Strategic Tillage in the Mediterranean: No Universal Gains, Only Contextual Outcomes

Abstract

In Mediterranean drylands, where year-to-year climatic variability and soil constraints (e.g., compaction or shallow profiles) often limit the feasibility of strict no-tillage (NT), strategic tillage (ST) has emerged as a pragmatic support tool within conservation agriculture. To evaluate its short-term effects, multi-country field trials were established in Morocco, Tunisia, Türkiye, and Spain across a rainfall gradient (250–580 mm). We assessed soil water content (SWC), crop biomass, and yield under ST compared with NT systems. Results were context-dependent. SWC responses varied: largely unchanged in Morocco and Tunisia, slightly increased in Morocco in 2023, and significantly reduced in Spain in 2022. Biomass generally showed no significant change, with modest decreases in Morocco and modest increases in Tunisia. Yield effects were more pronounced: pooled data from Morocco indicated a significant reduction under ST, and Tunisia showed a significant yield loss in 2021. Türkiye exhibited non-significant declines in both SWC and yield, while Spain experienced yield-neutral but SWC-reducing outcomes. Overall, ST did not have negative effects across sites. Instead, its impacts were strongly conditioned by local soils, rainfall distribution, and crop context. These findings highlight that ST can be considered as a pragmatic tool to overcome some of the agronomic difficulties in the Mediterranean region with little or no negative effects on productivity of soil moisture.

1. Introduction

Agricultural tillage practices significantly influence key hydrological processes in terrestrial ecosystems [1]. Tillage intensity affects soil structure, altering macropore networks and soil organic matter content, which in turn impacts water infiltration, retention, and runoff [2,3]. Conservation tillage practices, such as no-tillage or reduced tillage, generally improve soil water retention capacity and increase cumulative soil water infiltration during rainfall events compared to conventional tillage [4]; These practices also enhance soil aggregation and maintain surface residues, which help control erosion and reduce surface runoff [5]. However, the effects of tillage on hydrological processes can vary depending on factors such as soil type, climate, and crop management practices [2,6]. Understanding these complex interactions is crucial for optimizing agricultural water management and maintaining sustainable crop production in various ecosystems.

The advantages of no-till systems in Mediterranean environments are numerous, ranging from reducing annual sediment loss [7] and enhanced SOC storage [8] to superior yields under water deficit conditions compared to conventional tillage (CT) [9]. Conservation agriculture (CA)-based no-till practices also offer significant socio-economic advantages, such as reducing labor time and fuel consumption compared to conventional tillage [10]. Particularly, in response to increasingly frequent extreme droughts and heatwaves in the Mediterranean basin, the relevance of no-till and reduced soil disturbance practices is gaining recognition for their role in enhancing soil resilience and supporting sustainable agriculture under climate stress [11]. Despite its recognized advantages, the concept of no-tillage (zero soil disturbance) is the most fundamental, yet least acceptable aspect of CA for farmers [12]. Soil tillage is a central feature of agriculture for Mediterranean farming systems, and symbolizes ownership and management of resources [12,13]. Additionally, tillage is perceived by farmers as one of the most effective tools for weed control, increasing soil water infiltration and N mineralization [14]. As such, strict promotion of CA principles such as no-tillage is at odds with the perceptions and realities of the Mediterranean agriculture [15].

Despite this paradox, there is an urgent need to reduce intensive soil disturbance in the Mediterranean region. Introducing strategic and reduced tillage as a scale-appropriate, pragmatic tool within the context of CA may be beneficial and improve the perception of CA-based no-till by farmers. Thus far, CA or no-till promotion efforts in the Mediterranean region have been non-compromising in regard to tillage. There is a general perception in research communities that long-term benefits of no-till may be lost when soil is disturbed; however, there is little evidence to support these claims. A one-time strategic tillage (ST) event applied after 44 years of continuous no-till or conventional tillage had little effect on soil biological properties, microbial diversity and activity, biomass, and enzymatic activity, demonstrating that this method can control weeds and diseases without significantly impacting soil health [16]. Recently, a number of researchers have been questioning the strict adherence to no-till principles and displaying the positive effects of strategic tillage practices under various scenarios and soil types [17,18,19]. Coupled with the difficulty of managing weeds in the absence of expensive herbicides, farmers are seeking solutions in tillage. A pragmatic approach of reducing tillage intensity, while diversifying rotations with pulses and legume-based forages, may be more effective considering the Mediterranean context [15]. More than a decade of research in reduced tillage in organic agriculture have shown that shallow inversion tillage systems could accumulate more C and have negligible yield reductions compared to deep inversion tillage [20]. There is a growing body of literature illustrating that reduced tillage systems may capture and store more water [21,22], reduce soil compaction and improve seed emergence [23,24], and improve yields [25,26] more than strict no-till systems. There are also serious challenges to the claims of soil carbon build up and soil biodiversity improvements by CA [23,27,28]. It is clear that even in countries with larger mechanized farms, CA is applied with pragmatism, where occasional tillage is perceived as a necessary tool to manage a variety of problems built up by long term no-till [6,17,26,27,29].

