Managing nitrogen and nutrient balances for long-term sustainable rice production with a changing climate
2018
Sabina, D.
Rice is the major staple crop for nearly half of the global population and with the population growth the demand for rice continues to increase. Rice cultivation is in crisis because of the shrinking area, fluctuating annual production, stagnating yield and escalating input costs. There is clearly an urgent need to find ways to grow more rice using sustainable management practices. As judicious nutrient management during rice production can improve crop yield, this study focused on how we can achieve sustainable rice production under changing climatic conditions by managing N and other nutrients in the soil. Phosphorus and K balances in long-term continuous rice cropping systems were established, effect of timing and distribution of N fertilizer on crop phenology, biomass production and yield among contrasting rice cultivars was determined, and the climatic variability in rice response to N was assessed. Results showed that the P balances developed for all N treatments in a continuous rice cropping system were all positive. As the N level increased, P balances decreased. In contrast, K balances were all negative and decreased or became more negative with increasing N level. Application of N at late booting stage during dry season resulted in better yield than in the other treatments. Solar radiation and N management practices play important roles in the crop's response to N. Maximum and minimum temperatures have less effect on the grain yield compared to solar radiation. Optimum N was higher in the dry season compared with the early wet season.
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