Evaluating the Effects of soil Residue of Nicosulfuron Herbicide on Wheat (Triticum aestivum), Barley (Hordeum vulgare) and Rapeseed (Brassica napus)

To study effects of nicosulfuron herbicide in soil on wheat, barley and rapeseed after corn harvesting, a field experiment was conducted at the research fields of Ferdowsi University of Mashhad, Iran. The experimental design was arranged in completely randomized blocks design with factorial arrangement of treatments with three replications. The factors included organic fertilizers at 4 levels (cow manure at 40 tons ha-1, vermicompost at l0 tons ha-1, 250 g m-2 mycorrhiza and control treatment without fertilizer). Nicosulfuron (Cruz®,4% SC) rates included 40 and 80 g ai ha-1, with and without the adjuvant (HydroMax™) at 0.5% (v/v). Each plot was divided into two halves with and without the herbicide application, in the corn farm. After harvest of corn, each plot was divided into three longitudinal sections and canola, wheat and barley were planted in each section. Results indicated that plant height, number of ears or silique per square meter, number of seeds per ear or silique, 1000-grain weight, shoot biomass and grain yield of rapeseed, wheat and barley significantly reduced when herbicide was applied at recommended dose. The addition of HydroMax with nicosulfuron, reduced aboveground biomass of mentioned crops, significantly. While organic matter decreased herbicide residue of nicosulfuron and increased plant growth. However, the highest seed yield and the lowest percentage of damage were 63, 419 446 g m-2, and 33%, 23%, 28% in rapeseed, wheat and barley respectly, when cow manure was used plus nicosulfuron at 40 g ai ha-1. In this study, crops sensitivity to soil residue of nicosulfuron herbicide in soil was ranked as rapeseed> barley> wheat.