382 PRINCIPLES OF AGRICULTURAL CHEMISTRY 



duction of flesh. As the plants approach maturity, the per- 

 centages of non-proteid nitrogen decreases. 



The fat is irregular, though it shows a tendency to decrease. 

 The crude fiber increases with most plants. Indian corn is an 

 exception, since the production of a large quantity of starchy 

 seed decreases the percentage of fiber. The nitrogen- free extract 

 usually increases, though the changes are somewhat irregular. 

 The digestibility decreases. 



The total quantity of dry matter per acre appears to increase 

 during the entire period of growth. In the latter stages of 

 maturity of the plant, the increase is largely made up of crude 

 fiber. 



Some analyses of plants at different stages of growth are shown 

 in the table .- 1 



Time of Harvest. The best time to harvest depends on the 

 kind of plant and the purpose for which it is grown, as well as on 

 the weather of the harvesting period. 



Suppose hay is grown for market. The object then is to secure 

 the largest possible quantity of hay of the highest market value. 

 A large quantity of low grade hay may, or may not, be more 

 profitable than a smaller quantity of high grade hay. 



Suppose hay is grown for feed. The object is then to get the 

 largest possible amount of digestible nutrients per acre. The best 

 period of harvest for this purpose is when the plant is in full 

 bloom. 



Suppose the clover or grass is grown for seed. Then the object 

 is to produce the most seed of the best quality. The seed must 

 be well matured, but at the same time the harvest must not be so 

 late that any considerable quantity is lost by shattering. 



Other Factors which Influence Composition. Other factors 

 which influence the composition of crops are the seed, the soil, 

 climate, and method of preparation or preservation. 



The composition and individuality of the seed influence the 

 composition and size of the plant. In many cases, the heavier 

 1 Compiled from Bulletin n, Office Exp. Station, U. S. Dept. Agr. 



