Trends of litter decomposition and soil organic matter stocks across forested swamp environments of the southeastern US




A common idea in the discussion of soil carbon processes is that litter decomposition rates and soil carbon stocks are inversely related. To test this overall hypothesis, simultaneous studies were conducted of the relationship of environmental gradients to leaf and wood decomposition, buried cloth decomposition and percent soil organic matter in Taxodium distichum swamps across the Mississippi River Alluvial Valley (MRAV) and northern Gulf of Mexico (GOM) of the US. Decomposition of leaf tissue was 6.2 to 10.9 times faster than wood tissue. Both precipitation and flooding gradients were negatively related to leaf and wood litter decomposition rates based on models developed using Stepwise General Model Selection (MRAV vs. GOM, respectively). Cotton cloth should not be used as a proxy for plant litter without prior testing because cloth responded differently than plant litter to regional environmental gradients in Tdistichum swamps. The overall hypothesis was supported in the MRAV because environments with higher precipitation (climate normal) had lower rates of decomposition and higher percent soil organic matter. In the MRAV, higher levels of percent soil organic matter were related to increased 30-year climate normals (30 year averages of precipitation and air temperature comprising southward increasing PrinComp1). Soil organic carbon % in inland vs. coastal Tdistichum forests of the MRAV were comparable (range = 1.5% to 26.9% vs. 9.8 to 31.5%, respectively). GOM swamps had lower rates of litter decomposition in more flooded environments. Woody Tdistichum detritus had a half-life of up to 300 years in the MRAV, which points to its likely role in the maintenance of inland “teal” soil organic carbon. This unique study can contribute to the discussion of approaches to maintain environments conducive to soil carbon stock maximization.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Trends of litter decomposition and soil organic matter stocks across forested swamp environments of the southeastern US
Series title PLoS ONE
DOI 10.1371/journal.pone.0226998
Volume 15
Issue 1
Year Published 2020
Language English
Publisher PLOS
Contributing office(s) Wetland and Aquatic Research Center
Description e0226998, 23 p.
Country United States
State Arkansas, Florida, Illinois, Louisiana, Mississippi, Missouri, Texas
Other Geospatial Mississippi River Alluvial Valley
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