284 



SOIL CONDITIONS AND PLANT GROWTH 



bacterial numbers begin to rise, and the connection between 

 the two quantities is normally so close as to indicate a causal 

 relationship ; the increased ammonia production is, therefore, 

 attributed to the increased numbers of bacteria. There is no 

 disappearance of nitrate; the ammonia is formed from 

 organic nitrogen compounds. 



Table LXXV. — Weight and Composition of Crops Grown on Partially 

 Sterilised Soils. Russell and Darbishire (2406). 



These conclusions are generally accepted. 



Table LXXVI. — Ammonia and Nitrate Accumulating in a Soil Kept 

 Twenty-three Days at About 15° C. in a Moist Condition, Parts per 

 Million of Dry Soil. 



(3) The increase in bacterial numbers is the result of 

 improvement in the soil as a medium for bacterial growth 



