Declining soil fertility and reduced crop yields in semi-arid regions necessitate the adoption of sustainable alternatives to conventional monocropping systems. Among these, agroforestry presents a promising and ecologically sound approach for restoring soil health and enhancing long-term agricultural productivity by integrating trees with crops to improve nutrient cycling, soil structure, and overall ecosystem resilience. This study, therefore, investigates how tree growth characteristics, in interaction with different cropping arrangements, influence key soil fertility parameters and the productivity of staple crops. A field experiment was conducted using a randomized complete block design (RCBD) with four treatments. The treatments included tree-row spacing of 900 cm with 180 cm plant-to-plant distance (30R6P), 1800 x 180 cm (60R6P), and 2700 x 180 cm (90R6P), which is also known as wider spacing, along with sole cropping of wheat and maize without trees as the control, and sole trees without crops as an additional reference for assessing tree physiology. The results showed that soil nitrate-nitrogen increased significantly (48.4%) with wider spacing, while phosphorus (24.4%) and potassium (5.6%) levels also increased across treatments. Tree growth was strongly influenced by spacing, with tree height and diameter increasing by 24.10% and 40.76%, respectively, compared with narrow spacing. Similar trends were observed in crops, grain weight and grains per spike improved progressively with wider tree spacing. Physiological traits such as photosynthesis rate, stomatal conductance, and transpiration were markedly higher in wider spacing, while intercellular CO2 concentration declined (28.80%), indicating more efficient carbon fixation (22.89%) in maize and (21.57%) in wheat. Overall, the findings demonstrated that integrated tree farming with wider spacing balances the dual goals of maintaining tree growth and ensuring competitive crop yields, while enhancing soil fertility. The study highlights integrated tree farming as a viable pathway to sustainable intensification in semi-arid agroecosystems, with important implications for food security, soil conservation, and climate resilience.