Investigation of nicosulfuron herbicide persistence in the soil affected to chemical and biological degradation under controlled conditions

Nicosulfuron belongs to the group of herbicides that has soil residue and its residue in the soil cause damage to sensitive crops in crop rotation.. In order to study the nicosulfuron herbicide persistence in the soil under biological and chemical degradation of nicosulfuron herbicide in soil, under controlled conditions, an experiment was carried out in a factorial randomized complete block design with three replications during 2015-2016. The first factor included conditions of sterile and non-sterile soil and fertilizer, the second factor included the application of organic and bio-fertilizers at four levels of cow manure, vermicompost, mycorrhiza (2 % w/w) and control treatment without fertilizer, the third factor also included incubating periods at eight levels 0, 4, 8, 16, 35, 50, 80, 100 days. The results showed that nicosulfuron degradation was chemical hydrolysis under sterile conditions, and was biodegradation and chemical hydrolysis under non sterile conditions. Nicosulfuron degradation rate was not significant difference in control treatment (without organic fertilizers application) under conditions of sterile, non-sterile fertilizer and soil, But increased with application of organic and bio-fertilizers and deacresed residue herbiced. The lowest residue rate was obtained from the application of cow manure under non-sterile (0.01 mg/kg/ day) and sterile 0.03 mg/kg/ day) conditions. The highest and the lowest degradation rate were obtained from the application of cow manure under non-sterile conditions and control treatment under sterile conditions. Also the lowest and the highest half-life was obtained by 15.33 and 38.5 day from the application of cow manure under non-sterile conditions respectively.