STORING WATER IN THE SOIL 



115 



smaller proportion reaches the greater soil depths. 

 In the Great Plains district, therefore, greater care 

 will have to be exercised during the summer in secur- 

 ing proper water storage than in the Great Basin, 

 for instance. The 



principle is, never- 

 theless, the same. 

 Burr, working under 

 Great Plains condi- 

 tions in Nebraska, 

 has shown that the 

 spring and summer 

 rains penetrate the 

 soil to the depth of 

 6 feet, the average 

 depth of the borings, 

 and that it undoubt- 

 edly affects the soil- 

 mo is ture to the 

 depth of 10 feet. 

 In general, the dry- 

 farmer may safely 

 accept the doctrine 

 that the water that 

 falls 'upon his land 



Fig. 30. Diagram to illustrate the degree 

 and depth to which the precipitation 

 of fall, winter, and earliest spring is 

 found in the soil at seed time. Lines 

 on the left indicate the percentage of 

 water in the soil in the fall; those on 

 the right, the percentage of water in 

 the soil in the spring at seed time. 



penetrates the soil far beyond the immediate reach 

 of the sun, though not so far away that plant roots 

 cannot make use of it. 



