180 ALFALFA FARMING IN AMERICA. 
cause I have seen such good effects come from its 
use in England, and because it did equally well on 
Woodland Farm. It will never perhaps be cheap 
enough for use west of the Allegheny Mountains, 
since it is all imported from England or Germany, 
but along the Atlantic seaboard it is now probably 
as cheap a source of phosphoric acid as anything 
known. With basic slag one gets quite a little lime 
free of cost, since usually there is about 55% of 
carbonate of lime in basic slag. It should sell for 
about $1 per unit; that is, a slag analyzing 18% 
phosphoric acid should sell for $18 per ton, when it is 
about as cheap as any other source of phosphorus 
with the lime thrown in. 
In England on old pastures basic slag works 
miracles. There with the sowing of no seeds at all 
clovers spring up and cover over the land, almost 
crowding out the grasses. The lime has sweetened 
the soil, the phosphorus fed it, the clovers result. 
Later the decay of clover leaves and stems fill the 
soil with available nitrogen which in turn feeds the 
grass. When will we learn in America to feed soils? 
Other Sources of Phosphorus——Prof. Alfred 
Vivian, of the Ohio State University, so clearly and 
concisely states the composition of phosphatic fer- 
tilizers in his admirable little book, ‘‘First Prin- 
ciples of Soil Fertility,’’ that we here quote: 
Phosphoric acid is present in the soil in much smaller quan- 
tities than potash, and experience shows that it is much more 
likely to become exhausted. In fact, there are sections of the 
country where no other fertilizers than those furnishing phos- 
phoric acid are used, while these are bought in large quantities. 
