CONCERNING THE TEXTURE OF THE SOIL 43 



2. The nature of the subsoil : 



Sand and clay subsoils act similarly with surface soils : 

 open subsoils open the top reservoir, stiff ones hold the 

 water fast. 



3. The amount of humus in surface soils : 



Where no humus is present, the water content is less, 

 since the air spaces are less in number and less able to 

 hold. Much humus in the soil enlarges the water-holding 

 capacity. 



4. The looseness of the soil : 



A loose, open soil, where humus components are pres- 

 ent, increases the absorption power, and may increase the 

 water-holding power. 



5. The physical condition of the soil : 



Where clods are present, the particles are tightly 

 pressed together, allowing neither air nor water to enter. 

 Open these clods, and you increase both the size and the 



TREES IN THE PRAIRIE REGION 

 Summer culture saves the moisture and the trees grow 



number. A soil well supplied with humus, and when fine 

 and mellow and in good high tilth, holds its maximum 

 quantity of available water. 



6. The method of surface treatment : 



Since water escapes rapidly through evaporation, it fol- 

 lows that any method of cultivation that reduces this loss 

 will enable the soil to hold its water longer. Any treat- 

 ment that fails in doing this assists in making the loss 

 constantly greater. 



