Soil Salinity Research Articles

Long‐term freezing saline water irrigation and cotton cultivation improved soil properties and maintained low salinity in the root zone of coastal saline soil

AbstractFreezing saline water irrigation in winter has been shown to be an effective method for improving heavy saline–alkali soil via the use of local high‐salinity water. However, the long‐term effects of freezing saline water irrigation on the soil physicochemical properties in the root zone are still unclear. In this study, the dynamics of soil water, electrical conductivity (ECe) and the sodium adsorption ratio (SARe), and changes in relevant soil physicochemical characteristics were investigated on the basis of 11 consecutive years of freezing saline water irrigation and cotton cultivation (FSICC). Although FSICC significantly increased water consumption (ca. 465.92 mm) compared with that of the CK (ca. 133.38 mm), a significantly lower soil ECe in the root zone was still obtained under FSICC than under CK. An annual decrease in soil ECe and an increase in seed cotton yield were observed during the initial 4 years of the FSICC. Thereafter, the soil ECe and SARe in the 0–20 cm layer were stably maintained below 6.1 dS m−1 and 12.9 (mmol L−1)0.5, respectively, and a stable seed cotton yield of 3.92 t ha−1 was obtained. Compared with those of the CK treatment, the long‐term FSICC increased the saturated hydraulic conductivity, water retention, soil organic matter and water‐stable aggregates in the 0–20 cm layer, which further increased the available water content and total pore volume (>0.2 μm). These results indicated that the long‐term FSICC significantly improved the soil physicochemical properties and maintained lower levels of soil salinity and SARe in the root zone, although it significantly increased water consumption.

Improving Sunflower Yield through Liming and Phosphorus Fertilizer Application in the South-Central Coastal Region of Bangladesh

Along with salinity, low soil pH is the major constraint for growing winter crops in the south central coastal region of Bangladesh. Extensive research has been done to manage soil salinity, where managing low soil pH for crop production is scarce. The aim of the experiment was to improve sunflower (Helianthus annuus L. cv. Hybrid Unisun) yield through liming and phosphorus fertilizer application in the acidic saline soil of Amtali upazila of Barguna district, Bangladesh. During the winter season of 2024 a field experiment was carried out comprising two rates of lime 0 and 2 t ha-1 and four levels of phosphorus (P) having 0, 12, 24 and 36 kg P ha-1 using RCBD design. Lime application at 2 t ha-1 rate significantly increased stem girth, head diameter, number of seeds per head, 1000-seed weight, and seed, stover and root yields of sunflower. The application of P up to the highest level (36 kg P ha-1) significantly increased the growth and yield of sunflower. Lime application increased the soil pH by 0.72 unit compared to non-liming plot. The application of lime (2 t ha-1) along with 36 kg P ha-1 recorded the highest sunflower seed yield of 3.21 t ha-1 in the soil of Amtali upazila of Barguna district, Bangladesh. The benefit cost ratio (BCR) of different rates of P application without liming ranged from 5.28-10.09 but it decreased drastically while P was applied with lime having the BCR between 0.15-1.82. J Bangladesh Agril Univ 22(3):352-359, 2024

Shifts in light availability driven by dieback across a marsh‐forest gradient

AbstractEcological zonation in coastal forests is driven by sea level rise and storm‐surge events. Mature trees that can survive moderately saline conditions show signs of stress when soil salinity increases above its tolerance levels. As leaf burn, foliar damage, and defoliation reduce tree canopy cover, light gaps form within the crown. At the forest‐marsh edge, canopy cover loss is most severe; trunks of dead trees without canopies form “ghost forests.” Canopy thinning and light from the edge alter conditions for understory vegetation, promoting the growth of shrubs and facilitating establishment and spread of invasive species that were previously limited by light competition. In this research, we present an analysis of illuminance and temperature in a coastal forest transitioning to a salt marsh. Light sensors above the ground surface were used to measure light attenuation of trees and understory vegetation and to observe the effect of reduced canopies at the forest‐marsh edge. Farther from the marsh, where salinity is lower and trees are healthy, dense canopies attenuate light. We estimate that during the growing season, tree canopies intercept 50% of illuminance on average. Closer to the marsh, canopy thinning, and tree death allow greater light penetration from above, as well as from the adjacent marsh. These illuminance values are further increased by light penetration from the forest‐marsh edge (edge effect). Here, higher illuminance may permit Phragmites australis expansion. At intermediate locations, trees intercept between 32% and 49% of light and the understory shrub Morella cerifera intercepts a further 45% of penetrating light based on comparisons of illuminance above and below shrub canopies. Light penetration from the edge can also be felt. The presence of M. cerifera reduces the air temperature close to the soil surface, creating a cooler summer microclimate. The tree health state is reflected in the canopy size. The canopy patterns and the edge effect are responsible for light availability distribution along forest‐marsh gradients, consequently affecting the understory vegetation biomass. We conclude that during forest retreat driven by sea level rise, tree dieback increases light availability favoring the temporary encroachment of Ph. australis and M. cerifera in the understory.

