a comparative emergy analysis of rice and cotton farming ecosystems: implications for sustainability

Environmental degradation stemming from excessive consumption of natural resources and chemical inputs threatens resource efficiency and the long-term sustainability of agricultural ecosystems. this study employed a comprehensive questionnaire survey combined with emergy evaluation to assess and compare the efficiency and sustainability of rice and cotton farming ecosystems in golestan province, iran, during the 2018–2019 growing season. results indicated that the total emergy input for rice cultivation (1.01e+17 sej ha⁻¹) substantially exceeded that of cotton (5.14e+16 sej ha⁻¹), highlighting a greater concentration of embodied energy in rice production. in both systems, non-renewable environmental inputs dominated over renewable environmental, purchased renewable, and purchased non-renewable flows. groundwater emerged as a critical input due to high crop water demand during summer cultivation and negligible seasonal rainfall in the region. the emergy analyses revealed that cotton was more productive per unit emergy invested. both ecosystems exhibited low emergy renewability, reflecting heavy dependence on non-renewable resources. cotton demonstrated superior resource efficiency, as evidenced by a higher emergy yield ratio. economic indicators, including standard and modified emergy investment ratios, showed that rice production incurred significantly higher economic costs and lower efficiency. environmental loading ratios further indicated that cotton imposed markedly lower environmental pressure, confirming its greater environmental sustainability. overall, cotton outperformed rice across multiple metrics: production efficiency, resource consumption efficiency, economic efficiency, and environmental sustainability. to enhance the sustainability of such agroecosystems, we recommend reducing reliance on non-renewable purchased inputs and advancing farmer awareness, education, and engagement in sustainable practices.