Occasional or strategic tillage can be used to disrupt disease and pest cycles, mechanically kill weeds, deal with herbicide-resistant weeds, or encourage weed seeds to germinate before a pre-season weed management operation (whether herbicide-based or not) to make it more effective. Tillage can be aimed at improving soil structure and water infiltration and reduce soil compaction, or incorporate organic matter—such as crop residue or livestock manure—into the soil to optimize the availability of the nutrients for crop development [30]. The contrasting reports of ST effects on soil properties arise due to differences in soil types, duration of no-till management, equipment used in tillage operations, frequency of occasional tillage, tillage depth, soil sampling depths, climate, and other environmental factors [29,30,31]. Daryanto et al. (2020) [32] suggest that the use of cover crops can mitigate the negative effects of strict no-till but the inclusion of cover crops implies the loss of a crop year in the dry areas. Limited precipitation in dry Mediterranean environments do not allow cover crops to be included within a cropping season. In some environments, such as the semi-arid Mediterranean coastal plains of France, no-tillage combined with chemical weeding was less effective in reducing soil erosion and improving organic matter content compared to superficial tillage, suggesting that strict no-tillage may not be suitable for all Mediterranean conditions [33]. For example, in southwestern Spain, reduced tillage has been introduced to balance the chemical and physical demands of the soil [24].

A study using moldboard plowing for downy brome control in reduced-tillage systems showed that occasional tillage significantly reduced weed populations while maintaining many no-till benefits [34]. Surface soil organic carbon declined, but deeper layers increased, balancing weed control with soil health. Similarly, Liu et al. (2016) [4] found that after 15 years of no-till, strategic tillage using a chisel cultivator or disc chain did not harm crop productivity or soil properties in the short term, indicating its potential for effective weed management without compromising soil health. Additionally, strategic inversion tillage initially had lower soil carbon and water-stable aggregates than no-till and herbicides, but after six years, all soil health indicators were similar, showing its long-term effectiveness [35]. In a long-term no-till system in a semi-arid region, strategic tillage controlled herbicide-resistant weeds with minimal impact on crop yields, reduced soil bulk density, and did not affect aggregate size or mean weight diameter, highlighting its potential for managing resistant weeds [36]. Furthermore, a two-year Mediterranean field experiment showed that strategic tillage with in-line tillage/roller crimper technology improved weed control, nitrogen use efficiency, yield, and reduced energy and labor compared to green manure and no-tillage treatments [37]. In Türkiye, strategic tillage improved soil quality by reducing bulk density and penetration resistance while increasing macroporosity and total porosity, which enhanced air circulation and water movement [29].

While the literature provides substantial evidence supporting the absence of detrimental effects from strategic or occasional tillage, the majority of these studies are context-specific and may not be representative of the broader regional conditions. Considering the diversity of soils and ecosystems in the Mediterranean region, the current study attempted to capture this variation by setting up strategic tillage experiments across four countries. Our objectives were to determine the soil water and crop productivity responses to strategic tillage in otherwise no-till systems. The results of this study are critical for promotion and adoption of sustainable soil management strategies in the Mediterranean and other dryland regions in the world.

2. Materials and Methods

2.1. Study Area

Trials were set up in four countries (Morocco, Tunisia, Türkiye, and Spain) across an annual rainfall gradient of 250 mm min to 580 mm max. In all countries except in Türkiye, the trials were set up on farms. Below, we provide a detailed description of each site.

