Response of Four Tropical Pasture Grasses to Nitrogen Application

Abstract

The response of Para (Brachiaria mutica), Rhodes (Chloris gayana), Buffel (Cenchrus eiliaris) and Giant pangola (Digitaria spp.) grasses to nitrogen fertilizer at 0, 30, 60, 90 and 120 kg N/ha/cut was conducted at Packchong Animal Nutrition Research Centre, Nakhon Rachasima from September 1979 to July 1980. Six harvests were made at 45-50 day intervals. Rhodes grass gave the highest total dry matter yield (22,049 kg/ha), followed by Buffel, Para and Giant pangola (21,644, 16,866 and 15,269 kg/ha, respectively). There was a significant response in dry matter production to the application of 60 kg N/ha/cut cut no significant response beyond that level due to the soil moisture and temperature limitations to growth. The nitrogen response recorded occurred mainly in the early rainy period towards the end of the experimental period. Crude protein contents of the grasses tended to increase with nitrogen fertilizer applications, being generally low in the October harvest but quite high in the March harvest at the end of dry season, especially in Giant pangola and para grass. Para and Giant pangola grasses were noticeably nore efficient in terms of dry matter production per kg of N applied (18 kg DM/kg N ; 17 kg DM/kg N respectively) than Rhodes and Buffel grasses (8 kg DM/kg N ; 5 kg DM/kg N respectively).