Mobilisation of inorganic phosphorus induced by rice straw in aggregates of a highly weathered upland soil

Authors

  • Longjun Ding,

    1. Key Laboratory of Agro-ecological Processes in the Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha 410125, China
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  • Professor Jinshui Wu,

    Corresponding author
    1. Key Laboratory of Agro-ecological Processes in the Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha 410125, China
    • Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha, Hunan 410125, China.
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  • Heai Xiao,

    1. Key Laboratory of Agro-ecological Processes in the Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha 410125, China
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  • Ping Zhou,

    1. Key Laboratory of Agro-ecological Processes in the Subtropical Region, Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha 410125, China
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  • J Keith Syers

    1. Faculty of Agriculture, Natural Resources and Environment, Naresuan University, Phitsanulok 65000, Thailand
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Abstract

BACKGROUND: Microorganisms mediate biochemical transformations of phosphorus (P) in soil. This is of particular importance in highly weathered soils, which are usually P deficient. This study aimed to extend understanding of the separate role of bacteria and fungi in P transformations in aggregates of a highly weathered soil, by adding P-stripped rice straw and microorganism inhibitors to aggregates.

RESULTS: The amount of microbial biomass phosphorus (MB-P) in the treatment with rice straw alone increased by over two-fold during 16 days. At the end of 28 d, the amount of inorganic-P in Fe-, Al-, and Ca-bound fractions decreased, whilst the amount of organic-P increased substantially (P < 0.01). The effect of bacterial inhibitors (tetracycline and streptomycin sulphate) on P immobilisation was very small in the early phase (0–4 d), but became pronounced after 8 days, whilst the fungal inhibitor (actidione) initially caused a decrease in P immobilisation by about 60%, but had no effect after that.

CONCLUSION: Fungi and bacteria immobilise P in soil aggregates, with fungi being responsible initially. However, bacteria become dominant subsequently and immobilise P from the inorganic fractions. Copyright © 2011 Society of Chemical Industry

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