
 
 Clearing and grading land for fruit. 9 
 
 Locating the tree rows. 10 
 
 Methods of irrigating orchards. 12 
 
 Furrow irrigation. 12 
 
 Earthen head ditches. .. 13 
 
 Short tubes in head ditches. 14 
 
 Head flumes. 15 
 
 Pipes and standpipes. 17 
 
 Making furrows. 19 
 
 Applying water to furrows. 20 
 
 The basin method. 22 
 
 The check method. 23 
 
 Time to irrigate orchards. 24 
 
 Number of irrigations per season. 25 
 
 Duty of water in orchard irrigation. 25 
 
 Evaporation losses from orchard soils. 2< 
 
 Effect of soil mulches in checking evaporation. 
 
 Loss of w T ater due to percolation. 
 
 Removal of waste water. . 
 
 Growing crops between the tree .. ^ 
 
 Winter irrigation of orchards. 
 
 404 
 
 *> 
 
 O 
 
ILLUSTRATIONS. 
 
 Page. 
 
 Fig. 1. Orchard tracts at Lewiston, Idaho. 6 
 
 2. Weir, with automatic register, used by the Temescal Water Company. 7 
 
 3. Concrete-lined canal of the Temescal Water Company. 7 
 
 4. Section of hydrant box of Riverside Water Company, showing device 
 
 for measuring miner’s inches. 8 
 
 5. Orchard tract under Gage Canal, Riverside, Cal. 8 
 
 6. Hexagonal method of setting out orchard trees. 11 
 
 7. Plan of planting apple trees with peach trees as fillers. 12 
 
 8. The use of the “A” scraper in building head ditches. 13 
 
 9. Wooden box placed in bank of head ditch. 14 
 
 10. Wooden check in head ditch. 15 
 
 11. Section of wooden head flume, showing opening and gate. 15 
 
 12. The use of low check in head flume... 16 
 
 13. Common sizes of concrete head flumes. 17 
 
 14. Earthen head ditch lined with concrete. , 17 
 
 15. The use of pipes in furrow irrigation. 18 
 
 16. Section of standpipe outlined in figure 15. 18 
 
 17. Method of irrigating from iron standpipes connected with pressure 
 
 pipes.• 19 
 
 18. Making furrows in orchard. 20 
 
 19. Furrow irrigation, showing dry spaces. 21 
 
 20. Cross furrowing the dry spaces. 21 
 
 21. Use of zigzag furrows. 22 
 
 22. Basin method of irrigation. 23 
 
 23. Ridger used in basin irrigation. 23 
 
 24. Combination of check and furrow methods. 23 
 
 25. Average duty per month under Riverside Water Company, December 
 
 1, 1901, to November 30, 1908 . 26 
 
 26. Relation between temperature and evaporation from a water surface 
 
 at Tulare, Cal. 28 
 
 27. Tank experiments at Reno, Nev., to determine effect of soil mulches 
 
 in checking evaporation. 30 
 
 28. Outlines of percolation under sixteen furrows in orchard 58 under the 
 
 Gage Canal Company, Riverside, Cal. 31 
 
 29. Soil auger used to locate ground-water level._. 32 
 
 30. Box drain. 32 
 
 31. Sand box in tile line. 33 
 
 32. Orchard, showing strawberries between rows of trees. 35 
 
 404 
 
 4 
 
IRRIGATION OF ORCHARDS. 
 
 SELECTION OF LANDS FOE OECHAEDS. 
 
 Care and good judgment should be exercised in the selection of an 
 orchard tract. If it turns out well the profits are high, but if it fails 
 the losses are heavy. It involves the setting aside of good land, the 
 use of irrigation water, and somewhat heavy expenses in purchasing 
 trees, setting them out and caring for them until they begin to bear. 
 
 Assuming that the climate and soil of the district selected are 
 adapted to the kind of trees to be grown, the next most important 
 things to consider are good drainage and freedom from early and late 
 frosts. Low-lying lands under a new irrigation system should be 
 regarded with suspicion, even if the subsoil be quite dry at the time of 
 planting. The results of a few years of heavy and careless irrigation 
 on the higher lands adjacent may render the lowlands unfit for or¬ 
 chards. On the other hand, the higher lands are not always well 
 drained naturally. A bank of clay extending across a slope may inter¬ 
 cept percolating water and raise it near the surface. Favored locations 
 for orchards in the mountain States are often found in the narrow 
 river valleys at the mouths of canyons. The coarse soil of these deltas, 
 the steep slopes, and the daily occurrence of winds which blow first 
 out of the canyons and then back into them, afford excellent conditions 
 for the production of highly flavored fruits at the minimum risk of 
 being injured by frost. 
 
 Proper exposure is another important factor. In the warmer re¬ 
 gions of the West and Southwest a northern exposure is sometimes 
 best, but as a rule the orchards of the West require warmth and sun¬ 
 shine, and a southerly exposure is usually most desirable. Natural 
 barriers frequently intercept the sweep of cold, destructive winds, and 
 when these are lacking, wind-breaks may be planted to serve the same 
 purpose. Depressions or sheltered coves should be avoided if the cold 
 air has a tendency to collect in them, a free circulation of air being 
 necessary to drive away frost. The low-lying lands seem to be the 
 
 most subject to cold, stagnant air. 
 
 While experience has shown that orchard trees ot nearly all kind* 
 can be successfully grown on soils that differ widely in their mechan¬ 
 ical and chemical composition, it has also shown that certain t\pi* 
 of soils are best adapted to particular kinds of trees. 1 hus the best 
 
 404 
 
 5 
 
6 
 
 IRRIGATION OF ORCHARDS. 
 
 peach, almond, apricot, and olive orchards of the West are found on 
 the lighter or sandier loams; the best apple, cherry, and pear orchards 
 on heavier loams; while walnut, prune, and orange orchards do best 
 on medium grades of soil. The requirements of all, however, are a 
 deep rich, and well-drained soil. 
 
 TYPICAL WATER SUPPLIES FOR ORCHARDS. 
 
 Formerly most western orchards were supplied with water through 
 earthen ditches. These leaky, unsightly channels, by reason of their 
 
 J 1_1 L 
 
 BRYDEN AVE. 
 
 n i—;-—-1 r 
 
 Fig. 1 . —Orchard tracts at Lewiston, Idaho. 
 
 cheapness, would have been quite generally retained had it not been 
 for the increasing value and scarcity of water. The value of w T ater 
 for irrigation purposes has increased beyond the average of that 
 given by the census report of 1902 over 300 per cent. In many locali¬ 
 ties there is likewise great scarcity at certain times. These rapidly 
 changing conditions have induced many water companies to save 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 7 
 
 
 ®Wfe. 
 
 *$gp1°r *\ * At 
 ''/ 
 
 ^isddt&d-'d. 
 
 some of their heavy losses in conveying water supplies by substituting 
 pipes for open ditches in earth, or else by making the ditches water¬ 
 tight by an impervious lining. 
 
 The high value and scarcity of the water in natural streams have, 
 likewise induced orchardists to install pumping plants to raise water 
 from underground 
 sources. It was esti¬ 
 mated that in 1909 
 20,000 of these plants 
 were in operation in 
 California alone. In 
 other parts of the 
 West reservoirs are 
 being built to supple¬ 
 ment the late summer 
 flow of streams which 
 fail to provide enough 
 water for all. 
 
 The few typical ex¬ 
 amples which follow 
 may not only give the 
 reader an idea of how 
 orchards are supplied with water, but indicate also the customary 
 division into tracts to serve this and other purposes. 
 
 The Lewiston Basin is located where Clearwater River flows into 
 the Snake River in western Idaho, and varies from 700 to 1,900 feet 
 above sea level. A few years ago water was brought from neighbor¬ 
 ing creeks and stored in a reservoir. The water required for orchard 
 
 irrigation is conducted 
 from this reservoir 
 under pressure in two 
 lines of redwood stave 
 pipes over the rolling 
 hills which separate 
 the reservoir from the 
 orchard lands. On 
 these lands contour 
 lines were first estab¬ 
 lished, and each quarter section was afterwards divided into 10-acie 
 tracts by 60-foot streets. These were further subdivided into eight 
 5-acre tracts, with a 20-foot alley through the center. ligme 1, 
 showing block 28 of the survey, indicates the general arrangement. 
 The large conduits from the reservoir are connected to smaller lateral 
 
 Fig. 2.—Weir with automatic register, used by the 
 Temescal Water Company. 
 
 fo/ned p/dsfer. : 
 
 2'/z /ned concrete * {55 
 
 '/otnedp/oster 
 2'/i/ncti concrete 
 
 •' -.V: • 3 /o'd fnc/> concrete '•: ' 
 
 Fig. 3.—Concrete-lined canal of the Temescal Water 
 
 Company. 
 
 404 
 
8 
 
 IRRIGATION OF ORCHARDS. 
 
 pipes laid in the alleys, and these in turn are tapped by 3-inch pipes, 
 which furnish water to the 5-acre tracts. 
 
