By Emily Unglesbee
If you can’t beat them, crowd them out! That’s the wisdom from a new meta-analysis on the effect of narrow rows in corn and soybeans on weed control.
The study, authored by a multi-state team of researchers led by University of Nebraska weed scientist Dr. Amit Jhala and graduate student Mandeep Singh, examined 35 studies from 12 states between 1961 and 2018.
The researchers came to a pretty clear conclusion: Narrow rows (fewer than 30-inches wide) suppressed weed density, size (biomass), and weed seed production, and bumped yields up, but only in soybeans.
“Overall results suggest that narrow row spacing can potentially be used as an integrated weed management tool in combination with herbicides in soybean for the management of herbicide-resistant weeds,” the researchers concluded.
Small Row Space, Big Weed Suppression
The study’s results are largely focused on soybeans, which accounted for nearly 80% of the studies the researchers examined.
In narrow rows, soybeans canopy faster, stealing precious sunlight from their weedy interlopers between the rows. So while it’s not terribly surprising that the practice would suppress weeds overall, the numbers the researchers uncovered were eye-opening.
Within narrow-row soybean fields, on average, the density of weed populations thinned out by up to 42%, and weed size (or biomass) shrank up to 71%. Weed seed production also fell by 45% on average. Fields with multiple applications of herbicides and 7.5-inch rows showed the most statistically significant drops in weed seed production, the researchers noted.
Soybean yield also fared well in narrow rows, with the researchers finding an average increase of 12% across the studies they examined.
The study, authored by a multi-state team of researchers led by University of Nebraska weed scientist Dr. Amit Jhala and graduate student Mandeep Singh, examined 35 studies from 12 states between 1961 and 2018.
The researchers came to a pretty clear conclusion: Narrow rows (fewer than 30-inches wide) suppressed weed density, size (biomass), and weed seed production, and bumped yields up, but only in soybeans.
“Overall results suggest that narrow row spacing can potentially be used as an integrated weed management tool in combination with herbicides in soybean for the management of herbicide-resistant weeds,” the researchers concluded.
Small Row Space, Big Weed Suppression
The study’s results are largely focused on soybeans, which accounted for nearly 80% of the studies the researchers examined.
In narrow rows, soybeans canopy faster, stealing precious sunlight from their weedy interlopers between the rows. So while it’s not terribly surprising that the practice would suppress weeds overall, the numbers the researchers uncovered were eye-opening.
Within narrow-row soybean fields, on average, the density of weed populations thinned out by up to 42%, and weed size (or biomass) shrank up to 71%. Weed seed production also fell by 45% on average. Fields with multiple applications of herbicides and 7.5-inch rows showed the most statistically significant drops in weed seed production, the researchers noted.
Soybean yield also fared well in narrow rows, with the researchers finding an average increase of 12% across the studies they examined.
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