stimulating and temporary.

What Phosphorus Did on One Farm

On his 500-acre farm near Gilman, in the heart of the Illinois Corn
Belt, Mr. Frank I. Mann has produced a 70-bushel average yield of
corn for a five-year period, and with 200 acres of land in corn
annually. It cost him only $1 an acre a year in fine-ground natural
rock phosphate to produce increased yields of 16 bushels more corn,
23 bushels more oats and 1 ton more clover than the average yields
secured without adding phosphorus.

But this progressive, practical farmer is only putting into
profitable practice the results of the long-continued careful
investigations with raw phosphate conducted by such public-service
institutions as the agricultural experiment stations of
Pennsylvania, Maryland, Rhode Island, Massachusetts, Ohio and
Illinois. He knows also that on four different fields of typical
Corn-Belt land in McLean county, Illinois, the total crop values per
acre for a period of ten years were $148.75 $151-30, $149.43 and
$149.96, respectively, and that on four other adjoining or
intervening fields, which differed only by two liberal additions of
phosphorus during the ten years, the respective crop values for the
same time were $229,37, $221.30, $229.20 and $225.57.

Of course, Mr. Mann does not buy nitrogen, but be takes it from the
inexhaustible supply in the air by means of clover and alfalfa or
other legumes. He does not buy potassium because he knows how to
liberate it from the inexhaustible supply contained in the soil, and
because he knows that in the Illinois investigation just cited the