Staff aging and turnover in agricultural research: a case study on the Burkina Faso Environment and Agricultural Research Institute

Non-PRIFPRI2; ASTIEPT

The re-greening of the Sahel : natural cyclicity or human-induced change?

The Sahel has been the focus of scientific interest in environmental-human dynamics and interactions. The objective of the present study is to contribute to the recent debate on the re-greening of Sahel. The paper examines the dynamics of barren land in the Sahel of Burkina Faso through analysis of remotely-sensed and rainfall data from 1975–2011. Discussions with farmers and land management staff have helped to understand the anthropogenic efforts toward soil restoration to enable the subsistence farming agriculture. Results showed that area of barren land has been fluctuating during the study period with approximately 10-year cyclicity. Similarly, rainfall, both at national and local levels has followed the same trends. The trends of the area of barren land and rainfall variability suggest that when rainfall increases, the area of barren land decreases and barren land increases when rainfall decreases. This implies that rainfall is one of the main factors driving the change in area of barren land. In addition, humans have contributed positively and negatively to the change by restoring barren lands for agriculture using locally known techniques and by accelerating land degradation through intensive and inappropriate land use practices

Structure, composition spécifique et diversité des ligneux dans deux zones contrastées en zone Sahélienne du Burkina Faso

Cette étude menée au Sahel burkinabé fait l’état actuel de la végétation ligneuse de cette région afin d’établir le lien entre la réalité du terrain et les observations satellitaires dans deux sites dans chacune des deux zones contrastées, l’une présentant un certain taux de reverdissement et l’autre de dégradation. Elle analyse aussi la composition spécifique, la structure, la diversité des ligneux et les similitudes entre les quatre sites (deux sites par deux zones). L’étude a utilisé une méthode d’échantillonnage stratifiée aléatoire analysant 104 placettes de 20 x 20 m². L’analyse statistique a montré des différences significatives de la densité, du nombre d’espèces, de la classe des hauteurs, de la classe des diamètres et des indices de Simpson et Shannon entre les deux zones. Les valeurs les plus importantes ont été observées dans la zone en reverdissement. Nous avons noté aussi une différence significative de la densité, des diamètres et des hauteurs en fonction de l’occupation des terres. Les champs de la zone en reverdissement possèdent les valeurs les plus importantes de densité et des hauteurs, mais ont les diamètres les moins élevés. Le reverdissement au Sahel est donc plus apparent dans les champs.This study conducted in the Sahel of Burkina Faso presents the current state of woody vegetation in this region so as to establish the link between the reality on the ground and satellite observations in two sites within each of the two contrasted zones ; one presenting a certain rate of re-greening and the other of degradation. It also analyzes the specific composition, the structure, ligneous diversity and the similarities between four sites (two sites by two zones). The study used a stratified random sampling method analyzing 104 plots of 20 x 20 sqm. Statistical analysis showed significant differences in density, number of species, height class, diameter class and Simpson and Shannon indices between the two zones. The highest values were observed in the re-greening zone. We also noted a significant difference in density, diameters and heights according to land use. The fields in the re-greening zone have the highest values of density and height, but the lowest diameters. The re-greening in the Sahel is more apparent in the fields

Structure, composition spécifique et diversité des ligneux dans deux zones contrastées en zone Sahélienne du Burkina Faso

This study conducted in the Sahel of Burkina Faso presents the current state of woody vegetation in this region so as to establish the link between the reality on the ground and satellite observations in two sites within each of the two contrasted zones ; one presenting a certain rate of re-greening and the other of degradation. It also analyzes the specific composition, the structure, ligneous diversity and the similarities between four sites (two sites by two zones). The study used a stratified random sampling method analyzing 104 plots of 20 x 20 sqm. Statistical analysis showed significant differences in density, number of species, height class, diameter class and Simpson and Shannon indices between the two zones. The highest values were observed in the re-greening zone. We also noted a significant difference in density, diameters and heights according to land use. The fields in the re-greening zone have the highest values of density and height, but the lowest diameters. The re-greening in the Sahel is more apparent in the fields