No. 6. DEPARTMENT OF AGRICTXTURE. 346 



Table IV. 



:;tionofSoiL -Hi 



sS- 



5 E"' 



N: : : ' S 



Soil No. 2. J'i H 94 



Sen xo. a. 



Sell Xo. 4, 



S'3ii Xo. 5, 



Sou Xqs. S. 



Soa Xo. 7. 



ScU Xo. S, 



Sea Xo. ?, 



Sou Xo. 1?. 



S-il X-. 1' 



•7^-:T--;.r- : salt nicriEed after 1C6 days, ten:!:- ry. 



From this table it is seen that the maximum rate of nitrification 

 took place in the soil with a proportion of clay Tarving from 10-20 

 per cent, with from 80-9" ent. of sand respectivelT. the rate 



diminishing as it is either lighter or heavier than the above mean. 

 Xitrification. other things being equal, is. therefore, most active in 

 soils which are neither too light nor too heavy. 



The soil best meeting these conditions are the sandy loams which 

 occupy an intermediate position between the heavy grass lands of the 

 timer margin of the costal plain and the light truck lands of the sea- 

 board. One way in which soil texture affects rate of nitrification is 

 by its effect on available water. 



The finer particles of heavy soils have such a strong attraction for 

 water that a large part of the soil moisture is rendered unavailable 

 for the use of the nitric ferment. 



(<f. ) The Rate of ^.tr litigation in the Soil. 



When samples of soil are taken and kept loosened and stirred, 

 and under favorable conditions of temperature and moisture, the 

 rates of nitrification therein are exc-eedingly high, as shown by the 

 f.^llowing Table T-'- from experiments by Lawes and Gilbert: 