 The town of Corona, Cal., is hemmed in on all sides by lemon and 
 orange orchards. The chief water supply for these groves comes from 
 Perris Basin, 40 miles distant. The Temescal Water Company owns 
 
 Fig. 4.—Section of hydrant box of Riverside Water Com¬ 
 pany, showing device for measuring miner’s inches. 
 
 3,GOO acres of water¬ 
 bearing lands in this 
 basin, and at favor¬ 
 able points pumping 
 plants have been in¬ 
 stalled. These plants 
 are operated by mo¬ 
 tors supplied with 
 current from a central 
 generating station lo¬ 
 
 cated at Ethenac. The discharge from each pump is measured over a 
 rectangular wier having an automatic register. This device is shown 
 in figure 2. Small lined channels convey the water from the pumps 
 to the main conduit shown in cross-section in figure 3. The con¬ 
 crete lining of this 
 conduit is composed 
 of one part cement 
 to seven parts sand 
 and gravel, having 
 
 a 
 
 slop( 
 
 r/rrigotino Flume 
 
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 9Z8.0C 
 
 Irrigating Flume 
 
 
 
 
 
 - 
 
 
 
 
 
 
 
 
 
 
 
 
 
 92 5. 50 
 
 J 
 
 thickness on the 
 >es of 2^ inches 
 and on the bottom 
 of 3 to 4 inches. 
 
 The lining is ren¬ 
 dered still more im¬ 
 pervious by the ad¬ 
 dition of a plaster 
 coat one-fourth of 
 an inch in thick¬ 
 ness, composed of 
 one part of cement 
 to two parts of 
 sand. The cost was 
 5J cents per square 
 foot, or 55 cents per 
 linear foot. The main conduit consists of about 30 miles of lined 
 canal and 10 miles of piping 30 inches in diameter. The groves are 
 laid out as a rule in 10-acre tracts, and piping of various kinds con¬ 
 veys the water from the main to the highest point of each tract, from 
 which it is distributed between the rows in furrows. 
 
 LINCOLN AVENUE 
 
 926.40 
 
 305.40 
 
 fHydrant 
 
 926.90 
 
 929.90 
 
 Fig. 
 
 -Orchard tract under Gage Canal, Riverside, Cal. 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 9 
 
 A large part of the water used by the Riverside Water Company 
 is pumped from the gravelly bed of the Santa Ana River. From 
 thence it is conveyed in a main canal to the orchard lands and dis¬ 
 tributed to the groves in cement and vitrified clay pipes. The owner 
 of a tract, whether it be 10, 20, 30, or 40 acres in extent, receives his 
 supply at the highest corner through a hydrant box. Each hydrant 
 box not only allows the water to pass from the end of a lateral pipe 
 to the head flume of the tract to be irrigated, but also measures the 
 amount in miner’s inches under a 4-inch pressure head as it passes 
 through. A section of the hydrant box showing the adjustable steel 
 slides to regulate the opening is given in figure 4. 
 
 On the Gage Canal system in Riverside County, Cal., the water 
 supply for the tiers of 40-acre tracts is taken from the canal in riveted 
 steel pipes varying from 6 to 10 inches in diameter. These larger 
 mains are connected with 4, 5, and 6 inch lateral pipes of the same 
 material, which convey the water to the highest point of each 10-acre 
 tract. This general arrangement is shown in the sketch, figure 5. 
 
 The ditches conducting water from gravity canals to orchard tracts 
 do not differ from the supply ditches for other crops which have 
 been described in previous publications of this Department.® 
 
 CLEARING AND GRADING LAND FOR FRUIT. 
 
 As a rule fruit trees are planted on land previously cultivated and 
 cropped. One of the best preparatory crops for orchards is alfalfa. 
 This vigorous plant breaks up the soil and subsoil by its roots, collects 
 and stores valuable plant foods, and when it is turned under at the 
 end of the second or third year leaves the soil in much better condi¬ 
 tion for the retention of moisture and the growth of young trees. 
 
 In the Bitter Root Valley, Montana, new land is first plowed 8 to 12 
 inches deep, then carefully graded and smoothed and seeded to red 
 clover for one or two seasons. On the west side of this valley pine 
 trees and pine stumps are encountered. These can best be removed 
 by burning. A hole 1^ inches in diameter is bored through the base 
 of the stump or tree in a slanting direction. It is near the surface 
 of the ground on the windward side and about 18 inches above the 
 surface on the leeward side. A fire is then built in the hole, using 
 small twigs to start it. As the fire burns the opening is increased 
 and larger limbs are inserted. In two or three days the stump v>\\\ 
 have burned out, the fire burning down into the roots to a depth of 
 12 to 14 inches. The cost of such clearing varies with the charactei 
 of the land and the density of the growth. From $10 to $b> an acie 
 will clear the land of stumps and it then costs $5 to $10 to get the 
 unburnt roots plowed out and the land ready for planting._ 
 
 a u. S. Dept. Agr., Farmers’ Bills. 263 and 373, 
 
 41647—Bull. 404—10-2 
 
10 
 
 IRRIGATION OF ORCHARDS. 
 
 Iii recent years lar^e areas of wooded lands in both the Hood River 
 
 %j o 
 
 and Rogue River valleys of Oregon have been cleared in order to 
 plant apple trees. One of the methods employed in the Hood River 
 district to rid the land of its growth of fir, pine, scrub oak, and laurel 
 is similar to that just described. Another method consists in split¬ 
 ting open the stumps with giant powder and then pulling out the 
 roots with a stump puller. Stump pullers of various kinds are used 
 in California for a like purpose. The most powerful of these con¬ 
 sists of a portable engine, windlass, and cable similar to an ordinary 
 hoisting plant. A heavy chain is fastened to the tree at the proper 
 height above the ground. To this chain the pulling cable is hooked 
 and when the power is applied the tree is pulled out by the roots. 
 
 In New Mexico and Texas the mesquite is usually grubbed out by 
 Mexicans, but in California, where labor costs more, such shrubs as 
 mesquite, manzanita, and chaparral can be more cheaply removed by 
 a stout pair of horses and a logging chain. 
 
 Devices for the removal of ordinary desert plants, such as sage¬ 
 brush and grease wood have been described in a previous bulletin. 0 
 
 An effort should be made to establish a fairly uniform grade from 
 top to bottom of each tract. This is done by cutting off the high 
 points and depositing the earth thus obtained in the depressions. 
 The length of the furrows should not exceed one-eighth of a mile 
 and in sandy soil they should be shorter. As a rule, it is not difficult 
 to grade the surface of an orchard so that small streams of water 
 will readily flow in furrows from top to bottom. 
 
 LOCATING THE TREE ROWS. 
 
 In setting out orchards which are to be irrigated, the elevation of 
 the surface of the ground should first be ascertained? This is usually 
 done by making a contour survey by which each tract is divided up 
 into a number of curved strips or belts by level lines. Such contours 
 are shown in figure 1, page G, the vertical distance between them in 
 this particular case being 1 foot. With these as a guide the direction 
 of the tree rows can be readily determined. Where the trees are 
 watered in basins or checks, flat slopes are not so objectionable, but in 
 furrow irrigation a slope of about 2 inches to the 100 feet is necessary 
 to insure an even distribution of water. When streams are to be run 
 in the furrows the slope of the furrows may be increased to 8, 10, and 
 even to 12 inches to the 100 feet. On slopes varying from 10 to 40 
 feet to the mile, the tree rows may therefore be located at the proper 
 distance apart down the steepest slope. Under such conditions the 
 trees are most commonly planted in squares. The location of the 
 
 404 
 
 a U. S. Dept. Agr., Farmers’ Bill. 373. 
 
IRRIGATION OF ORCHARDS. 
 
 11 
 
 trees can be best fixed by the use of a surveyor’s transit and steel tape 
 When these are not available, a woven-wire cable about three-six¬ 
 teenths of an inch in diameter will answer the purpose. If apple 
 trees are to be set out and it is desired to have them 32 feet apart 
 tags are inserted between the strands of the cable to mark this exact 
 distance. A base line at the proper distance from the fence or one 
 margin of the field is then laid down and long sighting stakes driven 
 at each tag. The corner is then turned and a similar line is laid out. 
 This process is continued until the location of the trees around each 
 of the four sides of the tract has been fixed. The corners can be^t 
 be turned with a 100-foot tape or link chain. First measure from 
 the end of the base line a distance of 30 feet. Hold the one-hundred 
 end of the chain at this point, and the 10-foot link at the corner; take 
 the tape or chain at the 50-foot mark or link and pull both lines taut. 
 
 A stake driven at this vertex will establish a point on a line at right 
 angles to the first. When 
 stakes have been set on all 
 four sides the intermediate 
 locations for the trees can 
 be readily ascertained by 
 sighting between corre- 
 
 Fig. 6. 
 
 -Hexagonal method of setting out orchard 
 trees. 
 
 sponding marginal stakes. 
 
