Performance of Sorghum ( <i>Sorghum bicolor</i> (L.) Moench) Under Marula Tree, <i>Sclerocarya birrea</i> (A. Rich.) Horchst Subspecies <i>birrea</i> in Northwestern Drylands of Tanzania

ABSTRACT Introduction Unsustainable agricultural practices contribute to biodiversity loss globally, calling for efforts to reconcile agricultural productivity and biodiversity conservation in agroecosystems. However, the potential benefits of Sclerocarya birrea in drylands agroforestry are not documented. This study investigated the effects of S. birrea subspecies birrea on soil chemical properties, sorghum productivity and nutritional quality in Northwestern drylands of Tanzania. Materials and Methods Field experiments were conducted in the 2019/20 and 2020/21 farming seasons with three treatments (i) the presence of marula tree, (ii) tree sex nested within tree treatment, and (iii) control (no tree). Thus, the treatments were arranged in a nested block design (NBD) experimental design. Results The soil pH, organic carbon (OC), total nitrogen (TN), electrical conductivity (EC), manganese (Mn), calcium (Ca), cation exchange capacity (CEC), and potassium (K) were significantly ( p &lt; 0.05) higher in soils under the tree canopies than in no tree during the 2019/20 farming season. Similarly, OC, EC, Ca, CEC, Mg, and K were significantly ( p &lt; 0.05) higher in soils under the tree canopies than in no tree during the 2020/21 farming season. Sorghum plants basal diameter, stem height, chlorophyll concentration, and sorghum grain yields were significantly ( p &lt; 0.05) higher under trees canopies than in plots with no trees. Sorghum grain yields were 3 359.38 kg/ha and 3 305.21 kg/ha under tree canopies while in no tree plots were 2 146.43 kg/ha and 2 050.00 kg/ha for 2019/20 and 2020/21, respectively. Iron concentration in sorghum grains from sorghum plants grown under tree canopies was higher than those away from the canopies, but no significant differences in proximate composition and other minerals concentration in grains. Conclusion Subsp. birrea improved soil chemical properties, and sorghum yields. Thus, it is a potential tree for agroforestry in drylands.