PURDUE UNIVERSITY
Agricultural Experiment Station
Circular No. 79 LaFayette, Ind., February, 1918
INDIANA SOILS NEED PHOSPHATES
A. T. Wiancko
S. C. Jones
SUMMARY
Indiana soils are notably deficient in phosphorus.
Available phosphates are the most profitable fertilizers.
Acid phosphate has given the best results.
Basic slag and steamed bone meal have also given good results, standing next to acid phosphate in profitableness.
Rock phosphate has given good results in certain cases, although it has been the least profitable of any of the phosphates used.
As a general average for 95 crops of corn, wheat and clover on five experiment fields during the last 12 years, acid phosphate has yielded crop increases valued at $8.46 per acre per year, at an average cost of $1.38, while rock phosphate has yielded crop increases valued at $3.32 per acre per year at an average cost of $1.44.
In immediate returns on the first and second crops after application, acid phosphate has yielded crop increases from three to over 25 times as large as those secured from rock phosphate.
Neither acid phosphate nor any other phosphate will increase soil acidity or the need for liming, although soils needing phosphorus generally also need lime.
Neither acid phosphate nor any other phosphate will injure the physical condition of the soil if due care is exercised to maintain the organic matter supply.
The only means by which the phosphorus deficiency can be made up is by the purchase and application of phosphatic fertilizers. Fortunately phosphatic fertilizer materials are plentiful in this country and relatively cheap.
This circular briefly presents the results that have been secured by this station from the use of different phosphates on five experiment fields on different soil types in different parts of the State during the last 12 years.
For details of the crop yields and increases secured from the different phosphates on the different fields send for a copy of Bulletin No. 210 of this station.