130 



THE ROTHAMSTED EXPERIMENTS. 



nearly three times as much nitrogen as nitric acid as the 

 gramineous crop soil. 



TABLE 43. — Nitrogen as Nitric Acid per acre, lb., in Soils 

 op some Experimental Plots, without Nitrogenous Manure 



FOR MORE THAN 30 YEARS ; HOOSFIELD, ROTHAMSTED. Samples 



collected July 17-26, 1883. 



Nitrifica- 

 tion and 

 soil nitro- 

 gen. 



The difference is the greatest near the surface, but it is 

 very considerable down to the lowest depths. In the first 

 three depths there was more than twice as much nitrogen as 

 nitric acid in the Trifolium repens, as in the wheat-fallow 

 soil ; in the second and third three depths, there was more 

 than three times ; and in the fourth, three more than four 

 times as much. Hence it is obvious, that any loss by drain- 

 age would be much the greater from the Trifolium plot, so 

 that the difference between the two plots was probably 

 greater than the figures show. 



In the case of both plots, the actual amount of nitrogen as 

 nitric acid was the greatest near the surface, indicating more 

 active nitrification ; and the greater amount in the Trifolium 



