MAKING THE SOIL PRODUCE CROPS 



within the previous several years, the precaution 

 of adding the proper bacteria should be taken. 

 In some sections, such legumes as red, alsike, 

 crimson and white clovers have been grown for 

 many years and the bacteria for these plants 

 are well distributed. There, inoculation is not 

 necessary for these crops, but it probably should 

 be practiced if other legumes such as alfalfa, 

 cowpeas or soybeans are to be grown on land 

 for the first time. 



The Value of Humus. In addition to the 

 chemical elements of plant food, all produc- 

 tive soils contain decaying vegetable matter, 

 generally classified under the term "humus." 

 Humus serves as a source of acid-generating 

 material which further breaks down soil particles 

 and, most important of all, serves as a food for 

 millions of microscopic plants which develop 

 and die quite beyond the scope of human vision. 

 These constitute a type of bacteria which are 

 distinctly beneficial and essential to human life 

 since they make possible the growth of larger 

 plants that serve as human food. 



Green plants, straw or leaves, when plowed 

 under or spaded in the soil, are attacked by 

 bacterial agencies which gradually turn these 

 products into humus. The same process occurs 

 when a "compost" is set up. This is made of 

 leaves, manure, soil, straw and other materials 



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