Influence of shrub proximity, species, and management on soil labile carbon, macrofauna, and sorghum productivity in Sudanian agroforestry systems

Abstract

While agroforestry is known to stabilize West African cereal yields, the comparative impacts of specific shrub species and management practices remain under-researched. We assessed the influence of P. reticulatum (DC.) Hochst. and G. senegalensis on sorghum (Sorghum bicolor) productivity, soil labile carbon, and macrofauna in northern Burkina Faso, using data from 252 long-established, farmer-managed subplots. By sampling across these multi-year cropping systems over two years, we captured the legacy effects of five distinct management strategies: an open-field control, (T0), coppiced P. reticulatum (T1), coppiced G. senegalensis (T2), unpruned P. reticulatum (T3), open-field mulched with a shrub mixture (T4). Shrub proximity significantly enhances both yield and soil health, even when coppicing biomass are exported in T1 and T2. P. reticulatum (T1) outperformed G. senegalensis (T2) in both grain and straw yields though soil labile carbon did not differ significantly between species. Standard coppicing (T1) represents a viable strategic compromise, allowing farmers to harvest essential wood and fodder without significantly compromising soil health or cereal productivity. Mulching in open fields (T4) achieved the highest overall performance, but high labor requirements may have limited local adoption. Despite these benefits, the dominance of just two shrub species signals a critical biodiversity bottleneck with potential long-term risks. Overall, a diversified mosaic of shrub management practices, particularly strategic coppicing of shrubs, offers a practical pathway for farmers to sustain yields while reinforcing soil health and ecosystem resilience.