52 THE CHEMISTRY OP THE FARM. 



The roots of grass being far shorter than those of the 

 cereals are less able to collect ash constituents from the 

 soil ; if, therefore, grass is mown for hay, manures con- 

 taining potash, lime, and phosphoric acid will generally 

 be required. Like the cereal crops, grass is greatly 

 increased in luxuriance by the application of soluble 

 nitrogenous manures. 



Farmyard manure, or the feeding of cake, corn, or 

 roots on the land, is the most appropriate manuring for 

 permanent pasture, if a high quality as well as quantity 

 of produce is desired. Large crops of hay may be 

 obtained by manuring with nitrate of sodium, together 

 with kainite and superphosphate ; but a continuance of 

 such treatment promotes a coarse herbage. 



The natural clovers of a meadow are destroyed by the 

 continued application of highly nitrogenous manures, a 

 hay consisting almost exclusively of grass being pro- 

 duced. The clovers are developed by the application of 

 manures supplying potash or lime without nitrogen. The 

 effect of pasturing is to check the development of coarse 

 herbage, and to promote the growth of the finer grasses 

 and clover. 



The perennial character of meadow herbage, which 

 usually includes a variety of leguminous plants, presents 

 favourable conditions for the collection of nitrogen from 

 the atmosphere : see pp. 65,66. 



Leguminous Crops. Some of these are grain crops, 

 as beans and peas ; others are fodder crops, as red clover, 

 sainfoin and lucerne. A striking characteristic of all 

 these crops is the large amount of nitrogen which they 

 contain, the quantity being about twice as great as that 



