58 The Rothamsted Wheat Experiments. 



and the other the mixed mineral manure alone. In the 

 next year, 1883, the portion which received the whole manure 

 in the previous year received mineral manure only ; whilst 

 the other portion received both minerals and ammonia-salts. 

 Tt is seen that in each year, 1882 and 1883, the nitrogenous- 

 manured portion yielded large crops (43^ and 45f bushels) ; 

 whereas, the portion on which mineral manures alone 

 followed ammonia-salts and large crops, yielded very small 



TABLE XIII. WHEAT GROWN YEAR AFTER YEAR ON THE SAME 

 LAND, STACKYARD FIELD, WOBURN. 



(1) Mixed min. man. alono. (2) Mixed min. man. and amm. -salts. (= 861b. nitrogen.) 



crops 13 and 17^ bushels respectively, against 14f and 

 17 1- bushels on a plot where the same mineral manures were 

 used year after year. There was, then, no available and 

 effective residue where the ammonia-salts had been previously 

 applied. Though in 1884 there was notable effect from 

 unexhausted residue of nitrogenous manure, this probably 

 arose from there being very little rain, and, consequently, 

 very little loss by drainage during the winter of 1883-4. 



SUMMAEY OF THE EESULTS OF FORTY YEARS' 

 EXPERIMENTS ON THE CONTINUOUS GROWTH 

 OF WHEAT UPON THE SAME LAND. 



The forty years' experiments on the continuous growth of 

 wheat have established, with regard to the soil, the following 



