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This article in SSSAJ

  1. Vol. 57 No. 1, p. 103-110
    Received: Feb 3, 1992

    * Corresponding author(s):


Evaluation and Improvements of a Sand-Alumina Culture Technique to Screen Plants for Low Phosphorus Tolerance

  1. C. J. P. Gourley ,
  2. D. L. Allan,
  3. P. R. Bloom and
  4. M. P. Russelle
  1. Ellinbank Dairy Research Institute, Victorian Dep. of Agriculture, Warragul South, Victoria, Australia, 3820
    Soil Science Dep., 439 Borlaug Hall, Univ. of Minnesota, St. Paul, MN 55108-6028
    USDA-ARS U.S. Dairy Forage Research Center, 439 Borlaug Hall, Univ. of Minnesota, St. Paul, MN 55108-6028



Simple and effective artificial cultures will greatly benefit selection of plants more tolerant to P-deficient soils. The sand-alumina culture technique developed by Coltman et al. appears to supply P at solution concentrations encountered in soils, while providing a solid medium for plant growth. We simplified the technique of loading alumina with P and assessed the effects of P-loading solutions, loading times, leaching treatments, and autoclaving on P concentrations ([P]) and long-term consistency of P supply in the medium. Physical and chemical changes of alumina granules were also investigated. Loading alumina with solutions of 75, 150, 300, and 600 mM P resulted in steady-state concentrations in sand-alumina media of 2.9, 6.9, 40, and 88 µM P, respectively; supply was stable for at least 52 d without plant growth but slowly declined with established alfalfa (Medicago sativa L.). A second batch of alumina, loaded with 75, 150, and 300 mM P, provided [P] in the medium of 4.3, 16.2, and 30 µM. Shortening the P-loading period or autoclaving decreased [P]. X-ray diffractometry and scanning electron microscopy indicated the alumina was boehmite and pseudoboehmite (AIOOH), which was substantially altered by P-loading solutions to form a poorly ordered, insoluble surface precipitate containing Al, K, and P. The sand-alumina medium proved to be simple, inexpensive, and effective for growing plants in a wide range of [P].

Joint contribution of the Minnesota Agric. Exp. Stn. and the USDA-ARS. Paper no. 19 662 of the Minnesota Agric. Exp. Stn. scientific journal series.

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