APPENDIX 347 



CLASSIFICATION AND REQUIREMENTS OF CROPS 



Group A: Wheat, barley, rye, oats, timothy hay, require 

 first nitrogen, next phosphoric acid, last potash. 



Group B : Corn, cotton, require first phosphoric acid, 

 next potash, last nitrogen. 



Group C : Peas, beans, clover, red clover, hay, require 

 first potash, next phosphoric acid, last- nitrogen. 



In this table, corn in its demand for nitrogen as com- 

 pared to potash and phosphoric acid is allied to clover rather 

 than being classed with wheat, barley, oats, timothy hay, etc, 

 as had been the rule previously. 



The estimated cost for fertilizer required for growing 

 these staple crops on average soils in this country was on the 

 following basis : Phosphoric acid and potash, full quantities 

 as shown by analysis to be contained in each crop, that is, 

 full rations ; nitrogen, one-half rations for wheat, barley, 

 oats, meadow hay, one-quarter rations for corn and one-tenth 

 ration for peas, beans and clover. 



In the New Jersey report for 1879, Mapes reviewed Lawes's 

 and Gilbert's manurial experimentation at Rothamsted for 

 thirty years. For the total period the wheat crop received 

 about 3540 pounds more nitrogen per acre in farm manure than 

 in chemicals or concentrated fertilizers, and barley received 

 3021 pounds more nitrogen per acre in farm manure than in 

 the concentrates. Yet in both experiments the results from the 

 concentrated manures were equally good in every particular. 

 What became of these differences in nitrogen, amounting in 

 the two cases to 6551 pounds per acre, representing probably a 

 value of $1200? 



Dr Lawes replied (seventh report New Jersey board of 

 agriculture) "that no subject has occupied our attention more 

 than that with relation to the assimilation, accumulation or 

 loss of nitrogen," and concludes that a considerable propor- 

 tion of it is retained in the soil. 



Mapes also emphasized that the plain superphosphate, even 

 with the addition of potash, magnesia and soda, but without 

 nitrogen, produced an average increase in the wheat crop of 

 only one and one-quarter bushels per acre per annum above 

 the yield from the natural unmanured soil. But when nitro- 

 gen was added, in the form of sulphate of ammonia, the yield 

 went up from seventeen to thirty-five bushels as the average 

 per annum per acre. 



Dr Henry Stewart and others proved by their experience 

 and writings that "if we had to supply all the nitrogen corn 

 consumes, it would cost more to grow the crop than it would 

 come to," whether the nitrogen were supplied in the form 

 of manure or of fertilizers. Stewart pointed out (eighth report 

 New Jersey board of agriculture, 1881) that, since it was neces- 



