284 



SOIL CONDITIONS AND PLANT GRO WTH 



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 

 improvement in the soil as a medium for 



is the result of 

 bacterial growth 