Study of the Physicochemical Properties of <i>Streptomyces</i> Cell Surface and their Relationship with Soil Salinity of Origin

Study of the Physicochemical Properties of <i>Streptomyces</i> Cell Surface and their Relationship with Soil Salinity of Origin

Spatial distribution of soil salinization under the influence of human activities in arid areas, China

Spatial distribution of soil salinization under the influence of human activities in arid areas, China

ENGINEERING-GEOLOGICAL ZONING OF THE FOUNDATION PROJECT ON SALINE SOILS OF KANLIKUL DISTRICT

The article is devoted to the engineering-geological zoning of the foundation project on the saline soils of the Kanlikul district. The features of the region's geological and hydrogeological conditions, as well as the influence of soil salinity on the stability and durability of building structures, are considered. The methods of engineering-geological zoning used to assess the suitability of soils for construction are described. The article proposes solutions for designing foundations taking into account the specifics of saline soils, as well as measures to reduce the negative impact of salinization on construction sites. The work is aimed at improving design and construction practices in the region's complex geological conditions.

Sustaining Soil Health in High Tunnels: A Paradigm Shift toward Soil-centered Management

This review was conducted to synthesize current knowledge, learn producer and Extension specialist perspectives, and identify gaps in understanding of the role of soil health in sustaining production in high tunnel (HT) systems. This synthesis includes findings from scholarly resources related to soil health in HTs, including research and Extension-based literature, perspectives from experienced HT producers and technical assistance providers, and the direct observations of a broad network of university research and Extension personnel working with HTs. Findings are intended to identify knowledge gaps and additional research and Extension resource needs of greatest priority to the HT producer community and technical assistance providers that support them at the time of publication. A review of 68 research articles and 58 Extension resources was conducted. Focus group interviews were conducted with small groups of experienced HT farmers in four regions of the eastern half of the United States, with in-depth farm case studies conducted in individual farmers in three of these regions. Growers across regions identified soil fertility management, soilborne diseases, soil compaction, and lack of consistency of soil analyses specific to HTs as the greatest soil-related challenges to HT production. Research and resources for technical assistance providers on mitigation strategies to remediate yield-limiting HT soil conditions, such as excessive soil salinity and high pathogen populations, were also lacking. As such, process-based research on techniques such as leaching, soil steaming, solarization, and anaerobic soil disinfestation in tunnels that consider short- and long-term costs, benefits, and effects on soil and plant productivity should be prioritized in the future when considering the impact of HT production on soil health. Interviews also indicated a need for networking opportunities for technical assistance providers across agencies (e.g., Natural Resources Conservation Service, Extension, nongovernmental organizations). Despite a high and increasing rate of adoption, there is currently a lack of information about maintaining HT systems. Given that HTs play a critical and growing economic role for specialty crop growers throughout the eastern United States, comprehensive intervention across the research–Extension spectrum to sustain productivity in HT systems is recommended.

