There’s no doubt that much of the rapid increase in no-tilled acres over the past 20 years is due to the extensive use of glyphosate-resistant corn and soybeans. Yet, extensive reliance on this single herbicide mode of action may be holding back the future growth of no-till. Even more worrisome is the impact it could have on simply maintaining the no-till acres we already have.
A report from the Council for Agricultural Science and Technology argues that glyphosate-resistant weeds pose one of the most significant threats to the future growth of notill. The scientists who authored this report say these concerns are already forcing some farmers to modify their conservation-tillage practices and even rely on more tillage to overcome these serious resistant weed worries.
The report’s authors even go so far as to point out the herbicide-resistant weed situation could undo much of the good no-till has brought to North American agriculture and the environment over the past 5 decades.
While scientists and growers have long recognized both the beneficial and detrimental aspects of tillage, glyphosate sharply reduced the role of tillage in controlling weeds under no-till conditions. This has taken place on a huge scale, despite the first instance of glyphosate resistance that showed up in several no-tilled soybean fields in Delaware back in 2000.
But even before then, we knew here were weed-resistance problems with glyphosate based on the earlier experiences of Australian growers.
Over the past few decades, extensive glyphosate usage has led to…