Marc Cotter

Investigating potential transferability of place-based research in land system science

Much of our knowledge about land use and ecosystem services in interrelated social-ecological systems is derived fromplace-based research.While local and regional case studies provide valuable insights, it is often unclear how relevant this research is beyond the study areas. Drawing generalized conclusions about practical solutions to landmanagement from local observations and formulating hypotheses applicable to other places in the world requires that we identify patterns of land systems that are similar to those represented by the case study. Here, we utilize the previously developed concept of land system archetypes to investigate potential transferability of research from twelve regional projects implemented in a large joint research framework that focus on issues of sustainable landmanagement across four continents. For each project, we characterize its project archetype, i.e. the unique land system based on a synthesis ofmore than 30 datasets of land-use intensity, environmental conditions and socioeconomic indicators.We estimate the transferability potential of project research by calculating the statistical similarity of locations across the world to the project archetype, assuming higher transferability potentials in locations with similar land system characteristics. Results show that areas with high transferability potentials are typically clustered around project sites but for some case studies can be found in regions that are geographically distant, especially when values of considered variables are close to the globalmean or where the project archetype is driven by large-scale environmental or socioeconomic conditions. Using specific examples from the local case studies, we highlight themerit of our approach and discuss the differences between local realities and information captured in global datasets. The proposedmethod provides a blueprint for large research programs to assess potential transferability of place-based studies to other geographical areas and to indicate possible gaps in research efforts. OPEN ACCESS

Potential of Rhizobacteria for Promoting Sorghum Growth and Suppressing Striga hermonthica Development

The objective of this study was to screen the potential of four plant growth promoting rhizobacteria (PGPR) for growth promotion in sorghum (Sorghum bicolor) and suppression of Striga hermonthica development. Bacillus subtilis Bsn5, B. subtilis GBO3, B. amyloliquefaciens FZB42 and Burkholderia phytofirmans PsJN were evaluated under controlled conditions in growth chambers. After 28 days of growth, the effect of selected PGPR on sorghum plant height, leaf chlorophyll (SPAD) value, biomass dry matter (DM), number of germinated and attached Striga plants and number of Striga plants that developed tubercles was analyzed. Inoculated Striga-free sorghum plants were significantly taller, with higher leaf chlorophyll SPAD values and higher dry matter than uninoculated Striga-free plants. However, there were no differences in sorghum height, SPAD value and DM between inoculated and uninoculated Striga-infected sorghum plants. In the absence of PGPR inoculation, differences in DM were observed between Striga-free and Striga-infected sorghum. Compared to the untreated control, Striga seed germination was lower in the sorghum plants treated with B. subtilis GBO3 and B. amyloliquefaciens FZB42. Of the germinated Striga seeds, the percentage that attached to the sorghum plant was lowest (23%) in the B. subtilis GBO3 treatment. The percentage of dead Striga tubercles in the PGPR treatments ranged between 35 and 59%, compared to 3% in the untreated control. This study identified B. subtilis GBO3, B. amyloliquefaciens FZB42 and Burkholderia phytofirmans PsJN with promising potential to promote sorghum growth and suppress Striga.