Potential Availability of Fertilizer Selenium in Field Capacity and Submerged Soils
- H. Lakmalie Premarathna *a,
- Mike J. McLaughlina,
- Jason K. Kirbyb,
- Ganga M. Hettiarachchibc,
- Doug Beakd,
- Samuel Staceya and
- David J. Chittleboroughe
- a School of Agriculture, Food and Wine, University of Adelaide, Prescott Building, Glen Osmond, SA 5064, Australia
b CSIRO Land and Water, Adelaide Laboratory, PMB 2, Glen Osmond, SA 5064, Australia
c Current: Dep. of Agronomy, 2107, Throckmorton, Plant Science Center, Kansas State University, Manhattan, KS 66506
d USEPA, Groundwater and Ecosystems Restoration Res., Ada, OK 74820
e Soil and Land Systems, School of Earth and Environmental Sciences, University of Adelaide, Glen Osmond, SA 5064, Australia
The potential availability (E) and partitioning (K d) of Se added to three soils as elemental Se (Se0), sodium selenite (SeO3 2−), and sodium selenate (SeO4 2−) were measured by isotopic dilution using either 75SeO3 2− or 75SeO4 2− The soils were kept either submerged or at 80% water-holding capacity for either 15 or 60 d. Both K d and E values were controlled by the type of Se, soil moisture content, and time after application. The K d values for SeO3 2− were largely controlled by soil type, with the soil having the lowest pH and highest concentrations of oxalate-extractable Al and Fe having the highest K d values. The K d values for SeO4 2−, on the other hand, were largely influenced by the incubation period, and to a lesser extent soil type and moisture conditions. Selenate K d values decreased with incubation and were higher under submerged conditions. The availability of Se0 as measured by concentrations of labile Se species was low due to limited oxidation to SeO3 2− or SeO4 2− Elemental Se is therefore not suitable for preplant Se fertilization of lowland rice (Oryza sativa L.) because it is not readily oxidized. In the submerged soils, concentrations of labile SeO3 2− and SeO4 2− were also low, with >80% of the Se added as either SeO3 2− or SeO4 2− being fixed into nonlabile pools, probably through reduction to Se0 Rates of oxidation of Se0 will play a critical role in determining whether reduced Se0 formed in submerged soils after fertilization will contribute to plant Se uptake through oxidation either during field drainage before harvest or in the rice rhizosphere.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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