Integrated Crop Management in the Eastern-Gangetic Plains of South Asia

摘要

Rice (Oryza sflriva)-wheat (Triticum aestivum) rotation is the major production system in the Indo-Gangetic plains of South Asia and mid hills and is important for the food security of the region. The productivity and profitability of the rice-wheat system are very low mainly because of inappropriate nutrient input and poor crop management practices. Field experiments were conducted in 21 farmers' fields in B ara and Parsa districts in the Eastern-Gangetic plains of Nepal from May 1999 to April 2002to evaluate site-specific nutrient management (SSNM) and integrated crop management (ICM) for improving rice-wheat productivity and profitability. Soil nutrient-supplying capacity (based on omission plot method) varied largely among farmers' fields. Ricesoil had a higher N, P, and K-supplying capacity (35-76, 8-17, and 63-98 kg ha~(-1), compared with wheat (16-41, 6-12, and 20-104 kg ha~(-1), respectively). Both SSNM and ICM strategies significantly improved the grain yields of rice and wheat. Overallyield increment by ICM over farmers' practice (FP) reached up to 2.3 Mg ha~(-1) (66%) in rice and 2.3 Mg ha~(-1) (87%) in wheat, suggesting that there is a large potential for increasing rice and wheat yields in Nepal. Yield gap 1 (maximum attainable yield-average yield in ICM) was 1.3 to 1.4 Mg ha~(-1) for rice and 0.3 to 1.0 Mg ha~(-1) for wheat. While yield gap 2 (maximum attainable yield-average yield in FP) ranged from 2.8 to 3.5 Mg ha~(-1) for rice and 2.3 to 2.8 Mg ha~(-1) for wheat. Rice N-use efficiencies increased up to 50% and 70% with SSNM and ICM, respectively, over FP. In wheat, N-use efficiency increased up to 46% by ICM over SSNM. The net profit gained by applying ICM over FP was higher in wheat (US 217 dollar) than in rice (US 73 dollar). The findings suggest the urgent need to develop an effective program for wider dissemination of ICM technology in the Eastern-Gangetic plains.