Increasing sustainability for rice production systems

Rice (Oryza sativa L.) is the staple food for millions of people in Asia and the world; however, it is also the largest consumer of freshwater resources worldwide. More than 75% of the world's rice is grown under flooded conditions. However, the long-term sustainability of this flooded system is threatened by the rapid changes in climatic events causing erratic rainfall and abiotic stresses, looming water and energy crisis, low nitrogen use efficiency, increasing micronutrient deficienties, increasing labor costs and reduced labor availability, increased methane emissions, yield stagnation, and the negative effects of rice crops on post-rice crops. The narrow genetic background in rice has also slowed the pace of breeding rice cultivars tolerant to abiotic and biotic stresses which has resulted in yield stagnation. While direct-seeded rice has become popular in developed countries, saving water and labor resources and reducing methane emissions, developing countries in Asia struggle to disseminate direct seeding technologies due to the lack of government support and policy. Weed management in direct seeded rice is still a major bottle neck in wide scale adoption of this rice system in developing world. Mechanical transplanting of rice is gaining momentum in Asia, reducing labor requirements, ensuring timely transplantation, and saving water during initial growth. Nonetheless, government support and strong policy are needed to boost its uptake by providing subsidies to purchase mechanical transplanters and training farmers to use this technology. With deteriorating soil health due to continuous cultivation of rice with cereals in rotation, overuse of synthetic fertilizers, and increased co-occurrence of abiotic and biotic stresses in rice, there is a need to adopt integrated crop management techniques, and to identify genes of interest and quantitative trait loci (QTL) for their introgression into desired plants. These interventions will improve the improve biotic and abiotic stress tolerance in rice. There is also a need for extensive campaign and policy support from the government to force farmers to harvest their rice crops using specific rice harvesters that can save the yield losses that occur when using wheat combine harvesters—a common practice in many developing countries.