The historical distribution of rainfall in the three locations presented a bimodal behavior ( Figure 1 ). During El Niño phases (dark yellow bars) in El Espinal locality ( Figure 1a ), significant negative precipitation anomalies occur, particularly in January-March (-23% to -25%) and June-August (with August showing the most extreme deficit at -48%). In contrast, La Niña phases (blue bars) demonstrate precipitation surpluses, notably in June (39%), July (56%), and August (38%). During El Niño phases for locality Honda ( Figure 1b ), marked rainfall deficiencies are evident, with the most pronounced reductions occurring in July (-64%), followed by substantial decreases in June (-34%) and December (-32%). This location exhibits just one significant positive deviation during El Niño conditions, which appears in January (+24%). Conversely, La Niña phases (represented by blue bars) typically bring abundant precipitation, with the most substantial excesses recorded in June (+45%), August (+44%), and December (+37%). Throughout La Niña phases, numerous months display positive anomalies that surpass 19% above normal values.

For locality Mariquita ( Figure 1c ), El Niño conditions consistently produce negative precipitation anomalies throughout the year, with the most severe reductions occurring in August (-46%), July (-39%), and February (-36%). Additional substantial rainfall shortfalls are observed in December (-31%) and June (-29%), creating extended dry periods. In contrast, La Niña phases (blue bars) generate significant precipitation enhancements across most months, with the most remarkable increases in August (+49%), July (+44%), and February (+34%). Several other months exhibit positive anomalies exceeding 15% during La Niña phases.

The daily crop ETc varied throughout the study period, influenced by meteorological conditions and crop development stages. The ETc values obtained from the three lysimeters showed consistent trends, with the highest water consumption recorded during peak maturity stage (average of 7.41 mm day^-1). Figure 2 shows the daily ETc during the entire experimental period. The three series vary with time in a qualitatively similar manner with a few exceptions. Daily ETc showed an ample range of variation, with ETc values ranging from 1.03–7.81 mm day^-1, and from 0.89–7.03 mm day^-1, and from 0.43–7.40 mm day^-1 for Lys1, Lys 2 and Lys 3, respectively. The maximum evapotranspiration rate, 45% of the total ETc, of basil occurred during the maturity stage, while 21% and 34% of ETc occurred in growth and senescence stages, respectively. The total ETc for the growing season was 228.82 mm. Figure 3 represents average daily ETc (mm day⁻¹) for the different growth stages. The results indicate that the growth and development stage has the lowest daily ETc compared to other growths stages. However, the highest daily ETc was found during the maturity stage. The daily ETc is affected by the cropping period, duration, weather condition, and crop characteristics. Using the equation presented by Allen et al. (44) calculated Kc values were 0.75, 0.98 and 0.76 for basil crops at growth and development, maturity and senescence stage, respectively. The Kc values exhibited a dynamic pattern, increasing progressively from the initial establishment phase to the mid-season stage, where maximum water demand was observed. Subsequently, a decline in Kc was noted as the crop reached maturity. These findings align with expected physiological water requirements of basil, where higher transpiration rates correspond to biomass accumulation and leaf expansion.

The results of the soil morphological characterization are reported in supplementary tables ( Supplementary Tables S1 , S2 ). The soil pedological composition of the study areas of the three municipalities was highly similar ( Supplementary Table S1 ). Results showed a presence of typical geomorphological features of alluvial plains, consisting of fluvio-volcanic sediment deposits that form terraces with particle sizes ranging from fine to coarse. The topography exhibits flat reliefs with slopes not exceeding 3%. The three study sites are classified as a tropical dry forest (bs-T), with a bimodal rainfall pattern and a warm dry climate. Taxonomically, the soils of the three municipalities share a common pedogenic origin as Typic Haplustepts ( Supplementary Table S1 ) derived from fluvio-volcanic alluvium yet exhibit critical differences in horizonation that directly influence plant-available water and irrigation efficiency.

The edaphological characterization of the three locations revealed a similar pattern composed of altered mineral horizons (Ap) associated with shallow depths (<15 cm). This could be explained by soil loss due to anthropogenic activities (more details in Supplementary Tables S2 ).

