The Influence of Organic Matter Additions on Rock Phosphate Availability to Crops

Abstract

A greenhouse experiment was conducted to evaluate the effects of adding organic matter to the soil on the availability of rock phosphate from two sources. The treated soils were cropped successively to Sudangrass, ryegrass, and two crops of red clover. Treatments receiving additions of organic matter yielded higher in most cases than the corresponding treatment without added organic matter. Increased yields were attributed to the additional P in the organic matter rather than to the beneficial effect of the organic matter on the availability of rock phosphate. Treatments receiving Florida rock phosphate yielded more than corresponding treatments receiving Tennessee rock phosphate.