326 Bulletin 179. 



either nitrogen or superphosphate. Potash, when used with nitrate 

 of soda, gave better results than when used with superphospliate. 



The results of these experiments would seem to indicate that a 

 complete fertilizer would give the best results when used on tliis 

 fiekl, and that the greater portion of it should be potash with only 

 a moderate amount of nitrogen and but little superphosphate. 



In 1S97 Air. Bonnell experimented with potatoes on another part 

 of tlio farm ; the results indicated tliat potash gave rather the best 

 results. In 1808 oats were grown on this piece of ground and the 

 snpei'pliosphate plats gave the best yields. Again in 1899, two years 

 after the fertilizers had been applied, wheat was grown on it. The 

 plats that had received superphosphate in 1897 still gave the largest 

 crops. These results indicated one of two conditions: either that 

 the cereal plants, oats and wheat, could not find enough phosphoric 

 acid in that soil, unless supplied in the fertilizers ; or that the cal- 

 clwni sulphate (gypsum or land-plaster), of which all superphos- 

 2)hates are largely composed, gradually made available some of the 

 tightly locked potash that existed in the soil, and that it was this 

 liberated potash and not \\\q phosphoric acid that gave such marked 

 results the second and third year following the application of the 

 fertilizers. 



It was formerly a common practice to use calcium sulphate (plas- 

 ter) upon land for the purpose of making av^ailable some of the 

 tightly locked plant-food, especially ^t>^(^5A. 



Experiments of Mr. A. 0. Stewart, Mariposa, N. Y. — Mr. 

 Stewart has experimented for the past three years, in 1897 and 1898 

 on potatoes and in L899 on corn for the silo. On Sept. 21, '99, one 

 squai-e rod of each plat was cut, shocked and photographed. (See 

 cuts, next page.) Then each shock was weighed and the yield per 

 acre estimated. Also after a week of warm weather the remaining 

 crops tm each plat were cut and weighed in order to determine 

 whether the estimated yield per acre would vary much whether 

 based on the yield of one square rod, or of eight square rods. In 

 general, the smaller the area taken for estimating the crop per acre, 

 the greater the probable errors in the calculation. These results 

 are tabulated on page 328. 



