EED CLOVER. 139 



is equal to 272 pounds of ammonia. Four tons of clover hay, the pro- 

 duce of one acre, must contain a large amount of nitrogen, and remove 

 from the soil a large quantity of mineral matters abounding in lime, 

 potash and also much phosphoric acid. Now comparing what is re- 

 moved by a crop of wheat, we find that in a clover crop we remove 

 fully three times as much of mineral matter, and a great deal more 

 six times as much I believe as' we do in a crop of wheat. The total, 

 to give the exact figures, of mineral matter removed in an average crop 

 of wheat amounts ts 175 pounds per acre. 



Assuming the grain of wheat to furnish 1. 78 per cent of nitrogen, 

 and wheat straw .64 per cent., and assuming also that 1500 pounds of 

 wheat and 3000 pounds of straw represent the average produce per acre, 

 there will be hi the grain of wheat per acre 26. 7 pounds of nitrogen, 

 and in the straw 19.2 pounds, or in both together 46 pounds of nitrogen, 

 in round numbers equal to about 55 pounds of ammonia, which is only 

 about one-fifth the quantity of nitrogen in the produce of an acre of 

 clover. 



Wheat, it is well known, is especially benefitted by the application 

 of nitrogenous manures, and as clover carries off so large a quantity of 

 nitrogen it is natural to expect the yield of wheat after clover to fall 

 short of what the land might be presumed to produce without manure 

 before a crop of clover was taken from , it. Experience, however, has 

 proved the fallacy of this presumption, for the result is exactly the 

 opposite, inasmuch as a better and heavier crop of wheat is produced 

 than without the intercalation of clover. 



I believe that a vast amount of mineral manure is brought within the 

 reach of the corn (wheat) crop by growing clover. It is rendered avail- 

 able to the roots of the corn crop. Clover, by means of its long roots, 

 penetrates a large mass of soil. It gathers up, so to speak, the phos- 

 phoric acid and the potash which are disseminated throughout a large 

 portion of the soil ; and when the ground is plowed the roots are left 

 in the surface, and in decaying they leave in an available condition the 

 mineral substances which the wheat plant requires to enable it to 

 grow. 



Although in clover hay these manurial matters are removed in great 

 quantity, yet the store of mineral food that we have in six or twelve 

 inches of soil is so great that it is utterly insignificant in comparison 

 with what remains. In other words, the quantity of mineral matter 

 which is rendered available and fit for use for the succeeding wheat 

 crop is very much larger than the quantity which is removed in clover 

 hay. 



But the accumulation of nitrogen after the growth of clover in the 

 soil is very large. Even when the clover crop is insignificant, a large 



