Soil Nutrient Dynamics and Their Influence on Shea Nut Productivity and Butter Quality

Shea tree–based agroforestry systems play a vital role in rural livelihoods and global vegetable fat markets, yet productivity and butter quality remain highly variable across savanna landscapes. This study investigates the influence of soil nutrient dynamics on shea nut productivity and shea butter physicochemical quality in selected shea parklands. Using a cross-sectional comparative field design, soil samples were collected beneath mature shea trees and analyzed for macronutrients, secondary nutrients, micronutrients, organic carbon, pH, cation exchange capacity, and texture. Shea nut yield indicators, including nut weight, yield per tree, and kernel recovery rate, were quantified, while butter extracted using a standardized procedure was evaluated for fat content, free fatty acid value, peroxide value, moisture content, color, and texture. The results reveal pronounced spatial variability in soil fertility, with widespread deficiencies in nitrogen, phosphorus, and organic carbon. These soil constraints were strongly associated with reduced nut yield, lower butter fat content, and elevated free fatty acid and peroxide values. Conversely, soils with improved nutrient status produced butter with higher fat yield, better stability, and greater market acceptability. The findings demonstrate that soil fertility is a key determinant of both agronomic performance and product quality in shea systems. The study highlights the importance of soil health–centered management strategies for improving processing efficiency, strengthening shea value chains, and enhancing the sustainability of savanna agroforestry systems.