Comparative Weed Control Byallelopathicinfluence of Sunflower and Johnson Grass Residues and Aquatic Extracts

Abstract

The impact of weeds has tremendously reduced per hectare yield of different crops due to their competition for water, nutrients and placement. Application of herbicides particularly in cereals and vegetables is unsafe as these are directly consumed by human beings and sometimes from the soil they are transported to water bodies and mixed with the drinking water.Therefore, keeping in view this study was framed with objectives to determine plants with high allelochemical properties that may be further applied in the field crops to control weed population through their allelopathic properties. The laboratory experiments were carried out in Seed Testing Laboratory, Department of Agronomy,Sindh Agriculture University Tandojam. The allelopathic impact of sunflower and johnson grass on germination and seedling growth of purple nutsedge (Cyperunsrotundus L.) and jungle rice (Echinochloacolonum L.)was studied and the results were found statistically significant (P<0.05) under various treatments. The results depicted thatallelopathic influence of sunflower and johnson grass residues and aquatic extract on purple nutsedge produced minimum seed germination (%), root length (cm), seedling vigor index, leaves seedling^-1, leaf length (cm), leaf area (cm²) with johnson grass aquatic extract 15 mL kg^-1 soil. Minimum shoot length (cm), fresh biomass (g) and dry biomass (g) per seedling was recorded with sunflower aquatic extract at 15 mL kg^-1 soil. The influence on jungle rice resulted minimum seed germination (%) and root length (cm) with sunflower aquatic extract at 15 mL kg^-1 soil. The minimum shoot length (cm), seedling vigor index, leaves seedling^-1 and dry biomass (g seedling^-1) was determined in johnson grass aquatic extract 15 mL kg^-1 soil. The minimum leaf length (cm) was recorded with johnson grass residue incorporation at 15 g kg^-1soil. The smallest leaf area (cm²) and fresh biomass (g seedling^-1) was recorded in sunflower residue incorporation at 15 g kg^-1soil.It is concluded from the study that sunflower and johnson grass residues and aquatic extract restricted the germination and normal growth of targeted weeds. Therefore, aquatic extracts of sunflower and johnson grass may be practiced in crop fields as alternate of herbicide which is not only economical but also environment friendly.