112 BULLETIN 699, U. S. DEPARTMENT OF AGRICULTURE. 
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. 4 
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 é 
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 : 
Ff 
2 
1 Wash. Agr. Expt. Sta., Popular Bul. No. 49 (1912). 
2W. Va. Agr. Expt. Sta., Bul. No. 28, pp. 57-60 (1892). 
3 Wis. Agr. Expt. Sta., 22d Ann. Rept., pp. 275, 281 (1905); Bul. No. 147, pp. 27-34 
(1907) ; 24th Ann. Rept., pp. 261—271 (1908) ; Bul. No. 202, pp. 8-11 (1911) ;.Bul. No. 
205, pp. 9-12 (1911). 
4 Wis. Agr. Expt. Sta., Research Bul. No. 20 (1912). 
5 Wis. Agr. Expt Sta., Research Bul. No. 29 (1913). 
6 Wis. Agr. Expt. Sta., Research Bul. No. 35 (1915), 