Statistical analysis showed no significant differences between the factors of location (Mariquita, Honda, and El Espinal) and soil depth (0–5 and 5–10 cm) (p>0.05). However, significant differences were found between locations and physical properties (ρa, Rd, Tp, FC, PWP and AW) (p<0.05) ( Supplementary Table S3 ). Results of soil physical properties per location were shown in Figure 4 . El Espinal recorded the highest bulk density (1.65 ± 0.02 g cm^-3), significantly surpassing Mariquita and Honda by 26.0% and 7.87%, respectively ( Figure 4a ). However, no significant differences were found in real density between El Espinal and Honda (p>0.05); while Mariquita showed a 6% reduction in real density compared to both locations ( Figure 4b ). Tp and FC were higher in Mariquita exceeding El Espinal and Honda by 30.5% and 17.5% ( Figure 4c ), and by 22.8% and 16.2% ( Figure 4d ), respectively. Finally, available water displayed this pattern, with Mariquita showing the highest value (3.59 ± 0.32%), followed by Honda (2.64 ± 0.2%) and El Espinal (2.41 ± 0.15%) ( Figure 4f ).

Regarding the sand, clay, and silt fractions, no significant interaction was observed between the factors of location and system (crop vs. relict) (p > 0.05) ( Supplementary Table S4 ). However, significant differences (p < 0.05) were found for these variables across the location factor ( Figure 5 ). The soil particle size fractions showed an inverse relationship across the localities, with higher sand content contrasting with lower silt and clay proportions. The sand fraction in Mariquita was the lowest with value of 55.90 ± 8.78%, differing significantly (p < 0.05) from the other two locations ( Figure 5a ). However, this location had the highest silt (25.00 ± 1.99%) and clay (19.10 ± 3.56%) fractions, with statistically significant differences (p < 0.05) compared to the other locations ( Figures 5b, c ).

The statistical analysis of chemical properties revealed that pH, CE, OC, TN, SK, Na, S, B, Fe, and Zn had no significant effects (p > 0.05) at any factor level or interaction. However, ECEC, OM, K, Ca, Mg, and SMg showed significant differences (p < 0.05) at the location level. Significant differences across both factors (location and system) and their interaction (p < 0.05) were found in SMg and Mn. For the cultivation system factor, significant differences were identified in P, SCa, SNa, and Cu ( Suplementary Table S5 ).

The LSD tests (p ≤ 0.05) for mean comparisons revealed significant differences in the factors location (Mariquita, Honda, and El Espinal) and system (crop vs. relict), as well as their interaction for the variable Mn content. The highest mean Mn levels were recorded in El Espinal, where the relict system exceeded Honda by 55% and Mariquita by 32%. The crop system showed 25% and 36% higher Mn levels compared to Honda and Mariquita, respectively ( Figure 6a ). For the OM variable, Mariquita exhibited the highest content, surpassing Honda by 35.5% and El Espinal by 55.3% ( Figure 6b ). A similar trend was observed for ECEC, with differences of 37.6% (Honda) and 50.5% (El Espinal) relative to Mariquita ( Figure 6c ). Finally, crop systems were 55% and 49.3% higher than relict systems, for P and Cu content, respectively ( Figures 6d, e ).

For chemical properties related to base saturation, significant differences in K (potassium) were observed across locations. Honda and Mariquita showed higher K contents with values of 0.39 ± 0.09 and 0.36 ± 0.04 cmol kg^-¹, respectively, which sharply contrasted with El Espinal (0.18 ± 0.03 cmol kg^-¹) ( Figure 7a ). Na saturation (NaS) was significantly higher in crop system with a value of 61% compared to relict systems ( Figure 7b ). Calcium (Ca) concentrations were higher in Mariquita, surpassing Honda and El Espinal by 33.8% and 49%, respectively ( Figure 7c ). However, Ca saturation (CaS) showed no spatial variation but differed between systems, with relict systems representing a 9.47% increase over crop systems ( Figure 7d ). Mg content was significantly elevated in Mariquita, exceeding Honda and El Espinal by 53.3% and 55.8%, respectively ( Figure 7e ). Crop systems in Honda and El Espinal showed a 35.8% higher MgS compared to relict systems, while Mariquita had no significant system-level differences ( Figure 7e ).

Figure 8 shows the correlation matrices between soil physico-chemical properties. A strong negative correlation was observed between ρ_a and TP (r = -0.906, p < 0.01) ( Figure 8a ), demonstrating an inverse relationship where increased soil bulk density corresponds to reduced total pore space due to soil compaction. Additionally, moderate positive correlations were found between ρ_a and PWP (r_s = 0.432, p < 0.05), as well as ρ_a density and RD (r_s = 0.397, p < 0.05). The positive relationship between ρ_a and RD reflects the natural influence of soil mineral particle density on overall compaction, although this relationship is moderated by factors such as structure and organic matter content. Figure 8b presents several significant associations between soil chemical and textural properties. Strong negative correlations were observed between sand and clay content (r_s = -0.840, p < 0.01), as well as between sand and silt (r_s = -0.827, p < 0.01), which is consistent with the complementary distribution of textural fractions. OM showed moderate positive correlations with clay (r_s = 0.512, p < 0.01) and ECEC (r_s = 0.559, p < 0.01), suggesting the important role of these properties in nutrient retention.

