PERMANENT FERTILITY 63 



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^ acres with farm manure alone produced 11^ bushels per acre. 



14 acres with farm manure and the one application of ground lime- 

 stone produced 15 bushels per acre. 



36 acres with farm manure and two applications of ground limestone 

 and two of fine-ground phosphate produced 35^ 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 con- 

 trary, 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 univer- 

 sity 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. 



