, Oct. 1906.] 



323 



MISCELLANEOUS. 



Notes on Methods of Irrigation in Arizona. II. 



By J. H. W. Park. 

 The object of the whole method of irrigation is to get as much water to pass 

 through the plants as possible, and to let as little of it as possible escape by seepage 

 and evaporation. The distribution of the water through the furrows only, and not 

 over the surface of the land, and the cultivation of the soil close the latter means of 

 escape, and it is assumed that the water so caught in the soil is retained there to be 

 extracted by the plants as they require it. 



There does not appear to be much doubt of the efficiency of the 

 method. The retention of the water in the soil is shown by the following 

 table taken from a report by the Professor of Agriculture in the University 

 of Arizona, which gives the percentage of water present in the upper five 

 feet of the soil of two fields eighty days after irrigation, the surface of one field 

 having been cultivated and the surface of the other having been left to dry without 



Cultivated. Uncultivated. 



7%3 ... 3-8 



126 ... 8-1 



15-6 ... 10-5 



15-0 ... 11-6 



121 ... 11-7 



62-6 45-7 



In this case the cultivated portion contained some thirty-three per cent 

 more water than the uncultivated portion, or roughly some two and one-half inches 

 of water over the whole area, and when it is remembered that the whole of the 

 moisture stored in the soil is not available for the support of plants, the advantages 

 of cultivation in retaining water in the soil which is so available becomes very 

 evident. 



As noted in the case given above a particular farmer received water for 2k 

 days out of every eleven. It must not, however, be supposed that he watered the 

 whole of his crops once every eleven days ; on the contrary he turned the supply to 

 a portion of his crops only, and the remainder went without water for a mucn longer 

 period, although the length of the period depended upon the nature of the crops. 



Crops Raised.— The whole method of irrigation may be illustrated by the 

 following notes on some of the different kinds of crops raised and on the irrigation 

 of them. 



-Egyptian Cotton.— Seven-tenths of a foot of water applied to land before 

 planting, planted in rows with furrows three feet apart, irrigated thirteen times 

 in 186 days with a total depth of water of five feet. Yield 400 lbs, per acre. 



Melons.— Seven-tenths of a foot of water applied before planting. Planted 

 in rows on the edge of the furrows which were eight feet apart, so that the roots 

 are watered from the furrows and the plants grow on the ground between them. 

 Irrigated twelve times in 114 days, total depth of water used 3*3 feet. Yield 27,000 lbs, 

 per acre. 



Wheat. — Sixth-tenths of a foot of water applied before planting. Seed sown 

 broadcast and the field furrowed two feet apart, the soil from the furrows being 

 turned over on the seed-forming plots of about 15 inches wide. No irrigation is 



First foot, moisture % 

 Second ,, ,, 

 Third „ 

 Fourth ,, ,, 

 Fifth „ 



Total 



