abstract
- Diversifying and intensifying the rice-based cropping systems in the southern coastal zone of Bangladesh is a government priority to meet the food, feed, and fiber demand of an increasing population and changing climate. This study was conducted for three years (2016-2019) in Polder 30 located in southwest coastal zone of Bangladesh with five cropping systems [improved varieties of rice-maize (R-M); rice-mungbean (R-MB); rice sunflower (R-S); traditional varieties of rice-mungbean (RTrad-MBTrad); and rice-fallow (RTrad-F)]. The objectives were to quantify yield gaps and spatiotemporal variability in rice production, evaluate various rice-based cropping systems for yield and profitability, and investigate individual crop and system-based stability and resilience in the coastal zone. Averaged over three years, results indicated an approximate 30% attainable yield gap on average within improved varieties and a 56% yield difference between traditional and improved rice varieties. Spatial autocorrelation analysis of both systems was positive and significant, suggesting crop yields in spatially closer locations were similar than those that were far apart. Lower spatial autocorrelation for the improved variety of rice compared to traditional varieties, indicates greater spatial dependence in addition to a narrow yield range for traditional rice. Overall, the improved rice-maize and rice-sunflower systems were the highest yielding and productive cropping systems, followed by the improved rice-mungbean. The traditional rice fallow system was the least productive. In a high climate-risk year, however, rice was the only crop with positive net income, and the traditional systems had a relatively higher income than the improved systems. In an average opportune year, maize had the highest net income, and all improved rice-based cropping systems had a relatively higher income than traditional systems.