Impact of shifting from rice to shrimp farming on migration aspirations in Bangladesh

AbstractThe Ganges–Brahmaputra–Meghna delta is one of the most populous deltas in the world, threatened by diverse environmental stressors, including salinity intrusion, causing adverse consequences on livelihood adaptation. Shrimp farming has been recognized as one of the most practiced livelihoods among various livelihood opportunities. Growing global demand and higher economic returns encouraged many farmers to convert their agricultural land to shrimp farms by intruding saline water into the farmlands to produce shrimps. In this study, we investigated whether the growing trend of shrimp farming influences the migration aspirations of the vulnerable coastal communities in Bangladesh. The study employed qualitative interviews with individuals in four villages in southwest coastal Bangladesh. Satellite images were analyzed to detect land-use changes and changes in soil salinity in the last 28 years, confirming a rapid increase in shrimp farms. Results from the qualitative interviews indicate that poor people with limited resources cannot produce paddy on their land because of increased soil salinity caused by shrimp farming. Such a situation leads them to aspire to migrate. Thus, our analysis contributes to the discourse on “aspiration and capability” in environmental migration by adding the impacts of land-use changes on livelihoods.

Влияние абиотических факторов на продуктивность тростника Phragmites australis в озёрах юга Западной Сибири

The article presents the results of studying phytomass, stem height and density of thickets (herbage) of Phragmites australis, one of the most common aerial-aquatic plant in the south of Western Siberia. This region is distinguished by a rare combination of chloride, sulfate and soda lakes in a relatively small space. As an eurybiont, reed is highly resistant to water and soil salinity, but high salinity adversely affects its growth and development. The aim of the work was to assess the degree of abiotic factors (pH, mineralization) effect on the quantitative characteristics of reed growing in water bodies with different water mineralization: from 0.005 to 387.6 g/L. In total, we studied 59 freshwater, brackish-water (oligo-, meso- and polyhaline) and hypersaline water bodies, located in various natural zones (southern taiga, forest, forest-steppe, steppe and dry-steppe) in the south of Western Siberia. The studies were carried out in late July – early August from 2012 to 2020 during the period of maximum vegetation of plants. As a result of the studies, it is shown that the optimal for reed growth and development is water mineralization from 0.5 to 5.0 g/L, when the highest values of biomass and plant height are observed. A model based on redundancy analysis (RDA) was built and a correlation analysis was carried out to assess the dependence of phytomass, shoot height and herbage density on abiotic factors. We took into account pH, salinity, and Ca2+, Na+, Mg2+, K+, HCO3-, Cl- and SO42- content. We found that pH and determined by Ca2+ water hardness are the limiting factors in freshwater lakes. In brackish-water meso- and polyhaline, as well as in saline hyperhaline water bodies reed phytomass is affected by a whole range of factors, while shoot height is affected by pH, chlorides, and water hardness, and grass stand density is affected by chlorides and sulfates.

Variation of Elemental Composition of Leaves in Nitraria schoberi L. and N. sibirica Pall. Depending on Edaphic Growth Conditions

A study was conducted about the variation of levels of macro- and microelements in the soil and leaves of two species of the genus Nitraria L. in various habitats in Siberia. New data were obtained on the concentration variations of K, Na, Ca, Mg, Fe, Mn, Zn, Cu, Ni, Li, Sr, and Cd in leaves of N. schoberi L. and N. sibirica Pall. It was found that the salinity of habitats of N. sibirica (up to 3.23%) can exceed salinity of soils under N. schoberi (up to 0.5%) by more than sixfold. Soils of N. schoberi habitats are characterized by lower contents of carbonates (1.0–3.8%) and of physical clay (2–19%) as compared to soils of N. sibirica habitats: 1.2–18.2 and 9–40%, respectively. An increase in the physical-clay content of soil positively correlated with the accumulation of Mg, Cu (p ≤ 0.01), and Mn (p ≤ 0.001) in the plant leaves. The degree of soil salinity was positively associated with the accumulation of Ca, Zn, Sr (p ≤ 0.01), Mg (p ≤ 0.05), and Cd (p ≤ 0.001) in the leaves. An increase in concentration of mobile Na in soil positively correlated with concentrations of Ca, Cu (p ≤ 0.01), and Zn (p ≤ 0.001) in the leaves. In N. sibirica leaves, the concentration of K, Ca, Mg, Fe, Sr, Mn, Zn, and Cu was 1.5–3 times higher than that in N. schoberi leaves. Both species are capable of accumulating very high concentrations of Na (N. schoberi: up to 83.8 g/kg and N. sibirica: up to 77.2 g/kg). In the leaves of N. schoberi plants of immature age, K and Na levels were seven times higher than those in leaves of adult generative plants, whereas Mg and Ca levels were 3–5 times higher. This study should expand the understanding of mechanisms of Nitraria species’ adaptation to high-salinity conditions.

