Caractérisation des pâturages herbacés sahéliens à accès limité : Cas du Centre Secondaire de Multiplication de Bétail de Sayam (Diffa).

Abstract

Objectifs : Cette etude vise a caracteriser l’etat actuel des paturages herbaces du Centre Secondaire de Multiplication de Betail de Sayam.

Méthodologie et Résultats : Quatre groupements pastoraux ont ete identifies et decrits a partir de 56 releves lineaires realises sur un transect Sud - Nord. Au total 98 especes herbacees reparties parmi 59 genres et 27 familles botaniques ont ete repertoriees. Les genres suivants : Eragrostis, Ipomoea, Aristida, Cenchrus, Indigofera, Digitaria et Brachiaria ont ete les mieux representes. Ils representent environ 50% du total et renferment l’essentiel des especes de bonne valeur pastorale. Le recouvrement global, les valeurs pastorales brutes et nettes sont respectivement de 85,5%, 75,05% et 67,56%, celles-ci attestent que le paturage du centre est de bonne qualite. La productivite globale en phytomasse herbacee a ete estimee 2,26 tMS/ha avec une capacite de charge globale de 0,40 UBT/ha/an soit 2,5 ha/UBT/an. L’analyse du spectre fourrager indique que les especes de bonne valeur pastorale et de faible valeur pastorale dominent le tapis herbace. La premiere categorie domine la zone centrale mieux protegee tandis que la derniere occupe les parties peripheriques soumises a une forte exploitation du betail.

Conclusion et application des résultats : Le front de colonisation des especes faiblement appetees (especes qui ont IS = 0 ou IS = 1) progresse vers le centre sous l’effet de la forte pression pastorale. D’ou l’urgence de cloturer l’ensemble du perimetre du centre afin d’eviter de creer un desequilibre ecologique prejudiciable a la survie de nombreuses especes infeodees a ces milieux particuliers. Dans les perspectives d’une gestion durable des ressources fourrageres des centres secondaire de multiplication de betail, ce travail fournit des informations scientifiques fiables sur l’etat actuel des paturages herbaces de ce centre.

English title: Characterization of Sahelian herbaceous pastures with limited access: Case of the Secondary Cattle Multiplication Center of Sayam (Diffa).

Abstract

Objectives : This study aims to characterize the current state of the herbaceous pastures of the Sayam Secondary Cattle Multiplication Center.

Methodology and Results : Four pastoral groups have been identified and described from 56 linear surveys carried out on a South - North transect. A total of 98 herbaceous species distributed among 59 genera and 27 botanical families have been listed. The best represented genera are: Eragrostis, Ipomoea, Aristida, Cenchrus, Indigofera, Digitaria and Brachiaria. They represent about 50% of the total and contain most of the species of good pastoral value. The overall recovery, the gross and net pastoral values are respectively 85.5%, 75.05% and 67.56%, these attest that the pasture of the center is of good quality. The overall productivity of herbaceous phytomass was estimated at 2.26 tMS / ha with an overall carrying capacity of 0.40 TLU / ha / year, ie 2.5 ha / TLU / year. Analysis of the forage spectrum indicates that species of good pastoral value and those of low pastoral value dominate the grass cover. The first category dominates the better protected central zone while the last occupies the peripheral parts subject to heavy livestock exploitation.

Conclusion and applicability of results : The colonization front of poorly palatable species is progressing towards the center under the effect of strong pastoral pressure. Hence the urgency to enclose the entire perimeter of the center in order to avoid creating an ecological imbalance detrimental to the survival of many species dependent on these particular miles. With a view to the rehabilitation and sustainable management of these pastoral centers, this study provides additional information on the current state of the herbaceous pastures in this center.

Keywords : Kouri, floristic composition, pastoral groups, pastoral quality, Sayam, Niger