02641nas a2200193 4500008004100000245013300041210006900174300001100243490000700254520196500261653002302226653002102249653001202270653003902282653000802321100001902329700001202348856008702360 2009 eng d00aCharacterization of the water soluble soil organic pool following the rewetting of dry soil in a drought-prone tallgrass prairie0 aCharacterization of the water soluble soil organic pool followin a21 -280 v413 a
To better understand the nature of the C flush that follows the rewetting of dry soil, we chemically characterized the water soluble pools following rewetting of soil dried to several different water potentials. To assess the impact that historical soil water status has on the size of the rewetting labile soluble pool, a laboratory water stress gradient was applied to soils that were collected from drought-prone and irrigated tallgrass prairie soils. In the laboratory, soils were either incubated at −33 kPa or dried steadily over a 0.6, 1, 2, or 3 day period to −1.5, −4, −15, and −45 MPa respectively. On the 4th day, samples were wetted back to −33 kPa and immediately assayed for soluble, microbial, or respiratory pools of carbon. After extraction, samples were also assayed using NMR, GC–MS, and LC–MS to assess carbohydrate, amino acid, osmolyte and sugar pools. The greater the degree of drying before rewetting was associated with greater concentrations of microbial, soluble and respiratory pools of carbon, increasing by 50, 400 and 250%, respectively, in the most water stressed compared to continuously moist soil. Compared to drought-prone soils, the amount of soluble C released as a result of rewetting was 30 to 50% greater in soils that were irrigated for 11 years. The pool of organics was not completely characterized and only small amounts of TBDMS and TMS derived compounds accounting for 2–4% of the soluble C pool were detected. In contrast, oligosaccharides constituted approximately 20–25% of the sample C. Our results suggest that the flush of C following wetting of a dry soil is not dominated by common microbial osmolytes (e.g. proline, glycine betaine, ectoine, glycerol, mannitol, trehalose). In light of this finding more research is needed to better understand the adaptations that microbial communities utilize to respond to the rewetting of dried soil.
10aCompatible solutes10aDrying-rewetting10aGC–MS10aMicrobial response to water stress10aNMR1 aWilliams, M.A.1 aXia, K. uhttps://www.sciencedirect.com/science/article/abs/pii/S0038071708002800?via%3Dihub