No. 1.] GRASSES AND FORAGE CROPS. 



205 



necessary to omit the plots with 50 pounds of nitrogen per 

 acre. For the timothy the percentage of protein with mineral 

 fertilizers only was 7.25 per cent, while with 75 pounds of 

 nitrogen it was a little over 9 per cent. With the meadow 

 fescue the percentage of protein was 7.25 per cent with 

 mineral fertilizers, but with 75 pounds of nitrogen it was a 

 little over 12 per cent. In the case of orchard grass mineral 

 fertilizers gave 8.16 per cent, and 75 pounds of nitrogen 

 gave 12.4 per cent of protein ; while with red-top and tall 

 meadow oat grass, although the experiments were fewer, a 

 similar increase in the percentage of protein may be noticed. 



Effect of Nitrogenous Fertilizers on the Percentage of Protein in 



Pure Species. 



The Meaning of the Experiments. — Grasses differ from 

 many other crops in the readiness with which they respond 

 to the use of nitrogenous fertilizers. While clovers and 

 other legumes seem to be able to gather much of the nitrogen 

 they need from natural sources, the true grasses must be 

 supplied with nitrogen in the manure or fertilizer, in order 

 to give much increase in yield. Thus there is a two-fold 

 value in the experiments. In the first place, they show 

 that the grasses call for the use of nitrogenous fertilizers, 

 and that very little increase of crop is to be expected from 

 mineral fertilizers alone. They indicate that where the 

 farmer uses stable manure, which contains relatively large 

 quantities of nitrogen, on his grass crop he is following a 

 wise practice, and that by the liberal use of manures rich 



