Chapter 44 - Soybean Mineral Composition and Glyphosate Use

Abstract

Glyphosate has become the most widely used herbicide in soybeans, primarily because of its use in transgenic, glyphosate-resistant (GR) cultivars of this crop. There have been claims that glyphosate reduces the levels of certain minerals, especially Mn, in GR crops. The published literature related to this topic is conflicting. Most of the greenhouse studies that have reported reductions in minerals that form divalent cations with glyphosate have examined only the foliage of glyphosate-treated, GR soybean. The only greenhouse study that analyzed mature seed from such plants found no effects on the content of the 14 minerals analyzed. Most of the field studies have found no effects of glyphosate on mineral content of the foliage of GR soybean. Only two studies have examined the mineral content of mature seeds from treated plants in field, and no effects were found. More studies of this important question are needed, using a range of GR cultivars on different soils and in different climates in order to resolve this question.