336 TALKS ON MANURES. 



crop the produce obtained, wliera mineral manures without 

 nitrogen were used. In 1853 this amount was three thousand 

 pounds, and in 1879 it was ons thousand two hu.idred pounds. 

 Deducting thsse amounts from the gross produce in each cass, 

 leaves si^: thousand three hundred and thirty as the produce 

 due to the nitrogen in the season of 1833, and two thousand six 

 hundred and fifty-nine as the produce due to the nitrogen in 

 1879. 



But in each case we applied the same amount of nitrogen, 

 eighty-seven pounds ; and as the amount of nitrogen in a wheat 

 crop, as carted from the field , contains less than one per cent, of 

 nitrogen, it is evident that if all that was contained in the 

 manure had been taken up by the plant, the increased crop 

 should have weighed ei^lib thousand seven hundred pounds in- 

 stead of six thousand thi\33 hundred and thirty. Thus even in 

 our best year, some of tho nitrogen applied failed to produce 

 growth ; and when we come to the bad year we find that only 

 twenty-six and a halt' pounds were taken up out of the eighty- 

 seven pounds applied, thus leaving more than two-thirds of the 

 whole unaccounted for. 



Seasons are only occasionally either very bad or very good. 

 What we call an average season does not differ very much from 

 the mean of the best and worst years, which in this caia 

 would be represented by a crop of four thousand four hundred 

 and ninety-four pounds, containing nearly forty-five pounds of 

 nitrogen. I may say that, although I have employed one per 

 cent, to avoid fractions in my calculations, strictly speaking 

 three-quarters of a per cent, would more nearly represent the 

 real quantity. If, however, on the average, we only obtain 

 about forty-five pounds from an application of about eighty- 

 seven pounds of nitrogen, it is evidant that not more than one- 

 half of the amount applied enters into the crop. 



Now in dealing with a substance of so costly a nature as am- 

 monia, or nitrate of soda the nitrogen contained in which 

 substances cannot cost much less than twenoy-five cents per 

 pound by the time it is spread upon the land, it becomes a ques- 

 tion of importance to know what becomes of the other half, 

 or the residue whatever it may be, which has not been taken 

 up by the crop. Part is undoubtedly taken up by the weeds 

 which grow with the wheat, and after the wheat has been 

 cut. Part sinks into the sub-soil and is washed completely 

 away during the winter. 



I, myself, am disposed to think that the very great difference 



