Vegetative Regrowth, Nodule development, and Nitrogen Fixation of Tropical Legumes after Harvest : III. Greenleaf Desmodium

Abstract

A sand culture pot experiment investigated effects of harvesting intensities on vegetative regrowth, nodule development and effeciency of N_2-fixation in Desmodium intortum cv. Greenleaf. Expansion of leaf area and dry matter of plant top and root systems increased at higher clipping height and more so when leaves remained on the stubble were not removed. Nodule development was affected by harvesting treatments in the same manner with plant dry weight, but their recovery rates were faster than plant dry weights in all treatments. Rates of acetylene reduction also changed in the same manner with plant dry weight. Rates of hydrogen evolution and efficiencies of N_2-fixation have dropped for a short period after harvest and increased again, but a definite trend was not observed in both parameters among harvesting treatments. A comparison of the present data with other reports suggested that Greenleaf desmodium tended to persist in lower clipping heights as compared to Leucaena and Siratro. The data also suggested that harvesting treatment affected efficiency of N_2-fixation for long periods.