Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/13/2007
Publication Date: 12/10/2007
Citation: Halvorson, J.J., Gonzalez, J.M., Hagerman, A.E., Smith, J.L. 2007. Tannic Acid Reduces Recovery of Water Soluble Carbon and Nitrogen from Soil. ASA-CSSA-SSSA Annual Meeting Abstracts. Available: https://www.acsmeetins.org/2007/poster_oral/#find
Technical Abstract: Tannins are plant-derived polyphenolic compounds that precipitate proteins, bind to metals and complex with other compounds but the fate of tannins after they enter the soil is not completely understood, especially the formation of complexes with organic and inorganic components. Solutions of tannic acid or other related phenolic compounds were added to surface (0-5 cm) and subsurface (10-20 cm) soil samples to determine if they would affect recovery of soluble soil-C (WSC) or –N (WSN). The amount of total net WSC and WSN extracted was less than the control, suggesting tannic acid-C added with water was sorbed on soil and/or formed complexes. Compared to tannic acid, non-tannin phenolics, like gallic acid or methyl gallate, had little effect on extraction of WSC or WSN while a simple gallotannin derived from tannic acid, 1,2,3,4,6-penta-O-galloyl-D-glucose, inhibited extraction most. The effects of tannins persisted in surface soil, even after 13 sequential water extractions and to a lesser degree in subsurface soil. Sequential additions of tannic acid to the surface soil resulted in an L-type sorption curve, suggesting that the soil in this study had a maximum sorption capacity for tannic acid-C. Though limited in scope, these studies indicate that abiotic reactions between some tannins and soil organic matter might rapidly decrease the solubility of labile soil C and N. However, further research is needed to determine mechanisms of interactions between tannins and related compounds and soil organic matter.