Poster Number 544
See more from this Division: S11 Soils & Environmental QualitySee more from this Session: General Soil and Environmental Quality Posters: II
Wednesday, October 19, 2011
Henry Gonzalez Convention Center, Hall C
Lake Champlain has persistent algal blooms associated with excess phosphorus (P) from the landscape. Streambank erosion is ubiquitous throughout the Champlain Basin with 75% of Vermont stream reaches classified as unstable. The P contribution of streambank erosion has not been well quantified, yet could be a significant source of non-point P. The objectives of this study were to 1) assess the variability in total P (TP) and soil test P (MM-P) for eroding riparian soils; 2) relate TP and MM-P with soil physical and chemical properties, including texture, Al, Ca, and Fe; 3) relate TP and MM-P to landscape parameters, including land use/land cover (LULC), landscape position, soil type and parent material; and 2) quantify the potential P load from eroding streambanks. Soil samples were taken from 76 erosion features to a depth of 90 cm on 4 streams in Chittenden County, Vermont and analyzed for texture, total P, Modified-Morgan’s P, and total aluminum, calcium, iron, and manganese. Landscape parameters were assessed using available spatial databases for LULC, parent material, soil type, landscape position. Mean concentrations of TP and MM-P were similar among the four streams and through depth, but not correlated with each other. A strong relationship existing between Ca and TP in excess of apatite ratios suggests apatite-P is a common P form in these soils. Low MM-P concentrations suggest that eroded streambank may act as sinks rather than a source of P. Landscape parameters including LULC and landscape position correlated with TP and MM-P. Streambank erosion from four streams in Chittenden County contributed a total of 11.2 to 14.1 MT of TP and 37.7 kg of MM-P to corresponding stream corridors. Estimated potential P load from eroding streambanks from 1999-2004 ranged from 16 to 95% of total non-point load depending on stream and estimation method.
See more from this Division: S11 Soils & Environmental QualitySee more from this Session: General Soil and Environmental Quality Posters: II