HORTICULTURAL DEPARTMENT. 115 



their gain over their nothing plot which shows that the trials are not 

 carried far enough yet to draw definite conclusions. Plots XV and XVI 

 treated to ground bone and sulphate of potash have produced better 

 Tesults than the same fertilizers with nitrate of soda added, as in plots XI 

 and XII, or with sulphate of ammonia added, as in plots VII and VIII, 

 which seems to show that a fertilizer rich in nitrogen is an injury to the 

 potato crop. This point should be more thoroughly investigated. 



Our experiments and those of others ' have led to the following con- 

 clusion, that on fairly rich soil the addition of nitrate of soda or sidjihate 

 of ammonia to hone and potash is done at a financial loss if not at a 

 reduction in yield. 



Plots XVIII and XIX with potash alone gave a very profitable increase 

 over the nothing plot in 1891, but it had much less effect in 1892, although 

 there was still an increase. Comparing these two plots with plots XV and 

 XVI in the first table of fertilizer tests, it will be seen that potash alone 

 increased the yield to within 9.6 bu. per acre, as much as the potash and 

 bone combined, the latter giving an average increase of 86.6 bu. over the 

 nothing plot of that row, the former an increase of 77 bu. This shows 

 that potash was the element largely needed in the soil. The yield of 1892 

 shows that the phosphoric acid in plots in XVIII and XIX has become 

 largely exhausted, as the gain of the potash and bone plots had increased 

 over the previous year, and the gain of the potash plots had largely 

 •decreased. 



Plot IX, to which was applied one bushel of wood ashes, produced less 

 than the nothing plot in 1891 and a gain of 25.7 bu. in 1892, which 

 may seem at a variance to plots XV and XVI, for ashes contain potash and 

 phosphoric acid, the two substances that seem essential on our soil; but 

 ashes have a tendency to harden and compact the soil, which on our clay 

 loam counteracted the beneficial action that it might otherwise have 

 effected. 



The conclusions are summarized as follows: 



1. Considering the cost, manure is more profitable than commercial 

 fertilizers. 



2. Coarse manure is best used as a mulch. 



3. Ground bone and potash furnish all the elements needed on the 

 average farming land. 



4. Nitrate of soda or sulphate of ammonia is added to the above at a 

 loss. 



5. Sulphate of potash will give as large an increase as muriate, and as 

 its cost is one third less, it is to be preferred as a fertilizer. 



6. Fertilizers unless especially prepared for potatoes, are applied at a 

 loss, as they contain too much nitrogen. 



7. Fertilizers prepared for potatoes should consist largely of potash 

 and phosphoric acid, with from three to four times as much of the former 

 as the latter. 



1 The report of the R. I. experiment station for 1890, p. 25, shows a reduction in yield from 144.66 bn. 

 to 55 ba. per acre by the addition of sulphate of ammonia to ground bone and muriate of potash. 



N. J. bulletin No. 80 shows that the addition of nitrate of soda to bone-black and muriate of potash 

 increased the yield 2.6 bu. per acre in one case, and reduced it 1.7 bu. in another, and 6.1 bu. in the third 

 <oaee. 



