Journal of Crop Production and Processing

In order to study the effect of adjuvant on nicosulfuron herbicide efficacy improvement in maize weed control under organic fertilizers application, field study was conducted during 2013- 2014 at research field of Ferdowsi University of Mashhad, Iran. Experiment was arranged in completely randomized design with factorial arrangement of treatments with 16 treatments and three replications. Factors in this experiment were application of organic fertilizers (cow manure and vermicompost) and bio fertilizer mycorrhiza, and a plot without fertilizer as control, nicosulfuron dose at 40, and 80 g a.i ha^-1 (Cruz®,4% SC) with and without the adjuvant of HydroMax™. Common purslane (Portulaca oleracea), black nightshade (Solanum nigrum L.), and redroot pigweed (Amaranthus retroflexus L) were the dominant weeds in the experimental fields. Black nightshade and common purslane had the highest relative density 20 and 45 days after spraying (DAS). Results showed that application of hydromax adjuvant increased herbicide efficiency, significantly. However dry weight of common purslane, black nightshade and redroot pigweed decreased 84, 71, 86 and 71, 79, 100 %, when nicosulfuron applied at reduced dose (40 g a.i. ha^-1) with adjuvant 20 and 45 DAS, respectively. On the other hand, seed yield and dry weight of maize increased 49 and 60 % respectively, when nicosulfuron applied at 40 g a.i. ha^-1 with Hydromax pulse cow manure.