Morocco

The on-farm trial was conducted in a long-term no-till system established in 2010 in the Meknes region (33°72′ N, 5°69′ W; 702 m a.s.l.). The site experiences a semi-arid Mediterranean climate with hot, dry summers and wet winters, classified as Csa (warm-temperate summer or dry hot summer) according to the Köppen climate classification [38] The soil is clayey (52% clay, 21% silt, 27% sand in the 0–40 cm layer), classified as Luvisol [39], and located on flat terrain. A detailed soil profile is presented in

Table 1. Selected soil physical and chemical properties of the experimental sites. SOM: Soil organic matter.

	Depth (cm)	% Clay	% Silt	% Sand	SOM (%)	pH (H2O)	Total N (%)
Morocco	0–20	50	24	26	2.84	7.0	0.14
	20–40	54	18	28	2.04	7.2	0.03
Spain	0–20	24.0	48.0	28.0	2.95	7.8	0.34
	20–40	29.1	45.2	25.7	2.32	7.9	0.01
Türkiye	0–20	49.7	32.5	17.8	2.27	8.2	0.12
	20–40	50.4	23.5	26.1	1.95	8.4	0.11
Tunisia	0–30	55.3	29.9	12.4	0.95	7.1	0.20
	30–60	48.4	33.1	15.5	1.0	7.3	0.55

. Meteorological data for the 2020–2021 and 2021–2022 growing seasons are shown in Figure 1, with cumulative rainfall from October to June totaling 344 mm and 376 mm, respectively.

Türkiye

The on-station experiment was carried out at the Bahri Dağdaş International Agricultural Research Institute Directorate (BDIARI) in Konya (37°51′42.5″ N, 32°33′56.8″ E; 1005 m a.s.l.). The site has a cold semi-arid climate with cold, wet winters and warm, dry summers, classified as BSk under the Köppen system. The long-term average temperature is 12.1 °C, and average annual precipitation is 332 mm. The soil is clay loam, loamy in the top 20 cm, light alkaline (pH 8.21), with very high potassium availability (1104 kg ha⁻¹), medium phosphorus availability (20 kg ha⁻¹), and high calcium carbonate content (26%) classified as Calcic Chernozem (Loamic, Eutric) (IUSS Working Group WRB, 2022), and located on flat terrain. The soil profile is detailed in Table 1.

Tunisia

The trial was conducted on a farm in the Joumine municipality, Bizerte governorate (36°51′01″ N, 9°30′18″ E; 301 m a.s.l.). The site has a semi-arid Mediterranean climate with hot, dry summers and wet winters, classified as Csa according to the Köppen climate classification. The mean annual rainfall is approximately 580 mm, and the mean annual temperature is 18.2 °C. Seasonal temperatures typically range from 7 °C to 35 °C, rarely falling below 3 °C or exceeding 40 °C. The soil is classified as Calcimagnesic clay.

Spain

The on-farm trials were implemented in Rubió, Anoia county, province of Barcelona (41°37′11″ N, 1°32′44″ E; 459 m a.s.l.). The site has a Mediterranean climate with hot summers and wet winters, classified as Csa under the Köppen system. The area receives approximately 546 mm of annual rainfall, and the mean annual temperature is around 13.8 °C. The soils are calcareous to slightly gypsum-rich.

2.2. Experimental Design

Morocco

The trials followed a split-plot design with three replications. The experimental plots were divided into three crop types: wheat, faba bean, and chickpea. Three tillage treatments were tested: (1) NT, continuous no-till with stubble retained and chemical weed control; (2) ST, shallow inversion tillage using a disk harrow. The treatments were applied once in November 2020, two days before sowing, and sowing was conducted on 12 November 2020. The plot sizes were 30 m × 36 m for wheat and 15 m × 36 m for faba bean and chickpea. Crop rotation patterns were implemented in the second year, with wheat, faba bean, and chickpea rotated in various combinations.

Tunisia

In Tunisia, an on-farm experiment aimed to evaluate the agronomic performance of durum wheat under (1) NT, continuous no-till with stubble retained and chemical weed control, and (2) ST, shallow inversion tillage using a disk harrow before sowing. The experimental design used simple bands with three repetitions per treatment within each plot. The plot size was 0.5 ha per treatment. A biannual crop rotation of durum wheat and chickpea was implemented.

