Effect of Manure Compost Enrichment with Different Amounts of Zeolite on Trifluralin Efficacy in Sunflower Weed Control under Different Irrigation Regimes



In order to investigate the effects of composted manure and zeolite on efficacy of trifluralin in control of weed natural population in sunflower under different irrigation regimes, an experiment conducted in 2009 in Tarbiat Modares University, Tehran, Iran. A randomized complete block design in factorial arrangement with three replications was used. First factor was irrigation regimes that involved normal irrigation (irrigation after reducing 35% soil available water) and limited irrigation (irrigation after reducing 70% soil available water). Second factor was zeolite using in 0, 100, 200 and 300 gm-2 which composted with manure. In this experiment 60% of nitrogen was supplied from chemical fertilizer and 40% by compost. Results indicated that using zeolite increased efficacy of trifluralin and reduced weed density under both normal and limited irrigations but weed density under limited irrigation was lower than normal irrigation. Weed dry matter reduced with increasing zeolite level under limited irrigation but did not change under normal irrigation. Results of field experiment and bioassay test revealed that crop yield and persistence of trifluralin increased significantly with increasing zeolite level.