50 



EXPERIMENTS UPON WHEAT 



otherwise the manuring 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. Although the ammonium-salts are soluble in water 



N. as Nitrate 

 IbjierAcre 



PlotV 



Spring Sowing to Harvest Harvest to SpringSowing Sprin^Sowing to Harvest Harvest to SpringSowing. 



1878. 1879/80. 1880. I88O/8I . 



V//S/M L ss f ".as Nitrates perAcre. kSSSNSl Loss of N.as Nitrates perAcre 



Drainag(inlnches)tlirough 60 Soil. V/////A Manure SprinfSown. ^ xx 



Manure Autumn Sown. 



FIG. 7. Loss of Nitrogen as Nitrates in the Drainage Water, Ib. per acre. 

 Comparison of Plot 7 manured with Ammonium-salts in the spring, and 

 Plot 15 in the autumn. 



they are caught by the soil and held very near to the surface, 

 so that the loss does not arise by the washing out of the 

 ammonium-salts themselves. They are, however, rapidly con- 

 verted into nitrates when the land is warm and moist, 

 especially after it has been recently stirred by the autumn 

 cultivations. The nitrates thus produced are not retained by 



