SUPPRESSING EFFECT OF SOYBEANS ON BARNYARD GRASS

Abstract

Greenhouse studies on soybean–barnyard grass (BG) interaction showed that soybeans (Glycine max (L.) Merr. Vansoy) had a strong suppressing effect on plant height, and dry matter productivity, of barnyard grass (Echinochloa crusgalli (L.) Beauv.). The least increase in the dry matter of BG occurred when they were planted with 6- to 10-wk-old soybean plants. There was a three- to fourfold increase in the total productivity of BG during the last 5 wk (11–15 wk) of its competition with soybeans. Barnyard grass plants growing with soybeans did not produce any caryopses when they were planted with 3-, 4-, and 5-wk-old soybeans in comparison to soybean-free control.