56 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



in the litter remains a very long time inactive. Hence the addi- 

 tion of nitrogen as nitrate of soda, ammonia salts, or guano to 

 farmyard manure has a very marked effect on garden produce 

 generally, and especially that required for early production. 



Table VII. gives the results of experiments on the growth of 

 potatos at Connecticut, United States, " On light soil " and 

 " On heavy soil." The illustration is a summary of the total 

 tubers obtained over four years, 1878-1881. The quantities are 

 given in bushels per acre, without manure and with various 

 artificial manures. 



Table VII.— Experiments on Potatos at Connecticut, United 

 States. Summary of the Produce of Marketable Tubers per 

 Acre. Average of four years, 1878-1881. Quantities in bushels. 



Manure? per acre 



Tubers per acre 



Gain over uumanured 



In light 

 soil 



In heavy 

 soil 



In light 

 soil 



In heavy 

 soil 





bushels 



bushels 



bushels 



bushels 





65-7 



97-9 





- 



Nitrate of soda, 200 lbs. . 



79-0 



98-5 



13-3 



0-6 



Superphosphate, 300 lbs. . 



911 



1321 



25-4 



34-2 



Muriate of potash, 200 lbs. 



965 



118-7 



30-8 



20-8 



Superphosphate, potash and nitrate 











of soda 



1389 



193-3 



1 73-2 



95-4 



The data thus given shows that in each case there were 

 considerably more potatos grown per acre on the "heavy" 

 than on the " light " soil. 



Thus, without manure, there was obtained on the "light " 

 soil about 65J bushels of marketable potatos per acre, while the 

 " heavy " soil yielded nearly 98 bushels. Nitrate of soda alone 

 raised the produce on the " light" soil about 13 bushels per acre, 

 but less than 1 bushel per acre on the "heavy" soil. Super- 

 phosphate alone is seen to confirm very remarkably the results 

 obtained at Rothamsted, by producing considerably more 

 potatos per acre than the nitrate of soda alone. Thus on the 

 " light " soil there was a yield of 91 bushels per acre, and on the 

 "heavy" soil a yield of 182 bushels per acre, a gain over the 

 unmanured of 25-1 bushels, and 84*2 bushels per acre, respectively. 



