10 



RESULTS OF EXPERIMENTS AT ROTHAMSTED, 



annum, under the influence of a complex mineral manure alone ; and 

 that the amount was increased to 1,590 Ibs. by the addition of 43 Ibs. 

 of nitrogen as ammonium-salts, to 2,222 Ibs. by 86 Ibs. of nitrogen as 

 ammonium-salts, and to 2,500 Ibs. by 86 Ibs. nitrogen as sodium- 

 nitrate. Accordingly, as shown in the second column, the increased 

 assimilation of carbon was, by 43 Ibs. of nitrogen as ammonium-salts 

 602 Ibs., by 86 Ibs. as ammonium-salts 1,234 Ibs., and by 86 Ibs. as 

 sodium-nitrate 1,512 Ibs. 



TABLE V. 



Estimates of the Yield and Gain of Carbon, and of the Gain of Carbohydrates, per 

 acre per annum, in various Experimental Crops, grown at Rothainsted. 



WHEAT 20 years, 1852-1871. 



BARLEY 20 years, 1852-1871. 



SUGAR-BEET 3 years, 1871-1873. 



MANGEL WURZEL 8 years, 1876-1883. 



POTATOES 10 years, 1876-1885. 



BEANS 8 years, 1862 and 1864-1870. 



Reckoned in the same way, the increased assimilation of carbon in 

 the Barley was, for 43 Ibs. nitrogen as ammonium-salts, 950 Ibs. pe.r 

 acre ; that is one-and-a-half time as much as by the same application in 

 the case of wheat. 



In the Sugar-Beet (the roots only), the increased assimilation of 

 carbon was 1,477 Ibs. per acre by the application of 86 Ibs. nitrogen as 



