Biochar Application Effects On Temperate Forest Soil Properties.

Bioenergy production from forest biomass offers a potential solution to reduce wildfire hazard fuel.  However, removing biomass reduces soil organic carbon and can have negative impacts on soil fertility. Portable pyrolysis technology uses biomass to generate biofuels and a carbon-rich, biochar product recalcitrant to decomposition that can be used as a soil amendment. Biochar utilization can increase SOC and retain nutrients on forestry sites.  Ideally, excess forest fuels could be used as a potential energy source and biochar can sequester carbon and improve soil quality while simultaneously reducing wildfire risk.  To evaluate the environmental potential of biochar in forestry, we investigated the effects of a single biochar source added to several forest soil types in laboratory experiments to identify changes in soil physical, chemical and biological properties.  Temperate forest soils were amended with various biochar rates and application methods, irrigated, and incubated for three to eight months.  Results show that effects of biochar on soil properties vary among soil type.  Biochar had a significant effect on soil pH, Mg, K, Total C, Total N and water holding capacity.  However, while most nutrient concentrations increased in biochar-amended soils, some cations decreased.  Based on literature reports, we expect biochar to benefit forest soils, but the extent appears to vary by soil type, rate, and application methods.  Results for microbial biomass and soil respiration also show variable results among soil types.  This research is meant to evaluate environmental implications of combining biochar soil management with energy production using pyrolysis.  Positive effects of biochar amendments on agricultural soil have been known for centuries and are well documented; however, little is known about the effects of biochar on temperate forest soil. Further research into the potential benefits of biochar in temperate forests is needed to make it an economically viable tool for forest managers.