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Vertical Distribution of Phosphorus in Agricultural Drainage Ditch Soils
- Vaughan, Robert E., Needelman, Brian A., Kleinman, Peter J.A., Allen, Arthur L.
- Journal of environmental quality 2007 v.36 no.6 pp. 1895
- soil pollution, polluted soils, phosphorus, agricultural soils, drainage channels, spatial distribution, soil chemical properties, soil horizons, Maryland
- Pedological processes such as gleization and organic matter accumulation may affect the vertical distribution of P within agricultural drainage ditch soils. The objective of this study was to assess the vertical distribution of P as a function of horizonation in ditch soils at the University of Maryland Eastern Shore Research Farm in Princess Anne, Maryland. Twenty-one profiles were sampled from 10 agricultural ditches ranging in length from 225 to 550 m. Horizon samples were analyzed for total P; water-extractable P; Mehlich-3 P; acid ammonium oxalate-extractable P, Fe, and Al (P, Fe, Al); pH; and organic C (= 126). Total P ranged from 27 to 4882 mg kg, P from 4 to 4631 mg kg, Mehlich-3 P from 2 to 401 mg kg, and water-extractable P from 0 to 17 mg kg Soil-forming processes that result in differences between horizons had a strong relationship with various P fractions and P sorption capacity. Fibric organic horizons at the ditch soil surface had the greatest mean P, Fe, and Al concentrations of any horizon class. Gleyed A horizons had a mean Fe concentrations 2.6 times lower than dark A horizons and were significantly lower in total P and P Variation in P due to organic matter accumulation and gleization provide critical insight into short- and long-term dynamics of P in ditch soils and should be accounted for when applying ditch management practices.