Vertical distribution of phosphorus in agricultural drainage ditch soils.
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 ox, Fe ox, Al ox); pH; and organic C (n = 126). Total P ranged from 27 to 4882 mg kg(-1), P ox from 4 to 4631 mg kg(-1), Mehlich-3 P from 2 to 401 mg kg(-1), and water-extractable P from 0 to 17 mg kg(-1). 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 ox, Fe ox, and Al ox concentrations of any horizon class. Gleyed A horizons had a mean Fe ox concentrations 2.6 times lower than dark A horizons and were significantly lower in total P and P ox. 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.
Vaughan
Robert E
RE
Dep. Environmental Science and Technology, University of Maryland, 1109 H.J. Patterson Hall, College Park, MD 20742, USA.
Needelman
Brian A
BA
Kleinman
Peter J A
PJ
Allen
Arthur L
AL
D000383:Agriculture; D008396:Maryland; D009930:Organic Chemicals / Q000737:chemistry; D010084:Oxidation-Reduction; D010758:Phosphorus / Q000032:analysis*; D011336:Probability; D012987:Soil / Q000032:analysis*; D013440:Sulfides / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D014872:Water Movements
D009930:Organic Chemicals; D012987:Soil; D013440:Sulfides; D014867:Water; D010758:Phosphorus