The Effect of Stubble Mulching on the Acid Soluble and Adsorbed Phosphorus in the Soil
1954
Withee, L. V. | McCalla, T. M.
Plots having a 13- and 15-year history of continuous plowing and stubble mulching were sampled and analyzed to determine if the two tillage practices had resulted in differences in the phosphorus content of the tilled layer. The plots were selected from two series of rotations of high and low fertility level established for the study of stubble mulching in relation to erosion, moisture storage and crop yields. The plots were sampled in three layers, 0 to 1, 1 to 3, and 3 to 6 inches. Determinations of acid soluble and adsorbed phosphorus were made on each of the composited soil samples. There was a significant increase in the acid soluble and adsorbed phosphorus content of the surface inch of soil over that in the 3 to 6 inch layer of the subtilled plots. The variation in the acid soluble or adsorbed phosphorus in different depths of the plowed plots was consistently less than that of the stubble mulch plots. In all instances the subtilled plots contained more acid soluble and adsorbed phosphorus in the surface inch than did the plowed plots. There was very little difference in the phosphorus content of the 0 to 6 inch depth of the plots in stubble mulching or plowing.
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