43 



lich 

 ygen 

 but 

 as 

 the 

 lout 

 iS of 

 |mch 

 3een 

 loils ; 

 [ding 

 |duc- 

 far 





I. 



Table XIIL— Hoosfield Clover, and Wheat and Fallow, Land. 



Nitrogen ;per cent, in dry Motdd, first 9 inches. 



[Experiments more than 30 years.] 



Mean. 



Mean of determinations on five separate samples, 

 Mean on the mixture of the five samples 



Mean , 



1881. 



Clover Land. 



Per cent. 

 -1007 

 -1055 



0-1061 



Fallow Land. 



Per cent. 

 0925 

 0-0984 



-0955 



It is true that the tendency of the evidence on the point is to show 

 that red clover derives, at any rate much of its nitrogen, from the 

 lower layers of the soil ; but it is surely significant that, after the 

 growth of heavy crops in 1849, when the land was in ordinary condi- 

 tion as to manuring and cropping, and the constant failure since, there 

 is, coincidently with this, nearly as low a percentage of nitrogen in the 

 surface soil as with alternate wheat and fallow without manure. It is 

 obvious that any accumulation near the surface, due to residue from 

 the small crops, has been more than compensated by exhaustion. The 

 evidence afforded by the figures may be said to be of a somewhat 

 negative character ; but it is at any rate clear that failure of growth 

 of the clover has been associated with a declining, and a very low, 

 percentage of nitrogen in the surface soil. 



The next results are of a very much more definite character. They 

 relate to the two portions of the field which had grown six corn crops 

 in succession by artificial manures alone, was then divided (in 1873), 

 and on one half clover (sown in the previous year), and on the other 

 half barley, was grown. Table I shows that in the clover crops 

 151 "3 pounds, and in the barley only 37"3 pounds of nitrogen were 

 removed. Yet, in the next year (1874), barley being grown over 

 both portions, the one which had yielded 151-3 pounds in clover 

 now yielded 69*4 pounds in barley ; and the other, which had yielded 

 only 37"3 in barley, now yielded only 39-1 pounds in barley. 



In October, 1873, after the clover and barley had been removed, 

 and before the land was ploughed up, samples of the soil were taken 

 as follows : From each portion four separate samples, each 12 by 12 

 inches area and 9 inches deep, and the nitrogen was determined in 



