236 SOILS AND FERTILIZERS 



to its food requirements. An excess of easily soluble 

 plant food is injurious while a lack is equally so. An 

 abundance of food in organic forms is most essential. 

 Heavy dressings of farm manures may be applied. 

 Where hops are grown there is a tendency to use all 

 of the manure on the hops while the rest of the farm 

 is left unmanured. Very light applications of com- 

 mercial fertilizers may be used in connection with sta- 

 ble manure, but such use should be made only after a 

 preliminary trial on a smaller scale. 



305. Hay and Grass Crops. — Most grass crops have 

 shorter roots than grain crops ; they are surface feed- 

 ers and not so able to secure mineral food. When a 

 number of crops have been removed the soil may stand 

 in need of available mineral matter. Farm manures 

 are particularly well adapted for fertilizing grass. Ap- 

 plications of nitrogenous manures result in discoura- 

 ging the growth of clover. Heavy manuring of grass 

 land has a tendency to reduce the number of species 

 and one kind is apt to predominate. 81 On some soils 

 ashes, and on others lime fertilizers, have been found 

 very beneficial. The manuring of grass lands must 

 be varied to meet the requirements of different soils. 

 Permanent meadows require different manuring from 

 meadow simply introduced as an important crop in the 

 rotation. 



306. Leguminous Crops. — For leguminous crops pot- 

 ash and lime fertilizers have been found of most value. 



