The Use Of Irrigation For 

 Different Crops 



E. J. WICKSON, Protessar of Agricultural Practice ia the University of California. 





F ONE could prepare plain sched- 

 ules of the amounts of water to 

 use for different crops with the 

 dates at which the water should 

 be applied, and could make such 

 a schedule in all respects con- 

 ducive to the highest success 

 with all of the plants specified, 

 the service would be worth more 

 to the country than the thirty odd 

 millions of dollars which are now lying in the 

 treasury at Washington awaiting expenditure in 

 irrigation development. But no one can ever 

 perform such a valuable service; in fact, no one 

 can ever make out such a schedule for a single 

 one of the numerous crops which are grown by 

 irrigation which would be more trustworthy than 

 was the old "farmers' almanac," as a weather 

 prophet. It is a wise man who knows just when 

 to use water and just how much to use for the 

 best growth of the crops on his own farm. It is 

 beyond human wisdom to prescribe times and 

 amounts for all crops in all places. This proposi- 

 tion should be generally understood, for it 

 is fundamental in irrigation practice and 

 the following truths are involved in it: 

 (a) Different plants require different 

 imounts of water and the same plant 

 may require different amounts of water 

 at different times in the growing season. 



(b) Different soils require different amounts 

 of water to produce satisfactory growth of 

 plants. 



(c) Different local climates, chiefly because 

 of the different degrees of thirst in the air, require 

 different amounts of water and different inter- 

 vals between applications, for the same crop. 



It appears, then that the irrigator must know 

 the needs of his plants, the water-capacity of his 

 soil and the rate of use by the plant as well as 

 the rate of waste at different times of the year. 

 It would be exceedingly hard to express any of 

 these mathematically and with such variable 

 conditions the most accurate expression of that 

 kind would have very narrow application. Fortu- 

 nately, however, the plant itself is an unerring 

 revelator and gives signs of thrift, content, pro- 

 ductive ability, or the reverse of these, as the 

 case may be, and these are the signs which the 

 irrigator must learn to recognize, for they con- 

 vey the deepest meaning to the intelligent ob- 

 server. Do not look, then, for easy recipes for 

 irrigation. Receive suggestions from the methods 



