POSSIBLE UTILIZATION OF ALLELOCHEMICALS AS A NATURAL HERBICIDE FOR WEEDS CONTROL AND OPTIMUM GROWTH OF WHEAT CROP

ABSTRACT Mechanical methods are labor-intensive and time-consuming whereas, using herbicides not only creates hazardous impacts on agricultural products but also enhances environmental pollution. Therefore, allelopathic approaches have been considered to suppress weeds in agricultural systems. Field experiments were conducted during the Fall season of 2011 and were repeated during Fall 2012 at the experimental field of Agricultural Research Institute, Tarnab, Peshawar, Khyber Pakhtunkhwa, Pakistan. The treatments were sprayed as post-emergence and the weedy check was maintained as a control treatment for comparison. Statistical analysis of the data showed that the allelopathic effect of plant water extracts in combination with reduced doses of herbicides had a significant effect on fresh and dry weed biomass (kg ha-1), plant height (cm) and yield attributes. However, the improvement in leaf area plant-1of wheat was found insignificant. Lower fresh weeds biomass (253 kg ha-1) and dry weeds biomass (87.5 kg ha-1) was noted in Parthenium hysterophorus + ½ Buctril super treated plots. Both the fresh and dry biomass was almost 80% lower than the control treatment. During the instant studies, it was observed that taller plants were observed in plots treated with Datura alba + ½ Puma super and Datura alba + ½ Buctril super as compared to untreated plants that produced short stature plants. D. alba + ½ Puma super and D. alba + ½ Buctril super gave a maximum (400 and 396) number of spikes compared to control plots that produced 244 spikes. The treatment combination of allelopathic plant water extract with a reduced dose of herbicides produced 63.46 and 63.20 grain spike-1 in Phragmites australis + ½ Puma super and Phragmites australis + ½ Buctril super, respectively. Biological treatment with highly allelopathic plants like P. australis, P. hysterophorus, D. alba and Oryza sativa seems to be environment friendly, and economical in many cases. In this way, we can manage the weed problem in our fields as well as could be used as a bio-fertilizer because some allelopathic plants have a positive effect on crop vegetative parameters, yields and yield components.