Performance of Soil Moisture Sensors at Different Salinity Levels: Comparative Analysis and Calibration.

Soil dielectric sensors have been widely used to obtain real-time soil moisture data, which are important for water resource management. However, soluble salts in the soil significantly affect the accuracy of these sensor measurements. Therefore, it is crucial to select suitable soil dielectric sensors for soil moisture measurements at different salinity levels. Eight mainstream sensors (EC-5, 5TE, Teros12, Hydra-probe II, TDR315L, TDR315H, TDR305H, and CS655) were selected and tested at four different soil salinity levels (EC1:5 = 3.0, 1.5, 1.0, and 0.75 dS·m-1). The measured values using the factory calibration formulas were compared at six soil moisture levels. The results showed that the measured soil moisture values from various sensors exhibited varying degrees of overestimation, which increased with increasing salinity. Only EC-5 did not exhibit distortion at high-salinity levels, with the measured values showing a good linear trend compared to the standard values. Mutational distortion of the measured apparent dielectric permittivity occurred in TDR315L, TDR315H, Hydra-probe II, and 5TE at EC1:5 = 3.0 dS·m-1. Insensitive distortion of the measured apparent dielectric permittivity occurred in Teros12 and TDR305H at EC1:5 = 3.0 dS·m-1 as well as in Teros12, TDR305H, 5TE and Hydra-probe II at EC1:5 = 1.5 dS·m-1. All tested sensors performed reasonably well at EC1:5 ≤ 1.0 dS·m-1. Seven sensors (excluding CS655) were calibrated within the distortion threshold. The soil moisture accuracy using the calibrated formulas could reach ±0.02 cm3·cm-3. At EC1:5 ≤ 1.0 dS·m-1, most sensors in this study could be applied with the factory calibration formulas. TDR series, EC-5, 5TE and Teros12 were recommended after calibration for EC1:5 > 1.0 dS·m-1. For extremely high soil salinity levels, the TDR series and EC-5 may be the best choices.

Evaluating machine learning performance in predicting sodium adsorption ratio for sustainable soil-water management in the eastern Mediterranean

Soil salinization is a critical global issue for sustainable agriculture, impacting crop yields and posing a threat to achieving the Sustainable Development Goal (SDG) of ensuring food security. It is necessary to monitor it in detail and uncover its underlying factors at a regional scale. In this context, the present study aimed to evaluate soil health in the eastern Mediterranean region by using the Sodium Adsorption Ratio (SAR) as an indicator of soil salinity in three distinct soil horizons. The main objective of the research was to evaluate the performance of four machine learning (ML) models, including Random Forest (RF), Nu Support Vector Regression (NuSVR), Artificial Neural Network-Multi Layer Perceptron (ANN-MLP), and Gradient Boosting Regression (GBR), for accurate prediction of SAR following the Recursive Feature Elimination (RFE) as a feature selection method. Moreover, SHapely Additive exPlanations (SHAP) was applied as sensitivity analysis to identify the most influential covariates. Main findings of the research revealed that the average clay content in the surface horizon (H10-25cm) was 50.5% ± 10.4, which significantly increased to 57.5% ± 8.7 (p < 0.05). No significant mean differences were detected between the studied horizons for SAR and Na+. ML output revealed that NuSVR outperformed other algorithms in accurately predicting outcomes during both the training and testing stages. Moreover, Scenario 2 (SC2) with seven selected features from the RFE method facilitated highly accurate SAR predictions. Overall, the performance of ML models is ranked as NuSVR > GBR > ANN-MLP > RF. Lastly, SHAP sensitivity analysis identified CEC, Ca+2, Mg+2, and Na+ as the most influential variables for SAR prediction in both the training and testing stages. Hence, the research yielded valuable insights for efficient agricultural soil management at a regional level using state-of-the-art technology.

