The Sustainability of Rice-Based Cropping Systems in Coastal Bangladesh: Bio-Economic Analysis of Current and Future Climate Scenarios

Abstract

Agricultural sustainability is an issue of great significance for Bangladesh, especially in thenvulnerable conditions of the south-west coastal region. This is the case both currently and in light ofnprojected climate and salinity trends in the coastal region. The research reported in this thesis aimednto assess the current and future sustainability of rice-based cropping systems in the south-west coastalnregion and to identify options to improve the livelihoods and food security of coastal dwellers. Tonachieve this aim, the research sought to evaluate the contributions of rice and other crops to the agroeconomicnviability (profitability and risk) of current cropping systems; to assess the implications ofnprojected future climate and salinity for the economic viability of alternative cropping systems; andnto explore the dynamics of farm-level adaptation to changes in climate and salinity.The farm household was taken as the basic unit of analysis and conventional techniques of farmnmanagement research (partial, enterprise, whole-farm, and stochastic budgets) were used,nsupplemented with the results of climate and crop simulation models to project economic viability innfuture scenarios. Tools from rural livelihoods analysis were also applied to the study of householdnadaptation strategies. Two contrasting villages in Dacope Sub-district were chosen for the research.nIn Shaheberabad arable land was widely used for rice and non-rice cropping, while farmers in UttarnKaminibasia practised rice/fish farming in the wet season and brackish-water shrimp farming in thendry season. Four household types were identified n large, medium, small, and landless n to capturenthe range of circumstances within each village. A range of quantitative and qualitative techniquesnwere used to collect data from these villages and household types, including group interviews, keyninformant interviews, household case studies, and household questionnaire surveys.Rice farming was the most important livelihood activity in the wet season in both villages, providingnfood, cash, and employment. In the dry season, the rice fields were used for a range of non-rice cropsnin Shaheberabad or for brackish-water shrimp in Uttar Kaminibasia. In addition, homesteadngardening, aquaculture, and livestock rearing were undertaken, more in the first village than thensecond. Wage employment and/or self-employment activities were also integral to the livelihoods ofmost households. This diversification itself contributed to sustainability.nThe currently-practised rice/non-rice and rice-fish/shrimp systems were economically viable givenntypical seasonal yields and prices. However, seasonal variability in yields and prices affected thenprofitability of the cropping systems. The profitability of dry-season crops in Shaheberabad wasnfrequently affected by climatic stresses (erratic rainfall and drought) and soil salinity, due mainly toninadequate access to freshwater irrigation. Likewise, the profitability of shrimp in Uttar Kaminibasia was affected by climatic factors and variation in prices. Nevertheless, the major cropping systems asna whole faced relatively low risk of falling below benchmarks for economic viability, partly becausenof the increased productivity and stability of wet-season rice.Farmers perceived significant climate changes and analysis of local long-term climate data largelynconfirmed farmersr perceptions. Farmers also perceived significant changes in the local environment,nespecially increased soil and water salinity. Households in both villages had undertaken a variety ofnfarm and non-farm adaptation strategies. The collective initiatives of households, communities, localngovernment, national government agencies, NGOs, and traders had facilitated the development andnadoption of these adaptation strategies. However, farmers felt a need for increased research andnextension to enable them to adapt to projected future conditions.Allowing for the many uncertainties inherent in the modelling process, the modelling results indicatednthat loss of crop production would be negligible under projected 2030 conditions for climate andnsalinity, even with farmersr current practices. The effect of projected 2060 conditions was negativenon dry-season and early wet-season crops but, allowing for farm-level adaptation (especially changingnplanting dates), the loss of production was more than offset.Overall, the bioeconomic modelling indicated that climate change in itself does not appear to pose anmajor risk to the sustainability of crop production and aquaculture in the south-west coastal regionnover the next 15-45 years. The combinations of wet season rice and shrimp or wet season rice andndry season crops (current and novel) were projected to be economically viable and risk-efficient innfuture climate scenarios. Some current dry-season crops such as water melon would drop out, whilenother such as pumpkin, along with potential new crops such as sunflower and maize, would likelycome in, due to their higher returns and greater tolerance of environmental stress. Ongoingnsalinisation, though partly linked to climate change, represented a greater threat. While some adaptivenmeasures have been taken, such as adoption of saline-tolerant crop varieties and changed cropnschedules, regional investment in mitigation structures would likely have a high payoff.n