The effect of nitrogen source and clipping on the absorption of N, P, and K by Tifgreen bermudagrass (Cynodon dactylon x C. transvaalensis L.)

Abstract

Three controlled environmental experiments were conducted using a hydroponic design to study effects of repeated clipping, various N, P, and K substrate levels, and N forms on the uptake of N, P, and K by Tifgreen Bermudagrass (Cynodon dactylon x C. transvaalensis L.). The levels of N, P, and K used were 300, 150, 25 ppm N; 5, 30, 90 ppm; and 50, 250, 400 ppm K. Plants, when harvested, were separated into three fractions, (roots, mat, and clippings) and each fraction analyzed for N, P, and K content. Clipping every three days over a 21 day period caused no significant changes in the total uptake of N, P, and K. The greatest variation in uptake was found in the mat fraction. Initial uptake curves for N, P, and K at three substrate levels over a six-day period indicated a direct relationship between substrate levels and rate of uptake. There was a direct relationship between N and K substrate levels and the dry weight of clippings removed, whereas an inverse relationship was observed for P substrate levels. ...