Root Biomass Distribution in Shea Tree (Vitellaria paradoxa C. F. Gaertn) Parklands of the Southern Sudanian Zone, Burkina Faso

Abstract

Background and Aims: Agroforestry is identified as a system that could contribute to mitigating climate change in sub-Saharan countries. Vitellaria paradoxa C. F. Gaertn parks are widespread in Burkina Faso and are recognized for their significant socio-economic and environmental value. The aim of this study was to assess the distribution of root biomass in Vitellaria paradoxa parks. Methods: The research was conducted in four locations in the southern Sudanese zone, where three trees per site were selected. For each tree, pits were dug in two separate areas: under the canopy and outside the canopy (halfway between the tree and its nearest neighbour), for a total of 24 pits. Root sampling was carried out at five depths (0-100 cm) with manual separation of roots by species and category (fine and coarse). Results: The results reveal a significantly higher biomass of coarse roots under the canopy (5.21 ± 0.32 t ha-1) than outside (2.18 ± 0.32 t ha-1). The biomass of fine roots was highest in the topsoil layer (0–20 cm) (2.06 ± 0.12 t ha-1), with higher values under the canopy (1.27 ± 0.08 t ha-1). The highest density of fine roots belonged to herbaceous plants (Sorghum bicolor (L.) Moench and weeds, 0.79 ± 0.09 t ha-1), while those of V. paradoxa were found in deeper layers. Conclusions: This differential root distribution confirms the low underground competition between V. paradoxa trees and crops, validating the sustainable potential of these agroforestry parks. Furthermore, the significant root biomass highlights their role as a significant carbon sink. Appropriate management of these systems therefore represents a promising solution for national climate change mitigation strategies.