Submitted to: Agricultural Experiment Station Publication
Publication Type: Government Publication
Publication Acceptance Date: 1/30/2010
Publication Date: 2/1/2010
Citation: Krutz, L.J., Locke, M.A., Steinriede Jr, R.W. 2010. Cover Crops Reduce Water, Sediment, and Herbicide Loss in Acreage Requiring Tillage to Control Glyphosate-Resistant Weeds. Agricultural Experiment Station Publication, Crop Production Systems Research Unit. Fact Sheet 2010-2. Interpretive Summary:
Technical Abstract: Glyphosate-resistant crops (GRCs) facilitated the adoption of no-tillage cropping systems. No-tillage, that is, omitting all tilling, disking, or harrowing operations, promotes crop residue accumulation on the soil surface. Crop residues protect the soil surface from rainfall impact, impede surface crust formation, and reduce soil erosion. No-tillage also improves soil structure, often enhances water infiltration, and purportedly reduces pesticide runoff. Since GRCs lead to the widespread implementation of no-tillage, GRCs are accredited with improving U.S. soil and water quality. Unfortunately, glyphosate-resistant weeds threaten the environmental gains afforded by GRCs. The number of glyphosate-resistant weeds and the acreage they infest are increasing. The current recommendation for the control of glyphosate-resistant weed biotypes in GRCs is integrated weed management, that is, tillage coupled with the application of pre- and post-emergence herbicides. This recommendation could reduce no-tillage acreage across the U.S. For example, in Tennessee no-tillage cotton decreased fourfold from 2005 to 2008 because tillage was needed to control glyphosate-resistant horseweed. Thus, if environmental gains afforded by GRCs are to be maintained, then a viable alternative to strict no-tillage is required to combat glyphosate resistant weeds.