How Eco-Efficient Are Low-Input Cropping Systems in Western Europe, and What Can Be Done to Improve Their Eco-Efficiency?

摘要

Low-input cropping systems were introduced in Western Europe to reduce the environmental impacts of intensive farming, but some of their benefits are offset by lower yields. In this paper, we review studies that used Life Cycle Assessment (LCA) to investigate the effects of reducing external inputs on the eco-efficiency of cropping systems, measured as the ratio of production to environmental impacts. We also review various cropping system interventions that can improve this ratio. Depending on the initial situation and the impacts considered, reducing inputs will in itself either reduce or increase environmental impacts per product unit—highly eco-efficient cropping systems require application of optimum instead of minimum quantities of external inputs. These optimum rates can be lowered by utilizing positive synergies between crops to minimise waste of nutrients and water and by utilizing locally produced organic waste; both from within the farm as well as well as from the surrounding sociotechnical environment. Eco-efficiency can also be improved by increasing yields in a sustainable matter. Strategies such as breeding, increasing diversity, no-tillage or intercropping will not be effective under all conditions. LCA provides a useful framework to identify environmentally optimum levels of inputs and trade-offs between various intensification scenarios.