PREPARATION OF SOILS FOR CROPS 



in September was dry and lumpy ; the early plowed 

 mellow land gave a yield of 31.3 bushels per acre and 

 the late plowed lumpy land produced only 13.3 bushels. 



348. Influence upon the Seed Bed of Pulverizing and 

 Fining the Soil. --If the land is lumpy and the lower 

 stratum of the seed bed is not pulverized and firmed, the 

 soil water is readily lost by percolation, evaporation takes 

 place rapidly, and the crops are poorly fed because the 

 roots are unable to penetrate the hard lumps and secure 

 plant food. If a soil is inclined to be lumpy, the cul- 

 tivation, including the plowing, should be carried on 

 largely with the view of thorough pulverization. When 

 a seed bed is well prepared, the soil warms up more 

 readily ; the loosening and pulverizing enable the 

 heat of the sun's rays to more readily penetrate the 

 soil and bring it into good condition for promoting 

 growth. 



349. Aeration of Seed Bed Necessary. Crop roots 

 require air for functional purposes. In sand and loam 

 the air spaces make up half or more of the total 

 volume. It is not necessary to cultivate such soil with 

 the view of increasing the air spaces, but with compact 

 soils, as heavy clays, plowing should result in aeration 

 of the soil and an increase in the number of air spaces, 

 as the air of the soil takes an important part in render- 

 ing plant food available. (See Section 59.) If soils are 

 plowed when too wet, they are not sufficiently aerated. 



