Circular No. 242
Purdue University Agricultural Experiment Station Lafayette, Indiana
May, 1939
SOILS AND CROPS EXPERIMENT FARM
Department of Agronomy A. T. Wiancko, Chief
R.	R. Mulvey, Associate in Crops
S.	R. Miles, Assistant in Agronomy
REPORT OF PROGRESS, 1915-1938
The Soils and Crops Experiment Farm, located immediately to the east of Lafayette, is representative of the great body of central' Indiana land, commonly called “black and clay,” and is classified as Miami or Crosby silt loam in the higher portions and Clyde or Brookston silt loam in the depressions. The land was in a good state of fertility to begin with.
The results of the experiments on this farm will closely indicate what may be expected from similar soil management, cropping systems, and crop varieties wherever the same types of soil are found.
On the Miami and Crosby or “clay” soil, where the principal fertility experiments are located, the differences between the untreated and manured or fertilized plots are already quite remarkable, averaging about 34 bushels of corn, 22 bushels of wheat and 2,400 pounds of clover hay per acre during the last nine years. Crop yields on the improperly treated land went down rapidly, while the properly treated land is improving from year to year.
Comparison of Cropping Systems on One-Half Acre Plots
The object of this experiment is to determine the relative merits of the different cropping systems shown in the following table. Each cropping system has as many one-half acre plots as there are crops in the rotation so that each crop is grown every year.
The soil treatments for all the rotations follow good farm practice where most of the produce, except the small grain, is used on the farm and the manure and crop residues returned to the land. In addition to the manure and crop residues, enough commercial fertilizer is used to fully maintain the phosphorus supply of the soil and to replace some of the potash removed that is not returned in manure. Legumes are largely depended upon to maintain the nitrogen supply of the soil, but a little commercial nitrogen is applied in the fertilizer for wheat and oats at seeding time.	.
In rotations 1 to 10 inclusive, manure is applied at the rate of 1,000 pounds per 1,000 pounds of produce removed, except wheat and oats grain and in the case of rotation 10 half of the alfalfa, and the grain farming systems where the roughage is left on the ground or returned for plowing under and no manure is used. M^heat after corn is top-dressed with two tons of manure in winter. The rest of the manure produced by the rotation is plowed under for corn. Soybean straw is returned for the following wheat crop.