i86 



Nature- Study Agriculture 



Too much 

 straw 



Effect on 

 dry land 



The 



increased 

 yield due 

 to fertilizer 



A 58-year 

 test 



If there is much coarse, dry straw with the manure, 

 only a moderate amount should be put into the soil. 

 A layer of straw a few inches under the surface will 

 break the connection between the surface soil and the 

 moist earth below, so that capillary action cannot bring 

 water up to the roots of the crop. 



In very dry climates fresh manure in large amounts 

 may burn out the crop. The water which should 

 nourish the plants is used in fermenting the fertilizer. 

 Only manure that has already been rotted should be 

 used where the soil is likely to become very dry. 



The farmer will be well rewarded for his use of fer- 

 tilizer. Experiments with and without fertilizer ex- 

 tending over a period of more than fifty years were 

 made at the Rothamstead experiment station. The 

 fertilizer used on one plot of wheat each year was barn- 

 yard manure. On a similar plot, wheat was raised 

 without any fertilizer. The average annual yields of 

 wheat in bushels for different periods were as follows : 



The unfertilized plot, in the latest of these yields, 

 showed a falling off of about one third from tne first 

 yield, while the plot receiving manure showed an in- 

 crease in yield. Even from the start about twice as 

 much wheat was produced with fertilizer as without, 

 and after many years of cropping the fertilized field 

 yielded three times as much as the other. 



