Page:Popular Science Monthly Volume 84.djvu/67

Rh application of manure and the same rotation of crops as the remaining 37 acres, but no phosphate was applied to this strip, and no limestone was applied to it until the fall of 1912, when the regular application (about 2 tons per acre) was applied to one half (three rods) of the six-rod strip.

Only 39 acres of this field were seeded to wheat in the fall of 1912, a lane having been fenced off on one side; and the 1,320 bushels were produced on the 39 acres.

The actual yields were as follows:

1$1⁄2$ acres with farm manure alone produced 11$1⁄2$ bushels per acre.

1$1⁄2$ acres with farm manure and the one application of ground limestone produced 15 bushels per acre.

36 acres with farm manure and two applications of ground limestone and two of fine-ground phosphate produced 35$1⁄2$ bushels per acre.

The cost of two tons of limestone delivered at my railroad station is $2.25, and raw rock phosphate has averaged about $6.75 per ton, making $9 per acre the cost for each six years.

To this must be added the expense of hauling these materials two miles from the station and spreading them on the land, which I estimate at 50 cents per ton. This makes the average annual cost $1.75 per acre for the limestone and phosphate spread on the field, and this average annual investment resulted in the increase of 24 bushels of wheat per acre in 1913.

Thus we may say that the previous applications of these two natural stones in this system of farming brought about the production in 1913 of 864 bushels of wheat, sufficient to furnish a year's supply of bread for more than a hundred people. And the soil is not being stimulated or depleted of any element in which it is naturally deficient. On the contrary, there is positive soil enrichment; "new" nitrogen is secured from the air, the phosphorus content has already been increased to that of the $200 corn-belt land, and sour land is changed to a "limestone soil." No high-priced or artificial commercial fertilizers are used on this farm; and the results secured from 40-acre fields on a 300-acre farm are practically the same as on the one fifth-acre plots of the state experiment fields under similar systems.

Poorland Farm is usually inspected each year by my class of university students in soil fertility, about one hundred of whom saw the fields of wheat and clover in June, 1913. It is for the benefit of such as these, who desire to know the truth regarding economic systems of permanent soil improvement, that this brief statement is published.