Growing crops in a changing climate is tough enough, but when weeds factor in, soybean yields take a massive hit. That’s according to new research from the University of Illinois and the USDA Agricultural Research Service, and it means farmers will need to achieve greater weed control than ever to avoid yield loss.
The researchers analyzed factors leading to soybean yield loss in a 26-year herbicide evaluation dataset spanning hundreds of weather environments in Illinois. Inadequate late-season weed control – anything less than 76% – was responsible for a colossal 41% yield loss. And when drought and heat hit, even high levels of weed control (up to 93%) couldn’t stave off significant yield losses.
“You need almost perfect weed control to avoid yield losses in hot, dry conditions. Unfortunately, we have a lot of weed escape in soybean,” says Marty Williams, USDA-ARS ecologist, affiliate professor in the Department of Crop Sciences at Illinois, and co-author on a new study in Science of the Total Environment.
Crucial as it may be, achieving complete weed control with existing chemical tools is increasingly difficult, given the increased frequency of herbicide resistance in major weed species such as waterhemp, Palmer amaranth, and others.
Read more at: University of Illinois Urbana-Champaign
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