 Where the slope is steep 
 and difficulties are likely to 
 be encountered in distribut¬ 
 ing water, the equilateral, 
 hexagonal, or septuple 
 method of planting, as it 
 is variously termed, should 
 be adopted. The manner of marking the ground for this method is 
 indicated in figure 6. It will be observed that in this method the 
 ground is divided up into equilateral triangles, with a tree at each 
 vertex. The trees likewise form hexagons, and when one includes 
 the center tree of each hexagon they form groups of sevens. Hence 
 the name equilateral, hexagonal, and septuple. 
 
 The chief advantage of this mode of planting in irrigated districts 
 is that it provides three and often four different directions in which 
 furrows may be run. Having the choice of so many, it is not diffi¬ 
 cult to select the one which is best for any particular tract. 1 he 
 ground can likewise be cultivated in more ways, and about one- 
 seventh more trees can be planted to a given area than is possible in 
 the square method. 
 
 In the past the trees of irrigated orchards have been planted too 
 close. This is made clear to even the casual observer who visits the 
 
 404 
 
12 
 
 IRRIGATION OF ORCHARDS. 
 
 old orange groves of Riverside, Cal., the deciduous orchards of the * 
 Santa Clara Valley, California, or the apple orchards of the Hood 
 River district in Oregon. Under irrigation systems peach trees 
 should be spaced 20 to 22 feet, olive, pear, apricot, and cherry trees 
 from 22 to 28 and 30 feet, orange trees 22 to 24 feet, apple trees 30 
 to 3G feet, and walnut trees from 48 to 5G feet apart. 
 
 On the Pacific coast the tendency toward wide spacing has induced 
 many growers to insert peach fillers between other slower maturing 
 trees, such as the apple and walnut. A common practice in this 
 direction is shown in figure 7,- which represents the arrangement 
 of trees in a young orchard in Douglas County, Wash. Here the 
 trees are set in squares 18 feet each way, but in every other row peach 
 trees alternate with the standard apple trees. In the remaining rows 
 winesap apple trees are used for fillers. As the apple trees grow and 
 begin to crowd the fillers, the peach trees are removed. If more 
 
 Spitz Peach Spitz 
 
 iff -*- /S' 
 
 iff 
 
 id' 
 
 Jonathan 
 
 Ffeach 
 
 a 
 
 Jonathan 
 
 A. 
 
 Spitz 
 
 Jonathan 
 
 Winesap 
 
 Jonathan 
 
 B. 
 
 Spitz Spitz 
 
 a 
 
 Jonathan 
 
 Fig. 7.—Plan of planting apple trees with peach trees as fillers : A, Trees as planted at 
 
 first; B, peach trees removed ; C. Winesap removed. 
 
 space is required the winesaps can be taken out, leaving the apple 
 trees in squares 36 feet apart both ways. 
 
 METHODS OF IRRIGATING ORCHARDS. 
 
 FURROW IRRIGATION. 
 
 The usual way of irrigating orchards is by means of furrows. 
 These vary in depth, length, and distance apart, but this diversity 
 does not tend to create different kinds of furrow irrigation. The 
 division of this subject is rather due to the means employed in dis¬ 
 tributing water from the supply ditch to the furrows. In some 
 cases the distribution is effected by making openings in an earthen 
 ditch, in others by inserting wooden or iron spouts in the ditch banks, 
 while in many others flumes having the desired number of openings 
 or pipes with standpipes divide the supply among the requisite num¬ 
 ber of furrows. These designs and methods will be described under 
 their respective headings. 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 Earthen Head Ditches. 
 
 13 
 
 Permanent ditches at the head of orchard tracts should be located 
 by a surveyor. The proper grade depends chiefly on the soil. If 
 the soil is loose and easily eroded, a slow velocity is best. On the 
 other hand, the velocity must be sufficiently rapid to prevent the 
 deposition of silt and the growth of water plants. In ordinary soils, 
 a grade of 2^ inches to 100 feet for a ditch carrying 2 cubic feet 
 per second is not far out of the way. The amount of water to be 
 carried varies from J to 2 or more cubic feet per second. A 
 ditch having a bottom width of 24 inches, a depth of G inches, and 
 sloping sides, ought to carry 1^ cubic feet per second on a grade of 
 
 Fig. 8.—The use of the “A” scraper in building head ditches. 
 
 half an inch to the rod or 3 inches to 100 feet. Such a ditch may 
 be built by first plowing four furrows and then removing the loose 
 earth either with shovels or a narrow scraper. The loose earth may 
 likewise be thrown up on the sides and top b}^ means of the home¬ 
 made implement shown in figure 8. Canvas dams, metal tappoons, 
 or other similar devices are inserted in the head ditch to raise the 
 surface of the water opposite that part of the orchard where furrows 
 have been made and which is about to be watered. The chief diffi¬ 
 culty in this mode of furrow irrigation arises in withdrawing water 
 from the ditch and in distributing it equally among a large number 
 of furrows. A skilled irrigator may adjust the size and depth of 
 the ditch bank openings so as to secure a somewhat uniform flow in 
 the furrows, but constant attention is required in order to maintain it. 
 
 404 
 
14 
 
 IRRIGATION OF ORCHARDS. 
 
 If the water is permitted to flow for a short time unattended the dis¬ 
 tribution is likely to become unequal. Parts of the ditch bank 
 become soft, and, as the water rushes through, the earth is washed 
 away, permitting larger discharges and lowering the general level 
 of the water in the ditch so that other openings may have no dis¬ 
 charge. Some of the orchardists of San Diego County, Cal., insert in 
 niches cut in the bank pieces of old grain sacks or tent cloth. The 
 water flows over these without eroding the earth. Another device is 
 to use a board pointed at the lower end and containing a narrow 
 opening or slot through which the water passes to the furrow. Shin¬ 
 gles are also used to regulate the flow in the furrows. The thin ends 
 of these are stuck into the ground at the heads of furrows. 
 
 Short Tubes in Head Ditches. 
 
 In recent years short tubes or spouts have been used in many of 
 the head ditches of orchards to divert small quantities of water to 
 
 furrows. These tubes are usually 
 made of wood, but pipes made of 
 clay, black iron, galvanized iron, 
 and tin are occasionally used. 
 
 For nurseries and young trees 
 especially, and also for mature 
 trees, a cheap and serviceable 
 tube may be made from pine 
 lath, such as are used for plaster- 
 The 4-foot lengths are cut 
 
 Fig. 
 
 9.—Wooden box placed in bank of 
 head ditch. 
 
 mg. 
 
 into two equal parts and four of 
 these pieces are nailed together to form a tube. One of these tubes 
 when placed with its center 2 inches below the surface of the water 
 in the head ditch discharges nearly three-quarters of a miner’s inch 
 of water, and if placed 4 inches below the surface will discharge 
 more than 1 miner’s inch. In southern Idaho the lumber mills manu¬ 
 facture a special lath for this purpose. It is 4 inch thick, 2 inches 
 wide, and 36 inches long. If such tubes when thoroughly dry are 
 dipped in hot asphalt they will last a much longer time. In some 
 of the deciduous orchards of California a still larger wooden tube 
 or box is used. Figure 9 represents one of these. It is made of four 
 pieces of J by 3J inch redwood boards of the desired length. The 
 flow through this tube is regulated by a cheap gate, consisting of a 
 piece of galvanized iron fastened by means of a leather washer and 
 a wire nail. 
 
 The orchardist who lives near a manufacturing town or citv can 
 
 O r- 
 
 often purchase at a low figure pieces of worn-out and discarded 
 piping varying from f to 2 inches in diameter. Such pipes when 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 15 
 
 cut into suitable lengths make a good substitute for wooden spouts. 
 Tin tubes one-half inch in diameter and of the proper length have 
 been used with good success. In compact soils, through which water 
 passes very slowly, 
 the furrows must be 
 near together, and 
 under such condi¬ 
 tions small tin tubes 
 are to be preferred. 
 
 In making use of 
 tubes of various 
 kinds to distribute 
 water to furrows it 
 is necessary to main¬ 
 tain a constant head 
 in the supply ditch. 
 
 This is done by in¬ 
 serting checks at 
 regular distances. 
 
 These distances vary 
 with the grade of 
 the ditch, but 150 feet is not far from being an average spacing. 
 In temporary ditches the canvas dam is perhaps the best check, but 
 in permanent ditches it pays to use wood or concrete. An effective 
 wooden check is shown in figure 10. In this the opening is con¬ 
 trolled by a dashboard 
 which may be adjusted so 
 as to hold the water at 
 any desired height and 
 at the same time permit 
 the surplus to flow over 
 the top to feed the next 
 lower set of furrows. 
 
 Head Flumes. 
 Formerly head flumes 
 
 for orchards were built 
 of wood, but the steady 
 increase in the price of 
 lumber and the decrease 
 in the price of Portland 
 
 cement have induced many fruit growers to use cement in tt.A 
 When built of wood, the length of the sections varies from 1- 
 20 feet, 16 feet being the most common. The bottom width nm* 
 
 404 
 
 Fig. 11. 
 
