Essences végétales et techniques de restauration des zones d’érosion (dongas) du Parc W et de sa périphérie à Karimama (Nord-Bénin)

Abstract

Objective: This study examines the best plant species and soil and water conservation management techniques for restoring degraded ecosystems in northern Benin. Methodology and Results: A multifactorial experiment using a Split Pot design with 3 factors was conducted in Karimama during 105 days: 5 species (Khaya senegalensis (African mahogany), Jatropha curcas (Purging nut), Moringa oleifera (drumstick tree), Parkia biglobosa (stink bean), Balanites aegyptiaca (desert date) selected following their economic and socio cultural values. These were cultivated under 3 techniques (Zai, half moon and control) on 2 sites (donga and versant). Parameters such as mortality, diameter and height were recorded during fourteen weeks to evaluate the plant growth. Survival rates were high on the slopes (77.4 % versus 74.8 %). Balanites aegyptiaca showed the highest value (88.9%) on the slumpfaction and the lowest (68.5%) on the slopes where Jatropha curcas expressed the highest value (88.9%). The growth in diameter was the lowest with Parkia biglobosa and the highest with Jatropha curcas (0.34 versus 1.62 mm week-1). The growth in the height ranged from 1.69 to 4.51 mm week-1, and was the highest with Balanites aegyptiaca (4.51 mm week-1). Conclusions and applications: Jatropha curcas and Balanites aegyptiaca grew more quickly in diameter and height at the juvenile stage in the half-moons and the Zai as well on the dongas on slope. Among the techniques of water and soil management and conservation tested, only the zai is easily used at farmer level. These bioenergy and wild fruit plants already domesticated for their substantial contributions to farmers’ income and sociocultural well being would be adequate in a large extent to the development of sustainable strategies for restoration of degraded Sudano-Sahelian areas. However, data from dry season will help to conclude definitively in the long term.