Türkiye

In Türkiye, the on-station experiment aimed to evaluate the effects of ST (rotary tiller at a depth of 6–8 cm) in no-till (NT) systems under a wheat–chickpea rotation. The experimental design was a randomized complete block design (RBCD) with four replications and a plot size of 10 m × 6 m. The experimental area had been practicing wheat-chickpea rotation under conservation agriculture (CA) since 2015. Sowing was conducted in September for cereals and March for chickpeas.

Spain

In Spain, an on-farm experiment was conducted in two phases. The first phase began in 2020 in Rubió, province of Barcelona, on a flat field intended for barley cultivation in the first year and wheat in the second year. The experiment aimed to evaluate the agronomic performance of barley and wheat in a typical small-grain rotation system under no-till and strategic tillage (ST, applied with a fast harrow). The experimental design included six replicates, with ST treatments applied by passing the harrow twice across the field to form blocks. Each block contained three pairs of NT and ST plots side by side, resulting in a total of six replicates. The plot size was 120 m² per treatment. Crop, weed, and soil variables were monitored throughout the two years.

2.3. Measurements

In this study, we investigated the effects of tillage options on the performance of the cropping system through three main indicators. Crop performance was evaluated using yield and biomass, which are critical factors for assessing farmers’ livelihoods and the sustainability of the system. Yield and biomass were measured by sampling quadrats of various sizes at crop maturity, and all data were converted into tons per hectare (t/ha). For biomass, samples were dried at 60 °C for at least two days and then weighed. Yield data from Spain were missing due to drought conditions. Soil water content was evaluated using the gravimetric method. Soil water content is considered a key indicator of system performance as it is one of the major limiting factors for crop production in the dry Mediterranean region. Most research teams (Morocco, Tunisia, Spain) measured soil water content at various points during the spring to enable a comprehensive assessment over the crop growing season. In contrast, in Türkiye, soil water content was measured only once during a critical stage for chickpea development.

2.4. Statistical Analysis of Data

The raw dataset was reviewed and organized based on treatment groups, years, and observed experimental values (no tillage and strategic tillage). For each year, observed values were normalized relative to the mean value of no-tillage, expressed as a percentage. This transformation enabled the data to be interpreted as the relative percentage difference compared to no-tillage.

$$\mathrm{Percent} \mathrm{Value}=({\displaystyle \frac{\mathrm{O}\mathrm{b}\mathrm{s}\mathrm{e}\mathrm{r}\mathrm{v}\mathrm{e}\mathrm{d} \mathrm{V}\mathrm{a}\mathrm{l}\mathrm{u}\mathrm{e}}{\mathrm{M}\mathrm{e}\mathrm{a}\mathrm{n} \mathrm{V}\mathrm{a}\mathrm{l}\mathrm{u}\mathrm{e} \mathrm{o}\mathrm{f} \mathrm{N}\mathrm{T}}})\times 100$$

Each year was analyzed independently by dividing the dataset into subsets by year. A Generalized Linear Mixed Model (GLMM) was fitted for each subset to evaluate the differences between treatments. The GLMM results included estimates of the percentage differences between treatments relative to NT. The estimate represents the percentage difference between treatments, where a negative value indicates a lower performance compared to NT. For example, an estimate of −1.5 indicates that the treatment produced values 1.5% lower than NT.

To account for variability between years, a combined GLMM was applied to the entire dataset, including year as a random effect. This approach allowed for an overall assessment of treatment effects while accounting for inter-annual variability and addressing potential imbalances in year-specific data. The combined analysis provided a more comprehensive evaluation of overall trends across the dataset.

