Relationships between root density of the African grass Hyparrhenia diplandra and nitrification at the decimetric scale: an inhibition-stimulation balance hypothesis.

J. C. Lata 1, 2 K. Guillaume V. Degrange 3 Luc Abbadie 1, 4 R. Lensi 3
1 Bioemco - Biogéochimie et écologie des milieux continentaux
2 ESE - Ecologie Systématique et Evolution
3 LEM - Laboratoire d'Ecologie Microbienne - UMR 5557
4 Laboratoire Ecologie et évolution
Abstract : Previous studies have shown that Lamto savannah exhibits two different types of nitrogen cycle with high and low nitrification sites and suggested that the perennial grass Hyparrhenia diplandra is responsible for this duality at a subpopulation level, with one ecotype being thought to be able to inhibit nitrification. The present work aimed to investigate the relationships between nitrification and the roots of H. diplandra at two scales. (i) Site-scale experiments gave new insight into the hypothesized control of nitrification by H. diplandra tussocks: the two ecotypes exhibited opposite influences, inhibition in a low nitrification site (A) and stimulation in a high nitrification site (B). (ii) Decimetric-scale experiments demonstrated close negative or positive relationships (in sites A or B, respectively) between the roots and nitrification (in the 0-10 cm soil layer), showing an unexpectedly high sensitivity of the nitrification process to root density. In both soils, the correlation between the roots and nitrification decreased with depth and practically disappeared in the 20-30 cm soil layer (where the nitrification potential was found to be very low). Therefore, the impact of H. diplandra on nitrification may be viewed as an inhibition-stimulation balance.
keyword : Hyparrhenia diplandra Lamto roots nitri¢cation potential savannah
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Journal articles
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https://hal-bioemco.ccsd.cnrs.fr/bioemco-00353791
Contributor : Jean-Christophe Lata <>
Submitted on : Friday, January 16, 2009 - 2:40:37 PM
Last modification on : Monday, December 16, 2019 - 2:28:02 PM

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BIOEMCO | CNRS | INRA | ENS-PARIS | AGROPARISTECH | UPMC | BIOENVIS | LAMTO | PSL | UNIV-LYON1 | SORBONNE-UNIVERSITE | UDL

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J. C. Lata, K. Guillaume, V. Degrange, Luc Abbadie, R. Lensi. Relationships between root density of the African grass Hyparrhenia diplandra and nitrification at the decimetric scale: an inhibition-stimulation balance hypothesis.. Proceedings of the Royal Society B: Biological Sciences, Royal Society, The, 2000, 267 (1443), pp.595-600. ⟨10.1098/rspb.2000.1043⟩. ⟨bioemco-00353791⟩

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