Olive orchards in semiarid areas are maintained under bare soil conditions, with significant effects on soil properties. This study examined the roles of orchard age (OA) and Cropping System (CS) based on Cover crop (CC) on Soil Organic Carbon (SOC), Bulk Density (BD), and other soil traits in a semi-arid region of Tunisia. Two olive orchards 50 and 15 years old respectively, subjected to tillage were investigated. The CS consisted of 3 contrasting CC treatments: faba bean (FB) CC, vetch-oat (VO) intercrop CC, and bare soil (NC) as a control. Samples were taken below the olive canopy (0–30 cm) layer. The experimental design was a split-plot with orchard age as a main plot. Non-correlated variables at |r| > 0.7 were selected, standardized, and included in a specific multivariate analysis namely canonical discriminant analysis (CDA) to capture the multivariate effect of treatments on the variability and the relationship among variables. A general linear mixed model checked the response variable differences by the treatments and interaction of each variable. A negative correlation was found between SOC and BD (r = -0.98). No significant effects of the CS were detected for individual soil variables and most variables, including soil texture, were not significantly affected by OA. Significant differences associated with OA were observed only for CaCO₃, Ca, and assimilable P, which were higher in the older orchard and may reflect differences in long-term management history (e.g., fertilization and erosion processes) rather than OA alone. The CDA yielded one significant CDA axis explaining 80.9 The graphical abstract summarizes the experimental framework, analytical approach, and key findings of a study conducted in a semi-arid olive orchard system in Siliana, northwest of Tunisia. Soil samples were collected from the 0–30 cm layer in two orchards of contrasting age (50 and 15 years old) to assess how OA and short-term CC management are associated with soil physicochemical variability. Two CC systems, vetch oat and faba beans, were compared using multivariate statistical tools, particularly CDA, to capture subtle treatment related patterns. The results indicate that differences between orchards of contrasting age were the main source of variation in soil properties, exceeding the short-term influence of CC. However, these differences likely reflect the combined effects of OA and site-specific management history. Young orchards showed more distinct multivariate response particularly under vetch-oat CC, suggesting a higher sensitivity to recent management practices. In contrast, the older orchard was associated with higher phosphorus and calcium levels, which may be related to long-term nutrient accumulation and legacy management effects. A strong negative correlation between SOC and BD highlights the role of soil organic matter (SOM) in improving soil physical structure and fertility. Although short-term CC effects on individual soil parameters were limited, multivariate analysis revealed detectable shifts in soil functioning. These findings emphasize the importance of considering OA as a proxy for long-term soil processes, while acknowledging the influence of site history, when designing sustainable orchard management strategies aimed at enhancing soil health, nutrient cycling, and long-term agroecosystem resilience under semi-arid conditions. Soil variability was more strongly associated with differences between orchards of contrasting age and management history. Canonical analysis showed strong differences between young and old orchards, while short-term CC effects were subtle. P, Ca, and Mg increased with OA, whereas SOC, pH, and EC showed opposite trends. Short-term CC weakly affected single soil traits but shifted overall soil functioning. SOC was strongly negatively correlated with BD, improving soil physical quality. Multivariate tools effectively detected early soil responses, supporting soil health assessment in perennial systems.

The present experiment aims at investigating the medium-term effect of sewage sludge as an organic amendment to a degraded, saline soil in Central West Tunisia. The field research plot measures 4.22 ha, and 5 t/ha of sewage sludge dry powder was applied. Soil and leaves samples were collected after six months of application and two years later to assess the immediate and medium-term effects of Sludge on soil quality, from the first layer of the soil horizon (0–30 cm). Before the application, soil pH was neutral at about 8.0; since then, it has slipped towards 7.6. Electrical conductivity was already high (roughly 17.1 mS/cm) and climbed to 25.1 mS/cm in 2023. Organic matter rates were under 1 The graphical abstract outlines a story of an agricultural plot with a measured area of 4.22 ha, situated in a semi-arid region in the central west of Tunisia. The area was widely affected by climate change and the poor soil management practices, intensive agricultural practices (tillage), and the non-return of crop residues, leading to a depletion of organic matter. The farmer was open to changing traditional agricultural practices and agreed to try sewage sludge as an organic amendment. The field trial was conducted during 2023–2025. After proceeding with sludge treatment, the plot was treated with two doses of dry sewage sludge powder around 5t/ha. Soil samples were collected at 0–30 cm depth six months and two years after sludge application. Results were promising after suldge application during the year of 2023, the improvement was mostly noted in organic matter amounts, heavy metals were higher but remained within limits. Additional analyses were done in 2025, showing a notable stabilization of all physicochemical analyses, mainly in organic matter, showing the potentiality of Sewage sludge as an amendment for immediate fertility, and mid-term organic matter conservation, notably in arid and semi-arid regions. However, careful monitoring is always advised.

