Use of native woody shrubs for restoration of degraded soils in Soudano-Sahelian agro-ecosystems

Supervisors

Georges Félix (FSE WageningenUR)
Johannes Scholberg (FSE WageningenUR)
Laurent Cournac (IRD France)

Introduction

Approximately 13% (out of 24%) of global degrading lands are located in sub-Saharan Africa (SSA; Bai et al., 2008) and include intensively weathered and infertile soils (Bationo et al., 2007). Although agricultural-based economies prevail, low yields limit socio-economic development due to degraded soils, shallow rooting, poor water infiltration, retention, and storage along with limited inherent soil fertility (Lahmar et al., 2012). In Burkina Faso, degraded soils represent 4% of the land area and affect more than 1 million farmers (Bai et al., 2008). On top of that, the human population and cattle densities are ever-increasing while agricultural lands are shrinking, making it more complicated to restore fertility with periodic fallows (i.e. itinerant agriculture). If restored, these degraded soils could potentially contribute to local food provision and global carbon sequestration. Increasing soil organic matter is closely related to soil fertility enhancement. Innovative practices that indigenous farming families are applying include the use of biomass from the native woody shrubs (NWS) that naturally occur in the landscape as soil amendments. These “cut-and-carry” systems are currently being studied in experimental stations with promising results. This perspective MSc thesis aims to map local innovative systems, evaluate agronomic performances and analyse their development potential, taking into account resource availability and social, environmental and economic issues. This knowledge will be used to analyse and explore the potential role of NWS as a central component in existing no-till mulch-based cropping systems as proposed by Lahmar et al., (2012).

Objectives

Characterize the temporal and spatial availability of ligneous resources within local farm communities and outline landscape-level allocation rules as related to the use and management of NWS as a soil amendment.

Procedures

  • determining the social demands for ecosystem services in a case study area by interviews, household surveys, participant observation, and literature study
  • generating vegetation maps (i.e. local vegetation types classification, native woody shrubs abundance, use and management of ligneous resources)
  • applying policy (and local by-laws) definition frameworks and tools
  • determining social and institutional implications of selected policies/practices

Experiences gained

  • preparation of a detailed MSc proposal
  • working as part of an interdisciplinary project team within a case study in Burkina Faso
  • interviewing farmers and other relevant stakeholders
  • resource management techniques related to indigenous agroforestry systems
  • spatial assessment of ligneous resource availability, local practices and community institutions regulating access to woody resources through participatory rural assessments (ethnobotany)
  • vegetation and household data collection and analyses
  • developing and/or applying bio-economic models and policy frameworks
  • writing an MSc thesis (and preferably a manuscript for a journal) in English