WHEAT 



29 



ammonium -salts is applied in the autumn, otherwise the maimring is 

 identical with that of Plot 7. The crop, however, on Plot 15 is on the 

 average below that of Plot 7, showing that some loss takes place when 

 the ammonium-salts are applied before the plant is able to utilise them. 

 Plots 17 and 18 further illustrate the fate of ammonium-salts. These 

 plots receive the dressing of Plot 7 — 400 lb. ammonium-salts and com- 

 plete minerals — but the ammonium-salts and the minerals are applied in 

 alternate years to the two plots. Thus in 1906 Plot 17 receives ammo- 

 nium-salts but no minerals, and Plot 18 the minerals without the 

 ammonium-salts, and the treatment is reversed in 1905 and again in 1907. 

 The plot which in any year is receiving minerals without nitrogen derives 



Total Produce 

 per Acre 



6000 lb — 



40OO 



Straw per Acre, lb. 



Gram per Acre, lb 



Fig. 9. — Comparison of Nitrate of Soda and Ammonium-salts on Wheat 

 Ten years (1893-1902), All Plots receive Minerals alike. 



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



