La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Edaphic changes along a gradient of grazing intensity in a steppe of Algeria
Auteurs :	A. Aidoud, Auteur ; H. Slimani, Auteur ; F. Aidoud-Lounis, Auteur ; J. Touffet, Auteur
Type de document :	Article
Dans :	Ecologia Mediterranea (25(2) 1999)
Article en page(s) :	163-171
Résumé :	A set of soil characters are analysed, in an arid steppe subject to desertification, along a transect that presents three levels of grazing intensity. The pre-existing system had been, about twenty years ago, a pure steppe dominated by alfa-grass that was the typical landscape of the whole region under relatively homogeneous environmental features. Results show a relative stability in the non-grazed area where soil characters remain similar to those of the pre-existing system. In the open rangelands, freely used and marked by over-grazing, the more significant changes are declining rates of organic matter (38%) and of clay and fine silt (43%). These changes are highly significant but are more important at the surface layer. At a local scale, changes concern both soil underneath the tussock and the interstitial one. The destruction of the alfa-grass tussocks has led to the loss of its edaphic functions by breaking down the soil structure. Our results confirm those obtained on vegetation and strengthen the hypothesis of irreversible changes of main vital attributes of the system.

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