Eco-efficient agriculture: concepts, challenges, and opportunities.

Eco-efficiency in the simplest of terms is about achieving more with less�more agricultural outputs, in terms of quantity and quality, for less input of land, water, nutrients, energy, labor, or capital. The concept of eco-effi ciency encompasses both the ecological and economic dimensions of sustainable agriculture. Social and institutional dimensions of sustainability, while not explicitly captured in eco-effi ciency measures, remain critical barriers and opportunities on the pathway toward more eco-effi cient agriculture. This paper explores the multidimensionality of the eco-effi ciency concept as it applies to agriculture across diverse spatial and temporal scales, from cellular metabolisms through to crops, farms, regions, and ecosystems. These dimensions of eco-effi ciency are integrated through the presentation and exploration of a framework that explores an efficiency frontier between agricultural outputs and inputs, investment, or risk. The challenge for agriculture in the coming decades will be to increase productivity of agricultural lands in line with the increasing demands for food and fiber. Achieving such eco-effi ciency, while addressing risk and variability, will be a major challenge for future agriculture. Often, risk will be a critical issue influencing adoption; it needs explicit attention in the diagnosis and intervention steps toward enhancing eco-effi ciency. To ensure food security, systems analysis and modeling approaches, combined with farmer-focused experimentation and resource assessment, will provide the necessary robust approaches to raise the eco-effi ciency of agricultural systems.