508 ALPAIiPA FARMING IN AMERICA. 



and turning all under. Untreated phosphatic rock 

 becomes available only by the action of the decay 

 of vegetable matter in the soil, and it is probable 

 that the phosphate should be in intimate contact with 

 the decaying vegetable matter. It seems to me that 

 this substance should always be used in stables, 

 sprinkled over the manure. Unhappily we left no 

 check strips to determine the effect of the phos- 

 phorus that we applied, so we do not know. Dr. 

 Cyril G. Hopkins in Dlinois gets imdoubted results 

 from turning under raw phosphate in connection 

 with green manures or stable manures. Prof. C. E. 

 Thorne of Ohio gets undoubted results when it is 

 used in connection with manure, in intimate contact. 

 Theoretically the raw phosphate, very finely groimd, 

 is the material to buy for soil-building. One gets 

 about four times as much of the element phosphorus 

 for his dollar in raw rock phosphates as in any other 

 form. He should be sure that he gets the fine- 

 ground material — the finer the better. In my 

 opinion he should then as much as is possible use it 

 in his stables, in boxstalls, directly on manures. 

 Thus used, it seems always to become available. 



I ni mediately Urailahle Phosphates. — ^Neverthe- 

 less, we shall continue the use of immediately avail- 

 able phosphates for starting alfalfa and for feeding 

 it year by year after it is established. For this use 

 nothing seems quicker than acid phosphate, which 

 is the raw rock treated with sulphuric acid. It is 

 so soluble that even if it is not harrowed in it will 

 give results. Basic slag, when it can be harrowed 



