The Indo-Gangetic Plains (IGP) of South Asia play a crucial role in global rice production through the rice–wheat system, supporting the food and nutritional needs of 400 million people across approximately 24 million hectares (Mha) in Asia (Alhammad et al., 2023). In India alone, this system spans 10.5 Mha and supplies nearly half of the country’s total food consumption (Baghel et al., 2018). However, with the decline in available resources such as land, water, and energy, optimizing resource-use efficiency is an essential and a real challenge for assessing the viability of rice-based cropping systems (Ray et al., 2020; Kumawat et al., 2025). Diversifying and intensifying crop cultivation can help reduce risks related to yield fluctuations, market instability, and environmental degradation while promoting national goals such as self-reliance on essential crops, foreign exchange earnings, and job creation (Saleem et al., 2025). Due to heavy demand and being the main staple food in Eastern India, rice is very difficult to replace, particularly in the rainy season due to specific soil and climatic conditions. Therefore, the practical solution is to replace wheat in the winter season and add crops in the summer season to diversify and intensify the rice–wheat cropping system. In the highly productive IGP, the continuous practice of the rice–wheat system for over 40 years has threatened agricultural sustainability (Bhatt et al., 2016; Singh et al., 2019). In the lowland areas of IGP, completely replacing rice with another crop is not feasible (Kumar et al., 2022; Ranjan et al., 2024). However, diversification of the rice–wheat system is possible by incorporating oilseeds, grain legumes, and some short-duration vegetables and fodder crops, especially within an integrated farming system (Banjara et al., 2022; Liu et al., 2025; Saha et al., 2022). Energy is essential for human life and the economy, yet its role in crop production has been historically underemphasized. Greater focus is needed on renewable and non-commercial energy sources actively involved in crop production processes, which use intensive energies directly or indirectly. Crop production can be viewed as an energy conversion industry, where plants convert solar and soil-derived chemical energy into storable forms such as carbohydrates, fats, and proteins through photosynthesis (Singh et al., 2022). Excessive energy use leads to high production costs, reduced income, and decreased market competitiveness (Kachroo et al., 2012). Thus, crop diversification should aim not only for higher productivity and profitability but also for efficient energy conversion.

Environmentally and economically sustainable cropping systems are essential to replace rice–fallow systems in IGP (Reddy et al., 2025; Sahoo et al., 2024). Developing such systems requires a comprehensive understanding of the energy budget, global warming potential (GWP), and the input needs for water and fertilizers across diverse crops (Kumar et al., 2024; Yadav et al., 2017). Since energy consumption is closely linked to greenhouse gas (GHG) emissions (Kaur et al., 2021), improving energy efficiency through technological advancements can help conserve energy and reduce GHG emissions (Ray et al., 2020). Understanding the energy dynamics of different rice-based cropping systems is critical for designing sustainable and climate-resilient agricultural practices.

By analyzing energy budgeting, including input–output energy relationships, and energy-use efficiency, this study aims to identify an energy-efficient rice-based cropping system for the IGP of the sub-tropical region to enhance food and nutritional security, mitigate GHG emissions, and improve environmental sustainability. The study was designed to test the hypotheses that integrating a suitable energy-efficient cropping system with appropriate technological interventions can contribute to sustainable crop production in the IGP of the sub-tropical region. The findings of this research could have significant implications for sustainable rice production in the IGP of the sub-tropical region and beyond.

The results highlight the superiority of diversified and intensive cropping systems in enhancing economic yield, with notable performance differences across seasons. The significantly higher REY observed in the rice–cabbage + coriander leaf–sesamum system during winter (rabi) suggests that the crop diversification and the inclusion of short-duration intercrops contribute to improved productivity. The rice–chickpea + linseed–maize sequence further reinforced the advantage of strategic crop rotations during the zaid season. Notably, the rice–potato + radish–mungbean and rice–cabbage + coriander leaf–sesamum system outperformed others in systems with 300% cropping intensity, demonstrating its efficiency in maximizing land use and yield. The 11% higher REY recorded compared to the rice–maize + vegetable pea–sorghum + cowpea system underscores the benefits of integrating high-value crops. Additionally, all diversified cropping systems significantly outperformed the conventional rice–wheat system, emphasizing the potential for intensified and well-planned rotations for sustainable yield enhancement (Menia et al., 2025; Saha et al., 2022). REY of rice–wheat–mungbean was found low due to lower productivity of mungbean after the wheat crop, and after the wheat crop, only one picking is possible in mungbean crop. Higher productivity of systems by replacing the wheat crop in winter season with more productive crops, such as potato or leafy vegetables was also reported by (Baishya et al., 2016; Gatto et al., 2020; Prasad et al., 2013). According to Arvadiya et al. (2025), the inclusion of legumes such as mungbean, fodder cowpea, vegetable fenugreek, and cluster bean in rice-based systems enhanced rice yield, promoted nutrient recycling, reduced soil compaction, increased soil organic matter, disrupted weed and pest life cycles, and mitigated adverse allelopathic effects.

