140 Agricultural Chemistry. 



Comparative Effect of Manure and Commercial Fertilizers. 



It will be seen that there was practically no difference between 

 the plots dressed with farm manure and those receiving commer- 

 cial fertilizers. In fact the test was hardly fair to the manure, 

 as excessive quantities' of commercial fertilizers were applied. 

 The amount of nitrogen added to the wheat was equal to that 

 contained in 800 pounds of nitrate of soda, an excessive amount. 

 It is believed by some authorities that had the experiment been 

 conducted in America the result would have been more favorable 

 to the barn yard manure. This judgment is based on the belief 

 that nitrification, due to the influence of climate, would be more 1 

 rapid in this country than in England. 



Lasting effect of manure. Barn yard manure, because of its 

 slow-decomposing organic matter, has a lasting effect when ap- 

 plied to the soil. Where, at Rothamsted, a plot was manured an- 

 nually for 20 years, and then received no manure for the next 

 20 years, this effect is clearly shown. The following table illus- 

 trates this effect. The figures represent the action of the residual 

 manure, as no fertilizer was added during the period covered by 

 the table. The crop grown was barley and is expressed in bush- 

 els per acre. 