 -Section of wooden head flume, showing 
 opening and gate. 
 
16 
 
 IRRIGATION OF ORCHARDS. 
 
 from 6 to 12 inches, while the depth is usually 1 to 2 inches less. 
 Redwood lumber If inches thick is perhaps the best for the bottom 
 and sides, and joists of 2 by 4 inch pine or fir are commonly used for 
 yokes which are spaced 4 feet centers. Midway between the yokes 
 auger holes are bored and the flow through these openings is con¬ 
 trolled in the manner shown in figures 11 and 12. A 2-inch fall 
 for each hundred feet may be regarded as a suitable grade for head 
 flumes, but it often happens that the slope of the land is much greater 
 than this, in which case low checks are placed in the bottom of the 
 flume at each opening, as shown in figure 12. 
 
 A head flume composed of cement, sand, and gravel costs as a rule 
 about twice as much as a wooden flume of the same capacity, but the 
 early decay of wood, especially if it comes in contact with earth, makes 
 the cement flume cheaper in the end. By means of a specially de¬ 
 signed machine, which is patented, cement mortar composed of one 
 
 part cement to about six 
 parts of coarse sand is fed 
 into a hopper and forced 
 by lever pressure into a set 
 of guide plates of the form 
 of the flume. Such flumes 
 are made in place in one 
 continuous line across the 
 upper margin of the or¬ 
 chard tract. After the 
 flume is built and before 
 the mortar has become 
 hard, small tubes from f 
 
 Fig. 12.—The use of low check in head flume. . , . ,. 
 
 to 14 inches m diameter, 
 the size depending somewhat on the size of the flume, are inserted 
 in the side next the orchard. The flow through these tubes is 
 regulated by zinc slides shown in figure 12. Flumes of this kind 
 are made in five sizes, the smallest being G inches on the bottom in 
 the clear and the largest 14 inches. 
 
 At a slightly greater cost a stronger flume can be built by the use 
 of molds. The increased strength is derived from a change in the 
 mixture. In the machine-made flume the mixture of one part cement 
 to five or six parts of sand is lacking in strength, for the reason 
 that there is not enough cement to fill all the open spaces in the sand. 
 In using molds medium-sized gravel can be added to the sand 
 and the mixture resembles that of the common rich concrete. Sucli 
 flumes can be built of almost any size from a bottom width of 10> 
 inches to one of 40 inches and from a depth of 8 inches to one of 24 
 inches, but when the section is increased beyond about 240 square 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 17 
 
 inches it pays better to slope the sides outward and adopt the form 
 of the cement-lined ditch. At present (March, 1910) the cost of 
 rich concrete in place would be about $9 per cubic yard for the larger 
 
 Fig. 13.—Common sizes of concrete head flumes. 
 
 flumes and $10.50 for the smaller sizes. The quantity of concrete 
 required per linear foot of flume depends on its size and the thickness 
 of its sides and bottom. The dimensions given in figure 13 are for 
 light rather than for heavy 
 flumes and are designed for 
 localities where there is little 
 frost. 
 
 For large head flumes and 
 laterals, many fruit growers 
 first carefully prepare an 
 earthen ditch which has car¬ 
 ried water for at least one 
 season and afterwards line 
 the inner surface with cement concrete. Figure 14 shows a section 
 of such a ditch. 
 
 Several years ago 3,200 linear feet of head ditches were lined for 
 26^ cents per foot; they were 14 inches on the bottom with 18-inch 
 sides and a 2-inch lining. The cement cost $2.85 per barrel, gravel 
 75 cents per yard, and labor $1.75 to $2.50 per day. 
 
 Pipes and Standpipes. 
 
 Head flumes, being placed on the surface of the ground, interfere 
 with the free passage of teams in cultivating, irrigating, and harvest¬ 
 ing the crop. Dead leaves from shade and fruit trees also clog the 
 small openings in the flumes. These and other objections to flumes 
 have induced many fruit growers of southern California to conve} 
 the water in underground pipes and distribute it through standpipes 
 placed at the heads of the rows of trees. Both cement and clay pipes 
 are used for this purpose. 
 
 Fig. 14.—Earthen head ditch lined with concrete. 
 
 41647—Bull. 404—10 
 
 3 
 
18 
 
 IRRIGATION OF ORCHARDS. 
 
 The former are usually molded in 2-foot lengths, with beveled lap 
 joints, and consist of a 1 to 3 or 1 to 4 mixture of cement and 
 
 fine gravel and sand. 
 The most common 
 
 Turnout Stand _ . 
 
 Private Lotero/ ___ sizes are (*), 8, 10, and 
 
 Weir 
 Box X 
 
 £ 
 
 Ss 
 
 ok 
 
 tin 
 
 <c£ 
 
 M 
 
 w . m 
 
 M M M 
 
 Overf/ow 
 
 Stand 
 
 m 
 
 jw 
 
 m 
 
 ,3 
 
 "m 
 
 
 
 iii 
 
 Overf/ow 
 
 Stand 
 
 m 
 
 Fig. 15.—The use of pipes in furrow irrigation. 
 
 12 inches in diam- 
 —- eter, having a thick- 
 
 — ness of shell in the 
 
 — 12-inch pipe of 1^ 
 
 — inches which is re- 
 
 — duced to a trifle more 
 
 — than 1 inch in the 
 6-inch pipe. Piping 
 
 — of this kind, when 
 well made and care- 
 
 — fully laid, will with- 
 
 — stand a head of 10 
 
 — to 16 feet. The clay 
 
 — pipe is similar to 
 
 — that used in cities for 
 
 — sewers and, having 
 stronger joints, with¬ 
 stands a greater pres¬ 
 sure but costs more. 
 
 A line of pipe is laid about 2 feet below the surface from the feed 
 main and measuring box across 
 the top of the orchard, and as each 
 row of trees is passed a stand¬ 
 pipe is inserted. The general plan 
 is shown in outline in figure 15. 
 
 Various devices are employed to 
 convey the water from the pipe to 
 the surface of the ground at the 
 head of each tree row and divide 
 it up evenly among 4 to 6 furrows. 
 
 One of the most common consists 
 of a series of standpipes, the top 
 of each set rising to the same 
 elevation. At each change of ele- 
 vation special standpipes are used 
 and in these are inserted gates pro¬ 
 vided with overflows. The man¬ 
 ner of distributing the water from 
 a standpipe to the furrows of any one row is shown in figure 16. 
 
 404 
 
 Fig. 16.—Section of standpipe outlined 
 in figure 15. 
 
IRRIGATION OF ORCHARDS. 19 
 
 Occasionally a high-pressure pipe is substituted for cement and 
 clay. This is tapped at the head and in line with each row of trees, 
 and a small galvanized-iron pipe is inserted. These standpipes are 
 capped by an ordinary valve which regulates the flow to each row 
 of trees. This method is shown in operation in figure 17, where a 
 young orchard is being irrigated from f-inch galvanized-iron stand¬ 
 pipes connected to a 3-inch wooden pipe. 
 
 Making’ Furrows. 
 
 The length of the furrow is often governed by the size of the 
 orchard. The rows of citrus trees seldom exceed 40 rods in length, 
 
 o 7 
 
 Fig. 17.—Method of irrigating from iron standpipes connected with pressure pipes. 
 
 but the apple orchards of the Northwest are larger as a rule. Even 
 in large tracts it is doubtful if it ever pays to run water in furrovs 
 more than about 600 feet. Where the soil is open and water sinks 
 readily through it, short furrows should be used, otherwise much 
 water is lost in deep percolation on the upper part of the tract. 1 i of. 
 H. Culbertson, of San Diego County, Cal., after a careful investiga- 
 tion of this subject has reached the conclusion that on sand\ oi 
 gravellv soil having a steep slope the proper length of funovs is 
 200 feet, while on heavier soils and flatter slopes the length may Ini 
 
 increased to 600 feet. . . 
 
 The grade of furrows varies quite widely. In flat valleys it is 
 
 often not possible to obtain a fall greater than 1 inch to i t 
 feet, while on steep slopes the fall may reach 20 inches per 100 feet. 
 
 404 
 
20 
 
 IRRIGATION OF ORCHARDS. 
 
 Oil ordinary soils a grade of 3 to 4 inches is to be preferred, and where 
 the fall exceeds 8 to 10 inches to 100 feet the trees should be set out 
 in such a way as to decrease the slope of the furrows. 
 
 The number of furrows in orchards depends on the age of the 
 trees, the space between the rows, the depth of furrow, and the 
 character of the soil. Nursery stock is irrigated by one or two fur¬ 
 rows and young trees by two to four. A common spacing for shal¬ 
 low furrows is 2J feet, while deeper furrows are made 3 to 4 feet 
 apart. The general trend of orchard practice is toward deep rather 
 than shallow furrows, a depth of 8 inches being frequently used. 
 
 Fig. 18.—Making furrows in orchard. 
 
