The Effect of Cordia africana Lam on Selected Soil Properties and Maize (Zea mays L.) Yield and Yield Components in South Wollo Zone, Ethiopia

For efficient utilization of land, it is important to study the impact of locally suited agroforestry tree species on soil properties and their implications for crop yield and yield components. The aim of this study was to investigate the effects of Cordial africana Lam (C africana) on selected soil properties, yield, and yield components of maize (Zea mays L.). Soil data were collected from five radial transects at distances of 2 m (middle of the tree canopy), 4 m (edge of the tree canopy), 6 m (1-fold distance from the edge of the tree canopy), 8 m (2-fold distance from the edge of the tree canopy), and 20 m (control point). Three similar C. africana trees were purposefully selected from cultivated land. Maize was cultivated underneath the C. africana tree using a randomized complete block design (RCBD), and data on yield and yield components were collected from five radial transects. Soil bulk density (P = 0.003) significantly increased with increasing distance from the tree trunk. In contrast, soil organic carbon (P = 0.001), total nitrogen (P < 0.0001), available phosphorous (P = 0.001), cation exchange capacity (P = 0.02), and exchangeable calcium (P = 0.04) significantly decreased with increase in distance from C. africana tree trunk and were lowest at 20 m control plots. Flowering and maturity dates exhibited a substantial variation with distance from the tree trunk. Grain yield (P = 0.003), aboveground biomass (P = 0.004), and hundred-seed weight (P = 0.003) were significantly different with respect to the distance from the tree trunk. The 100 seed weight of maize was significantly higher (34.7 g) 6 m from the tree trunk. Maize grain yield (4.98 ton ha-1) and aboveground biomass (12.92 ton ha(-1)) were significantly higher at 6 m distance from the C. africana tree trunk showing similar trend with that of 100 seed weight. These findings suggest that incorporating C. africana tree species into agricultural land can enhance soil fertility and maize productivity, and help mitigate climate change.