IMPACT OF RICE EXTRACT TYPE, CONCENTRATION AND APPLICATION TIME ON WEEDS BIOMASS AND GRAIN YIELD OF WHEAT

Higher weeds infestation is one of the major yield reducing factors. Synthetic herbicides are generally used for weed control. However, their uses may sometimes lead to environmental pollution as well. Alternative strategies are needed for management of weeds to overcome the problems created by synthetic chemicals. Field experiment was conducted at the Agronomy Research Farm of the University of Agriculture Peshawar, Pakistan during 2014-15 to assess the effect of rice water extract (RWE) on weeds’ weight and yield of wheat. Three concentrations i.e. 1:3, 1:4 and 1:5 kg: L^-1 of stem and leaf extracts of rice were applied at three stages (emergence, tillering and half at emergence + half at tillering) of the crop. Hand weeding (HW), herbicides and control (no weeding) plots were also included for comparisons. Herbicides treated and HW plots produced lighter weeds biomass, more tillers, longer spikes and more grain yield of wheat compared with RWE treated plots, whereas RWE was more effective compared with control. The RWE at 1:3 concentration drastically reduced weeds biomass and increased number of tillers m^-2, spike length and grain yield. The RWE sprayed at emergence resulted in lower weeds weight, more tillers m^-2, longer spike and higher yield. Leaf water extract was more effective than stem water extract. It is concluded that RWE has the capability to be used for control of weeds. Leaf water extract of rice at 1:3 sprayed at emergence reduced weeds biomass and increased number of tillers m^-2, spike length and grain yield of wheat.