 The furrowing implement most commonly used by the orcliardists 
 of Orange County, Cal., consists of a sulky frame to which are at¬ 
 tached two or three double moldboard plows. Those who prefer a 
 small number of deep furrows use a 12 to 14 inch corn lister. In 
 figure 18 is shown a furrower made by attaching an arm to a culti¬ 
 vator and then fastening two shovels to the arm. In the view the 
 space between the furrows is 4-J feet and the depth is regulated by the 
 lever arm of the cultivator. 
 
 Applying- Water to Furrows. 
 
 In the Payette Valley, Idaho, 200 or more miner’s inches are turned 
 into the head ditch and divided up by means of wooden spouts into 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 21 
 
 a like number of furrows. On steep ground much smaller streams are 
 used. The length of the furrow varies from 300 feet on steep slopes 
 to GOO feet and more on flat slopes. The time required to moisten the 
 soil depends on the length of the furrow and the nature of the soil. 
 In this locality it varies from 3 to 36 hours. 
 
 J. H. Foreman owns 20 acres of bearing orchard under the Sunny- 
 side Canal in the Yakima Valley, Washington, and waters it four 
 
 times in each season with 14 __ 
 
 miner’s inches (0.35 cubic 
 foot per second). He makes 
 three furrows between the 
 rows, which are 40 rods long. 
 
 
 The total supply is applied 
 to one-lialf the orchard (10 
 acres) and kept on 48 hours. 
 
 On the clayey loams of 
 the apple orchards on the 
 
 r „ . Fig. 19.—Furrow irrigation, showing dry spaces. 
 
 east bench ol the Fitter 
 
 Root River, Montana, Prof. R. W. Fisher has found, as a result 
 of experimenting, that it requires from 12 to 18 hours to moisten 
 the soil in furrow irrigation 4 feet deep and 3 feet sideways. 
 
 In 1908 Mr. Struck, of Hood River, Oregon., irrigated 3 acres of 
 apple trees in furrows 350 feet long, spaced 3 feet apart. About a 
 miner’s inch of water was turned into each alternate furrow from a 
 wooden head flume (fig. 11, p. 15) and kept on for about 48 hours. 
 After the soil had become sufficiently dry it was cultivated, and in 8 or 
 
 10 days thereafter water 
 was turned into the alter¬ 
 nate rows, which were 
 left dry during the first 
 irrigation. 
 
 For the most part, the 
 furrows are made parallel 
 to the rows of trees. An 
 arrangement of this kind 
 
 ---- is satisfactory in young 
 
 Fig. 20.— Cross furrowing the dry spaces. orchards, but as the trees 
 
 reach maturity their branches occupy more of the open space be- 
 tween the rows and prevent the making of furrows near the trees. 
 This is shown in figure 19 where a space of 6 to 12 feet square, 
 according to the size of the trees, is not furrowed. This space 
 usually becomes so dry that it is worthless as a feeding giomm 
 for roots. In order to moisten these dry spots, a larger stream is 
 often carried in the two furrows next to each low ol U<i 
 
 404 
 
22 
 
 IRRIGATION OF ORCHARDS. 
 
 surplus is led across in short furrows in the manner shown in figure 
 20. Instead of continuing straight and cross furrows, as is done in 
 figure 20, use is frequently made of diagonal furrows, figure 21, to 
 moisten the dry space between the trees. This last method is best 
 adapted to grades of 5 inches to the 100 feet or more. 
 
 A method and the cost of one irrigation is described as follows: 
 
 The implement used to make furrows consists of three shovels 
 • attached to a beam which is mounted on a pair of low wheels. The 
 
 driver sits on a riding 
 seat and by operating a 
 lever can regulate the 
 depth of the furrows. A 
 man and two horses will 
 furrow out 10 acres in a 
 day. For a distance of 
 150 feet from the top of 
 the orchard the furrows 
 are straight. They are 
 then zigzagged to within 
 60 or 70 feet of the bottom, where the last three rows of trees are 
 irrigated by basins which catch the surplus. In the case described 
 the depth of furrow was 6 inches, length 800 feet, and distance apart 
 3 feet. A head of 50 miner’s inches (1 cubic foot per second) was 
 used on 10 acres. The streams when first turned into the furrows 
 averaged about 2 miner’s inches, but as the water approached the 
 lower end they were reduced to 1 miner’s inch or less, and this flow 
 was run in each furrow for 12 to 24 hours. 
 
 The items of cost for 10 acres were as given below: 
 
 Making furrows and basins_$6. 50 
 
 Irrigating_ 3. 00 
 
 Fifty inches of water, 24 hours, at 40 cents an hour_ 9. 60 
 
 Rent of water stock_12.00 
 
 Total_31.10 
 
 THE BASIN METHOD. 
 
 Orchards are sometimes irrigated by first forming ridges midway 
 between the rows in tAvo directions at right angles to each other. This 
 divides up the tract into a large number of squares with a tree in 
 the center of each, as may be observed in figure 22. 
 
 When the ground is hard or covered with Aveeds, a disk plow is 
 first run betAveen the roAvs and then the loosened earth is formed into 
 a ridge by a riclger. If the soil is light, sandy, and free from Aveeds, 
 the disking is not necessary. Ridgers are made in various Avays of 
 both AA 7 ood and steel or some combination of both. A common kind 
 is shown in figure 23. It consists of two deep runners 14 to 18 inches 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 23 
 
 Fig. 22.—Basin method of irrigation. 
 
 high, 2 inches thick, and 6 to 8 feet long. These runners are shod 
 with steel which extends 
 
 part way up the inner side. 
 
 They are 4 to 5 feet apart 
 at the front end and ta¬ 
 pered to 1G to 24 inches at 
 the rear. The runners are 
 held in position by cross 
 pieces on top, a floor, and 
 straps of steel in the man¬ 
 ner shown. The height of 
 the ridges varies with the 
 depth of water applied, 
 which is from 4 to 9 inches. 
 
 The ridges should be sev¬ 
 eral inches above the surface of the water when a basin is flooded. 
 
 Several methods of flood¬ 
 ing basins are practiced. 
 In one a ditch is run from 
 the supply ditch at the 
 head through each alter¬ 
 nate row space and the 
 basins on each side are 
 flooded in pairs beginning 
 with the lowest. This plan 
 is shown in outline in 
 figure 22. In the other 
 method water is allowed to flow through openings into each basin 
 of a tier in a zigzag course from the 
 top to the bottom of the orchard. In 
 this plan the upper basins receive the 
 most water. Under gravity canals, 
 where water is abundant, the water is 
 turned into the upper basin until it is 
 full, when it overflows into the next, 
 and so on down the tier. The irrigator 
 then begins at the lower end and repairs 
 the breaks, leaving each basin full of 
 water. 
 
 THE CHECK METHOD. 
 
 Fig. 23.—Ridger used in basin irrigation. 
 
 4 
 
 I 
 
 V 
 
 Fig. 24.—Combination of check and 
 furrow methods. 
 
 Where this method is practiced it 
 frequently happens that land on which 
 alfalfa has been grown is planted to fruit trees. In plowing down 
 
 404 
 
24 
 
 IRRIGATION OF ORCHARDS. 
 
 the alfalfa and setting out the trees, the levees undergo little change 
 and the checks can be flooded if it is considered best. A better 
 plan is to furrow the floor of each check as shown in figure 24. The 
 water is admitted through the check box which was used for the 
 alfalfa and conducted into a short head ditch, from which it is dis¬ 
 tributed to the furrows. The chief objection to this method is that 
 the checks are too small for orchard tracts in furrow irrigation. 
 
 TIME TO IRRIGATE ORCHARDS. 
 
 The best orchardists believe that frequent examinations of the 
 stem, branches, foliage, and fruit are not enough. The roots and 
 soil should likewise be examined. The advice of such men to the 
 inexperienced is: Find out where the bulk of the feeding roots is 
 located, ascertain the nature of the soil around them, and make 
 frequent tests as to the moisture which it contains. In a citrus 
 orchard of sandy loam samples are taken at depths of about 3 feet, 
 and the moisture content determined by exposing the samples to a 
 bright sun for the greater part of a day. It is considered that G per 
 cent by weight of free water is sufficient to keep the trees in a vigorous 
 condition. 
 
 Doctor Loughridge, of the University of California, in his experi¬ 
 ments at Riverside, Cal., in June, 1905,® found an average of 3.5 per 
 cent in the upper 2 feet and an average of G.1G per cent below this * 
 level in an orchard which had not been irrigated since October of the 
 preceding year. It had received, however, a winter rainfall of about 
 1G inches. On examination it was found that the bulk of the roots 
 lay between the first and fourth foot. These trees in June seemed to 
 be merely holding their own. When irrigated July 7 they began to 
 make new growth. A few days after the water was applied the 
 percentage of free water in the upper 4 feet of soil rose to 9.G4 per 
 cent. The results of these tests seem to indicate that the percentage 
 by weight of free moisture should range between 5 and 10 per cent 
 in orchard loams. 
 
