Genetically engineered crops get undue credit for reducing soil losses on cropland, says the Environmental Working Group. In a three-page analysis, EWG says the credit really should go to so-called conservation compliance and the Conservation Reserve, both created by the 1985 farm law. Conservation compliance requires farmers to control soil erosion if they want federal farm supports. The Conservation Reserve pays landowners an annual rent to idle fragile land for 10 years or more.
“The steep drop in soil erosion occurred before GE varieties were even on the market,” said the EWG report. It said USDA estimated soil erosion was more than 4 tons an acre nationwide on cropland when the 1985 law took effect. By the early 1990s, when the conservation requirements were taking effect, the rate was 3.44 tons an acre. It dropped to 3.1 tons around 1997 and has been fairly stable since. GE crops were introduced in the mid-1990s.
EWG said the development of “super weeds” that are resistant to herbicides indirectly could lead to higher erosion losses. Growers often use herbicides such as the popular glyphosate in combination with low- or no-tillage practices when growing GE crops. If herbicides fail to control weeds, growers may respond with mechanical weed controls.