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Measuring Phosphorus Release in Laboratory Microcosms for Water Quality Assessment
Published on: July 22, 2019
Spatial variation of soil phosphorus within a drainage ditch network.
Robert E Vaughan1, Brian A Needelman, Peter J A Kleinman
1Department of Environmental Science and Technology, University of Maryland, College Park, MD 20742, USA.
Journal of Environmental Quality
|May 29, 2007
Summary
Agricultural drainage ditches are significant phosphorus (P) pathways. Soil P levels within these ditches show high spatial variation, influenced by P sources, necessitating targeted management strategies.
Area of Science:
- Environmental Science
- Soil Science
- Agricultural Science
Background:
- Agricultural drainage ditches act as conduits for phosphorus (P) transport to surface waters.
- Limited understanding exists regarding the spatial distribution of P at the soil-water interface within these ditch networks.
Purpose of the Study:
- To quantify the spatial variation of surficial soil P within vegetated agricultural ditches.
- To investigate the relationship between P and soil properties like Fe, Al, and pH in these ditches.
Main Methods:
- Sampling of ditch soils from 10 ditches at 10-m intervals.
- Analysis of acid ammonium oxalate-extractable P, Fe, Al (P(ox), Fe(ox), Al(ox)), and pH.
- Spatial autocorrelation analysis of measured variables.
Main Results:
- Significant spatial autocorrelation was observed for P(ox), Fe(ox), Al(ox), and pH.
- Soil P(ox) exhibited high spatial variability (mean 700 mg kg(-1), SD 580 mg kg(-1)), with localized hotspots linked to P sources.
- Al(ox) showed a stronger correlation with P(ox) (r = 0.80) across all ditches compared to Fe(ox) (r = 0.44).
Conclusions:
- High spatial variation in soil P within agricultural ditches underscores the need for spatially distributed sampling.
- Understanding this variability is crucial for effective targeting of best management practices and accurate modeling of P transport and fate.
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