 Many fruit growers do not turn on the irrigation stream until the 
 trees begin to show visible signs of suffering, as a slight change in 
 color or a slight curling of the leaves. In thus waiting for these 
 signals of distress, both trees and fruit are liable to be injured. On 
 the other hand, the man who ignores these symptoms and pours on a 
 large quantity of water whenever he can spare it, or when his turn 
 comes, is apt to cause greater damage by an overdose of water. 
 
 404 
 
 a U. S. Dept. Agr., Office Expt. Stas. Bill. 20o. 
 
IRRIGATION OF ORCHARDS. 
 
 25 
 
 NUMBER OF IRRIGATIONS PER SEASON. 
 
 For nearly half the entire year the fruit trees of Wyoming and 
 Montana have little active, visible growth, whereas in the citrus dis¬ 
 tricts of California and Arizona the growth is continuous. A tree 
 when dormant gives off moisture, but the amount evaporated from 
 both soil and tree in winter is relatively small, owing to the low tem¬ 
 perature, the lack of foliage, and feeble growth. A heavy rain which 
 saturates the soil below the usual covering of soil mulch may take 
 the place of one artificial watering, but the light shower frequently 
 does more harm than good. The number of irrigations likewise de¬ 
 pends on the capacity of the soil to hold water. If it readily parts 
 with its moisture, light but frequent applications will produce the 
 best results, but if it holds water well a heavy application at longer 
 intervals is best, especially when loss by evaporation from the soil is 
 prevented by the use of a deep soil mulch. 
 
 In the Yakima and Wenatchee fruit-growing district of Washing¬ 
 ton the first irrigation is usually given in April or early in May. 
 Then follow three to four waterings at intervals of 20 to 30 days. At 
 Montrose, Colo., water is used three to five times in a season. At 
 Payette, Idaho, the same number of irrigations is applied, beginning 
 about June 1 in ordinary seasons and repeating the operation at 
 the end of 30-day intervals. As a rule, the orchards at Lewiston, 
 Idaho, are watered three times, beginning about June 15. From two to 
 four waterings suffice for fruit trees in the vicinity of Boulder, Colo. 
 The last irrigation is given on or before September 5, so that the new 
 wood may have a chance to mature before heavy freezes occur. In 
 the Bitter Root Valley, Montana, young trees are irrigated earlier and 
 oftener than mature trees. Trees in bearing are, as a rule, irrigated 
 about July 15, August 10, and August 20 of each year. In San Diego 
 County, Cal., citrus trees are watered six to eight times, and deciduous 
 trees three to four times in a season. 
 
 DUTY OF WATER IN ORCHARD IRRIGATION. 
 
 The duty of water for 1 acre as fixed by water contracts varies all 
 the way from one-fortieth to one four-hundredths of a cubic loot per 
 second. In general, the most water is applied in districts that require 
 the least. Wherever water is cheap and abundant the tendency seems 
 to be to use large quantities, regardless of the requirements ot the 
 fruit trees. In Wyoming the duty of water is seldom less than at the 
 rate of a cubic foot per second for TO acres. In parts oi southci n ( il- 
 ifornia the same quantity of water not infrequently serves 400 acres, 
 
 404 
 
26 
 
 IRRIGATION OF ORCHARDS. 
 
 yet the amount required by the fruit trees of the latter locality is far 
 in excess of that of the former. 
 
 In recent years the tendency all over the West is toward a more eco¬ 
 nomical use of water, and even in localities where water for irrigation 
 is still reasonably low in price it is rare that more than 2J acre-feet 
 per acre is applied in a season. This is the duty provided for in the 
 contracts of the Bitter Root Valley Irrigation Company, of Montana, 
 which has 40,000 acres of fruit lands under ditch. Since, however, 
 the water user is not entitled to receive more than one-half of an acre- 
 
 -Avcrage duty per month under Riverside Water Company, December 1, 1901, to 
 
 November 30, 1908. 
 
 foot per acre in any one calendar month, it is only when the growing 
 season is long and dry that he requires the full amount. 
 
 In the vicinity of Boulder, Colo., the continuous flow of a cubic foot 
 per second for 105 days serves about 112 acres of all kinds of crops. 
 This amount of water, if none were lost, would cover each acre to a 
 depth of 1.0 feet. In other words, the duty of water is a trifle less 
 than 2 acre-feet per acre. 
 
 In 1908, the depth of water used on a 21^-acre apple orchard at 
 Wenatchee, Wash., was measured and found to be 23 inches. The 
 trees were 7 years old and produced heavily. This orchard was 
 watered five times, the first on May 13 and the last on September 23. 
 In San Diego County, Cal., one miner’s inch (one-fiftieth of a cubic 
 
 404 
 
IRRIGATION OF ORCHARDS. 27 
 
 foot per second) irrigates from G to 7 acres near tliQ coast where the 
 air is cool and evaporation low, but 20 miles or so inland the same 
 amount of water is needed for about 4 acres. 
 
 On the sandy loam orchards of Orange County, Cal., it has been 
 demonstrated that 2 acre-inches every sixty days is insufficient to 
 keep bearing trees in good condition. The rainfall of this locality 
 averages somewhat less than 12 inches per annum, but about 95 per 
 cent of the total falls between November and May, inclusive. 
 
 The most reliable and in many ways the most valuable records 
 pertaining to duty of water on orchards have been obtained by the 
 water companies of Riverside County, Cal. Here more or less irri¬ 
 gation water is used every month of the year. Figure 25 is a graphic 
 representation of the average amount of water used per month in 
 a period of seven years by the Riverside Water Company in irri¬ 
 gating about 9,000 acres, of which nearly 6,000 acres are planted to 
 oranges and the balance to alfalfa. The figures given in the diagram 
 represent depth in feet over the surface watered. In the following 
 table is given the average duty of water per month in acre-feet per 
 acre under the same system from December 1, 1901, to November 30, 
 1908, a period of seven years. The table also includes the average 
 monthly rainfall at Riverside, Cal., for the same period, and adding 
 the quantity of water applied in irrigation in any one month to the 
 rainfall of that month gives the total moisture received by the soil. 
 
 Water used under Riverside Water Company's system {1901-1908). 
 
 Month. 
 
 Average 
 depth 
 per acre. 
 
 Average 
 
 rainfall. 
 
 Total 
 
 water 
 
 applied. 
 
 Month. 
 
 Average 
 depth 
 per acre. 
 
 Average 
 
 rainfall. 
 
 Total 
 
 water 
 
 applied. 
 
 December. 
 
 January. 
 
 February . 
 
 March. 
 
 April. 
 
 Mav. 
 
 June. 
 
 Feet. 
 
 0.159 
 
 .123 
 
 .046 
 
 .078 
 
 .177 
 
 .291 
 
 .274 
 
 Feet. 
 
 0.109 
 .170 
 .190 
 .316 
 .068 
 . 023 
 .003 
 
 Feet. 
 
 0. 268 
 .293 
 .236 
 .394 
 .245 
 .314 
 .277 
 
 July. 
 
 August. 
 
 September. 
 
 October. 
 
 November. 
 
 Total. 
 
 Feet. 
 0.272 
 . 269 
 . 243 
 .189 
 .169 
 
 Feet. 
 
 0.002 
 
 .015 
 .043 
 . 073 
 
 Feet. 
 
 0.274 
 .269 
 .258 
 . 232 
 .242 
 
 2.29 
 
 1.01 
 
 3. 30 
 
 EVAPORATION LOSSES FROM ORCHARD SOILS. 
 
 A light shower followed by warm sunshine may refresh the foliage 
 of fruit trees, but its effect on the soil is more likely to be injurious 
 than otherwise. A brief, pelting rain followed by sunshine forms a 
 crust on the surface of most soils, and if this is not soon broken up b\ 
 cultivation it checks the free circulation of air in the soil and a ho 
 tends to increase the amount of water evaporated. 
 
 It has been found a that the amount of moisture held b\ the M)il, 
 the* temperature of both soil and air, and the rate of wind motion 
 
 404 
 
 a U. S. Dept. Agi\, Office Expt. Stas. Bui. ITT. 
 
28 
 
 IRRIGATION OF ORCHARDS. 
 
 are the chief factors in the evaporation of water from soils. The 
 influence of moisture is shown in the following figures, obtained from 
 tank experiments made at Tulare, Cal., in 1904: 
 
 Evaporation from Tulare soils which received different amounts of water , June 
 
 15 to September 15, 190.[). 
 
 Numbers of tanks. 
 
 Amount 
 of water 
 applied, 
 inches. 
 
 Loss by evapora¬ 
 tion. 
 
 Inches. 
 
 Per cent. 
 
 1 and 2. 
 
 0.0 
 
 0.45 
 
 
 3 and 4. 
 
 3.3 
 
 3.5 
 
 106.0 
 
 5 and 6. 
 
 4.9 
 
 4.6 
 
 94.0 
 
 Numbers of tanks. 
 
