Extended exergy analysis (EAA) of two canola farming systems in Khorramabad, Iran

Abstract

Extended exergy analysis (EEA) is a novel method in evaluation of agricultural ecosystems. In this study, a comprehensive analysis of the sustainability of an agricultural system was carried out using this method. Specifically, we looked for sustainable patterns of canola production by performing EEAs of two canola production systems, commercial and traditional, located in Khorramabd, Iran using data from the 2017–2018 crop year. The EEA of these two systems showed that the exergy of the environmental remediation cost (EEE) for the traditional system was less than that of the commercial system by 2.69 × 104 MJ ha−1. Accordingly, the ecological sustainability of the traditional system was found to be two times higher than the commercial system. In contrast, the values of thermodynamic indicators such as the capital conversion factor of the annual monetary value of product sales (KcapEEA), the extended exergy efficiency (ŊEEA), and the cumulative degree of perfection (CDP), respectively, indicate the higher economic value, the higher thermodynamic efficiency, and the greater optimality of the commercial system compared to the traditional system. The high consumption of inputs led to increased cumulative exergy consumption (CExC) in the traditional system. The high amount of CExC in the traditional system caused its thermodynamic indices to decrease. On the other hand, the high consumption of resources such as chemical fertilizers caused the EEE of the commercial system to increase. Therefore, based on the results of the EEAs performed in this study, we recommend designing new patterns for managing agricultural production systems, whereby through choosing the appropriate type and amount of inputs for each production system and by employing the required knowledge and technology for optimum production, the costs of environmental remediation will be reduced, and the thermodynamic-economic indexes will be improved.