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Soil-plant potassium transfer: impact of plant activity on clay minerals as seen from X-ray diffraction

Abstract : Potassium (K) availability influences many processes in cultivated and natural ecosystems. Several studies suggest that "non-exchangeable" K+ ions fixed in 2:1 clay mineral interlayers contribute to plant nutrition. Although depletion of these K+ ions could be observed by X-ray diffractometry, this technique has never been considered for the observation of short-term changes in illitic 2:1 clay minerals. We established in this study that new treatments of X-ray diffraction patterns allow quantification of short-term 2:1 clay mineral changes through K addition in solution and removal of interlayer K by Lolium multiflorum. Moreover, we obtained a significant relationship (r(2) = 0.95, P < 0.0001) between an indicator calculated from X-ray diffraction patterns and analyzed clay K content. X-ray diffraction should therefore be considered as an appropriate tool to follow qualitatively and quantitatively clay mineral modifications induced by soil K balance. Our results suggest that 2:1 clay minerals behave as a huge, renewable K reservoir whose theoretical capacity in fertile soils could exceed 3 t/ha. Beyond obvious agronomical implications, this new vision of soil K cycle raises ecological questions about plant inter specific competition and soil fertility. Finally, our study clearly shows that soil 2:1 clay minerals could react as quickly as a biological system.
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Contributor : Luc Abbadie Connect in order to contact the contributor
Submitted on : Wednesday, July 4, 2007 - 4:54:42 PM
Last modification on : Friday, October 21, 2022 - 1:12:07 PM


  • HAL Id : bioemco-00160016, version 1
  • PRODINRA : 251241


Pierre Barre, Nicole Catel, Bruce Velde, Luc Abbadie. Soil-plant potassium transfer: impact of plant activity on clay minerals as seen from X-ray diffraction. Plant and Soil, 2007, pp.137-146. ⟨bioemco-00160016⟩



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