Effect of Organic and Biofertilizers and HydroMax adjuvant on Persistence of Nicosulfuron Herbicide in Soil

In order to study the effect of Hydromax adjuvant and application of organic and biofertilizers on persistence of nicosulfuron herbicide in soil, an experiment was carried out as a factorial arrangement based on completely randomized block design with three replications during 2014-2015. The first factor included the use of cow manure, vermicompost, biological fertilizer of mycorrhiza with a control treatment, the second factor included the use of 80 and 40 g a.i ha-1 of the recommended dose of nicosulfuron herbicide, and the third factor included the use of Hydromax adjuvant and without adjuvant. To determine nicosulfuron soil residue after herbicide spray, soil sampling was done from 0-15 cm depth of soil at different periods of 0, 2, 5, 8, 16, 30, 60, 90 days after spraying and then the herbicide residue was determined using both HPLC. Results showed with increasing of nicosulfuron rate, it’s soil residue increased. By increasing the rate of herbicide application, degradation rate decreased from 0.039 to 0.037 μg/kg/day, but half-life increased from 17.77 to 18.83 days. Also nicosulfuron degradation rate decreased from 0.037 to 0.034 μg/kg/day, and half-life increased from 18.73 to 20.39 days in soil when Hydromax adjuvant applied with nicosulfuron at 80 g a.i ha-1.