THE DUTY OF WATER. 



It is safe to say that, at the present time, there is absolutely no 

 standard or basis for accurately estimating the "duty of water." So many 

 conditions are to be taken into consideration in determining how much 

 water may or may not be needed for any given crop, and so little thought 

 has, until quite recently, been devoted to the matter of economizing water, 

 that little data that is at all reliable can be given. Broad generalization, 

 bordering closely on to "guess work," has been the rule. That there are 

 difficulties in the way of arriving at accurate conclusions in these investi- 

 gations, must be seen at a glance. Local conditions, character of the soils, 

 slope of the land, cultivation, humidity, evaporation, precipitation, drain- 

 age and capillary action, are so widely at variance in different localities, 

 that there is small hope of getting any formula that will admit of extended 

 application. Then, too, the demands of plant life are variable. 



As no two trees are precisely alike, so it follows that their require- 

 ments may not be the same in all respects. Again, the products of different 

 latitudes, even of the same varieties, are influenced by local surroundings. 

 The plant that requires a gallon of water a day in one locality might 

 demand more or less in another. The tree that would drink up five 

 hundred gallons of water per day in Colorado, might be easily satisfied 

 with half that quantity in Illinois. 



It would be quite as logical to say that the dweller in the " Land of the 

 midnight sun " should have the same food regimen as the dusky being on 

 the burning sands of the equator, as to assert that products of the vegetable 

 life should have the same treatment the world over. The best, then, that 

 can be done in efforts to formulate conclusions on the duty of water, is to 

 say that, given certain specified conditions, approximate requirements 

 would be the same. 



The author of "Man and Nature" says that, "as near as can be 

 ascertained, the amount of water applied to irrigated lands is scarcely 

 anywhere less than the total precipitation during the season of vegetable 

 growth, and in general it much exceeds that quantity." 



