Author ORCID Identifier

https://orcid.org/0009-0007-3880-6367

Date Available

8-12-2025

Year of Publication

2025

Document Type

Master's Thesis

Degree Name

Master of Science (MS)

College

Agriculture, Food and Environment

Department/School/Program

Plant and Soil Sciences

Faculty

Brad Lee

Faculty

Arthur Hunt

Abstract

The USDA NRCS Agricultural Conservation Easement Program Wetland Reserve Easements is focused on converting marginal agricultural lands to wetlands to restore hydrologic function and enhance wetland habitat. There is a gap in knowledge of how phosphorus (P) dynamics develop as these wetlands are converted from row crops to wetland vegetation over time. Recently converted wetlands have the potential to develop into P sinks. In this study, a chronosequence of former farmlands converted to forested palustrine wetlands in the northern Mississippi Embayment was used to evaluate the potential mobility of P post-conversion. Three soil depth intervals were analyzed for water-soluble P, ammonium oxalate extractable P, iron, and aluminum on a 10-m grid from a chronosequence of wetlands (0, 7, and 33 yr). A calculated phosphorus saturation ratio (PSR) was used to determine if the wetland soils were likely to be a P source or sink. The mature wetlands had significantly higher PSR in the 0-10 cm depth (range: 0.041-0.12, mean: 0.065), relative to the younger wetlands (range: 0-0.124 and mean: 0.053). The mature wetlands had 20.9% of samples above the threshold PSR (0.1) relative to the intermediate (9.5%) and transitional (0.3%), indicating that as converted wetlands age, surface soils are more likely to release P.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2025.351

Funding Information

This work was supported by the United States Department of Agriculture Natural Resources and Conservation Service award (68-5C16-17-018).

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