Soil profiling is important for understanding soil evolution in space and time and its ability to deliver ecosystem services. It reflects the soil's physical, chemical, and biological, along with its management history. As a fundamental step in assessing soil health, it helps determine the soil’s potential for the provision of ecosystem services and its suitability for various agricultural and land-use applications. Soil profiling allows for the classification of soil types across different regions, contributing to soil mapping and enabling informed decisions for sustainable soil and land management. This study describes and classifies four soil profiles in Tunisia using the WRB classification system. The main areas of the WRB soil classification are soil Reference Soil Groups (RSG) mainly defined by diagnostic horizons, and qualifiers used to provide additional information about the soil's characteristics. The four soil profiles analyzed are Luvisol, Cambisol, Vertisol, and Fluvisol each exhibiting distinct physical, chemical, and morphological properties. Luvisol in Cap Negro (northern coast) is moderately fertile but vulnerable to erosion, necessitating protection measures. Cambisol in Oued Zarga (northern continental area) supports field crops but faces threats such as soil compaction and erosion, which can be mitigated by reduced tillage and providing soil cover after the harvest. Vertisol in Béja (northern continental area), characterized by high clay shrink-swell activity, is cultivated with winter cereals, where appropriate tillage and irrigation practices help manage soil stability. Lastly, Fluvisol in Oued Meliz (north-western continental area) benefits from high fertility due to alluvial deposits but requires careful water management to erosion. By providing detailed soil classification and management insights, this study contributes to deepen our understanding on soil classification, sustainable land use planning in Tunisia.

This study aimed to assess the effects of B addition on lettuce grown in soil and hydroponically and to determine the adequate B concentration enhancing plant growth and development. B concentration was measured in the soil (available and total B) and lettuce. Additionally, photosynthetic parameters (NDVI, total chlorophyll content, photosynthetic efficiency and performance index), and dry matter were measured in lettuce. The results showed that the lettuce B concentration increased with increasing B treatments in both experiences. The lettuce hydroponically grown has greater photosynthetic performance and dry matter content. However, a toxic effect was pronounced at high B treatment where B concentrations in lettuce were extremely high (196.4 mg/kg). This negatively impacts plant physiology. Thus, the optimal B concentration in lettuce hydroponically grown was determined to be 0.5 mg/kg. Regarding the soil grown lettuce, the low B treatment recorded the highest values for the physiological parameters, dry matter and lettuce B concentration. And no toxic effect was revealed at high B treatment. Total B and available B concentrations in the soil increased with B treatments. Soil available B concentrations ranged between 0.5 and 2.0 mg/kg considered a sufficient range for both treatments. Therefore, these results indicate that soil appears to be a better environment for the efficient growth of lettuce and acts as a buffer for nutrient problems and disease.

Abstract As urban agriculture increasingly becomes part of our regional food systems, its role in sustainable urban development grows. Urban agriculture can sustain food demand and contribute to food security, environmental sustainability, and community health. However, soil‐related factors in urban agricultural systems pose unique challenges not found in more rural environments, and issues such as soil fertility, soil biodiversity, soil contamination, and existing policy demand further investigation to deepen and enhance the potential contribution of urban agriculture to livability in urban areas. This special issue collects studies to support the need for sustainable soil management, crop diversification, and management strategies for optimal soil health and good crop yield and quality. In addition, the issue examines recent advances in remote sensing technologies and deep learning techniques that offer potential tools for soil health monitoring and plant disease detection related to existing plant‐based contamination, providing a way forward to make informed decisions for policy stakeholders and land planners. Combining these initiatives into urban planning and public health policies could have a considerable impact on urban well‐being and resilience.

Boron (B) is vital for optimal crop growth and soil health, with its distribution influenced by several factors such as soil properties, environmental conditions, and land management practices. Therefore, understanding its distribution is crucial for developing effective soil management strategies. Currently, there is a lack of information regarding the status of B in Tunisia, highlighting the need for research into its distribution and the factors affecting its availability in Tunisian soils. This study aimed to quantify B fractions and investigate the distribution of available B in particle-size fractions, as well as total B in humic substances, at different depths of soils located in northwest Tunisia. Four agricultural soil types (Luvisol, Vertisol, Cambisol, Fluvisol) and two forest soil types (Luvisol) were selected and analyzed for physicochemical properties and B fractions (Rs-B, Ox-B, Org-B, Res-B, total-B). Additionally, particle size (sand, silt, clay) and humic fractionation (fulvic acid, humic acid, humin) were conducted to quantify B content in each fraction. The results revealed that forest soils exhibited higher available B content, particularly in deeper layers, while agricultural soils (sedimentary rock) had higher total B amounts compared to forest soils (igneous rock), indicating the influence of soil parent material. The distribution of B forms followed Res-B > Org-B > Ox-B > Spa-B > Rs-B, with dynamic equilibrium observed. Moreover, available B predominated in silt fractions, and total B in humic acid fractions. These findings provide insights into B dynamics concerning soil properties and land use, with implications for optimizing crop production and soil fertility in northwest Tunisia, contributing to sustainable agricultural development.

