John Libbey Eurotext

Science et changements planétaires / Sécheresse

Lessons learnt from trials to regenerate Sahelian rangelands Volume 17, issue 1, Janvier-Juin 2006

Authors
Unité de recherche en partenariat Pôle pastoral zones sèches (URP PPZS), Centre de coopération internationale en recherche agronomique pour le développement (Cirad)/Institut sénégalais de recherches agricoles (Isra), BP 2057, Dakar-Hann Sénégal
  • Key words: rangelands, Sahel, rehabilitation, arid zone
  • Page(s) : 72-5
  • Published in: 2006

In the Sahel of tropical Africa, the degradation of natural pastures is part of the desertification process mainly due to increasing human rural activities. A quick analysis of the vegetation changes describes the phenomenon, leading to understand the main causes: after excessive use of vegetation, a bad water balance and storage in soils due to compaction of topsoil and erosion increase. Several trials using agricultural technologies and tools, carried out in the past, are revisited and the results analysed. The best procedures create artificial obstacles to run-off, such as ploughing interrupted strips or crescents (demi-lunes). Water is stopped behind these mini-dams and penetrates into the soil. But following the mechanical works on soil, the protection of the area is essential. The actual conditions of success for operating regeneration programmes over wide areas are linked to the communal status of the rangelands. Based on past experience, a four-step rehabilitation procedure is proposed: i) stop the causes of degradation; ii) reach a wide consensus among rangeland users on the limits of the area to be improved and as to how regeneration should be implemented; iii) select the technologies and soil profile modifications adapted to the soils; iv) protect the area a sufficient number of years for the regeneration process to become spontaneous.