SOIL CONDITION AND NITRIFICATION 



417 



spot nearby. These may be termed unaerated and 

 aerated soils. Both were kept at the same temperature 

 and moisture content in the greenhouse, but no plants 

 were grown upon them. The production of nitrates 

 was as follows: 



Table LXIII 



283. Effect of sod on nitrification. Nitrification 

 proceeds slowly on sod land, especially if the soil is 

 heavy. On the same type of soil as that used in the 

 experiment last described, the average quantities of 

 nitrates for each month of the growing season in the 

 surface eight inches of sod land as compared with 

 maize land under the same manuring were as follows: 



Table LXIV 



Month 



April . 

 May .. 

 June. . 

 July . . 

 August 



Nitrates in dry soil, parts per million 



AA 



