The Use of Sediment Removal to Reduce Phosphorus Levels in Wetland Soils and the Distribution of Plant-Available Phosphorus in Wetland Soils and its Potential Use as a Metric in Wetland Assessment Methods

Abstract

Plant-available phosphorus (P) in wetland soils and its relationship with wetland communities and condition is somewhat unknown in the Prairie Pothole Region (PPR) in North America. Research objectives were to determine if 1) sediment removal reduced P in seasonal wetlands; 2) P could be used as an indicator in wetland condition assessments; 3) a gradient in P amount and wetland elevation existed; and 4) differences of sampling and extraction methods change Olsen P results as a metric in assessments. Soil samples from North Dakota wetlands were collected from two depths (0-15 and 15-30 cm) and analyzed for pH, electrical conductivity (EC), and P (Olsen and water-extractable (WEP)). Sediment removal does not reliably reduce P in the shallow marsh zone based on the variability within and between locations. Phosphorus should not be used in wetland assessments, although the shallow marsh zone typically had the most P of the three landscape positions.