Study on the Effects of Manure Amendments on the Sulfosulfuron Herbicide Residues in Soil By Test Plants

In order to study the responds of some crops to sulfosulfuron residues in soil of wheat field, a split-plot factorial experiment was conducted at the research field of Faculty of Agriculture, Ferdowsi University of Mashhad in three replications. Main plots were the application of animal manure at 40 t ha-1 and no application, and subplots included sulfosulfuron application dose (recommended and 30% overdose). The bioassay test using sunflower, canola, soybean, bean, pea, lens, sorghum, barley, corn and sugar beet was set at 98 days after the herbicide application in greenhouse conditions. Results showed 24 days after seeding in the pots the most sensitive crop based on dry weight per plant was canola which had lower weight in the un-amended soil or higher application rate. Soybean and lens were the next sensitive crops respectively. The damage symptoms of the herbicide included roots stunt, chlorosis and epinasty in the shoots were more obvious in bean, soybean, sugar beet and canola.