RESTORING FERTILITY TO THE SOIL. 335 



In support of this view, I may mention that we have clear 

 evidence in some of our experiments of the wheat crop taking 

 up both phosphates and potash that were applied to the land 

 thirty years ago. 



To suppose, therefore, that, if the ingredients which exist in 

 twenty bushels of wheat and its straw, are simply applied to a 

 barren soil, the crop will be able to come in contact with, and 

 take up these substances, is to assume what certainly will not 

 take place. 



I have often expressed an opinion that arable land, could Dot 

 be cultivated profitably by means of artificial manures, unless 

 the soil was capable of producing, from its own resources, a 

 considerable amount of produce ; still the question had never 

 up to this time come before me in a distinct form as one upon 

 which I had to decide one way or the other. I had, however, 

 no hesitation in coming to the conclusion, that grain crops could 

 never be grown at a profit upon my relation's land, and that 

 consequently, for some years, it would be better to give up the 

 attempt, and try to improve the pasture. 



After what I have said about the insolubility of potash and 

 phosphoric acid, it may possibly be asked why not give a good 

 dose of these substances at once, as they do not wash out of 

 the soil say enough to grow sixty crops of grain, and apply 

 the nitrate, or ammonia every year in just sufficient amounts 

 to supply the wants of the crop ? 



The objections to this plan are as fellows: assuming the most 

 favorable conditions of climate, and the largest possible pro- 

 duce, the wheat could certainly not take up the whole of the 

 thirty-two pounds of nitrogen applied, and the crop which re- 

 quires nearly one pound of nitrogen in eveiy one hundred 

 pounds of gross produce, would be certainly less than three 

 thousand two hundred pounds, if supplied with only thirty-two 

 pounds of nitrogen. If we take the total produce of the best 

 and worst wheat crop, grown during the forty years of our ex- 

 periments, we shall arrive at a better understanding in the 

 matter. The following are the figures : 



WEIGHT OF DRY PRODUCE OF WHEAT PER ACRE. 



Straw and Grain. 



1863 ---- 9330 Ibs. 



1879 3859 " 



In order to ascertain the increase due to the nitrogen of the 

 salts of ammonia or nitrate of soda, we must deduct from the 



