Submitted to: Indiana Certified Crop Advisors Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2010
Publication Date: 12/13/2010
Citation: Kremer, R.J. 2010. Interactions of Glyphosate with Soil and Plant Microbial Communities and Activities [abstract]. Indiana Certified Crop Advisors. 2010 CDROM. Interpretive Summary:
Technical Abstract: Impacts of glyphosate on soil and plant microbial interactions have received considerable attention in the last 10 to 15 years as glyphosate-resistant crop technology became the dominant management option for major crop production systems. Although effective weed management is the goal of this technology, the annual applications of glyphosate to glyphosate-resistant varieties in the standard corn-soybean rotation prompted investigations into potential indirect or “non-target” effects due to continuous exposure of soil to the herbicide. The indirect effects of glyphosate were examined on plant nutrient availability, soil microbial nutrient transformations, and beneficial and detrimental soil and/or plant microorganisms. A survey of recent reports reveals a wide range of non-target effects ranging from no effect to the promotion of disease and suppression of beneficial microorganisms by glyphosate. Because research on glyphosate –microbe-plant interactions conducted to date is limited and often with conflicting results, no definite conclusions regarding detrimental effects of the interactions can be made. However, research suggests that several major factors need consideration when discerning whether potential glyphosate interactions may be affecting crop growth and microbial activity. These factors consist of nutrient status (including micronutrients) of soil and their levels within the crop plant (based on plant leaf or tissue analysis); environmental conditions during the growing season; soil characteristics; and crop variety. This presentation will cover a description of potential glyphosate-microbe-plant interactions based on principles of plant physiology and microbiology; review of current published findings on these interactions; role of the major soil, crop, and environmental factors in expression of the interactions; and suggested approaches for overcoming effects of those interactions that might be suspected to adversely affect crop productivity.