A generalized environmental sustainability index for agricultural systems

This paper presents the design and development of an Environmental Sustainability Index (ESI) and describes a case study used to evaluate the performance of the index. The objective of the index was to provide a modelling-based, quantitative measure of sustainability from an environmental perspective, comprising both on- and off-site environmental effects associated with agricultural systems. A performance approach was utilized for the ESI, having inputs that were derived from long-term simulations of crop management systems with the EPIC model (Erosion Productivity Impact Calculator). 15 sub-indices for representing sustainability were chosen employing a dual framework for characterizing environmental sustainability, embodying the agricultural system's: (i) inherent soil productivity and groundwater availability; and (ii) potential to degrade the surrounding environment. A case study was developed based on prevalent corn and wheat agricultural production systems in Baca County, located in southeastern Colorado. Principal components analysis was employed to assess the information content of the 15 sustainability sub-indices. Sensitivity analysis was performed to evaluate the effects of model input uncertainty on the index. The effect of the time frame over which the index is computed was also examined for time frames ranging from 50 to 300 years. Results show that the ESI is capable of demonstrating clear differences among crop management systems with respect to sustainability. (C) 2000 Elsevier Science B.V.