ARTIFICIAL MANURES AND HORTICULTURAL PRACTICE. 57 



Muriate of potash alone, gave a better result on the "light "soil than 

 did the superphosphate, but a worse result on the " heavy " soil, 

 pointing to the fact that the " heavy " soil contained a sufficient 

 supply of available potash, but that it was lacking in assimilable 

 phosphoric acid. 



A mixture of superphosphate, potash, and nitrate of soda, 

 raised the crop of tubers on the " light " soil to nearly 139 

 bushels per acre, and on the " heavy " soil to more than 193 

 bushels per acre, a gain over the unmanured of 73 bushels on 

 the " light " soil, and of 95 bushels on the " heavy " soil. 



The incapacity of the potato crop to avail itself of the 

 supplied nitrogen in manure, in the absence of a sufficient avail- 

 able supply of mineral constituents, is here very strikingly 

 illustrated on each description of soil. 



Table VIII. is an illustration of experiments on the growth 

 of tomatos at New Jersey. The figures show the yield of fruit 

 per acre, without manure, with various artificial manures, and 

 with farmyard manure. The quantities are given in pounds. 



Table VIII. — Experiments on Tomatos at New Jersey. Yield of 

 Fruit per Acre. Quantities in pounds. 



Manure per acre 



Quantity of 

 fruit 



Gain over 

 unmanured 





lbs. 



lbs. 





452 





Nitrate of soda, 160 lbs 



646 



194 





600 



148 



Nitrate of soda, superphosphate and potash . 



728 



276 



Farmyard manure, 20 tons 



698 



246 



The results show that without manure a yield of 452 lbs. of 

 tomatos per acre was obtained ; nitrate of soda alone produced 

 646 lbs. of fruit, a gain of 194 lbs. per acre over the unmanured. 

 Superphosphate and potash applied together yielded less than 

 did the nitrate of soda alone ; but when these ingredients — the 

 minerals and the nitrogenous manure — were supplied in com- 

 bination, there was obtained 728 lbs. of tomatos per acre, a gain 

 over the unmanured of 276 lbs. 



Farmyard manure applied at the rate of 20 tons per acre, 



