508 ALFALFA 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 Illinois gets undoubted 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 ground, 
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. 
Immediately Available 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 1s not harrowed in it will 
give results. Basic slag, when it can be harrowed 