Knowledge of the soil organic carbon (SOC) and total soil nitrogen (STN) stocks and their temporal changes are key to establishing sustainable land management and climate change mitigation strategies. For this reason, our study focused on determining the SOC and STN stock dynamics from 1971 to 2019 (48 years) in three layers of two soils in the northwest of Tunisia. As expected, SOC and STN content decreased with depth in both sites. SOC and STN concentrations decreased from 1971 to 2019, especially in the surface layer (0–30 cm), with a more substantial decline for STN (− 34

. - Boron (B) is a crucial micronutrient needed for plant growth. This study investigated the effect of B addition (0.5 mg kg-1-low, and 5 mg kg-1-high) on lettuce (Lactuca sativa L.) plants grown in the soil and hydroponically. The results showed that B addition causes a differential increase in B concentration in lettuce leaves depending on the cultivation system. In soil-grown plants, a statistically significant increase in lettuce B concentration was shown with increasing B treatments compared to the control. Moreover, the B concentrations measured in lettuce were within the optimal level for healthy lettuce. While hydroponically-grown plants showed a statistically significant increase in lettuce B concentration at high B treatment compared to the control and low B treatment. However, the high B treatment in hydroponics caused a very high B concentration in lettuce (196.4 mg kg-1) leading to toxicity expressed by the decrease in normalized difference vegetation index (NDVI) and chlorophyll content. Therefore, B concentration should be below 5 mg kg-1 for hydroponically-grown lettuce. Soil total and available B concentrations increased with B addition and considered a sufficient level. The other soil physicochemical parameters did not reveal a statistically significant difference with the B treatments, except a modest increase in pH, suggesting that the soil has a great homeostatic capacity. Additionally, the results showed that hydroponically-grown lettuce performs much better in terms of biomass production.

Information on spatial and temporal changes in the soil organic carbon (SOC) and soil total nitrogen (STN) stocks are crucial to support sustainable land management strategies. However, such information is scarce mainly for arid and semi-arid regions. The present research aimed to determine SOC and STN stock dynamics with depths during the 1971–2019 period. Thus, two soil types were selected in north Tunisia: a Luvisol under forest vegetation and a Cambisol under cereal crop and analyzed for SOC, STN, rock fraction, and bulk density from the surface (0–30 cm), middle (30–50 cm), and deep layers (50–100 cm) in 1971, 2005, 2012, and 2019. SOC and STN contents decreased with depth in both soils. The Luvisol exhibited the highest SOC and STN contents. From 1971 to 2019, SOC and STN contents decreased more in the surface layer in both soils with sharpest decrease for STN than SOC. The stocks were calculated taking into account the rock fractions avoiding overestimation. Stocks recorded in the surface layer corresponded to 68% of total SOC stock and 58% of total STN stock in both soils. From 1971 to 2019, the reduction of SOC and STN stocks was more important in the Cambisol than in the Luvisol in all layers, mainly in the surface layer. Such reductions could have important implications for soil fertility and global warming.

Soil organic matter has generated international interest in carbon and nitrogen sequestration. In reality, small fluctuations of soil organic stock could have large impacts on global warming. Therefore, quantification of Soil Organic Carbon (SOCs) and Total Nitrogen (TNs) stocks in surface and deep horizons are important to control the release of greenhouse gases. The present research was undertaken in order to determine SOCs and TNs evolution over 50 years. For this aim, we selected two soils (P1 and P2) developed under contrasted pedogenetic conditions in North-West of Tunisia (Beja governorate). P1 is a Luvisol located in a forest region. However, P2 is a Cambisol situated in an agriculture zone. Soil samples were gathered from surface (0-30 cm) and deep (50-100 cm) horizons in 1971, 2005, 2012 and 2019. SOCs declined in surface and deep horizons during the experimental period in both studied soils. In the case of Luvisol, the values declined from 91.01 t/ha to 75.54 t/ha and from 53.00 t/ha to 24.51 t/ha, respectively in surface horizons and deep horizons. Likewise, the SOCs values decreased from 84.24 t/ha to 25.52 t/ha in surface horizons and from 24.45 t/ha to 14.20 t/ha in deep horizons of the Cambisol. The TNs recorded lower values than SOCs. Nevertheless, they showed the same behavior. Our results showed that the highest values of SOCs and TNs were recorded in the Luvisol. This soil exhibited the greatest amount of organic matter since it was developed under forest vegetation. In addition, the results showed an enrichment in SOCs and TNs of superficial horizons to the detriment of the deep horizons. Nevertheless, this decrease in organic stocks with depth occurred following different patterns according to soil type. In fact, the Cambisol reported an important depletion of soil organic stocks as compared to the Luvisol. The loss of SOCs and TNs were estimated to be 69.71% and 54.17% in surface horizon, and 41.94 % and 28.28 % in deep horizon, respectively. Indeed, the land-use change increases the decomposition of soil organic matter principal source of SOCs and TNs. Such a reduction has wider implications on global warming and soil fertility.

