ON THE GROWTH OF LEGUMINOUS CROPS. 



3 



annum, due to the accumulations from comparatively recent nitrogenous 

 manuring. But, it is seen that, after these accumulations had been 

 reduced, Swedish Turnips gave over 15 years, an average of only 18 '5 

 Ibs., Sugar-Beet over the next 5 years, an average of only 14'7 Ibs., and 

 Mangel-Wurzel over the succeeding 10 years, an average of only 14'0 

 Ibs. of nitrogen, per acre per annum. Or, reckoned over the whole 

 period of 30 years, after the recent accumulations had been worked 

 out, the root-crops gave an average of only 16 '4 Ibs. of nitrogen per 

 acre per annum. 



TABLE I. 



Nitrogen per acre per annum, in various Crops grown at Rothamsted, with 

 Mineral, but without Nitrogenous Manure. 



* 13 years crop, 2 years failed. 



t 9 years beans, 1 year wheat, 2 years fallow. 



t 6 years clover, 1 year wheat, 3 years barley, 12 years fallow. 



$ Superphosphate only. 



It is remarkable, how very similar is the amount of nitrogen 

 annually accumulated in Gramineous, Cruciferous, and Chenopodiaceous 

 crops, after the soil had been exhausted of the more recent and more 



