Effect of Tree Densities on Soil Physical Properties in Agroforestry Parkland Systems Dominated by Shea Trees in Burkina Faso

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Résumé

Aims: The overall objective of this study was to assess the effect of different densities of tree dominated by V. paradoxa and dendrometric parameters on the selected soil physical properties.
Study Design: This study was conducted in the municipality of Sapone (12.03´N, 1.43´W) located 30 km south of Ouagadougou, Burkina Faso.
Place and Duration of Study: The experimental design was made of 20 plots randomly. The studied factor was the tree density (D) in each of our plots, with 5 tree density levels being designed. The first density class (D1) was 0 trees/ha, i.e. 0 tree in the plot, the second was 16 trees/ha, i.e. 4 trees in the plot (D2), the third was 28 trees/ha, i.e. 7 trees in the plot (D3), the fourth was 36 trees/ha i.e. 9 trees in the plot (D4), and finally the fifth was 48 trees/ha i.e. 12 trees in the plot (D5). Each density class is repeated four times. In each plot, 9 subplots were set up for evaluating water infiltration, bulk density, soil moisture and texture. Study was conducted in 2023.
Results: the results showed that tree densities levels affected the soil texture. The sand content in plots with trees was much higher than that in plots without trees. On the other hand, the silt and clay content was much higher in plots without tree compared to those with trees. Shea dominated tree density affected significantly soil water infiltration speed (P ≤ 0.001). The average soil infiltration rates were higher in fields with trees densities (16 trees/ha, 28 trees/ha, 36 trees/ha and 48 trees/ha) with average values between 3.02 and 3.64 L/h than those in fields without tree density (0 trees/ha) with an average value of 1.65 L/h.
Conclusion: This research is a contribution to better understanding soil-plant relationships in Sub-Saharan African agroforestry parklands. It providing information on the expression of soil physical properties in the most widespread parklands according to different levels of tree densities.

Mots-clés

Agroforestry parklands, bulk density, Burkina Faso, tree cover, water infiltration