Ecological Management of the Nitrogen Cycle in Organic Farms

Abstract

Nitrogen availability is among the major limiting factors for the production of organic crops. A central goal of organic farming, according to certification standards, is to rely on ecological and biological principles to build and maintain soil health. Nitrogen is among the most complex nutrient elements with respect to its different chemical forms and its flow within the environment at the soil, microbial, plant, aquatic, and atmospheric levels. Because, from an ecological perspective, all production variables on the farm are interrelated, a challenge for scientists and practitioners is to better understand nutrient cycles on the farm with respect to how particular production practices may improve N availability during particular stages of crop growth while minimizing potential environmental losses that may lead to contamination of the groundwater and aquatic habitats or to undesirable greenhouse gas emissions. Here, based on a selected review of the literature, we evaluate N cycles at the farm level and present key ecologically-based management strategies that may be adopted to improve internal N cycles. Given the location-specific nature of most ecosystem interactions, a participatory agroecology approach is proposed that incorporates the knowledge of indigenous and traditional cultures to better understand and design resilient and socially-equitable organic systems.

Keywords

• agroecology
• intercropping
• legumes
• microbial activity
• nitrogen cycles
• organic matter