248 AGRICULTURAL CHEMISTRY 



Nitrogen is assimilated by the plant more rapidly than 

 any of the elements which form a part of the organic 

 compounds. When the plant has completed half its 

 growth, under normal conditions about 85 per cent, of 

 the total nitrogen required by the crop has been taken 

 from the soil. This is one reason why nitrogen and the 

 essential ash elements should be present in the soil in 

 available and liberal amounts for a wheat crop. When 

 the largest amount of any element or compound is taken 

 as loo, the corresponding amounts present during the 

 different stages of growth of the wheat plant are as 

 follows : 



Wheat, 50 Wheat, 65 Wheat, 80 Wheat, 

 days, before days, headed days, milk harvest 

 heading out. out. state. time. 



Total dry matter 46 59 95 100 



Organic matter 44 57 90 100 



Total nitrogen 86 89 96 100 



Potassium oxid 45 88 100 94 



Calcium oxid 67 91 100 96 



Magnesium oxid 57 68 99 100 



Phosphoric anhy drid .... 80 83 98 100 



351. Clover; Rapidity of Growth. In clover, the same 

 general order of changes occurs at the different stages of 

 growth as in wheat, but as the two plants are so unlike, 

 clover being a biennial and a legume, and wheat an 

 annual and a grain, the rapidity of growth and formation 

 of organic compounds in the two plants are naturally 

 dissimilar. The largest amount of the dry matter in 

 clover is produced between early and full bloom. During 

 this period about 60 per cent, of the organic compounds 

 are formed. As in the case of wheat, the nitrogenous 



