The Allelopathic Effect of Sunflower Residue on the Emergence and Growth of Some Weeds and Field Crops and Soil Chemical Characteristics

Abstract

To investigate the allelopathic effect of sunflower residue on emergence and growth of some weeds, field crops and soil chemical characteristic,two experiments have been conducted during 2013 and 2014 at College of agriculture / University of Wasit . The first experiment is conducted in pots using CRD design to test the allelopathic effect of two rates of sunflower residue (3 and 6g per kg soil) on emergence and growth of wheat , barley , broad bean and six species of broad and narrow leaves weeds . The second experiment is applied in a field using RCBD design to study of sunflower residue effectiveness (rate 6 g per kg soil) on growth of broad bean and companion weeds , and some soil characteristics compared with Trifluralin herbicide( 600ml per dunam). Pots experiment result show a high significant effect of sunflower residue on weed suppressive, specially, narrow leaves species is compared with broad leaves weeds. Sunflower residue have significant effect on wheat and barley crops , while it has no significant effect on broad bean. Field experiment result show the same trend of sunflower residue effect on weed biomass and without significant effect with trifluralin herbicide treatments. However, it was an increased in dry weight of broad bean is compared with control and herbicide treatment. Positive effects of sunflower residue has appeared on availability of some minerals nutrient in soil such as nitrogen , potassium , calcium , magnesium , sulfur , and organic matter , while , lowering PH. electrical conductivity (EC), sodium and chlorine are slightly increased a result of sunflower residue, but not arrived critical level that has effect on the crop. In conclusion, sunflower residue could be used as a feasible and environmentally sound weed management and enhancement of soil characteristics and broad bean growth.