I02 



NITROGENOUS MANURES [chap. in. 



number of plants counted on each plot, which is set out 

 in Table XXXI. 



Table XXXI.— Effect of Manures upon the Number of Roots. 



ROTHAMSTED MANGOLDS, 1876-1902. 



Plot. 



4C 

 4A 



4N 



Manures 



Complete Minerals with Rape 

 Cake 



Complete Minerals with Am- 

 monium Salts . 



Complete Minerals with Ni- 

 trate of Soda 



Average Crop 

 per acre. 



Tons. 

 21-3 

 14.9 

 1 8-0 



Average Number 

 of Boots 

 per acre. 



Number. 



17,474 

 14,802 

 14.130 



In ordinary farming the effect upon the soil is never 

 likely to become so pronounced as in these experiments 

 at Rothamsted, but without a doubt a considerable 

 element in the extra value which the farmer sets on 

 organic nitrogen must be put down to its improvement 

 of the texture of the soil, a factor the farmer rightly 

 regards as of the first importance. 