The PCA biplot analysis revealed distinct patterns in both soil physical and chemical variables. For physical properties ( Figure 9a ), the first principal component (Dim1) explains 48.1% of the total variability, while the second component (Dim2) contributes 20%, with both accumulating 68.1% of the variance. The Espinal locality showed a strong association with ρ_a and moderate correlation with PWP and RD, being predominantly located in the right quadrant of the graph. In contrast, Mariquita was mainly characterized by high HR, PT and AWC values, being positioned in the left region of the biplot. Honda presented intermediate behavior, although with greater affinity towards the variables in the right sector.

In chemical variables ( Figure 9b ), the first principal component (Dim1) explains 51.5% of the total variability, while the second component (Dim2) contributes 25.6%, accumulating 77.1% of the variance. The locality Mariquita is strongly associated with the variables Clay, Mg, ECEC, Silt, Ca and OM, being predominantly located in the right sector of the biplot. In contrast, locality Espinal shows a vertical distribution along the Dim2 axis, influenced mainly by the Sand variable in the left region and with some samples affected by NaS. Locality Honda presented a more dispersed distribution, mainly in the lower left quadrant, showing affinity with the Sand and CaS variables.

The climatic variability observed in the Tolima region played a fundamental role in dictating the water requirements of basil. Our long-term climate characterization, based on more than 30 years of temperature and precipitation records, revealed a bimodal rainfall pattern with marked anomalies during El Niño and La Niña events. During El Niño phases, significant precipitation deficits were recorded, with reductions of up to 48% in certain months, while La Niña conditions produced substantial surpluses. Such fluctuations affect the soil moisture regime and, consequently, the crop water balance. Chaali et al. (38) highlighted that the bimodal behavior of the historical distribution of rainfall is related to the presence of the Intertropical Confluence Zone (ITCZ), which affects the annual distribution of precipitation. The latter influence the spatial distributions of precipitation, inducing a seasonality in the meteorological phenomena and regional climate. El Niño is generally associated with below average rainfall, higher temperatures and vapor-pressure deficit, which increase crop water demand and irrigation requirements and, unless compensated by targeted irrigation, tend to lower water productivity and yields. By contrast, La Niña usually brings above-average rainfall and reduced evaporative demand but increases risks of waterlogging, percolation losses and disease that can also undermine effective water productivity (32, 45). Accordingly, irrigation should be ENSO-responsive: under El Niño prioritize water conserving measures and targeted-deficit scheduling informed by site measured ETc (lysimeter-derived Kc) and seasonal forecasts, while under La Niña prioritize reduced irrigation frequency, improved drainage and disease management.

