Addressing resource conservation issues in rice-wheat systems of South Asia: a resource book

Rice-wheat systems are critical to South Asian food security. Over a billion people depend on these systems for their food. More than 150 million people support themselves by growing rice in rotation with wheat in 13.5 million hectares of land in the lndo-Gangetic Plains (IGPs) of India, Pakistan, Nepal and Bangladesh. Indeed the livelihoods of millions of farmers and workers are dependent on these systems. The pressures on natural resources are immense: soils are less able to sustain crops as a result of continuous and intensive cropping and reduced organic matter levels. The development of sodicity and salinity on irrigated land and the depletion of groundwater in areas irrigated by tubewells and water quality concerns have brought about heightened awareness of the need for the judicious use of water. Tillage costs are rising, which accentuates the already serious labor shortages during peak periods of land preparation and harvest. For these and other reasons, the sustainability of these systems is in question. The Rice Wheat Consortium for the lndo-Gangetic Plains (RWC), an initiative that puts national agricultural systems in the above-mentioned countries at the forefront of efforts to address these issues, has supported the development of a wide range of resource-conserving technologies. Improved tillage and crop establishment practices, especially for rice, show real potential for sustainably improving the productivity and profitability of rice-wheat systems. Reduced and zero tillage can improve yields, raise input-use efficiency, reduce the intensity of machinery use and lower production costs. Zero-tillage allows farmers to establish a wheat crop almost immediately after rice harvest, thereby improving yields and input use efficiency. Surface seeding technologies can increase the use of underutilized ‘rice fallows’ in the eastern lndo-Gangetic Plains. Scientists are working jointly with farmers to find ways to manage rice and wheat residues that typically amount to as much as 7-8 tons per hectare each year. When burnt during land preparation, the residues instantly generate as much as 13 tons of carbon dioxide per hectare, contaminating the air, depriving soils of organic matter, and constraining supplies of fodder for livestock. Because zero-tillage involves the direct seeding of wheat and several other crops in rice residues, residual moisture use is increased and as much as 10 cm-hectares (approximately 1 million liters per hectare) of irrigation water is saved. It is thus no wonder that farmers have been quick to adopt zero tillage and other resource conserving technologies. From a modest 3,000 hectares of zero-till wheat in India and Pakistan in 1998-99, area surpassed 200,000 hectares in 2001. Another innovation being tested and promoted with farmers is the planting of wheat and rice on raised soil beds, where the furrows facilitate the movement of mechanized equipment and serve as a waterway. Water requirements are 503 less than those under conventional tillage systems. The major savings in water use will come from planting the rice on raised beds, and early results from tests with farmers suggest this system improves both yields and water use efficiency. Bed planting can also be used for legumes, maize, potato, vegetables, and other crops that would normally not be raised in a rice field. Good opportunities exist for better integration of ruminant livestock, with profitable conversion of crop by-products, increased use of manure and treatment of straw, among other benefits. Such intensification and diversification both offer opportunities to boost food security and incomes among the smallholders. The RWC is also working on new options for efficiently synchronizing nutrient management with crop nitrogen demands to reduce the use of chemical fertilizers. Thus, a “tillage revolution” is sweeping across the lndo-Gangetic Plains of South Asia, and may be one of the best opportunities to foster sustainable improvements in productivity and livelihoods for vast numbers of people in one of the poorest regions on earth. Because national research systems are at the forefront of this work and because it is done with farmers in their fields, adoption is accelerated. The RWC is pleased to share this collection of field-tested and farmer-proven, resource-conserving technologies. Local governments, NGOs, the private sector, extension agencies and research centers are encouraged to test and adapt these approaches and feature them in rural development strategies. Policy makers will benefit from these short summarized discussions of problems and tested solutions. Hopefully, policy implications can also be derived to promote the efficient use of land, water and other inputs. While the countries in the region currently have adequate quantities of grain stocks, demands are expected to increase dramatically within the next 2-3 decades, increasing pressures on the resource base. New problems and new challenges in South Asia’s breadbaskets require new approaches that are sensitive to concerns about food security, resource use and the environment in general.