Yield effects associated with glyphosate use in non-GMO arable farming: A review

Abstract

Glyphosate is the most commonly used herbicide worldwide as well as in European non-GMO cropping systems. In recent years, many economic studies have attempted to assess the benefits of glyphosate use in European arable farming. Among impact on fuel consumption, labour costs and other agronomic factors, yield effects of glyphosate play a central role in economic calculations. So far, these yield effects have been based generally on estimates. To determine whether existing research gives evidence for yield effects in European cropping systems, we reviewed articles by combining bibliometric and meta-analysis approaches. We searched 11,900 peer-reviewed journals for glyphosate-related studies to get an overview of glyphosate research in general and of studies on glyphosate yield effects in non-GMO arable farming in particular. In all, we located 6,841 articles that address glyphosate topics. A cluster analysis showed that a large part of the research is related to glyphosate-resistant cropping systems and toxicological topics. However, information on glyphosate yield effects in non-GMO cropping systems is also available—albeit rarely. Sixty-seven papers address the yield and/or weed control effects of either postharvest, presowing or preharvest treatment, while only 42 address yield effects and of these, four studies were carried out in Europe. Considering the highly diverse glyphosate application patterns, after presenting and discussing the results of all 65 articles, we conclude that there is no scientific basis for published economic calculations on glyphosate yield benefits. To cover current cropping systems adequately, future studies need to be adapted to Europe-specific arable farming conditions.