Studying the effect of crop straw burning on germination and growth of weeds.

Abstract

Abstract : Recently different thermal methods are applied for the control of weeds. A knowledge of weed responses to these control methods is required to extend and increase the effectiveness of the methods. Thus, greenhouse study was conducted to evaluate the effect of burning treatments (burning wheat straw, burning+ash, ash only and control) on seedling emergence and growth of seven weeds. In laboratory, the effect of high temperatures (50 and 80°C) at two exposure times (4 and 8 h) on either dry or imbibed seeds of six weeds was studied. Burning wheat straw (with or without ash) reduced the seedling emergence of all weeds by 40 to 80%. However, the responses of weeds to the presence of ash varied from negative (wild barley, Jimsonweed) to neutral (common purslane, London rocket) or to positive (wild mustard). The seedling growth (height and dry weight) was not affected by burning treatments in canarygrass, common purslane and redroot pigweed but highly reduced the growth of others with 87% reductions in wild barley dry weight compared to untreated control. High temperatures caused drastic decreases in germination of all imbibed seeds but such an inhibitory effect on dry seeds was only seen in wild barley but not others.