3. Results

Weather

Weather conditions during the development of the study across all four sites are summarized in Figure 1. Below, we provide a brief overview of the climatic context for each location during the experimental period. In Morocco, cumulative rainfall during the 2020–2021 and 2021–2022 growing seasons was 344 mm and 376 mm, respectively—slightly below the long-term average of approximately 400 mm. Most precipitation occurred during the winter months, while spring remained drier than usual, limiting soil water recharge during the grain filling period. In Türkiye, the average precipitation from 2016 to 2023 was 332 mm. During the experimental years, precipitation ranged from 44 to 214 mm below this long-term average. Specifically, 2022 recorded 178 mm and 2023 increased to 223 mm. Average temperatures were 11.46 °C in 2022 and 12.55 °C in 2023. The 2021 growing season was the driest, with only 118 mm of rainfall, most of which occurred in winter. Overall, the experimental period exhibited notable climatic variability, with 2022 being cooler and drier, and 2023 warmer and wetter than average (Figure 1). In Tunisia, annual rainfall during the experimental period was approximately 580 mm, consistent with the long-term mean. However, rainfall distribution was uneven. The 2021 season experienced slightly below-average rainfall with dry spells in spring, while 2022 was wetter than average, particularly during the winter months. In Spain, total annual rainfall during the trial years was lower than the regional long-term average of approximately 600 mm. The 2022 season was notably dry, with rainfall deficits concentrated in late winter and spring. Although 2021 received rainfall closer to the average, monthly distribution remained irregular. These conditions contributed to pronounced crop water stress and explain the significant reduction in soil water content observed under ST in 2022.

Soil Water Content

There were yearly variations in soil water content across the years and countries (Figure 2). In most cases, SWC did not significantly change after ST compared to NT. Despite the no significant difference (p = 0.0596), in 2023, the SWC increased slightly after ST compared to NT in Morocco. However, in Spain, SWC was significantly reduced after ST compared to NT in 2022 (p = 0.0454). Overall, SWC did not change in Morocco and Tunisia under ST but, in Spain and Türkiye, there was a non-significant reduction in SWC under ST.

Biomass

There were yearly variations in biomass across the years and countries (Figure 3). In most cases, biomass did not significantly change after ST compared to NT. In Morocco, the overall trend was reduction in biomass production after ST compared to biomass under NT (p = 0.0767). In Tunisia, the overall trend suggested an increase after ST compared to NT but the change was not statistically significant.

Yield

There was a general reduction in crop yields under ST compared to NT (Figure 4). In Morocco, when pooled across the years the reduction in yield was statistically significant (p = 0.0319). In Tunisia, crop yield under ST was significantly lower than NT in 2021 (p = 0.0138). In Morocco, chickpea yield across treatments ranged from 0.2 t/ha to 3.9 t/ha. For faba bean, the yield across treatments ranged between 0.49 t/ha and 6.79 t/ha. In the case of durum wheat, yields under no-till ranged from 1.51 t/ha to 6.81 t/ha, while strategic tillage produced yields between 1.05 t/ha and 4.27 t/ha. In Türkiye, chickpea yields ranged from 0.89 t/ha to 3.46 t/ha. In Tunisia, durum wheat yield in no-till treatment ranged from 2.00 t/ha to 4.00 t/ha, while in strategic tillage, it ranged from 1.47 t/ha to 4.29 t/ha.

4. Discussion

This study aimed to evaluate the effects of one-time strategic tillage (ST) compared to continuous no-till (NT) practices on soil water content, crop yield, and biomass production across diverse Mediterranean environments. While the multi-country dataset provides a valuable overview of ST performance under varying conditions, the results suggest that its agronomic impacts are generally minor, often transient, and largely non-significant. Rather than supporting ST as a strategic intervention, the findings indicate that its integration into conservation agriculture (CA) frameworks should be approached with caution and tailored to specific site constraints, where strict NT adoption may be limited by agronomic or socio-cultural factors.

4.1. Soil Water Content (SWC) Response to Strategic Tillage

Mediterranean dryland farming is governed by high inter- and intra-annual rainfall variability and hot, evaporative summers. Crop response to tillage hinges as much on rainfall timing and distribution within the crop season as it does on annual totals. Across sites and seasons, ST effects on SWC were small to moderate and directionally inconsistent, indicating the dominant role of local soil physical status, residue cover at the time of disturbance, and seasonal rainfall distribution. In clay-rich soils prone to surface sealing, shallow ST prior to sowing could temporarily enhance near-surface infiltration where residue cover was patchy [40,41,42]. Under severe drought, however, disturbance that disrupts protective mulch generally accelerates evaporation from the upper profile, reducing SWC—an effect documented in Mediterranean Iberian systems [43]. In semi-arid settings with shallow or stratified soils, shallow rotary operations (6–8 cm) often did not relieve deeper compaction layers; regional vertisol studies show that deeper, one-off chiseling or inversion at low frequency can reduce surface compaction and improve porosity without large shifts in profile water status [29,44]. In higher-rainfall environments, short-term evaporation changes following disturbance can be offset by subsequent rainfall recharge, and CA benefits to plant-available water accrue mainly through multi-season residue accumulation and cover management [45,46].

