61 



a very heavy crop that year, another in 1909 and another last year. The 

 orchard is one of the best cared for as well as one of the best producers of 

 the Wenatchee district. The irrigation was done with more than ordinary 

 care and intelligence. But the soil texture is rather coarse and the water 

 holding capacity low, thus favorable to^Jarge percolation losses in the sub- 

 soil. Undoubtedly a considerable saving in water would have been pos- 

 sible had the furrows used been only 330 feet long instead of twice that 

 length." 



"Another Wenatchee orchard of 50 acres, including apples, peaches and 

 other fruits, used 16 inches in 1908 and 17.5 inches in 1910. The soil here 

 was somewhat heavier than in the former case, but the furrows used were 

 twice as long and besides the run off was considerable. Part of the orch- 

 ard, however, was not in bearing and none of it so uniformly good as the 

 other example cited. The annual precipitation at Wenatchee is about 6 

 to 8 inches and comes late in the fall, winter and early spring." 



"The records of one of the Spokane valley companies show that on that 

 system a depth of 14.7 inches was applied in 1905, 19.2 inches in 1906, 

 22.8 inches in 1907 and 17 inches in 1910. The annual precipitation at 

 Spokane is about 18 inches of which less than a fourth occurs during the 

 irrigation season." 



In the Bitter Root Valley of Montana, measurements were made on a 

 40 acre tract of orchard trees. The tpp soil was a vegetable loam under- 

 laid by a gravel and small cobbles subsoil. In 1900 the 5 year old orchard 

 was irrigated in April, June, July and August. The total depth applied in 

 the four irrigations was about 18 inches and the rainfall during the irri- 

 gation season was 1^ inches. In 1901 the 6 year old orchard received 

 four irrigations and the total depth applied was 18.7 inches; the rainfall 

 during the season was 5.9 inches. In 1902 the orchard received 21 inches 

 of irrigation water and the rainfall for the season was 8 inches. 



These measurements and others made by the U. S. Department of Agri- 

 culture are assembled in the following table. 



Xet Duty of Water for Orchards. 



Acre a... Year. 



This table shows that from 1.23 to 2.25 acre feet per acre were used on 

 these orchards, with an average of 1.62 acre feet per acre or a depth of 

 about 19% inches. This is equivalent to a net duty of 1 cubic foot per 

 second for 148 acres during an irrigation season of 4 months. Expressed 

 in British Columbia miners' inches, it would be 1 miners' inch to a little 

 over 4 acres. 



Professor Portier, Chief of Irrigation Investigations for the U. S. De- 

 partment of Agriculture, makes the following statement in Farmers' Bul- 

 letin 404, Irrigation of Orchards: 



