Publications des agents du Cirad


Vegetative propagation at low costs: A method to restore degraded lands

Bellefontaine R., Malagnoux M.. 2008. In : Lee Cathy (ed.), Schaaf Thomas (ed.). The future of drylands : International Scientific Conference on Desertification and Drylands Research, Tunis, Tunisia, 19-21 June 2006. Dordrecht : Springer [Pays-Bas], p. 417-433. International Scientific Conference on Desertification and Drylands Research, 2006-06-19/2006-06-21, Tunis (Tunisie).

Many multipurpose woody plants in arid and semi-arid zones are indangered species. The natural or induced vegetative propagation (NIVP) of these species can be very beneficial in reversing this trend so as to increase the living standards of impoverished populations, control erosion and combat desertification. Different species can propagate thanks to rhizomes, runners, suckers or rooting of living branches that are in contact with the soil - terrestrial layering. This NIVP alternative to plantation is currently being investigated in different countries from the Mediterranean region to tropical Africa. Some of the trial results carried out in Tunisia, Togo, Niger and Burkina Faso are discussed. Generally speaking, this method, which does not disturb the soil, is well adapted to the restoration and protection of degraded lands against erosion and desertification. Traditional knowledge in NIVP should also be considered. For instance, in Mauritania, hedgerows are gradually created by planting Balanites aegyptiaca while maintaining a large distance between the rows. By watering the length of the row, it induces the roots to grow mainly along these lines and produce root suckers that form the hedgerow. In order to regenerate a degraded woodlot, and prior to the complete removal of the remaining vegetation, suckering is induced by slightly wounding the roots. This is carried out at a specific time and has been shown to be less expensive than replanting. This process may take longer, but it is the most cost-effective, time-effective (availability of workers just before the rainy season), and erosion control-effective (less soil disturbance) method. These forms of asexual regeneration have not been sufficiently considered to date.

Mots-clés : plante ligneuse; zone aride; multiplication végétative; tunisie; burkina faso; togo; niger

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