In our dataset, SWC increased slightly after ST at one fine-textured site (Morocco 2023, p = 0.0596), decreased significantly under drought when residue was disrupted (Spain 2022, p = 0.0454), and showed no significant change across measurement dates at higher-rainfall or single-sampling sites (Tunisia; Türkiye). Overall, Morocco and Tunisia exhibited no net SWC change under ST, whereas Spain and Türkiye showed non-significant reductions, consistent with the climate- and residue-mediated mechanisms above. Collectively, these patterns align with broader syntheses showing that ST impacts on SWC depend on texture, antecedent compaction, disturbance depth and aggressiveness, residue management, and rainfall after tillage [4,6,29,36,44,47].

Where growing-season rainfall fell below long-term means—especially during stem-extension to grain-fill cereals’ growth stages—differences in soil cover and disturbance are expected to have greater impact on plant-available water [4,6,31,42,43,47,48]. Importance of rainfall timing for wheat WUE and yield stability under reduced disturbance is reported in Moroccan dryland CA studies [40,41,42]. Simulation and field research indicate that under Tunisian conditions, residue retentive CA buffers wheat yield and water use efficiency under projected climate variability, but seasonal distribution remains critical [45,46]. Mediterranean Iberian work comparing tilled vs. conservation systems shows that soil cover helps moderate evaporative losses and runoff under such dry spells [43]. Seasonal water deficits interacting with shallow soils can moderate tillage effects; strategic disturbance to relieve surface sealing has been explored in regional vertisols [29].

4.2. Crop Performance

Yield and biomass responses to ST were similarly context-dependent and often modest. Yield penalties occasionally appeared in seasons with late-season drought even when SWC differences at sampling were small, implying mechanisms beyond instantaneous water status such as disrupted seed–soil contact, altered nutrient placement accumulated under long-term NT, or increased early evaporation [4,36,40,41,42,44]. In our dataset, for example, a statistically significant yield reduction under ST across cereals and pulses was observed in Morocco (overall p = 0.0319) with only a trend toward lower above-ground biomass (p = 0.0767), consistent with late-season water constraints despite adequate early-season recharge (rainfall 344 and 376 mm in two years, each slightly below the ~400 mm mean) [40,41,42]. By contrast, the Tunisian site exhibited higher vegetative biomass under ST but lower grain yield in a drought-affected season (p = 0.0138), indicating that vigor did not translate into reproductive success under terminal stress; long-term experiments and modeling in the region similarly show that CA improves yield stability and N-use efficiency across variable rainfall regimes, while episodic disturbance in dry years can depress harvest index if moisture or N becomes limiting post-tillage [45,46]. Where shallow ST (6–8 cm) was employed, moderate, non-significant yield declines suggest that insufficient depth failed to address deeper compaction common to calcareous/vertisol soils; Turkish long-term experiments demonstrate that deeper, low-frequency interventions can restore structure and sustain performance within otherwise NT systems [29,44]. Finally, residue-disturbing passes prior to a dry year can compromise establishment and early water conservation in cereals, as shown in Mediterranean Iberian studies [43].

Taken together, our multi-site evidence indicates that ST is neither universally beneficial nor universally detrimental; outcomes hinge on seasonal water supply, the severity and nature of soil constraints targeted by ST, implemented aggressiveness, and the speed at which residue cover is re-established—conclusions that accord with global syntheses on occasional/strategic tillage [4,36,44,47].

