Soil microbial biomass C and symbiotic processes associated with soybean after sulfentrazone herbicide application
2007
The aim of this work was to evaluate the effects of the herbicide sulfentrazone on soil microbial biomass C and on symbiotic processes associated with soybean (Glycine max (L). Merril). The experiment was conducted in greenhouse using a Red-Yellow Oxisol soil collected from Embrapa Meio Ambiente's experimental field, in Jaguariúna, São Paulo, Brazil and included the following treatments: control, without herbicide and sulfentrazone herbicide application (0.7 mg kg-¹ soil) and three harvest periods. The nodule number and nodule dry weight on the onset of soybean development were negatively affected by the presence of the herbicide, as also observed for shoot biomass and shoot total N content. Pod dry weight and pod total N content decreased by 45% in the presence of the herbicide. The percentage of mycorrhizal infection was 50% lower in pots that received sulfentrazone throughout the soybean growing season. Microbial biomass C was lower in the presence of the herbicide only in the initial period of soybean development. Mycorrhizal and rhizobial performance in soybean were reduced by sulfentrazone use, and both possibly contributed to reduced plant growth.
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