Intercropping cowpea (Vigna unguiculata) with Ziziphus spina christi was carried out under the saline soils south of Khartoum State. The objectives were to find out the most appropriate agroforestry system that can suit these soil types of the semi-arid zones of Sudan as well as to investigate the performance of the tree species in terms of their growth under a supplemental irrigation regime. The study was carried out during the period of March to November 2017 using a randomized complete block design experiment with 3 replicates. The woody component Ziziphus spina christi spaced at 4×4 m and the crop was cowpea which was sown relative to tree trunks, namely at 1 m (S1) and 1.5 m (S2) apart from the trunks. Cowpea was sown at inter and intra-row spacings of 50 cm and 25 cm, respectively. In addition, some trees and pure crops stands were incorporated using the above spacing as controls. Soil samples were taken at depths of 0-10 cm, 10-30 cm, 30-60 cm, and 60-100 cm from an excavated soil profile (1×1 m and 1.5 m deep) to determine the soil’s physical and chemical properties. The measured tree parameters for Z. spina christi were namely tree height, tree collar diameter, and tree crown diameter. The Cowpea crop parameters determined were biomass of straw and yield per hectare. Accordingly, the land equivalent ratio was calculated. The data revealed an increase in tree collar diameter which was higher under the wider spacing (1.5 m) as compared to the other (1 m) spacing and the control. Cowpea straw biomass recorded significant differences under the intercropping system as compared with the control, whereas crop yield did not record any significant differences. There was an increase in LER of 1.3 and 3.3 under the wider spacing for both crop and straw yields, respectively. Overall, this agroforestry system has resulted in the provision of both foods for farmers besides fodder for their animals.