PREPARATION OF SOILS FOR CROPS 



silt soils of the Northwest it has given excellent results 

 and is beneficial in promoting crop growth. 



351. Mixing of Subsoil with Seed Bed. Some soils 

 are improved by deep plowing and mixing the surface 

 and subsoils to form the seed bed. Such soils are 

 usually acid in character and contain a large amount 

 of organic matter, in which case the mixing of the 

 surface and subsoils improves both the physical and 

 chemical properties. With sandy soils the mixing of 

 the surface soil with the subsoil is not advantageous, as 

 it dilutes the stores of plant food which are greater in 

 the surface soil ; then, too, the physical properties of 

 the soil are not improved. Combining the surface and 

 subsoils in the case of heavy clays should be done 

 gradually and at each period in the rotation after an 

 application of farm manure. In the cultivation of clay 

 soils it should be the aim to secure a deep layer of 

 thoroughly pulverized, aerated, and fertilized soil. In 

 the preparation of the seed bed, the character and con- 

 dition of the subsoil is equally as important as of the 

 surface soil. 



352. Cultivation to Destroy Weeds. One of the chief 

 objects of cultivation is to destroy weeds, and for this 

 purpose it should be given early in the year before 

 the weeds become firmly established. Weeds are most 

 easily destroyed at the time of germination and before 

 the leaves appear above ground. The plow should be 



