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Abstract
A defined methodology to characterize biochar is necessary to predict how specific biochars will affect C and nutrient mineralization when amended on cropland soils. We amended Tifton soil (Fine-loamy, siliceous, thermic Plinthic Kandiudults) with Peanut Hull (Arachis hypogaea; PH) and Pine Chip (Pinus taeda; PC) biochar and monitored C and N mineralization. In addition, we characterized each biochar using thermogravimetric analysis with mass spectrometer (TGA-MS), proximate analysis, Fourier transform infrared spectroscopy (FTIR), and total mineral analysis. Carbon mineralization from chars added to soils was correlated with estimated aliphatic content determined by TGA-MS but not with volatile content indicated by proximate analysis. Nitrogen was not mineralized from either biochar, indicating that biochar should not be considered a source of nitrogen for plant growth. The nitrogen in biochar may be contained in the stable aromatic structures of the biochar, as indicated by TGA-MS, and not available to soil microbes.