Yield‐of‐Phosphorus Curves

This paper embraces a study of the curves relating the total phosphorus absorption by plants with the fertilizer phosphorus additions (yield‐of‐phosphorus curves) and may be summarized as follows: For applications up to 160 pounds P 2 O 5 per acre mixed throughout the soil, the “normal” yield‐of‐phosphorus curve was found to be an ascending straight line. Extrapolation of the yield‐of‐phosphorus curves to the point of intersection with the X axis gave a measure of the available soil phosphorus which approximated the ‘A’ value. Estimates obtained by extrapolation of yield curves gave values about half has large. The slope of the yield‐of‐phosphorus curves is to a degree influenced by the phosphate fixation processes.