950 EXPERIMENT STATION RECORD. 



It was found that for the crops under test, corn, oats, wheat, clover, 

 timothy, and potatoes, and for the soils upon which they were grown, 

 phosphoric acid was the most important fertilizer constituent, with 

 nitrogen and potash following, in the order named. The largest increase 

 in yield was obtained with the complete fertilizers containing all these 

 constituents, but it is believed that the use of nitrogen and potash in 

 the same proportion to phosphoric acid in which they are found in the 

 crops is unnecessary under present conditions, and that the quantity of 

 phosphoric acid should considerably exceed that of either nitrogen or 

 potash in applications for corn, oats, or potatoes, while for wheat the 

 proportion of nitrogen may closely approximate that of phosphoric 

 acid. Dissolved boneblack seemed more effective than raw bone meal 

 or acid phosphate; basic slag stood next to it in effectiveness. 



"Nitrate of soda is apparently tlie most effective carrier of nitrogen in common use 

 as a fertilizer. . . . Slaughterhouse tankage ... is probably a less effective carrier 

 of nitrogen than nitrate of soda, but the cost of nitrogen in unmixed tankage when 

 due allowance is made for the phosphoric acid carried by the tankage is so much less 

 than in nitrate of soda that tankage becomes a much more ecouomical source of 

 nitrogen to the Ohio farmer than nitrate of soda. 



"This advantage in tankage disappears, however, when it is purchased in the 

 ordinary factory-mixed fertilizer, since the price at which such fertilizers are gen- 

 erally sold brings the cost of their nitrogen to a higher figure than its necessary cost 

 in nitrate of soda." 



The results further show that the phosphoric acid of finely ground 

 bone meal and tankage is as effective as the available phosphoric acid 

 of acid phosphate, and that when these materials are finely ground no 

 further treatment with sulphuric acid is necessary to render their phos- 

 phoric acid available. 



The fertilizing constituents of barnyard manure acted more" slowly 

 than those of commercial fertilizers, but as they cost much less in 

 manure it became the cheapest fertilizer. Applying manure to the sur- 

 face instead of plowing it under proved to be most advantageous. 



"The increase from fertilizers in these experiments was unusually large in 1897, 

 this being the first season of the experiments at this station in which the cereal crops 

 have given a general increase sufficient to cover the cost of fertilizers. In the aver- 

 age of the 4 seasons . . . the value of the increase of crop has only equaled the 

 cost of the fertilizer in a few instances. The most profitable increase in the average 

 is found in the crop which has received a fertilizer mixed from tankage and acid 

 phosphate, with a small addition of muriate of potash, used only on corn and wheat." 



Third report on potato culture, I. P. Roberts and L. A. Clinton 

 (New York Cornell Sta. Bid. 156, pp. 175-184). — This work is in contin- 

 uation of experiments now in progress for 4 years. Previous results 

 have been reported in former bulletins (E. S. R., 9, p. 345 and p. 1044). 

 The results for 1898 are reported, and the soil conditions, the various 

 operations, and other details of the experiment are described. Direc- 

 tions for making Bordeaux mixture are given, and the ferro-cyanid of 

 potassium test for the purpose of determining the amount of lime 



