Effect of Phosphate Fertilization on Biological Compatibility of Chlorisgayana and Centrosemapubescens Mixture

. Intercropping between grass and legume in recent years has received great attentions because of potential advantage it offers to improved utilization of growth resources. In this respect, an experiment on biological compatibility of Rhodes grass (Chloris gayana) planted with Centro (Centosema pubescens) and applied with phosphate fertilizer had been conducted. The experimental design used was randomized block design arranged in factorial combinations of five Rhodes grass Centro mixture with the ratios of 4 0, 3 1, 2 2, 1 3 and 0 4, and two levels of phosphate application. The biological compatibility indices used were relative yield total, relative crowding coefficient and aggressivity index. Competition indices revealed that all mixtures showed Relative Year Total (RYT) values of greater than one, with 2 2 ratio in unfertilized and 1 3 ratio in fertilized mixtures resulted in the highest RYT value. Relative crowding coefficient of Rhodes in mixtures were higher than that of Centro except for 1 3 Rhodes Centro mixture. Aggressivity index revealed that Rhodes was the most aggressive at 3 1 in unfertilized mixture and Centro was the most aggressive at 1 3 in phosphate fertilized mixture. Rhodes Centro in the ratio of 2 2 and fertilized with phosphate was the most compatible combination. Centrosema pubescens, Chloris gayana, phosphate fertilization, plant composition, biological compatibility