584 EXPEEIMENT STATION EECOED. 



water requirements. Grains and cultivated crops in general require less irriga- 

 tion water tlian the other common crops of south Idaho. . . . Grains require 

 the largest amount of water at the flowering or soft-dough stages. . . . Alfalfa 

 has a decided tendency to increase in yield as the amount applied is increased 

 until at least as much as 4 acre-feet per acre have been applied. While some 

 crops increase in yield as the amount of water applied is increased, the increase 

 in yield is rarely proportional to the increase required in the amount of water. 

 The average waste from grain fields has been 35.3 per cent and 19.1 per cent from 

 alfalfa. . . . The average length of the irrigation season for alfalfa for the 

 four years of the investigation was 97.6 days, and 42.5 days for grain. . . . 



" Sufficient water for the production of profitable and nearly maximum crops 

 must be delivered to the individuals in order that a project may be successful, 

 but a higher duty is justified in cases where water is very valuable and land 

 comparatively cheap than where water is cheap and the land is valuable. . . . 



" Ninety per cent of a normal Idaho project is irrigated each year. The total 

 waste and unirrigated areas seldom equal 10 per cent. Where rotation systems 

 are used the interval between rotations should seldom exceed from ten to four- 

 teen days. 



"There are now at least 163 electrically operated pumping plants in the 

 vicinity of Weiser and Payette. The plants tested during 1913 pumped varying 

 amounts of water, the amounts pumped per acre ranging from 0.4 to 5.99 acre- 

 feet. The costs of the power for pumping varied from 54 cts. per acre-foot to 

 $6.50, and per acre irrigated from $1.77 to $7. There is not sufficient incentive 

 to save water where a flat season rate is paid for power. The investigation 

 indicates that the cost of lifting water over 100 ft. with small plants is at pres- 

 ent prohibitive. Serious loss and waste of power is now talking place in many 

 instances due to faulty design and cheap, careless installation of the plants. 

 Small and medium-sized plants should develop efficiencies of at least 50 per cent, 

 and only such plants as can be guarantied to do this or better should be 

 Installed. 



" Successful irrigation in Idaho under present economic conditions demands 

 that at least 2 acre-feet per acre be supplied for, and retained upon, each 

 irrigated acre." 



Irrigation works in Italy, L. Luiggi {Jo%ir. Dept. Agr. Yictoria, 12 {Wilt), 

 No. 10, pp. 577-600, figs. 11; ads. in Internat. Inst. Agr. [Rome], Mo. Bui. Agr. 

 Intel, and Plant Diseases, 6 {1915), No. 1, pp. 43-45; Jour. Roy. Soc. Arts, 62 

 {1914), No. 8228, pp. 94O-943). — This article reviews the irrigation situation in 

 Italy, with particular reference to the storage, distribution, and economic use 

 of irrigation water. 



About 3,458,000 acres of land are under irrigation, derived from wells, 

 streams, and stored rain water. Where land can be superirrigated, it is stated 

 that about 2S4.210 to 355,263 cu. ft. of water are required per acre, at a cost 

 of about $1.50 to $3.50. The water is applied in rotations every 15 to 20 days 

 at the rate of from 11,368 to 14,210 cu. ft. per acre. Water is applied at the 

 rate of about 213,158 cu. ft. per acre to irrigated meadows. In the Eoman Cam- 

 pagna where the land is less permeable than in Lombardy the water neces- 

 sary during the dry season for irrigated meadows varies from about 245.000 

 to 350,000 cu. ft. per acre, and is applied at the rate of about 17,500 to 21,000 

 eii. ft. every 10 to 12 days. In the southern Provinces which receive 7 to 8 in. 

 of rain during the growing season between March 15 and May 15 it is stated 

 that irrigation water may be profitably applied at the rate of about 28,000 to 

 35,000 cu. ft. per acre in four irrigations. 



The conclusion based on Italian experience is that irrigation prevents a 

 complete loss of the crops in years of drought. " In normal years it affords a 



