79 



TABLE I. The Effect of Sand and Lime on Nitrification. 



A review of the foregoing table prominently asserts at least two facts 

 the enormous increase in nitrates under the influence of lime and the failure 

 of sand to stimulate nitrate formation in clay soils. The actual depression 

 of nitrification in the presence of sand which is true throughout the ex- 

 periment is hardly to be expected. Such an influence would not 

 unlikely be exerted on the Norfolk sandy loam, a soil which is well enough 

 aerated in its natural condition, and the addition of sand would only dilute 

 the organic matter present. Pure sea sand practically free from organic 

 matter was used in the experiment and there was some loss in total organic 

 matter wherever it was introduced. Yet this fact scarcely accounts for the 

 falling off in nitrification, as nitrogen was abundantly supplied by the am- 

 monium sulphate. In the control pots, which received no treatment what- 

 ever, nitrification proceeded more rapidly in the clay soils than in the 

 Norfolk soil. On the other hand the use of lime was attended with uni- 

 formly better results with Norfolk soil than with the clays, and the maximum 

 amount of nitrate found was in Norfolk soil with .15 percent CaC0 3 after 

 twelve weeks. The more rapid formation of nitrates in heavy soils than in 

 light open ones was reported as recently as 1911 1 and the notable response 

 of Norfolk soil to lime has been often noted at this station. It would seem, 

 therefore, that the action of lime in the present experiment is not to be 

 attributed to any physical influence it exerted on the soil, and attempts to 

 parallel such action had it been achieved with lime by the use of sand in 

 soils were accompanied by an actual depression of nitrification. By 



'Fischer, H. Landw. Jahrb. 41:755-822. 1911. 



