PREPARATION OF SOILS FOR CROPS 



are left after nitrification in a more available condition. 

 The mineral as well as the organic matter of the soil 

 is subject to the action of micro-organisms, and the 

 cultivation which the soil receives can be made either 

 to accelerate or to retard this action. Many of the 

 chemical changes which take place in the soil result- 

 ing in the liberation of plant food are induced by aerobic 

 organisms, hence the importance of thorough cultiva- 

 tion to induce bacterial action. Each type of soil has 

 its own characteristic microscopic flora, which can be 

 either favorably or unfavorably influenced by cultivation. 



354. Cultivation for Special Crops. While the gen- 

 eral principles of cultivation apply to all crops, the ex- 

 tent to which loosening or compacting should be carried 

 must be determined by the character of the soil and the 

 crop that is to be produced. Methods of cultivation 

 must be varied to meet the requirements of different 

 soils and different crops. The physical condition of 

 the soil for general farm crops is discussed in Chapters 

 I and XI. For the production of a special crop, the 

 cultivation must be adapted to the specific needs as 

 to manner of growth, kind of food needed, physical 

 condition of the soil, temperature, and moisture. A 

 knowledge of these requirements can be obtained only 

 by experimental methods. The cultivation of a new 

 crop should not be attempted on a large scale without 

 a preliminary study of the crop. The production of 

 sugar beets for the manufacture of sugar, of flax for 



