Crop Diversification in Rice—Based Cropping Systems Improves the System Productivity, Profitability and Sustainability

Cropping systems in the Level Barind Tract (LBT) of Bangladesh are highly diverse, as Transplanted (T.) Aman and Boro (T. Boro) rice are a common practice in the area. Although. T. Aman is generally cultivated in the rainy (monsoon) season, but the T. Boro rice is the intensive irrigation-based winter rice with high establishment costs as a result of exhaustive tillage and high labours for transplanting of seedlings. Furthermore, pumping of a large amount of irrigation during T. Boro cultivation declines the level of groundwater, which is not environmentally friendly nor cost-effective. Therefore, the replacement of the T. Boro rice from the cropping pattern in the LBT area is the major concern of policymakers. In this context, a replicated three to four crop-based cropping systems (CS) field trial was conducted in LBT of Gaibandha, Bangladesh for consecutive three years (2018–2020) to evaluate productivity, profitability and sustainability of the multiple crop-based cropping systems. Among these CS, existing three crops based CS, CS1: T. Aman–Potato–T. Boro (introduction of the local potato in the existing cropping system) were compared with four crops based CS2: T. Aman–Potato–Cucumber–T. Aus (Introduction of high yielding potato, cucumber and T. Aus as an improved cropping system). After two years of observations, significantly higher system productivity (rice equivalent yield; REY) was found in the improved CS2 than that of existing CS1 in both years (two years’ average 49% or 11.1 t ha−1). As a result of the introduction of the high yielding potato, cucumber and T. Aus rice instead of the T. Boro rice. The CS2 was also found profitable as compared to the CS1 in terms of higher gross margin (by 74%), net return (double) and benefit-cost ratio (BCR) (1.69 vs. 1.44) due to higher gross return with slightly higher (by 28%) production cost. It is due to farmers received higher prices for potato, cucumber and two rice crops in the improved CS2 than the existing CS1. On the other hand, protein and energy output was lower (by 17% and 9%, respectively) in the CS2 than the existing CS1, due to the less content of protein and energy value in the vegetable cucumber. The results of the study revealed that crops diversification in the existing T. Boro based CS with high yielding potato, cucumber, and T. Aus rice, improved the system productivity, profitability and sustainability; which lead to improve the food security of the increasing population and also reduce the adverse effect on the environment.