Effects of understory intercropping with salt-tolerant legumes on soil organic carbon pool in coastal saline-alkali land

Phytoremediation through understory intercropping with salt-tolerant legumes (forest-green manure composite patterns) efficiently and sustainably enhances saline-alkali soils, while significantly improving the stability of monoculture forest ecosystems and the efficacy of soil upgrades. However, exactly how forest-green manure patterns regulate the dynamics of the soil organic carbon (SOC) pool and related mechanisms remain unclear. For this study, a pure forest was used as the control, and three leguminous herbaceous plants (M. sativa, S. cannabina, and C. pallida) were intercropped under two forest stand types (T. hybrid ‘Zhongshanshan’ and C. illinoensis). The variable characteristics and control factors of SOC and its components under different patterns were elucidated by analyzing the soil physical and chemical properties, enzyme activities, and microbial communities. The results revealed that the composite pattern improved soil salinization and increased the activities of β-1,4-glucosidase, polyphenol oxidase, peroxidase (PER), invertase (INV), and urease, as well as the carbon pool management index and the proportion of active organic carbon. At the T. hybrid ‘Zhongshanshan’ experimental site, planting M. sativa effectively increased the total carbon (TC) content. The ammonium nitrogen, soil moisture content, total phosphorus, alkaline phosphatase, PER, and polyphenol oxidase were the primary driving factors that affected the SOC pool. At the C. illinoensis experimental site, S. cannabina planting was observed to increase the TC content, with the TC, exchangeable Na+, β-1,4-N-acetylglucosaminidase, and INV being the main driving factors that impacted the SOC pool. The composite pattern can indirectly influence the SOC pool by altering the soil properties to regulate the microbial community. Further, it was found that soil inorganic carbon (SIC) was the main contributor to increasing the soil carbon pool following the short-term planting of legumes; thus, there may have been a transfer process that occurred from the SOC to SIC. Our study suggests that the forest-green manure pattern has more positive effects on improving soil quality and the carbon pool in saline-alkali land.

Multi‐Scale Soil Salinization Dynamics From Global to Pore Scale: A Review

Multi‐Scale Soil Salinization Dynamics From Global to Pore Scale: A Review

Optimizing Soil Fertility through Machine Learning: Enhancing Agricultural Productivity and Sustainability

Nowadays, the sustainability of agriculture and food security have an increasing importance on soil fertility. Soil fertility is defined as the capacity of a land to grow crops and its potential crop productivity. However, factors such as increasing population, climate change, land use changes and environmental pollution threaten soil fertility. These threats can result in problems such as erosion, soil salinisation and organic matter depletion. Soil fertility is critical for the long-term health of agriculture and food security. Artificial intelligence techniques used to determine and manage soil fertility analyse the minerals present in the soil as well as other factors. These analyses assess the amount of minerals present in the soil, the availability of nutrients and important parameters such as pH. This information guides farmers in selecting the most appropriate crops. Furthermore, the integration of Internet of Things (IoT) technologies allows real-time monitoring of minerals and nutrients in the soil and optimising irrigation and fertilisation processes based on this data. These developments have the potential to improve soil fertility management and increase agricultural productivity.

About the Need to Study the Effect of Soil Salinity on Diseases

The article is devoted to the issues of diseases and their development characteristic of the conditions of saline lands, which have received little attention so far. Due to deficiencies in irrigated agriculture, salinization is increasing more and more. In some countries, the share of saline land is 32% - 78% of the total used land. As a result of some studies, it was found that in areas with a lot of saline land, there is a higher incidence of diseases of the digestive organs and even cancer. In Mingbuloq District, Namangan Region of Uzbekistan, there was a high incidence of “Certain disorders related to the immune mechanism of diseases of blood and blood-forming organs (including anemia)” in adolescents under 14 years of age. Almost 2 times more was found. Judging from statistical data, it is possible to note a high level of infant mortality in many countries with saline lands. These data indicate that the study of the effects of salt-flooded lands on diseases is the most urgent problem.

Integration Linkage Mapping and Comparative Transcriptome Analysis to Dissect the Genetic Basis of Rice Salt Tolerance Associated with the Germination Stage.