Daily evapotranspiration (ETc) measurements obtained via volumetric lysimeters showed that basil water consumption varied markedly with its developmental stages. Peak water consumption occurred during the maturity stage (average 7.41 mm day^-1), accounting for approximately 45% of the total seasonal water use. The dynamic behavior of the crop coefficient (Kc), calculated as 0.75 for the growth stage, rising to 0.98 at maturity and decreasing to 0.76 during senescence, reflected the basil physiological adjustments to changing environmental conditions. When comparing our observed Kc values (0.75, 0.98, 0.76) with existing literature, some interesting patterns emerge. In a field study of basil in Valle del Cauca (Colombia), Daza-Torres et al. (35) reported much lower Kc values: 0.45 (± 0.02) in the initial stage and 0.59 (± 0.02) in the mid-maturity stage. Meanwhile, under semi-arid conditions in Iran, Ghamarnia et al. (46) derived single and dual Kc values for basil of approximately 0.71, 1.11, 1.39 (initial, development, mid stages) in one treatment group, and 0.57, 0.97, 1.26 in another (somewhat higher mid season). More extremely, Martins et al. (30) in Brazil measured Kc values in greenhouse lysimeter settings ranging from 1.5 to 2.8 (depending on days after transplant, leaf area and coverage). These discrepancies are readily explained by methodological and environmental controls, principally canopy cover, the relative contribution of soil evaporation, irrigation regime, crop water status, and atmospheric demand that alter the transpiration and evaporation partition and thus apparent Kc. Given that our experiment was maintained under full (non-stress) irrigation and produced a dense canopy while using a lysimeter design intended to minimize edge and advection artefacts, we interpret the reported Kc as empirically calibrated, site-specific values appropriate for irrigation scheduling under the local climatic regime. Given the increasing challenges posed by climate change in Tolima region, including rising temperatures, erratic precipitation, and more frequent extreme weather events (47), the observed variability in ETc and Kc emphasizes the critical need for adaptive irrigation management. Precise, stage specific irrigation scheduling can optimize water use efficiency, ensuring that basil receives adequate moisture during periods of peak demand while minimizing water waste. Such approaches are vital for maintaining both yield and phytochemical quality, as water stress not only reduces biomass accumulation but can also alter the synthesis of key bioactive compounds (48). It was reported that basil can be grown in a soilless water-based system. It had a higher yield in the soilless system compared to the conventional system (49). According to previous studies, Rakocy et al. (50) conducted a study on basil to compare the batch and staggered cropping system. It was reported that grown under aquaponics had more yield with 1.8 kg m² than grown under field conditions with 0.6 kg m². These studies revealed that basil could be produced in both hydroponic and aquaponic systems together with restricted water and without soil. These systems affect the morphological and yield properties of basil genotypes positively under different growing conditions (48).

Soil physical properties are fundamental factors for water availability, nutrient retention, and root development, which directly impact basil productivity. Soil characteristics are very important especially when dealing with basil oil quality, since they may also affect oil characteristics. Our study revealed significant spatial variability in these properties across the three study locations, which has important implications for basil cultivation in the Tolima region. The edaphological characterization showed different textures in the study region ranging from sandy to sandy clay loam, which could affect plant growth in different ways. In fact, plant roots grow faster in sandy soil, but water and nutrient uptake can be limited due to insufficient contact from the soil. On the other hand, the opposite situation occurs in clay soils (51), and this may lead to changes in the yield and essential oil components of plants (52). Essential oil compositions in basil plants vary based on various factors, such as, soil type, climatic conditions, growth period, harvest time, and post-harvest practices. Also, essential oil may differ in oil yield and quality according to soil type and this provides an opportunity to find out suitable soil for getting the highest essential oil yield and the best of its quality (53). Tursun (54) found that the highest essential oil yield was obtained in the basil plants grown in sandy soils while the least was obtained from clayey soils.

Bulk density was a critical parameter that reflects soil compaction and porosity. In fact, El Espinal showed the highest bulk density (1.65 ± 0.02 g cm^-3), which suggests a higher degree of compaction compared to Honda and Mariquita. High bulk density is typically associated with reduced pore space, leading to diminished water infiltration and lower aeration. Such conditions can restrict basil root growth and impair the soil holding capacity to store and transmit water, which is particularly problematic during periods of water scarcity (55). Compacted soils may also exacerbate water stress during critical growth stages by limiting the movement of water into the basil root zone.

