The oldest direct comparison between these two systems of farming,
so far as the writer has learned, is on the experiment fields of the
University of Illinois, where as an average of six years the yield
of corn has been 87 bushels an acre in grain farming and 90 bushels
in live-stock farming, the same crop rotation being practiced. Where
wheat was introduced the average yield for six years was 43.1
bushels in grain farming and 43.5 in live-stock farming.

No nitrogen was purchased in any form in either of these systems;
but clover is grown in the rotation to secure nitrogen from the air
and then the crop residues or farm manure is returned to the soil to
provide sufficient nitrogen for the grain crops. In all cases
phosphorus was used for these yields.

Even more encouraging than these six-year average results from
Illinois are the results of sixty years from Agdell Field at
Rothamsted.

Where mineral plant food was regularly applied, and where all the
manure produced by feeding the turnips was returned to the soil, in
a four-year rotation of turnips, barley, clover (or beans) and
wheat, with no other provision made for supplying nitrogen, the
yields per acre were as follows:

Turnips, 24,724 lbs. in 1848, and 26,410 in 1908.

Barley, 42.8 bushels in 1849 and 22.1 in 1909

Clover, 5586 pounds in 1850 and 7190 in 1910.