Agronomy Library > Annual Weeds

Growing, Optimizing, and Utilizing Grain Legume Nitrogen
Author: Sheri Strydhorst, University of Alberta
Date Created: November 21, 2007
Last Reviewed: January 26, 2009
Alberta cropping systems are heavily dominated by cereal and canola crops. The lack of species diversity in our agricultural ecosystems is a concern as these low diversity systems are fragile and unsustainable. More diverse cropping systems remain productive under fluctuating environmental constraints and require fewer external inputs (Altieri 1995). Increasing the use of nitrogen (N) fixing grain legume species in Alberta crop rotations and intercrops should increase ecological stability, reduce input costs, and reduce the energy footprint of Alberta cropping systems. Inorganic N fertilizer is a convenient and was a relatively cheap source of N to supply crop nutrients demands (Peoples et al. 1995a). However, only 18–49% of applied N fertilizers are typically used by our crops (Cassman et al. 2002) with the unused portion being lost to water sources and the atmosphere. With growing international concern over global warming, environmental degradation, and loss of natural resources, biological N fixation by grain legumes represents a renewable resource for sustainable agriculture which can partially replace inorganic N fertilizer (Peoples et al. 1995a). To maximize grain legume benefits, producers need to increase grain legume acreage, use management techniques to optimize N fixation, and understand the grain legume N contribution to cropping systems.  open the attached PDF for the complete paper