The South Asian rice-wheat rotation system is one of the world's principal agricultural production systems and covers 13 million hectares (ha), which is providing food security, income, and employment to over 200 million rural and urban people in Bangladesh, India, Nepal, and Pakistan.
According to a study by Asian Development Bank, the productivity growth in these production systems has stagnated due mainly to degradation of the resource base. Deteriorating soil fertility, weakening soil health, water scarcity, salinity and sodality, and weed and pest infestations pose increasing problems.
Tillage and establishment innovations, varietal changes, nutrient management, improved irrigation management, and diversification can address these problems. Large-scale adoption of resource-conserving technologies will have considerable environmental benefits, the ADB report said.
Through the rice-wheat rotation systems, ADB report says, farmers in South Asia have begun using practices that save water, fuel, and other inputs; facilitate timely planting; reduce tillage needs and burning of crop residues; and allow farmers to diversify the cropping system. The most prominent of these practices--zero tillage to sow wheat after rice--was used on nearly 1.3 million hectares during the 2003-04 wheat season, up from practically nothing just a few years before.
Adoption of zero tillage in a million hectares could save as much as 100 million cubic metres water/year plus 60 million litres diesel fuel. Use of zero tillage for wheat saves more than 50 litres diesel per hectare, representing a saving of 75 million litres, worth more than $40 million region-wide, and reduces the emission of greenhouse gases substantially,
Commenting over the 'Growth in Productivity and Incomes, and Poverty Reduction', the ADB report indicated that Regional Technical Assistance (RETA) outputs contributed towards improving the welfare of small farmers and reducing poverty. Some examples included virus-free sweet potato, which increased yield by 30 percent to 40 percent in China, and the lentil research that generated $12 million in annual benefits to Bangladesh.
The report said that the RETA projects yielded good economic returns in general. For example, the internal rate of return of the genetically improved carp strain ranged from 17 percent to 53 percent, and the national benefit was estimated to be as much as $76 million.
These benefit estimates included both production side (ie increased production of carp, which enhanced profits and provided farmers alternative sources of income) and consumption-side impacts.
Commenting over 'Natural Resource Management, Biodiversity, and Climate Change', the report indicated that most of the technologies generated or expected to be generated promote, directly or indirectly, more effective management of natural resources and protect the environment. Resource conservation technologies such as zero tillage on rice and wheat, alternate wetting and drying of rice farms, integrated crop and resource management, integrated pest management, and water harvesting technologies are not only friendly to the environment but are also efficient in terms of labour, water, energy, and nitrogen use.
Specific efforts related to biodiversity protection were promoted by the on-farm conservation of coconut genetic resources that safeguarded the characteristics of local coconut varieties and subsequently the economic base of coconut farmers primarily dependent on the coconut industry for livelihood. A similar effort in vegetables led to the accession of 4,326 indigenous vegetable cultivars kept in the gene bank of the World Vegetable Centre. Protection of these genetic materials enhanced the biodiversity of vegetables.
RETA-643932 is expected to deliver strategies and capacity to reduce production losses likely to result from extreme events and long-term climate changes. Annual losses resulting from typhoons and frequent incidence of drought phenomena are substantial. Better adaptation to climate change is expected to reduce the vulnerability and improve the livelihoods of rural farm households. The ongoing research on the topic includes development of adaptive strategies to reduce vulnerability to climate change, the report said.