30 



BROADBALK FIELD 



little or no benefit from the ammonia it had the year before. The crop 

 shows every sign of nitrogen starvation, and amounts on the average to 

 only 15*3 bushels of grain, as compared with 14"9 bushels on Plot 5 which 

 has received minerals without any nitrogen every year since 1852. On 

 the Rothamsted soil, then, we may conclude that the effect of sulphate of 

 ammonia applied to a cereal crop is confined to the season of its application. 

 In the seasons when the ammonium-salts are applied the crop is but little 



Total Produce 

 perAcre 



6000 lb. — 



18 



86lb.N. 



after Minerals only 



in Previous Year. 



Straw per Acre, lb. 



Grain per Acre, lb. 



Fig. 10. — Comparative Effects on Wheat of Ammonium-salts applied at different times. 



Averages— Plots 5, 17, and 18, 51 years (1852-1902). 

 Plots 7 and 15, 25 years only (1878-1902). 



The figures in the labels indicate bushels of Grain and cwt. of Straw. 



