248 THE LURE OF THE LAND 



other words, a pound of maize, grain, blade and stalk 

 in natural proportions, would require about 333 pounds 

 of soil for its production. We would hardly think in 

 looking at a loaf of bread weighing one pound and a 

 half that almost 1,000 pounds of rainfall and 333 

 pounds of soil were necessary for its production. 



In general it is found that taking soils as a whole, 

 the reduction of their water content to about 8 per cent, 

 would practically inhibit plant growth. It is some- 

 times almost a marvel that a plant can live at all dur- 

 ing periods of drought, when as far as the eye is con- 

 cerned no trace of moisture can be detected in the first 

 few inches of the soil of the field. It is not an unusual 

 thing, however, to see a crop revived and again placed 

 in vigorous growth after an abundant rain, which ap- 

 parently was beyond hope before the rain descended. 



In irrigated regions it has been possible to measure 

 very accurately the amount of water necessary for the 

 production of a crop, where the water is applied as 

 wanted, great economics are secured, and these measure- 

 ments confirm the statement above given. Measure- 

 ments made in Idaho with various crops have shown the 

 following ratio: 



1 pound of alfalfa requires 432 pounds of water. 



1 pound of beans requires 153 pounds of water. 



1 pound of beets requires 91 pounds of water. 

 1 pound of Indian corn requires 136 pounds of water. 



1 pound of oats requires 91 pounds of water. 



1 pound of potatoes requires 46 pounds of water. 



1 pound of wheat requires 66 pounds of water. 



Professor King found by measurements made in 

 Wisconsin with a controlled water supply that, on an 

 average, 446 pounds of water were required to produce 

 a pound of dry crop. This is a little higher than 