4.3. Reconciling Strategic Tillage with Conservation Agriculture Principles in Mediterranean Systems

Strict, year-after-year zero disturbance remains difficult for many Mediterranean farmers to sustain. Surveys and participatory research across the region show that farmers often view tillage as a key tool for weed control, resetting seedbeds, managing residue carryover, and stimulating nitrogen mineralization; zero-tillage is frequently cited as the least acceptable pillar of CA [15]. Socio-cultural dimensions also matter: in several smallholder contexts, field tillage is associated with stewardship and visible labor investment [15]. Within this reality, planned or occasional ST—applied at low frequency, shallow-to-moderate depth, and timed to low erosion risk—has been proposed as a pragmatic compromise that can relieve compaction, redistribute residues/nutrients, and manage herbicide-resistant or difficult weeds while retaining the longer-term soil quality gains of CA when soil cover is promptly restored. Broader CA/ecosystem-service reviews emphasize that the system benefits of CA are derived from the combined action of minimal disturbance, continuous cover, and diversified rotations; occasional departures from strict NT can be accommodated so long as the functional triad is quickly re-established [31,48].

4.4. Policy and Research Implications

• Shift from prescriptive to diagnostic CA policy. Mandating strict NT may limit adoption where farmers face episodic weed pressure, crusting, or compaction. Adoption studies recommend flexible guidelines that allow documented ST interventions triggered by measurable thresholds (e.g., penetration resistance, weed seedbank density, failed emergence risk), coupled with incentives to restore residue cover [15].
• Integrate ST with weed and nutrient management packages. Strategic disturbance is most effective when embedded in integrated weed management (IWM) and soil fertility programs; global syntheses show that ST combined with diversified rotations can reduce herbicide-resistant weeds and redistribute stratified nutrients with minimal lasting soil penalties when used sparingly [4,36,37,44,47].
• Target water-limited and compacted soils. Meta-analyses and regional vertisol studies suggest the greatest agronomic benefit from occasional disturbance occurs in soils prone to surface sealing, subsurface compaction, or nutrient stratification—conditions common across Mediterranean drylands [4,6,29,47].
• Monitor long-term soil function after ST. Even when short-term SWC, biomass, and yield effects are small (as in our study), repeated ST without monitoring could erode CA benefits. Tracking SOC distribution, infiltration stability, nutrient stratification, and biological indicators after ST events is recommended [31,47,48].
• Build learning platforms. Long-duration Tunisian CA experiments documenting concurrent improvements in soil health, wheat yield, and N-use efficiency illustrate the value of sustained farmer–researcher networks for scaling adaptive CA, including guidance on when and how to use ST [45,46].

4.5. Limitations and Future Research Needs

• Short observation window. Our measurements spanned ≤ 2 yr following a single ST intervention; slower-changing soil properties (SOC, aggregation below sampling depth, microbial community shifts) cannot be inferred. Longer monitoring is essential [31,47].
• Heterogeneous sampling protocols. SWC sampling frequency and depth varied by country (e.g., single sampling in Türkiye vs. multiple spring samplings elsewhere), constraining cross-site effect size comparisons. Harmonized protocols would strengthen inference.
• Unmeasured soil physical/chemical covariates. Bulk density, penetration resistance, and nutrient stratification—key triggers for ST—were not consistently measured across sites; future trials should include these diagnostics to link mechanism to response [6,29,47].
• Residue cover quantification. Post-ST residue retention strongly mediates evaporation losses yet was incompletely documented. High-resolution residue cover estimates (photo, drone) are recommended [6,48].
• Socio-economic drivers. Adoption decisions hinge on labor, fuel, herbicide cost, and cultural practice. Embedding bio-physical experiments within socio-economic surveys (as advocated in Mediterranean CA adoption analyses) will improve out-scaling relevance [15].

5. Conclusions

Across four Mediterranean dryland regions, the effects of strategic tillage (ST) proved highly variable, underscoring the importance of context in evaluating its role. In Morocco and Türkiye, ST tended to reduce yield and soil water conservation, while in Tunisia, it promoted biomass but compromised yield resilience under drought. In Spain, disturbance of protective cover exacerbated water loss during a dry year, reinforcing concerns about vulnerability in already water-limited systems. Taken together, these findings show that ST cannot be treated as a universal solution. Its impacts depend on rainfall timing, soil properties, and crop system interactions. Accordingly, ST should be applied only as a site-specific, diagnostic measure rather than a general recommendation for Mediterranean drylands. CA in Mediterranean drylands will be more adoptable if policies move away from rigid prescriptions of continuous no-till and instead allow occasional ST under documented constraints such as severe compaction, crusting, or herbicide-resistant weeds.