Soils in Mariquita demonstrated superior Tp and FC, with available water (AW) content reaching 3.59 ± 0.32%. High porosity enhances both water retention and air exchange, which are essential for robust basil root development and nutrient uptake (56). FC indicates the soil ability to retain water after drainage, ensuring that basil has access to moisture during dry periods. The higher available water in Mariquita soil suggested that these fields are better suited to withstand intermittent drought conditions, a crucial advantage in the context of Tolima bimodal rainfall pattern and high evapotranspiration rates. The inverse relationship between bulk density and Tp as observed in Espinal affects the root growth and also limits water retention capacity compared to Mariquita farms. The observed differences in soil physical properties among the three locations highlighted the need for location specific management practices. In areas like El Espinal, where high bulk density and low available water prevail, agronomic interventions such as the incorporation of organic amendments, reduced tillage, or the establishment of cover crops could help improve soil structure, increase porosity, and ultimately enhance water infiltration (36). These practices can reduce the negative impacts of compaction and support more effective root penetration, thereby improving water and nutrient uptake. Moreover, the physical properties of the soil act as one of the most determining factors in the essential oil composition of different aromatic plant species (57). Several researchers (53, 54, 57, 58) have focused on looking at the most suitable soil type to produce basil plants having essential oil with the best composition and concentration. Soils with inherently favorable physical properties, as observed in Mariquita, may require less intensive soil amelioration. However, even in such areas, precise irrigation scheduling is essential to align water application with the crop phenological stages. Basil exhibits significant variation in water demand during its lifecycle, low during the early growth and senescence stages, but peaking during the maturity phase when biomass accumulation is at its highest (35). Ensuring optimal soil moisture levels during these peak periods is critical not only for yield but also for maintaining the concentration of bioactive compounds that determine basil market value (59). The spatial heterogeneity observed in soil physical properties highlighted the limitations of a one size fit all irrigation strategy (60). Instead, precision agriculture approaches, such as the use of soil moisture sensors and remote sensing techniques, can facilitate real time monitoring of soil water content and compaction. This data can then be used to tailor irrigation and soil management practices to the specific conditions of each locality (17). Soils with high porosity (Mariquita) enhance drought resilience but increase nutrient leaching, while compacted soils (El Espinal) restrict root growth but potentially elevate essential oil concentration. This duality needs site specific management such as biochar amendments in El Espinal to alleviate compaction without sacrificing oil quality. Recent studies (61, 62) indicated that superabsorbent and biodegradable hydrogel soil conditioners can substantially increase soil water retention, reduce surface evaporation and percolation losses, and improve crop performance under water-limited conditions; such amendments therefore complement mulching and organic-matter additions as practical options to enhance water productivity for basil in El Espinal and other compacted soils. Further, by linking ENSO driven rainfall anomalies to real-time ETc, we enable irrigation protocols that reduce water use during El Niño, a step toward climate resilient precision agriculture. This integrated approach is novel in tropical aromatic crop systems and represents a disruptive advance in water use efficiency under ENSO driven climates.

Soil chemical properties fundamentally influence nutrient availability, root uptake, and overall crop performance, making them critical in understanding basil productivity in the Tolima region. Our analysis revealed substantial spatial variability in several chemical parameters, such as ECEC, OM, and key macronutrients (K, Ca, Mg, P) and micronutrients (Mn, Cu), across the study locations. This variability emphasizes the complex interplay between natural soil formation processes and anthropogenic influences, which are critical for optimizing basil growth and secondary metabolite synthesis.

The correlation analysis provided deep insights into the interrelationships among soil chemical properties. These relationships indicated that soils with higher clay and organic matter are inherently better at sustaining nutrient availability, a factor that is particularly beneficial for basil growth and metabolic functions (37). These soils were mainly characterized by higher clay, magnesium and ECEC contents (54, 63, 64). Thus, the soils of Mariquita presented potentially better nutrients and water retention capacity. For this locality, the higher clay content creates a structure with abundant micropores, crucial for water retention at higher tensions. This textural characteristic would allow the soil to maintain moisture available for basil plants during prolonged drought periods compared to sandy soils, which typically drain more rapidly (65).

Organic matter is a key driver of soil fertility, enhancing nutrient retention, water holding capacity, and soil structure. In our study, Mariquita soils showed the highest OM content, surpassing Honda by 35.5% and El Espinal by 55.3%. High OM is typically associated with increased microbial activity and enhanced formation of organo-mineral complexes that stabilize nutrients in the soil (Cotrufo et al., 2019). This relationship indicated that soils rich in OM are more efficient in retaining essential cations (Ca²⁺, Mg²⁺, and K⁺), thereby ensuring a more stable nutrient supply to basil plants. This latter is crucial for sustaining nutrient availability under the fluctuating moisture regimes characteristic of Tolima bimodal rainfall patterns.

Macronutrient balance is critical for plant growth, particularly in nutrient sensitive species such as basil. Our results revealed significant differences in P content between cultivation and relict systems, with cultivated systems exhibiting a 54.5% higher concentration. Both systems fell within the high to very high P range established for Colombian soils (66). This disparity is attributed to continuous fertigation using phosphoric acid (H₃PO₄ with 85% concentration) and pre-planting incorporation of phosphate rock as a soil amendment. Excessive P application through fertilizers has been shown to elevate soluble P fractions (67). Moreover, high P levels reduce Zn, Fe, and Cu uptake and translocation, inhibiting plant growth. For basil plant development, the optimal P level is ranging between 0.62 and 1.00% (68), serving as a structural component of cell membranes, DNA, RNA, and ATP (69). In medicinal plants, it further enhances essential oil synthesis and assimilation (70).

