59 



Fertilizer. Manure. Plaster. Lime. 



Value net increment due to $30.39 $33.10 

 Value of decrease due to $5.07 $4.05 



Financial result, 18.39gain S.lOgain 5.791oss 5.011oss 



These comparisons make it evident that potash was much more 

 beneficial than either phosphoric acid or nitrogen. Alone and in 

 every combination it much more than pays for itself ; but it is far 

 more effective when phosphoric acid is present than when used alone, 

 and produces a yet larger increase when used in conjunction with 

 both phosphoric acid and nitrate of soda, thus indicating a high 

 degree of general exhaustion in this soil. Only when tlie other impor- 

 tant elements are supplied also can the potash produce its maximum 

 effect. The "complete" fertilizer though supplying only : nitrogen, 25 

 pounds; phosphoric acid, 48 pounds ; and potash, 81 pounds, gave 

 a net increase of about 56 bushels of potatoes, while the manure 

 although supplying five and one-half times the nitrogen, more than 

 twice the phosphoric acid, and almost twice the potash, produced a 

 net increase of only about sixty bushels. The profit on the use of 

 the fertilizer was much larger than on the manure, although the latter 

 has undoubtedly left the soil in the better condition. 



Neither lirae nor plaster appears to have been beneficial, though it 

 is not to be supposed that these fertilizers were the actual cause of 

 the inferiority— as compared with the nothings — of the crops where 

 they were applied. 



A potato fertilizer for such soil as this should contain nitrogen^ 

 phosphoric acid and potash, and I should judge that materials furnish- 

 ing per acre: nitrogen, 30 pounds ; phosphoric acid, 60 pounds, and 

 potash, 100 pounds, might give a profitable crop. 



