Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 2000
Publication Date: N/A
Technical Abstract: Phosphorus (P) loading into nutrient-sensitive stream systems can be influenced by the P retention capacity of in-stream wetlands. The overall P retention capacity of these systems is dependent on sediment P uptake. We evaluated the P retention capacity of two Coastal Plain in-stream wetland systems that receive drainage water from land areas used for application of animal manure. Phosphorus input-output loads for each wetland system were determined by measuring dissolved P (DP) concentrations and inlet and outlet flow volumes. Additionally, we examined P fluxes between sediment and the overlying water column at locations within each wetland. Sediment P sorption isotherms were determined and passive diffusion samplers were used to measure in-situ DP concentrations in sediment pore water and the water column. Preliminary results showed that DP input-output loads varied with wetland system and, at times, the DP input loads were equal to DP output loads. Sediment pore water DP concentrations in the wetlands were found to vary greatly between years indicating major DP gradient shifts between the sediment and water column. Results suggest that these wetland systems have a low capacity to retain additional DP.