200 Fertilizers 



somewhat similar characteristics, particularly as to their 

 method and time of growth and their capacity for acquir- 

 ing food from soil sources. 



Characteristics of the cereal group. 



The cereals possess distinct characteristics of growth. 

 The roots branch just below the surface, and each shoot 

 produces feeding roots, which distribute themeslves in 

 every direction, and thus absorb food from the lower layers 

 of the soil as the plant grows older. Because of their wide 

 root system, and because of the character of their feeding 

 rootlets, they are able readily to acquire food from the 

 insoluble phosphates and potash compounds of the soil, 

 though they are unable to feed to any extent upon the 

 insoluble nitrogen. Furthermore, inasmuch as the most 

 rapid development of many of these crops takes place 

 early in the summer, before the conditions are favorable 

 for the rapid changing of organic nitrogen into nitrates, 

 they are, with the exception of Indian corn (maize), 

 specifically benefited by early applications of nitrogen in 

 the form of nitrate. The corn, on the other hand, which 

 makes its most rapid growth after the other cereals are 

 harvested, in July or August, when the conditions 

 are particularly favorable for the development of nitrates, 

 do not usually require as large proportions of nitrogen as 

 of the mineral constituents, particularly the phosphates. 

 That is, wheat, rye, oats and barley are specifically 

 benefited by the early application of quickly available 

 nitrogen. 



Characteristics of grasses and clovers. 



Forage crops, including both the grasses and clovers, 

 constitute another group, in so far as their use is concerned, 



