Page:Popular Science Monthly Volume 78.djvu/266

256 I lived on one field for thirty-one consecutive years, and as an average of the last six years the yield was only 23 bushels per acre. Thus it required three years to produce 69 bushels, whereas 87 bushels are now produced in one year under this system of permanent soil improvement in grain farming; and even 90 bushels per acre are produced where limestone and phosphorus have been used in the live-stock system, which, you remember, was also suggested by Doctor Science, and which we have been trying out on Field D."

The writer also has a confession to make:

The six-year averages of 87 bushels in grain farming and of 90 bushels in live-stock farming are the records of the Illinois Agricultural Experiment Station for the last six years, 1904 to 1909.

 Manure alone (on left) supplies but little phosphorus and will not correct the soil acidity. Manure, limestone and rock phosphate (on right) produces a large yield of clean clover. (If the Corn Belt needs limestone and phosphorus, what shall we say of "Egypt"?

During the same six years the average yield of oats was as follows:

As an average of three years during which the second crop of clover was harvested for seed, 1907, 1908 and 1909, the yield of clover seed was as follows:

As an average of the last three years, 1907, 1908 and 1909, the yield