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Research article2015Peer reviewed

Under-sown cover crops and post-harvest mowing as measures to control Elymus repens

Ringselle, Björn; Bergkvist, Göran; Aronsson, Helena; Andersson, Lars

Abstract

Two potential control methods for Elymus repens, which do not disturb the soil, are post-harvest mowing and competition from under-sown cover crops. Our aim was to quantify the effect of cover crop competition and mowing on E.repens and to evaluate the potential for combining the two methods. We present a two-factorial split-plot experiment conducted at three locations in Sweden, in two experimental rounds conducted in 2011-2012 and 2012-2013. A spring cereal crop was under-sown with perennial ryegrass, red clover or a mixture of the two (subplots). Under-sown crops were either not mowed, or mowed once or twice post-harvest (main plots). This was followed by ploughing and a new spring cereal crop the next year. Mowing twice reduced autumn shoot biomass by up to 66% for E.repens and 50% for cover crops compared with the control, twice as much as mowing once. Pure ryegrass and mixture treatments reduced E.repens shoot biomass by up to 40% compared with the control. Mowing twice reduced rhizome biomass in the subsequent year by 35% compared with the control, while the pure red clover treatment increased it by 20-30%. Mowing twice and treatments including red clover resulted in higher subsequent grain yields. We concluded that repeated mowing has the potential to control E.repens, but a low-yielding cover crop has insufficient effect on rhizome biomass. Clover-grass mixtures are of interest as cover crops, because they have the potential to increase subsequent crop yield and even at low levels they reduce E.repens above-ground autumn growth.

Keywords

Agropyron repens; Elytrigia repens; couch grass; competition; cutting; mechanical control; weed-crop interactions; perennial weed; subsidiary crops

Published in

Weed Research
2015, Volume: 55, number: 3, pages: 309-319
Publisher: WILEY-BLACKWELL