Fertilizer Management Strategies for Sustainable Rice Production

Rice cultivation is dominated by chemical fertilizers. Since 1960, the use of chemical nitrogen (N) fertilizers in agriculture has increased by ninefold and P by threefold and thus deteriorating soil health and polluting the environment. The role of chemical fertilizers in rice yield is c. 59%–69% only, but its use with organic nutrient sources can help in improving rice grain yield and soil carbon storage. Use of organic and inorganic nutrients is responsible for obtaining 0.78%–117% higher yield compared to chemical fertilizers alone. Application of biofertilizer along with 50% reduced N and phosphorus (P) gave 32% higher rice yield over chemical fertilizers. Contribution of diazotrophs for N nutrition in rice can be as high as 50–120 kg/N/ha. Phosphate-solubilizing microorganisms increase P bioavailability. Green manuring rice with Sesbania improves soil carbon status and increased yield by 9%–11% over chemical fertilizers indicating that it is a good option for organic rice farming. So, sustainable and ecosystem-friendly rice production will depend on combined use of inorganic and bioorganic fertilizers in future.