Resource-conserving technologies in the rice-wheat system of South Asia, field evaluation and simulation analysis
2009
Pathak, H. | Ladha, J.K. | Singh, Y. | Hussain, A. | Hussain, F. | Munankarmy, R. | Gathala, M.K. | Verma, S. | Singh, U.K. | Minh-Long Nguyen
Resource-conserving technologies (RCTs) have the potential to increase input- use efficiency and improve the sustainability of the rice-wheat (RW) systems of South Asia. The impact of RCTs on yield and N dynamics in RW systems was evaluated in field trials conducted at Lahore, Pakistan, Ludhiana and Modipuram, India, Ranighat, Nepal, and Meherpur, Bangladesh, for 4 years during 2002- 06. The RCTs gave similar wheat yield but lower rice yield by 0.9 to 1.3 1 ha-1 compared with conventional practices. The Crop Estimation through Resource and Environment Synthesis (CERES)-Rice and CERES-Wheat models were evaluated using the data from these trials. Genotypic coefficients for rice and wheat cultivars were derived in this study. The models simulated the phenology, of rice and wheat crops satisfactorily at all the locations. The deviation, as estimated using the root mean square error (RMSE), of the predicted days from the observed days to flowering and maturity was only 7.0% and 5.6% for rice and 7.0% and 5.9% for wheat, respectively. There was poor prediction of rice yield by the model (RMSE 2.0 [ha-1) obtained with different RCTs. The predicted grain yield of wheat, however, agreed well with observed yield in all the tillage and crop establishment practices (RMSE 0.6 t ha-1). There was poor prediction of N uptake by rice (RMSE 38.3 kg N ha-1) and wheat (RMSE 36.3 kg N ha-1). The study suggested that wheat can be satisfactorily grown with various RCT5 but, for rice, the RCTs need refinement in terms of water, nutrient, and weed management to improve yield. The CERES model was able to capture the phenology, of rice and wheat and yield of wheat with RCTs but needs improvement for the estimation of yield of nce and N uptake by rice and wheat.
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