Conservation agriculture based on no-tillage (NT) and crop rotation allows to enhance soil health. Based on data collected from long-term trials in a semi-arid region of Tunisia, results showed that NT increased significantly soil organic carbon stock (SOCS), soil microbial biomass carbon (SMBC), arbuscular mycorrhizal fungal (AMF) root colonization, and soil microbial respiration (CO₂) at 0–20 cm topsoil layer compared to conventional tillage (CT). Moreover, triennial rotation (TRI), based on annual succession of Faba bean-Durum wheat-Barley, and biennial rotation (BI), based on annual succession of Faba bean-Durum wheat, increased significatively SMBC, AMF, and CO₂. Likewise, a significant benefit of the two-way interactions Tillage × Rotation was observed. Furthermore, NT combined with TRI recorded the highest SOCS (2181 g C m⁻²), SMBC (515 mg C kg⁻¹ soil), AMF (14%), and CO₂ which is an indicator of soil microbial respiration (1071 mg CO₂ kg⁻¹ soil). The current results highlight the benefit adoption of minimum or (NT)combined with crop diversification on soil health.

Conservation agriculture (CA) has been proposed as a viable strategy to enhance soil health and the resilience of farms to climate change, and to support the sustainability of agricultural production systems. While CA is a well-established approach, research results are lacking regarding its long-term impact on nitrogen (N) dynamics in the soil–plant system. In this study, a 20-year experiment was used to investigate the long-term effects of no-tillage in CA on soil organic carbon (SOC) and nitrogen (N) mineralization, plant N uptake, grain yields, and the grain quality of durum wheat. A CA system based on no-tillage (NT) was evaluated and compared with conventional tillage (CT) used for wheat/legumes biennial crop rotation. Results showed that soil samples from CA plots experienced significantly more N mineralization than those under CT, which was attributed to increased SOC and N. Topsoil sampled from the CA plots 20 years after the implementation of the experiment had 43% more absolute potentially mineralizable N (N0) than the CT plots, with no significant differences observed in deeper soil layers (15–30 cm and 30–45 cm). The absolute potentially mineralizable carbon (C0) in soils from the CA system was 49% and 35% higher than in soils from the CT system, at soil depths of 0–15 and 15–30 cm, respectively. Furthermore, CA resulted in higher amounts of remobilized N and higher rates of N uptake during the critical growth stages of durum wheat. The amount of N remobilized during the kernel-filling phase under CA was 59% higher than under CT. Total N uptake in wheat plants was 45% greater under CA compared to CT. The most significant differences in N uptake between the CA and CT systems were observed during two critical growth stages: late tillering to heading (1.7 times higher in CA than CT) and heading to anthesis (1.5 times higher in CA than CT). The most significant differences for N uptake were shown during the late tillering to heading stage and the heading to anthesis stage. The amount of N remobilized during the kernel filling phase under CA was 59% higher than CT. CA adoption resulted in 21% and 35% higher grain and straw yields, respectively, compared to CT. The grain and straw N yields were 21% and 51% higher, respectively, under CA than CT. Moreover, the CA system exhibited higher partial factor productivity of nitrogen fertilizer (PFP N) for both grain and straw yields. Thousand kernel weight (TKW) and hectoliter weight were also significantly higher under CA than CT. The grain protein content, wet gluten content, vitreousness, and falling number were similar between the CA and CT systems. These results highlight the benefits of long-term CA adoption to increase soil N mineralization, providing a substantial base for N uptake during the critical growth stages of durum wheat, thus leading to increased crop yield. The findings underscore the potential of CA systems in promoting sustainable agriculture and mitigating the impacts of soil degradation.

Managing tillage intensity and diversifying crop rotation are important sustainability levers for conservation agriculture (CA) with the potential to enhance crop resilience, resource efficiency, and yield stability. Accordingly, this study aimed to determine the effect of reduced tillage intensities and cereal–legume rotation systems on the agronomic and physiological performance of rainfed durum wheat grown under Mediterranean semi-arid conditions. To this end, a two cropping seasons field experiment was conducted in northeast Tunisia where the combined effects of two reduced tillage intensities (minimum and no-tillage; MT and NT) and two legume-based crop rotation systems (biennial and triennial; B and T) were compared to the more traditional conventionally tilled monocropping system (CT and M). Crop rotation, particularly when integrated with no-tillage (NT), significantly improved wheat development and grain yield, along with key yield attributes such as thousand-kernel weight and spike density. The interaction between tillage and crop sequence was highly influential; for instance, the NT × T (no-tillage × triennial rotation) combination achieved the highest grain yields (240 and 236 g m⁻² in 2020–2021 and 2021–2022, respectively), while the CT × M (conventional tillage × monoculture) interaction resulted in the lowest productivity (143 and 135 g m⁻²). Physiologically, the integration of reduced tillage and legume–cereal rotations optimized the photosynthetic apparatus, as evidenced by significantly improved chlorophyll fluorescence parameters. However, a prominent trade-off was identified: while NT × T maximized productivity, conventional tillage (CT) maintained superior grain protein (18.6%) and gluten concentrations, indicating a nitrogen dilution effect in high-yielding conservation systems. These results demonstrate that while no-tillage and triennial rotations (faba bean–wheat–barley) are robust strategies for climate-resilient yields in semi-arid environments, they must be coupled with optimized nitrogen management to offset quality declines. Consequently, this study establishes the NT × T interaction as a superior model for sustainable rainfed farming, provided that nutrient synchronization is addressed to ensure nutritional security under increasingly unpredictable Mediterranean climates.