 Amount 
 of water 
 applied, 
 inches. 
 
 Loss by evapora¬ 
 tion. 
 
 Inches. 
 
 Per cent. 
 
 7 and 8. 
 
 6.6 
 
 5.5 
 
 83.6 
 
 9 and 10. 
 
 8.2 
 
 6.6 
 
 80.0 
 
 11 and 12. 
 
 9.8 
 
 7.9 
 
 79.5 
 
 The results of other experiments have shown that when the water 
 is applied to the surface of orchard soils the loss by evaporation is 
 very great so long as the top layer remains moist. Even in light irri- 
 
 1904 1905 
 
 Fig. 26.—Relation between temperature and evaporation from a water surface at 
 
 Tulare, Cal. 
 
 gations this loss in forty-eight hours after the water is put on may 
 amount to from 10 to 20 per cent of the volume applied. In order to 
 reduce this loss and moisten the soil around the roots of trees, the 
 practice of running small streams of water in deep furrows has 
 become quite common. In applying water in this way the top soil 
 remains at least partially dry, the bulk of the water soon passes 
 beyond the first foot, and the surface can be cultivated soon after the 
 water is turned off. 
 
 The well-known effect of temperature on evaporation is shown in 
 figure 26, The dotted line shows the mean monthly temperatures 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 29 
 
 Tulare, Cal., from January 1 , 1904, to December 31, 1905. and 
 the solid line the monthly evaporation from a water surface for the 
 same time. 
 
 EFFECT OF SOIL MULCHES IN CHECKING EVAPORATION. 
 
 The effect on evaporation of a layer of dry granular soil when 
 placed above moist soil has been shown by a series of experiments 
 conducted in tanks by irrigation investigations of this Office. These 
 tanks are water-jacketed and placed in the open under normal condi¬ 
 tions as regards sunshine, wind, and temperature. Each tank holds 
 about three-fourths of a ton of soil and is weighed at stated intervals 
 in a manner shown in figure 27. The results of experiments made at 
 Davis, Cal., in 1908 are given in the following table: 
 
 Evaporation from soils protected bp different depths of soil mulch at Davis, 
 
 Cal., September 1 to October 3, 1908. a 
 
 • 
 
 No mulch, 
 tanks land 2. 
 
 3-inch mulch, 
 tanks 3 and 4. 
 
 6-inch mulch, 
 tanks 5 and 6. 
 
 9-inchmulch, 
 tanks 7 and 8. 
 
 Average weight of tanks, Sept. 1...pounds.. 
 
 1,104.7 
 
 1,090.0 
 
 1,082.0 
 
 1,085.2 
 
 
 Per ct. 
 
 Per ct. 
 
 Per ct. 
 
 Per ct. 
 
 Per ct. 
 
 Per ct. 
 
 Per ct. 
 
 Per ct. 
 
 Average loss, 3 days, Sept. 1 to 4. 
 
 Average loss, 4 days, Sept. 4 to 8. . 
 
 16.75 
 
 17.83 
 
 1.75 
 
 1.86 
 
 0.0 
 
 0.0 
 
 0.0 
 
 0.0 
 
 4.5 
 
 4.79 
 
 .75 
 
 .80 
 
 .25 
 
 .27 
 
 - .5 
 
 - .53 
 
 Average loss, 3 days, Sept. 8 to 11. 
 
 Average loss, 4 days, Sept. 11 to 15. 
 
 3.0 
 
 1.5 
 
 3.19 
 
 1. 60 
 
 2.25 
 
 2 5 
 
 2.4 
 
 2.66 
 
 .75 
 
 .80 
 
 - .25 
 
 - .27 
 
 Average loss, 18 days, Sept. 15 to Oct. 3. 
 
 8.0 
 
 8.52 
 
 7.0 
 
 7.45 
 
 4. 75 
 
 5.05 
 
 2.25 
 
 2.4 
 
 Total loss, 32 days, Sept. 1 to Oct. 3. 
 
 33.25 
 
 35. 93 
 
 14.25 
 
 15.17 
 
 5. 75 
 
 6.12 
 
 . 75 
 
 .80 
 
 a U. S. Dept. Agr., Yearbook 1908, p. 468. 
 
 The soil first received an irrigation of 0 inches in depth over the 
 surface and in the tanks which had no mulch over one-third of this 
 amount was evaporated in thirty-two days, while less than 1 per cent 
 was evaporated in the tanks which were protected by a 9-inch mulch. 
 
 Similar experiments carried on at Wenatchee, Wash., in June, 
 1908, showed the following losses in twenty-one days: No mulch, 14J 
 per cent of water applied; 3-inch mulch, 4 per cent; 6-inch mulch, 
 2 per cent; and 9-inch mulch, 1 per cent. 
 
 From the foregoing it is evident that western orchardists can pre¬ 
 vent the greater part of the evaporation losses by cultivating orchards 
 to a depth of at least 6 inches as soon as practicable after each irri¬ 
 gation. 
 
 LOSS OF WATER DUE TO PERCOLATION. 
 
 In the preceding paragraphs attention has been called to the large 
 amount of water which is vaporized from warm, moist soil-, 
 above heading calls attention to another loss of a different character. 
 404 
 
30 
 
 IRRIGATION OF ORCHARDS. 
 
 In all modes of wetting the soil, but more particularly when deep 
 furrows are used to distribute the water, a part is liable to sink 
 beyond the deepest roots. As a rule, the longer the furrow the 
 greater is the loss from this cause. In furrows about one-eighth of 
 a mile long Doctor Loughridge found in his experiments at Riverside, 
 Cal.,° that in some parts of the orchard the soil was wet as a result 
 of a recent irrigation to depths of 20 to 20 feet, while in other parts 
 the moisture had not penetrated beyond the third foot. 
 
 One of the best ways of finding out whether much water is lost 
 
 by deep percolation is to 
 dig cross trenches as deep 
 as the feeding roots go. 
 The moisture which passes 
 the deepest roots in its 
 downward course may be 
 considered wasted. 
 
 An example of fairly 
 even and desirable mois¬ 
 ture distribution from fur¬ 
 rows is shown in Sections 
 XI and XII of figure 28, 
 where the three curved 
 lines show the margins of 
 the wetted soil at the end 
 of one, two, and three 
 days, respectively. 
 
 REMOVAL OF WASTE 
 WATER. 
 
 Fig. 27.—Tank experiments at Reno, Nev., to deter¬ 
 mine effect of soil mulches in checking evaporation. 
 
 The loss of water is not 
 the only effect of deep 
 percolation. The water 
 which escapes in this and 
 other ways usually moves 
 
 through the soil at a rather slow rate of speed until it reaches some 
 underground body of water at a lower level. In case orchards have 
 been planted at these lower levels when the subsoil was dry, care 
 should be exercised in observing the rise of the ground-water level. 
 
 The small post-hole auger shown in figure 29 is one of the most con¬ 
 venient tools to use in making test wells to keep track of the behavior 
 of the ground water. Before the deepest roots of the fruit trees are 
 
 U. S. Dept. Agr., Office Expt. Stas. Bui. 203. 
 
 404 
 
Fig. 28.—Outlines of percolation under sixteen furrows in orchard 58 under the Gage Canal Company, Riverside, Cal. 
 
 IRRIGATION OF ORCHARDS 
 
 31 
 
 404 
 
32 
 
 IRRIGATION OF ORCHARDS. 
 
 submerged, artificial drainage ought to be provided. Otherwise the 
 ground water will at first lessen the yield and finally destroy the trees. 
 
 The drainage of orchard tracts usually progresses in more or less 
 distinct and separate stages. When the ground water begins to be a 
 
 menace, the natural ravines in the vicinity are 
 cleared of weeds and other rubbish and deep 
 ened. If the ground water continues to rise, 
 the open drains are deepened and extended or 
 else the excess water is withdrawn through cov¬ 
 ered drains. Open drains in orchards occupy 
 valuable land, obstruct field work, and are ex¬ 
 pensive to maintain. Some of these objections 
 can be lessened if not removed by locating 
 such drains along the lower boundary of the 
 tract. When this plan is followed, covered 
 drains are frequently laid among the trees and 
 discharge into the open drains. Sometimes the 
 source and direction of the waste water which 
 is waterlogging an orchard can be traced be¬ 
 neath the surface, In this event it is well to 
 try to intercept its passage before it reaches 
 to locate ground-water the trees. This can be done by an open drain, 
 leveL but a covered pipe drain of the required size 
 
 is preferable. Where durable lumber is cheap, box drains similar 
 to that shown in figure 30 may be used. Where lumber is high in 
 price, it will be more economical to use pipe drains made of either 
 clay or cement. The former is 
 most frequently used for sizes 
 ranging from 4 to 8 inches in 
 diameter and the latter for sizes 
 10 inches and over. The clay or 
 tile drains are made 1 foot in 
 length, but in using cement for 
 the larger sizes the length may 
 be increased to 2 and even 3 feet. 
 
