THE IRRIGATION AGE. 



643 



Irrigation of Orchards 



BY SAMUEL FORTIER 



Chief of Irrigation Investigations, Office of Experiment 

 Stations, U. S. Department of Agriculture 



Applying Water to Furrows. 



In the Payette Valley, Idaho, 200 or more miners' 

 inches are turned into the head ditch and divided up by 

 means of wooden spouts into 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 600 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 Sunnyside Canal in the Yakima Valley,- Washington, 

 and waters it four times in each season with 14 miners' 

 inches (0.35 cubic foot per second). He makes three fur- 

 rows between the rows, which are 40 rods long. The total 

 supply is applied to one-half the orchard (10 acres) and 

 kept on 48 hours. 



On the clayey loams of the apple orchards on the 

 east branch of the Bitter 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 fur- 

 row 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 miners' inch o"f water was turned 

 into each alternate furrow from a wooden head flume 

 and kept on for about 48 hours. After the soil had become 

 sufficiently dry it was cultivated, and in 8 or 10 days there- 

 after water was turned into the alternate 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 satis- 

 factory in young orchards, but as the trees reach maturity 

 their branches occupy more of the open space between 

 the rows and prevent the making of furrows near the 

 trees. This is easily accomplished 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 ground for roots. In order to 

 moisten these dry spots a larger stream is often carried 

 in the two furrows next to each row of trees ar.cl the 

 surplus led across in short furrows, thus supplying water 

 to the dry spots. Instead of continuing straight and cross 

 furrows, as is sometimes done, use is frequently made 

 of the diagonal zig zag furrows, 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. 



1 



Fig. 22. Basin Method of Irrigation. 



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 

 furrows are straight. They are then zigzagged to 

 within 00 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 fiow 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 two directions at right 

 angles to each other. This divides up the tract into a 



Fig. 23. Ridger Used in Basin Irrigation. 



large number of squares with a tree in the center of each, 

 as maye be observed in Figure 22. 



When the ground is hard or covered with weeds, a 

 disk plow is first run between the rows and then the 

 loosened earth is formed into a ridge by a ridger. If the 

 soil is light, sandy and free from weeds, the disking is not neces- 

 sary. Ridgers are made in various ways of both wood 

 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 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 tapered to 16 to 24 inches at the rear. The run- 

 ners are held in position by cross pieces on top, a floor, 

 jind straps of steel in the manner shown. The height of 

 The ridges varies with the depth of water applied, which 

 is from 4 to 9 inches. The ridges should be several inches 

 above the surface of the water when a basin is flooded. 



Several methods of flooding basins are practiced. In 

 one a ditch is run from the supply ditch at the head 

 through each alternate 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 abun- 

 dant, 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. 



Where this method is practiced it frequently happens 

 that land on which alfalfa has been grown is planted to 

 fruit trees. In plowing down the alfalfa and setting out 

 the trees, the levees undergo little change and the checks 



