Submitted to: U.S. Biochar Initiative Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 2, 2010
Publication Date: N/A
The low pH and high P-fixing characteristics of many Appalachian soils render them unproductive and reduce the profitability of small farms. Soil pH can be improved by liming, typically with calcium carbonate, to improve nutrient availability but the byproducts produced during the production of biofuels, known as biochars, as may also act similarly. In this study we evaluated the use of biochars, derived from chicken manure as liming agents and soil amendments in a representative Appalachian soil. The slow-pyrolysis biochars/activated carbons were produced at two temperatures, 350 C degrees and 700 C degrees, and with or without steam-flow activation. Columns of mixed soil were amended with the four different biochars at five rates (0.0, 0.5, 1.0, 2.0, and 4.0 % by weight) and incubated in a climate-controlled chamber for eight weeks, divided into two-week wet/dry cycle intervals. Soil columns were weighed before and after the wet/dry cycles to determine water losses. A subsample of soil was collected and assayed for soil pH, and then the column was repacked and wetted. At the end of the incubation, the soil columns were leached with four pore volumes and the leachate was analyzed for ionic and elemental composition. The soil remaining in columns was analyzed to determine changes in chemical and physical attributes. Application of biochar resulted in a rate dependent increase in soil pH, increased water-holding capacity, and decreased water loss during the drying periods. Rate dependent differences among biochar types, observed by the second wet/dry cycle, indicated the 350 C degrees biochar had comparatively less effect on soil pH at the high application rates, probably because it contained less than half of the calcium carbonate equivalent as the other biochars. The results of this study suggested that biochar could be used as an effective liming agent in acidic, high P-fixing soils such as in the Appalachian region.