SOIL WATER 



329 



the little capillary tubes by which the soil water reaches 

 the surface were broken and the sunshine and air were kept 

 from the under part of the soil by a layer of finely divided 

 soil mulch. When the 

 surface of the soil is 

 thoroughly stirred or 

 cultivated the particles 

 are separated so far 

 apart that the water 

 cannot pass from one 

 grain to another, and so 

 is retained in the under 

 layer ready for the plant 

 roots. Thorough tillage 

 of agricultural crops is 

 perhaps the best way to 

 assure the plants suffi- 

 cient moisture in regions 

 subject to droughts. 



In some parts of the 

 arid region of the United 

 States dry farming is 

 practiced. The soil is 

 deeply plowed and the 

 plow often followed by 

 a bevel wheel roller called 

 a soil packer, in order to pack the under soil or subsoil so that 

 the air cannot circulate through it and dry out the upper 

 soil. The surface soil is then most thoroughly cultivated 

 so as to make as perfect a soil mulch as possible. Thus, 

 whatever moisture falls is kept from seeping below the reach 

 of the plant roots and from evaporating from the surface. 



KAFFIR CORN 

 A plant suitable for dry farming. 



