vii.] RECO VER V OF NITROGEN IN MANURE 2 1 1 



which shows the nitrogen removed in the mangold crops 

 at Rothamsted when grown with farmyard manure and 

 other sources of nitrogen. 



In this case yZ per cent, of the nitrogen applied as 

 nitrate of soda is recovered in the crop, and 71 per cent, 

 of that applied as rape cake, while only 32 per cent, of 

 that which was estimated to be included in the dung 

 has come back in the crop. This low figure is partly 

 due to the fact that the dung was put on year after year 

 in considerable quantities (14 tons per acre); hence all 



Table LXIV.— Fate of Nitrogen in Farmyard Manure, 

 APPLIED TO Wheat (Rothamsted). 



the wasteful processes are increased and there is also a 

 great accumulation of nitrogenous material in the soil. 

 How great the waste may become is seen by comparing 

 the nitrogen supplied to one of the permanent wheat 

 plots at Rothamsted, which receives 14 tons of farmyard 

 manure per acre every year, with the nitrogen stored up 

 in the soil and that removed in the crop. Table LXIV. 

 shows that only 26 per cent, was recovered in fifty 

 years, and that nearly 57 per cent, has been lost, since 

 it is accounted for neither in the crop nor in the soil at 

 the end of the period. 



These, however, are extreme cases ; on referring to 

 the crops grown with the rich and poor dung on p. 204, 