For K, Ca, and Mg, similar trends were observed across the study sites. K levels were significantly higher in Honda and Mariquita compared to El Espinal, ranging within the sufficient to high values established for Colombian soils (66). K is among the most abundant elements in basil leaves, with concentrations ranging from 1.55 to 2.05% (68). In fact, K plays a vital role in stomatal regulation and enzymatic activation, with deficiencies leading to impaired photosynthesis and reduced biomass accumulation (15). According to the Colombian soils classifications (66), the Ca content in Mariquita was very high, while in Honda and El Espinal ranged within high levels. Local agricultural practices include pre-planting dolomite (CaMg(CO₃)₂) amendments or calcium nitrate (Ca (NO₃)₂) fertigation to enhance phosphorus sorption via CaCO₃ interactions (71). Normally, foliar Ca concentrations range from 1.25 to 2.00%, reflecting its structural role in the cell wall middle lamella, where it binds to pectin carboxyl groups to promote cellular elongation in shoots and roots (68). Additionally, Ca stabilizes the mitotic spindle during cell division, supports pollen tube germination, and improves postharvest quality in exported basil by reducing cold damage and decay rates (72). As regards Mg concentrations (normal range between 0.60 and 1.00%), we found in this study very high levels in Mariquita and sufficient levels in Honda and El Espinal. However, Mg deficiency manifests as interveinal chlorosis in older leaves due to its role as a constituent of chlorophyll’s tetrapyrrolic ring. Mg also acts as a cofactor for kinases and activates ribulose-1,5-bisphosphate (RuBP) carboxylase during photosynthetic light reactions (73).

Soil pH of the three localities showed a slightly acidic to neutral pH range, thus facilitating CEC dominated by Ca²⁺, Mg²⁺, K⁺, and Na⁺ (74). Calcium saturation (CaS) was higher in was higher in undisturbed (relict) areas compared to cultivated plots. Nonetheless, CaS values remained within the established reference range of 65 to 75%, while magnesium saturation (MgS) levels aligned with the proposed 10 to 15% threshold. At the cultivated system level, MgS exceeded the upper reference limit, a consequence of periodic dolomite amendments (applied every 4 to 5 months) and magnesium sulfate (MgSO₄) fertigation. Although adjustments to the soil CEC complex did not translate into statistically significant yield gains, it is recommended to avoid extreme imbalances in base cation proportions to maintain soil health. Finally, sodium saturation values in both relict (0.78%) and cultivated (2%) systems remained within normal limits (0 to 5% of total CEC), indicating no sodicity concerns under current management practices (75).

Micronutrients, despite being required in lower amounts, play crucial roles in enzyme function and secondary metabolite biosynthesis (76, 77). In our study, we observed that Mn levels in soil were significantly higher in El Espinal, however, these concentrations remain below the lower critical threshold (< 5 mg kg^-1) for agricultural soils. Mn deficiency is common in alkaline soils due to redox reactions and other factors such as increased OM content, microbial activity, soil temperature, and water content. Although plants absorb only a small fraction of Mn for growth and developmental processes (78), basil requires foliar Mn concentrations between 30 and 150 ppm (68). Mn is critical for redox processes in plants and acts as an activator or cofactor for numerous enzymes, including proteins essential for light-mediated water oxidation in Photosystem II (PSII) (76, 79).

Regarding Cu, cultivated soils showed elevated concentrations, primarily attributable to the use of Cu based fungicides, which accumulate in plant tissues and subsequently leach into the soil (80). Nonetheless, the measured soil Cu levels (1–3 mg kg^-1) fall within the adequate range for the evaluated systems. In mineral soils, Cu concentrations should exceed 6 mg kg^-1, owing to its low soluble fraction (1 × 10–⁸ to 60 × 10–⁸ mol L^-1) and the fact that approximately 98% of Cu is bound to organic matter (68). In basil foliage, sufficient Cu ranges are reported between 5 and 10 mg kg^-1. Like Mn, Cu is integral to plant redox systems and serves as an enzymatic activator for superoxide‐detoxifying enzymes; it also participates as a redox cofactor in PSII‐mediated electron transport and in lignin biosynthesis (81). This highlighted the need for careful monitoring and management of micronutrient levels to maintain optimal basil quality. While this study quantifies key edaphoclimatic parameters of basil productivity, the absence of direct yield measurements (e.g., biomass, essential oil yield) limits causal inference. Future work should integrate field trials with controlled irrigation and fertilization treatments to quantify basil fresh or dry weight and essential oil yield under contrasting soil water regimes. Subsequent research will couple lysimeter based soil water monitoring with harvest assessments and phytochemical profiling of essential oils to link edaphic factors directly to basil yield and aroma quality.