Impact of Cereal–Legume Intercropping on Changes in Soil Nutrients Contents under Semi–Arid Conditions

Cereal–legume intercropping systems are not well studied under the semi–arid conditions of Southern Tunisia. Therefore, the present study aimed to investigate the effect of intercropping durum wheat (Triticum turgidum ssp. durum L.) with chickpea (Cicer arietinum L.) on crop grain yield and soil physicochemical proprieties such as carbon (C) and nitrogen (N) availability, microbial biomass nutrients (C and N) and plant nutrient content (N) in comparison to their monocultures. Field experiments were conducted during the 2020–2021 (EXP–A) and 2021–2022 (EXP–B) seasons in Medenine, Tunisia. The results revealed a significant augmentation (p < 0.05) in the total nitrogen proportions (Ntot) within the soil of intercropped durum wheat (DuWh–IR) compared to its monoculture (DuWh–MC). The observed variations amounted to 32% and 29% during the two growing seasons, identified as EXP–A and EXP–B. Additionally, the soil of intercropped durum wheat (DuWh–IR) significantly (p < 0.05) accumulated more total carbon (C_tot) than the monocrop (DuWh–MC) for both experiments, showing an increase of 27% in EXP–A and 24% in EXP–B. Simultaneously, the N− uptake of durum wheat significantly increased under the effect of intercropping, showing a rise of 26% in the EXP–A season and 21% in the EXP–B season. Similarly, the yield of durum wheat crops was comparatively greater in the intercropped plots as opposed to the monoculture crops, with variances of 23% in EXP–A and 20% in EXP–B. Intercropping cereals and legumes has the potential to enhance the soil fertility and crop production in the semi–arid regions of Southern Tunisia and contribute to environmental sustainability by reducing reliance on nitrogen fertilizers.