Submitted to: Society of Environmental Toxicology and Chemistry Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/22/2013
Publication Date: 11/21/2013
Citation: Bolster, C.H., Abit, S., Cantrell, K.B., Quijano, J., Walker, S. 2013. Biochar and soil properties affecting microbial transport through biochar-amended soils. Society of Environmental Toxicology and Chemistry Abstracts. http://nashville.setac.org/. Interpretive Summary:
Technical Abstract: The incorporation of biochar into soils has been proposed as a means to sequester carbon from the atmosphere. An added environmental benefit is that biochar has also been shown to increase soil retention of nutrients, heavy metals, and pesticides. We have recently conducted a series of experiments to evaluate whether biochar amendments can also affect microbial transport through soil. We have investigated the role of biochar feedstock type (poultry litter extract and pine chips), biochar pyrolysis temperature (350 and 700 oC), biochar application rate (1, 2, and 10%), soil moisture content (saturated and 50% saturation), soil texture (1 and 12 % clay content), and bacterial surface properties on microbial transport through biochar-amended soils. Under most conditions we found that biochar addition to soils could significantly reduce bacterial transport – in some cases up to five-orders-of-magnitude reduction in transport was observed. In general pine chip biochars were much more effective than poultry litter biochars at increasing microbial retention in our columns. Indeed, in some cases we observed an increase in microbial transport following addition of poultry litter biochars. High temperature biochars were generally more effective at increasing microbial retention in soils than low temperature biochars. Biochar addition to soils was observed to be more effective in partially saturated soils than fully saturated soils. We also found that bacteria with contrasting surface properties responded to biochar additions differently. Our results show that the addition of biochar can affect the retention and transport behavior of bacteria and that biochar application rate, biochar feedstock source, biochar pyrolysis temperature, soil moisture content, soil texture, and bacterial surface characteristics were all important factors determining the transport of bacteria through soil. Our results also suggest that the interactions between biochar and bacteria are complicated and need further investigations to determine the mechanisms involved.