. 1 Pihod 



New York Agricultural Experiment Station. 25 



(c) Ratio of profit of cheese to "batter, 1 : 2.62. 



(d) Ratio of profit of butter to cream^~~l„Ll2»83. ^ , 

 {e) Ratio of profit of milk to cream, 1 : 3.66. "~^—- '^ 



(/") Ratio of profit of cheese to cream, 1 : 7.40. 



VIII. Comparative Field-tests of Commercial Fertilizers Used 

 in Raising Potatoes. 



SUMMARY. 



I. Object and Plan of Investigation. — The object of the work 

 was to compare ten different brands of commercial fertilizers used 

 in raising potatoes. Potatoes were planted in 26 plots containing 

 about one-eighth of an acre each. In the use of one brand, the 

 fertilizer was put on in quantities equivalent to 1,000, 1,500 and 

 2,000. pounds an acre, being applied both broadcast and in the row. 

 In all other cases, the fertilizer was applied in the row in quantities 

 •equivalent to 1,000 and 2,000 pounds an acre. 



II. Soil. — The soil was a sandy loam underlaid with sand and 

 gravel. For five years previous it had been used in raising clover 

 and timothy without applipation of fertilizers. 



III. Composition of Fertilisers Used. — In the fertilizers used, 

 the nitrogen varied from 3.27 to 4.50 per cent. ; the available phos- 

 phoric acid, from 5.85 to 8.37 per cent. ; and the potash, from 6.15 

 to 11.55 per cent. 



lY. Amount of Fertilizing Constituents Applied on One 

 Acre. — Nitrogen was applied in quantities varying from 32.T to 90 

 pounds an acre; available phosphoric acid, from 58.5 to 167.4 

 pounds ; and potash from 61.5 to 231 pounds. 



Y. Yield of Potatoes. — (a) In every instance, the use of fer- 

 tilizers increased the yield of potatoes, the increase varying from 5.4 

 to over 81 bushels an acre, (b) The use of 2,000 pounds of fer- 

 ilizer an acre did not always increase the yield over that produced by 

 the use of 1,000 pounds, (c) The increased application of fertilizer 

 usually increased the proportion of marketable potatoes. 



YI. Relation of Yield of Potatoes to Cost of Fertilizer Used. — 

 (a) The value of the crop at 50 cents a bushel varied on the different 

 plots from $75.30 to $116.55. (b) Each bushel of potatoes due to 

 increased yield from use of fertilizer cost from 26.2 cents to $4.35. 

 (c) In the most favorable case, the extra yield of potatoes, due to 

 the use of fertilizer, was worth enough to pay for the fertilizer 



