EFFICACY OF RICE STRAW EXTRACTS IN CONTROLLING WEEDS AND ENHANCING THE PRODUCTIVITY OF WHEAT (Triticum aestivum L.)

Rice straw extracts (RSEs) have allelopathic impacts on specific plant species. To study the negative impacts of RSEs (boiled and unboiled) on weeds and their positive impacts on the productivity of wheat, laboratory and field experiments were conducted at the Agronomic Research Area, University of Agriculture Faisalabad, Pakistan during the winter of 2011-12. In laboratory experiments, at certain concentrations both RSEs (boiled and unboiled) caused statistically similar inhibitory effects on wheat seedling growth. In the field experiment, both RSEs were significantly effective in decreasing the total density and dry weight of weeds as compared to the untreated control, and improved wheat productivity by 27%. For two treatments (unboiled RSE at 18 L ha^-1 and boiled RSE at 9 L ha^-1 applied at 30, 45 60 DAS), the maximum number of productive tillers (445 and 444), grains per spike (41.00 and 41.33), 1000 grain weight (40.00 and 40.33 g), grain yield (4435 and 4420 kg ha^-1) and straw yield (6230 and 6215 kg ha^-1) were observed, respectively. It was concluded that the efficacy of the unboiled RSE was similar to the boiled RSE, and both could enhance the productivity of wheat by suppressing the total weed density, especially for Convolvulus arvensis L.; Avena fatua L. and Phalaris minor Retz. The unboiled RSE produced maximum yield as compared to the boiled one and was more economic.