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Evaluation and Improvements of a Sand‐Alumina Culture Technique to Screen Plants for Low Phosphorus Tolerance
Author(s) -
Gourley C. J. P.,
Allan D. L.,
Bloom P. R.,
Russelle M. P.
Publication year - 1993
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1993.03615995005700010020x
Subject(s) - boehmite , scanning electron microscope , soil water , leaching (pedology) , phosphorus , chemistry , materials science , metallurgy , composite material , aluminium , biology , ecology
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 m M P resulted in steady‐state concentrations in sand‐alumina media of 2.9, 6.9, 40, and 88 µ M 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 m M P, provided [P] in the medium of 4.3, 16.2, and 30 µ M . 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].