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Diversité fonctionnelle des graminées prairiales: conséquences pour la productivité et pour la valeur nutritive

Abstract : The aim of this study was to investigate the productivity and nutritive value of 13 co-occurring native grass species, sampled in semi-natural upland grasslands, and to gain functional understanding of these processes by studying above-ground plant functional traits. A fully factorial field experiment crossing the cutting frequency (3 and 6 cuts per year), the N supply (120 and 360 kg N ha-1 yr-1) and the plant species factors with three replicate blocks allowed to compare in monocultures the native grasses and a control cultivar of Lolium perenne. A total of 21 above-ground traits concerning morphology, phenology and chemical composition were studied during two years as well as the above-ground primary productivity and the pepsin cellulase dry matter digestibility and crude protein content. We show that distinct syndromes of traits affect the above-ground net primary productivity and the nutritive value of the grass species. Differences in N nutrition (N nutrition index and nitrogen use efficiency) among species are shown to affect the above-ground productivity. The leaf N and dry-matter contents are good indicators of the productivity and nutritive value of the grasses, which have been classified in four groups according to their trait values. An increase in cutting frequency triggered changes in leaf traits which reduced leaf lamina digestibility, which was interpreted as a grazing avoidance strategy. A deprivation of N induced increases in leaf dry-matter content and in leaf lifespan, which was interpreted as a nutrient conservation strategy. Species from more disturbed habitats displayed a set of leaf traits which tended to reduce their digestibility. Our results underline the large functional diversity of co-occurring pasture grasses and it is concluded that this diversity is likely to enhance the stability of productivity and nutritive value in semi-natural grassland communities.
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https://tel.archives-ouvertes.fr/tel-00124076
Contributor : Laise da Silveira Pontes <>
Submitted on : Friday, January 12, 2007 - 11:53:38 AM
Last modification on : Saturday, June 6, 2020 - 12:11:36 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 9:59:23 PM

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  • HAL Id : tel-00124076, version 1
  • PRODINRA : 252034

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Laise da Silveira Pontes. Diversité fonctionnelle des graminées prairiales: conséquences pour la productivité et pour la valeur nutritive. Ecologie, Environnement. Université Blaise Pascal - Clermont-Ferrand II, 2006. Français. ⟨tel-00124076⟩

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