SOIL INOCULATION 



plants are soil-restoratives. They are fertilizers 

 of the most approved type. They bring nitro- 

 gen to the soil and they take no element of fer- 

 tility from it. When a certain cereal has been 

 planted for a series of years upon a given soil, 

 as in the case of wheat, the nitrogen becomes 

 exhausted because of the exacting demands of 

 the wheat plant and the soil refuses longer to 

 produce a crop; it is worn out. The land is 

 abandoned for wheat culture possibly it lies 

 fallow for years. It is the part of the benefi- 

 cent bacteria, abounding in the tubercles on 

 the roots of the peas or beans or clovers, to 

 supply the waste nitrogen to the soil, taking 

 the free nitrogen of the vast reservoir of the air 

 and converting it into the proper form for as- 

 similation by the plant. In the case of the soy 

 bean planting in Kansas, the beans, where 

 there were no tubercles upon the roots, kept 

 on exhausting the soil as any other crop would, 

 but as soon as the bacteria were introduced, 

 inducing the growth of the tubercles, the 

 exhaustion of the soil was checked, the soil 

 became enriched. 



In the one case, the farmer of the Old Earth 

 would keep on planting crop after crop, 



39 



