Mungbean ( Vigna radiata L.) Residue and Nitrogen Rate Affected Growth and Yield of Direct Seeded Rice ( Oryza sativa L.) In Rainfed Riceland

摘要

An experiment was conducted in a farmer?s field in Ban Muong village, Muang district in Khon Kaen province in 2003. The objective of this study was to investigate the effect of mungbean ( Vigna radiata L.) residue and nitrogen rates (0, 30 and 60 kg N ha^-1) on growth and yield of direct seeded rice ( Oryza sativa L.) in rainfed riceland. The results showed that mungbean residue had no effect on tiller number, leaf area index and total top dry weight of rice in rice-mungbean intercropping or sole rice cropping. Also, mungbean residue had no significant effect on panicle number m^-2, spikelets number per panicle, 1,000 grain weight, percentage filled grain, harvest index or grain yield However, mungbean residue tendes to increase rice grain yield over sole rice by 0.33 t ha^-1(13 %) with had no nitrogen application. Rice grain yield was significantly affected by nitrogen rates. The highest rice grain yield (2.7 t ha^-1) was obtained with a nitrogen rate of 30 kg N ha^-1. Nitrogen fertilizer application at a rate of 60 kg N ha^-1 decreased grain yield , when compared with 30 kg N ha^-1.