 The drainage of irrigated 
 lands differs in many respects 
 from that common to the humid 
 States of Iowa, Illinois, or Ohio. 
 
 In irrigated districts the drains 
 are larger and are laid deeper. While 4-inch tile drains may be used 
 in places, 6-inch drains are to be preferred, and should be considered 
 as the smallest desirable size. The depth at which they are laid ranges 
 from 4 to T feet, and 5 to 6 feet are required for orchards. A grade 
 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 33 
 
 of 5 feet to the mile is about the least that should be used, and 
 wherever practicable it should be increased to 10 feet to the mile. 
 
 In laying drains that are likely to become clogged with silt or 
 roots, or both, a small cable is laid in each line, and at distances of 
 300 to 500 feet sand boxes similar to figure 31 are placed so as to 
 facilitate cleaning the tiles with suitable wire brushes. 
 
 GROWING CROPS BETWEEN THE TREE ROWS. 
 
 OTOW 
 
 The large majority of California fruit growers do not o 
 marketable crops between the trees. They believe in clean culture, 
 except where legumi¬ 
 
 nous crops are used to 
 renovate and fertilize 
 the soil. From the 
 standpoint of the large 
 commercial orchard 
 and the well to-do pro¬ 
 prietor, this practice 
 has much to recom¬ 
 mend it. The plant¬ 
 ing of such an orchard 
 is regarded as a long¬ 
 time investment. Lit¬ 
 tle if any returns are 
 expected for the first 
 few years, but when 
 the trees approach ma¬ 
 turity and are in full 
 bearing the anticipated 
 profits are supposed to 
 compensate the owner 
 
 for all the lean years. Any treatment, therefore, which tends to 
 rob the soil of its plant food when the trees are young or to retard 
 their growth is pretty certain to lessen the yields and the consequent 
 profits in later years. Prof. E. J. Wickson, director of the Cali oiiiia 
 Experiment Station, tersely expressed the prevailing opinion on t 
 question in California in his work, “California Fruits and How to 
 Grow Them,” in the following language: “All intercultures are a 
 loan made by the trees to the orchardist. The term may be long and 
 the rate of interest low, but sooner or later the trees, will need res i 
 tution to the soil of the plant food removed by intercropping 
 
 Mr. S. W. McCulloch, who controls 150 acres of cdri^ondnirdsm 
 
 southern California, goes further in stating.. is a <}» 
 
 404 
 
34 
 
 IRRIGATION OF ORCHARDS. 
 
 mental to the development of an orchard to grow crops between the 
 trees. In some cases the effect is not marked aside from securing less 
 rapid growth, but it will affect the crops of fruit for several years 
 and in the end nothing will be gained.’’ 
 
 Notwithstanding all this, the poor man must needs make the loan 
 or his children mav starve. The settler on a small tract set out to 
 young trees can not afford, if his means are limited, to wait four or 
 five years for the first returns. He must produce crops between the 
 rows, and the question for him to consider is how this can be done 
 with the least possible injury to the trees. A plentiful supply of 
 water and a deep rich soil are the essentials of intercropping. In 
 districts that depend on a meager rainfall of 15 to 20 inches per 
 annum, or where irrigation water is both scarce and costly, the prac¬ 
 tice becomes of doubtful value under an}^ circumstances. In most 
 of the fruit districts of the West water for irrigation is still reason¬ 
 ably low in price, and the extra amount required for intercropping 
 represents but a small part of the net gains from such crops. 
 
 Shallow-rooted plants are considered the most desirable for this 
 purpose. Squash, melons, sweet potatoes, tomatoes, and peanuts are 
 the most common in California. The cultivation is done with one 
 horse and a small cultivator. A clear space 3 to 4 feet wide is left 
 on each side of the young trees. In the Verde River Valley of 
 Arizona, strawberries, lettuce, onions, and melons are raised in the 
 young orchards. In parts of Idaho, alfalfa fields are frequently 
 plowed under to plant trees. When this is done, berries, beans, 
 melons, onions, and tomatoes can be grown between the rows for 
 several years without any apparent injury to young trees. In north¬ 
 ern Colorado, raspberries, gooseberries, currants, as well as corn, 
 beans, and peas are often planted in orchards, while in southwestern 
 Kansas it is usually cabbage, melons, and sweet potatoes. 
 
 In the young apple orchards of Hood River Valley, Oregon, straw¬ 
 berries are frequently planted between the rows. The manner in 
 which this is done, as well as the system of contour planting which 
 is there practiced, is shown in figure 32. The manager of a large 
 apple orchard company in Montana states that no appreciable effect 
 is noticed on apple trees as a result of growing potatoes, cabbage, 
 beans, onions, and other vegetables between the trees providing the 
 intercrops are well cultivated and irrigated. In the fruit districts 
 of Washington, intercropping is a common practice. In 1907 a fruit 
 grower raised on 10 acres of two-year-old trees cantaloups, tomatoes, 
 peppers, cucumbers, corn, radishes, beans, peas, potatoes, and turnips, 
 all of which netted him $2,086.50, or an average of $208.65 an acre. 
 
 While opinions differ regarding the wisdom of growing such crops 
 as have been named between the tree rows, most fruit growers are 
 404 
 
IRRIGATION OF ORCHARDS. 
 
 35 
 
 cr 
 
 convinced of the beneficial effects of cover crops. Notwithstanding 
 the scarcity and high value of water in the Riverside citrus district, 
 the superintendent of a large fruit company has for years grown peas 
 and vetch in the orange and lemon orchards under his management 
 and advocates the free use of irrigation water to supplement the 
 winter rains for the rapid and vigorous growth of such crops. In 
 the walnut groves of Orange County, Cal., bur clover is sown in the 
 fall, given one or two irrigations during the winter if the rainfall is 
 below the normal, and plowed under in April. 
 
 The cost of such cover crops as peas, vetch, or clover includes the 
 seed, the labor of sowing it, the water, and the time required to apply 
 
 Fig. 32.—Orchard showing strawberries between rows of trees. 
 
 it. These items, according to Dr. S. S. Twombly, of Fullerton, Cal., 
 amount to from $2.50 to $3.25 per acre. Twenty tons per acre of 
 green material is perhaps an average crop. In this tonnage there 
 would be about 100 pounds of nitrogen, which at 20 cents per pound 
 represents a value of $32 per acre for a cover crop like vetch. 
 
 Other beneficial effects of cover crops are quite fully summarized 
 by Prof. W. S. Thornber, horticulturist of the Washington Agricul¬ 
 tural Experiment Station.® 
 
 Washington Sta. Top. Bui. S. 
 
 404 
 
36 
 
 IRRIGATION OF ORCHARDS. 
 
 WINTER IRRIGATION OF ORCHARDS. 
 
 When water is used outside of the regular irrigation period or, 
 what is in many cases equivalent, outside of the growing season, it is 
 termed winter irrigation. Over a large part of the arid region the 
 growing season is limited by low temperatures to 150 days, or less, 
 and when the flow of streams is utilized only during this period much 
 valuable water runs to w T aste. 
 
 It was for the purpose of utilizing some of this waste that the 
 orchardists of the Pacific coast States and Arizona began the practice 
 of winter irrigation. The precipitation usually occurs in winter in 
 the form of rain, and large quantities of creek water are then avail¬ 
 able. This water is spread over the orchards in January, February, 
 and March, when deciduous trees are dormant. The most favorable 
 conditions for this practice are a mild winter climate; a deep, reten¬ 
 tive soil which will hold the greater part of the water applied; deep- 
 rooted trees; and a soil moist from frequent rains. 
 
 The creek water which was applied to some of the prune orchards 
 of the Santa Clara Valley, California, during the winter of 1904. was 
 measured by the agents of this Office with the following results: 
 From February 27 to April 23, 1,241 acres were irrigated under the 
 Statler ditch to an average depth of 1.58 feet. From February 12 to 
 April 23, 2,021 acres were irrigated under the Sorosis and Calkins 
 ditches to an average depth of 1.75 feet. In the majority of cases the* 
 orchards which are irrigated in winter in this valley receive no addi¬ 
 tional supply of moisture other than about 1G inches of rain water. 
 
 In the colder parts of the arid region winter irrigation is likewise 
 being practiced with satisfactory results. The purpose is not only to 
 store water in the soil but to prevent the winterkilling of trees. Ex¬ 
 perience has shown that it is not best to apply much water to orchards 
 during the latter part of the growing season, since it tends to produce 
 immature growth which is easily damaged by frost. In many of the 
 orchards of Montana no water is applied in summer irrigation after 
 August 20. Owing, however, to the prevalence of warm chinook 
 winds, which not only melt the snow in a night, but rob the exposed 
 soil of much of its moisture, one or two irrigations are frequently nec- 
 essarv in midwinter. 
 
 [A list giving the titles of all Farmers’ Bulletins available for distribution 
 will be sent free upon application to any Member of Congress or the Secretary 
 of Agriculture.] 
 
 404 
 
 o