XXXX Emission Reduction by Soil Amendment with Biochar.

@entity70690 @entity2199 @entity306 @entity46432
UNASSIGNED: Biochar has sorption capacity, and can be used to enhance the sequestration of volatile organic contaminants such as pesticides in soil. @entity46432 ( @entity306 ) is an important soil fumigant for the production of many fruit and vegetable crops, but its emissions must be minimized to reduce exposure risks and air pollution. The objective of this study was to determine the capacity of biochar to adsorb @entity306 and the effect of biochar amendments to soil on @entity306 emission, concentration in the soil gas phase, degradation in soil and @entity306 bioactivity for controlling soil borne pests. @entity306 emission and concentration in the soil air phase were measured from packed soil columns after fumigant injection at 20-cm depth and application of selected doses of biocharto the surface 5 cm soil. Laboratory incubation and fumigation experiments were conducted to determine the capacity of biochar to adsorb @entity306 , the effects on @entity306 degradation and, separately, @entity306 's bioactivity on soil borne pests in soil amended with biochar. Biochar amendment at 2% to 5% (w/w) greatly reduced total @entity306 emission losses by 85.7% - 97.7% compared to fumigation without biochar. @entity306 concentrations in the soil gas-phase, especially in the top 5 cm of soil, were reduced within 48 h following application. The half-life of @entity306 decreased from 13.6 h to 6.4 h as the biochar rate increased from 0% to 5%. @entity306 and its metabolite ( @entity70690 ) both degraded more rapidly in pure biochar than in soil. The biochar used in the present study had a maximum adsorption capacity for @entity306 of less than 5 mg g-1. There were no negative effects on pathogen and @entity2199 control when the biochar used in this study was less than 1% (on a weight basis) in soil. Biochar amendment to soil reduced the emissions of @entity306 . @entity306 concentrations in the top 5 cm of soil gas-phase were reduced. @entity306 degradation was accelerated with the addition of biochar. The biochar used in the present study had a low adsorption capacity for @entity306 . There were no negative effects on pathogen and @entity2199 control when the biochar amendment rate was less than 1% (by weight). The findings would be useful for establishing guidelines for biochar use in soil fumigation.