The rice–potato+radish–mungbean system (T₄) demonstrated the highest system productivity, reinforcing its potential for maximizing returns and resource utilization. Its statistical similarity to the rice–cabbage+coriander leaf–sesamum system (T₅) suggests that both sequences effectively optimize land and inputs. This was primarily due to the higher marketable returns from vegetable coriander leaf or radish and the oilseed crop sesamum compared to linseed, berseem, and fababean. A family nutrition-based farming system that integrated maize, cabbage, and sesamum achieved the highest rice equivalent yield (REY) of 24.95 t ha⁻¹, largely driven by the superior yield and economic value of cabbage and sesamum (Upadhaya et al., 2022). The significantly higher system profitability in three cropping systems, i.e., rice–maize +vegetable pea–sorghum + cowpea (fodder), rice–potato+radish–mungbean, rice–cabbage+coriander leaf–sesamum system led to increased REE in these cropping systems, further highlighting their resource-use advantage over other systems. While the lowest values recorded in the rice–mustard–mungbean system (T₈) indicate its relatively lower efficiency. The substantial 41% system profitability increase over the rice–wheat–mungbean system emphasizes the economic benefits of adopting cole crops and vegetables in diversified cropping sequences over conventional practices. This may be due to the higher market value of the component crops of these systems, and the leguminous or oilseed cropping patterns giving higher productivity as compared to the commonly practiced rice–wheat cropping pattern (Radheshyam et al., 2024; Paswan et al., 2023; Ray et al., 2009).

The energy dynamics of different rice-based cropping systems reveal significant variations in input and output efficiency, emphasizing the role of crop selection and management practices in optimizing energy use. Kachroo et al. (2012) working on different rice-based cropping sequences reported that rice–potato–maize+mungbean utilized higher energy input followed by the rice–potato–onion sequence. In the rainy season, energy production across different systems was similar due to the common crop (rice). However, significant differences were observed in the winter and summer seasons. Rice–maize +vegetable pea–sorghum + cowpea (fodder) attained the highest energy output, likely due to variations in plant type, production habits, capacity, and energy content of grains and straws. Cereal-based systems have higher energy production compared to vegetable-based systems (Kumawat et al., 2025; Saha et al., 2022). It has been earlier established that cropping sequences with higher intensity and highly productive short-duration vegetable component crops with the inclusion of legumes as fodder in cereal-based crop rotation reduce the consumption of non-renewable energy (Hisse et al., 2022; Meena et al., 2022; Sharma et al., 2008).

The highest energy output–input ratio was recorded in the rice–maize +vegetable pea–sorghum + cowpea (fodder) system (T₃), which may be attributed to greater system productivity and efficient energy utilization across diverse crop components (Kumar et al., 2024; Saha et al., 2022). The inclusion of energy-dense crops such as maize and vegetable pea, along with high-biomass fodder crops such as sorghum and cowpea, contributed significantly to gross and net energy outputs. Furthermore, the complementary nature of crop sequences likely enhanced nutrient cycling and input use efficiency, leading to an improved energy output–input ratio in this diversified system (Behera et al., 2024). Furthermore, the energy productivity was highest in the rice–cabbage + coriander leaf–sesamum system, which may be due to the higher yield of cabbage, along with the contribution of coriander leaf to the total productivity of the sequence. The rice–mustard–mungbean system produced less energy productivity than the traditional rice–wheat system mainly due to lower productivity of mustard crop in the winter season, as well as mungbean in the summer season (Singh et al., 2017). Similarly, Das et al. (2020) reported that conservation agriculture-based direct seed rice followed by mustard followed by mungbean produced 11.0% lower rice yield than the conventionally grown rice–maize system in IGP of India. Furthermore, it was observed that the rice–cabbage + coriander leaf–sesamum (T₅) and rice–maize + vegetable pea–sorghum + cowpea (fodder) (T₃) systems exhibited distinct superiority in terms of the lowest specific energy among all cropping sequences. This may be attributed to the higher system productivity per unit of energy invested, resulting from the inclusion of short-duration, high-yielding, and energy-efficient crops such as cabbage, coriander leaf, vegetable pea, and fodder cowpea. These crops not only ensured better resource use efficiency but also contributed significantly to economic yield with relatively lower energy inputs, thereby reducing the specific energy requirement (Dey et al., 2024; Soni et al., 2018; Yadav et al., 2017).

Crop diversification leverages the interaction between different crops to maximize resource use efficiency and system resilience over the rice–wheat cropping system. Integrating diversified crops (averaged of T₃–T₉) resulted in 51.6% higher system productivity over the traditional rice–wheat or rice–wheat–mungbean system (averaged of T₁ and T₂). Rice–potato + radish–mungbean and rice–cabbage + coriander leaf–sesamum system recorded high system rice equivalent yield and but rice–potato + radish–mungbean was not an energy efficient system. Thus, rice–maize + vegetable pea–sorghum + fodder cowpea and rice–cabbage + coriander leaf–sesamum systems were found most suitable in terms of energy dynamics, system productivity, and remunerative option under irrigated condition. Hence, to maximize productivity and resource use efficiency, farmers should adopt these two diversified rice-based cropping systems integrating high-yielding and energy-efficient sequences. Future research should focus on incorporating low-cost forage crops and sustainable management practices to further enhance system resilience and profitability.