112 BULLETIN 609, U. S. DEPARTMENT OF AGEICULTUBE. 



WASHINGTON AND WEST VIRGINIA- 



Only one field experiment ^ with raw rock phosphate has been pub- 

 lished by the Washington Experiment Station, and four^ by the 

 West Virginia station. None of these have been continued beyond 

 one year, so they are not repeated in detail. 



WISCONSIN. 



Four field experiments' with raw rock phosphate have thus far 

 been reported by the Wisconsin Experiment Station, but since none 

 of them have been continued beyond two years they are not consid- 

 ered in detail in this bulletin. 



The excellent work of Truog,* Tottingham and Hoffman" and 

 Fred and Hart * on the solubility and availability of phosphates and 

 the mutual action of bacteria and phosphates on one another is dis- 

 cussed elsewhere in this bulletin. 



While the results of the Wisconsin station's work on ground raw 

 rock are too limited to draw any definite conclusions, the indications 

 point to its value as a fertilizer on peaty soils. No comparison of 

 acid phosphate and raw rock phosphate, however, is warranted. 



EXPERIENCE OF FARMERS WITH RAW ROCK PHOSPHATE AS A 



FERTILIZER. 



While the field work of the State experiment stations is as a rule 

 much more valuable to the student of agriculture and their results 

 much easier of interpretation, at the same time the experience and 

 opinions of a large number of progressive farmers who have given 

 raw rock phosphate a fair trial, are of considerable value and 

 worthy of serious consideration. 



In order to determine the sentiment of such farmers toward raw 

 rock phosphate a letter and set of questions was sent to each of 1,000 

 farmers in various parts of the country who had ordered more than 

 one shipment of this material. It might be argued that this method 

 of choosing names was hardly fair and on its face favorable to raw 

 rock phosphate, since the fact that the orders for this material 

 were repeated indicates very strongly that the consumers considered 

 it effective. On the other hand it is probable that those who sent in 

 but one order for raw rock phosphate reached an unfavorable deci- 

 sion concerning its fertilizer value before they had given it a fair 



iWash. Agr. Bxpt. Sta., Popular Bui. No. 49 (1912). 



«W. Va. Agr. Expt. Sta., Bui. No. 28, pp. 57-60 (1892). 



» Wis. Agr. Expt. Sta., 22d Ann. Rept., pp. 275, 281 (1905) ; Bui. No. 147, pp. 27-34 

 (1907) ; 24tli Ann. Rept, pp. 261-271 (1908) ; Bui. No. 202, pp. 8-11 (1911) ; Bui. No. 

 205, pp. 9-12 (1911). 



«Wis. Agr. Expt. Sta., Research Bui. No. 20 (1912). 



»Wis. Agr. Bxpt Sta., Research Bui. No. 29 (1913). 



• Wis. Agr. Expt. Sta., Research Bui. No. 35 (1915). 