Boron is essential for crop growth. However, it is needed in very small amounts. The range between boron deficiency and toxicity in plants is quite narrow. These stressing conditions gravely reduce the yield and the quality of many crop species. Therefore, an understanding of the factors and the reactions affecting its availability in soil is necessary. Against this framework, our research aims to determine the available boron status in a semiarid soil of Dour Ismail irrigated perimeter (North Tunisia). The objective was also to investigate B distribution in different particle size fractions throughout the soil profile. For this purpose, one pit was dug in the field plot that had not received any B fertilization. Our results showed that the highest boron amounts were recorded in deep horizons and were greatly affected by organic matters and clay contents. However, the increase in pH level and the high percentage of TCaCO3 significantly diminished the available B contents mainly in surface horizons. The investigation of the depth boron distribution in the different particle-size fractions indicated a considerable contribution of the silt (2–50 µm) fraction (52% of the soil total available B) while the clay (<2 µm) and coarse (>50 µm) fractions seem to play a less important role.

Boron is essential for crop growth but needed in very small amounts. The range between boron deficiency and toxicity for plants is quite narrow. These stress conditions gravely reduce yield and quality of many crop species. Therefore, understanding the factors and the reactions affecting boron availability in soil is necessary. Against this framework, our research aims to determine the available boron status in a semiarid soil of Dour Ismail irrigated perimeter (North Tunisia). The objectives are also to investigate boron distribution in different particle-size fractions throughout the soil profile and to understand boron adsorption-desorption mechanisms according to some soil properties. For this purpose, one soil profile was dug in the field plot that had not received any previous boron fertilization. Soil samples were gathered from the different horizons of the profile and analyzed for the main physicochemical properties. Our results showed that the studied soil is Stagnic Fluvisol (clayic). The highest boron amounts were recorded in deep horizons and were greatly affected by soil salinity, organic matter, and clay contents. However, the increase in the pH level and the high percentage of total lime significantly diminished the available boron amounts in surface layers. The investigation of depth boron distribution in the different particle-size fractions indicated a considerable contribution of the silt (2–50 µm) fraction (52% of the soil total available boron), while the coarse (>50 µm) and clay (<2 µm) fractions seem to play a less important role. The adsorption data were fitted to Freundlich adsorption isotherm. It revealed that adsorption of boron increased with the increase of boron concentrations in soil solution. Desorption isotherm denotes that the accumulated boron in soil was not easily released. Adsorption and desorption of boron in soil were greatly affected by soil properties, such as pH, salinity, sand content, clay content, total organic carbon, total nitrogen, and cation exchange capacity.

Boron (B) is one of the seven essential micronutrients required for the normal crop growth and yield of most plants (Ali et al. in Am J Plant Sci 6:1391–1400, 2015).

Boron is an important micronutrient required for the growth of various types of plants. Both a deficiency in boron and its toxicity may lead to marked yield reduction and quality loss of many crop species. The range between these extremes is quite narrow. Therefore, the management of boron in soil has become a worldwide agricultural problem in the recent years. Facing this situation, the present research was undertaken in order to better understand boron distribution effect on sugar beet crop yield in two soils of Dour Ismail irrigated perimeter (North Tunisia). Two pits P1 and P2 were dug in field plots that had not received any boron fertilization. We followed the dynamic of the available boron and its depth distribution according to the three sugar beet cycle stages. Soil samples were taken from different horizons of the profile and analyzed for the main physicochemical properties. Both studied soils are Stagnic Fluvisols (Clayic) and the water used for irrigation comes from Oued Medjerda River. Our results showed that the highest boron values were recorded in surface horizons of the two studied soils. These amounts decreased with depth following different patterns according to the sugar beet cycle stages. The boron vertical distribution was similar to the total organic carbon and clay contents but was greatly affected by some soil properties such as pH, carbonate calcium content, and salinity. Sugar beet yield in P2 (100 t ha−1) was less than that of P1 (114 t ha−1) indicating a problem of boron availability.