LAWRENCE, Kan. — Buckwheat cover cropping can reduce both the emergence and growth of weeds, presenting an easy and economical alternative to herbicides, according to a new study analyzing the roles of both nitrogen and fungal pathogens in weed inhibition.
Results of the study are published in the latest issue of Weed Science.
Growing environmental and health concerns over the use of herbicides have resulted in an increasing demand for alternative weed management strategies, including cover crops.
Cover crops can be integrated into cropping systems for a range of benefits, including reduction of soil erosion, supply of nitrogen to subsequent crops, and improvements in nutrient cycling, soil quality, and pest management.
Buckwheat, a short-duration broadleaved annual cover crop, is useful as a summer cover crop because it grows rapidly, establishes canopy faster than most weeds, and hence provides very effective weed suppression during establishment.
Initial low nitrogen availability after cover crop incorporation is one possible mechanism of weed suppression.
Cover crops take up nitrogen during growth, reducing soil nitrogen. Initial low nitrogen availability during the early life stages of plant development might affect the growth of weeds more negatively than crops because weeds are adapted to early rapid growth and nitrogen uptake.
In addition, it is projected that nitrogen immobilization after buckwheat incorporation could reduce fungal effects on weeds.
In studying three weed species, researchers found that buckwheat-mediated changes in nitrogen accounted entirely for the suppression of weed growth, but that suppression varies by species.
Fungal and nitrogen effects accounted for the suppressed emergence of corn chamomile and shepherd’s-purse, but the mechanism of suppression for Powell amaranth remained obscure in the study.
To read the entire study, click here.
Weed Science is the official publication of the Weed Science Society of America.
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