Soil salinity poses a serious threat to rice production. The salt tolerance of rice at the germination stage is one of the major determinants of stable stand establishment, which is very important for direct seeding in saline soil. The complexity and polygenic nature of salt tolerance have limited the efficiency of discovering and cloning key genes in rice. In this study, an RIL population with an ultra-high-density genetic map was employed to investigate the salt-tolerant genetic basis in rice, and a total of 20 QTLs were detected, including a major and stable QTL (qRCL3-1). Subsequently, salt-specific DEGs from a comparative transcriptome analysis were overlaid onto annotated genes located on a stable QTL interval, and eight putative candidate genes were further identified. Finally, from the sequence alignment and variant analysis, OsCam1-1 was confirmed to be the most promising candidate gene for regulating salinity tolerance in rice. This study provides important information for elucidating the genetic and molecular basis of rice salt tolerance at the germination stage, and the genes detected here will be useful for improvements in rice salt tolerance.

Differential physiological responses to salt stress in rice landraces in Thailand

Soil salinity is a limitation factor for rice cultivation in the north-eastern Thailand. Understanding the mechanisms of salt stress tolerance is critical for maintaining or improving crop yield under salt stress. Over the past ten years, many landrace rice varieties have been examined for genetic diversity. To utilize the richness of natural resources and to explore novel genetic resources for developing a new variety, evaluating local rice varieties for salinity is still needed. This study investigated the physiological and biochemical responses of 8 landrace rice varieties in comparison to ‘Pokkali’, the standard salt-tolerant rice genotype, to clarify the major salt tolerance mechanisms in the landraces found in Thailand. After being exposed to 120 mM NaCl for 7 days, ‘Pokkali’ expressed physiological parameters in response to salt stress which are indicative of salt tolerance ability including low growth reduction, low Na+/K+ ratio, low chlorophyll degradation and low membrane integrity. In contrast, the landrace varieties displayed varying patterns of response. No landrace variety showed an outstanding ion exclusion mechanism as ‘Pokkali’, as evidenced by the fact that all landrace varieties showed approximately two times higher Na+/K+ ratios than ‘Pokkali’. However, it was found that ‘Surin’ had a similar salt stress response to ‘Pokkali’ (low growth reduction, low chlorophyll degradation, low membrane integrity), except for the markedly increased proline and sugar accumulation, suggesting an osmotic adjustment mechanism. Therefore, this variety could be a potential genetic resource to be developed as a donor for the osmotic adjustment trait to improve salt-tolerant rice in the future.

Mulched drip irrigation: a promising practice for sustainable agriculture in China’s arid region

The long-term practice of mulched drip irrigation (MDI) has significantly advanced cotton production in China’s arid regions. In this study, we conducted an evaluation of the changes to key soil environmental factors within cotton fields under MDI, providing a holistic assessment of MDI sustainability. Specifically, long-term MDI demonstrated numerous benefits including improved soil salinity management, nutrient retention, soil structure, and microbial functions. Collectively, these changes contribute to enhanced overall soil quality. Our research also confirms MDI as an effective integrated water-saving technology approach. Affirming the sustainability of widespread MDI promotion, our findings firmly support its potential as a sustainable and viable solution for oasis agriculture in arid lands, conferring long-term benefits to agricultural production in these regions.

Delineation of fresh groundwater potentiality zones in saline coastal aquifers, Southwest Bangladesh using remote sensing and GIS approaches.

Bay of Bengal in southern Bangladesh is a major source of water from coastal aquifers, but prone to contamination by seawater intrusion,making climate-vulnerable populations and economies unfit for potable, agricultural water, adopting crops, etc. The study area located in Khulna district lies in the southwestern coast of the country is among the most vulnerable due to its salinity issues. Therefore, this study identified fresh groundwater potential zones in the southwestern coastal zones of the country suited for community usage helping coastal peoples meet their demands. This study focused on twelve thematic layers employing remote sensing and GIS with analytical hierarchy process. Here, groundwater salinity is 84% brackish to saline over 70% of the region [electric conductivity: 295-16,295 micro-Siemens/cm]. However, groundwater chloride in 88% signifies a slightly to medium salty zone. The annual average rainfall reduced surface water infiltration in 75% of the area with little to very slightly soil salinity. The fresh groundwater resource zone has classified based on its potentiality as: very high (0.52%)-for drinking, agricultural irrigation, or industrial work; high (25%)-marginal salinity suitable for agricultural or industrial uses; low (11%)-low salinity, but usable for high salt tolerant crops in irrigation; and very low (64%)-very high groundwater salinity, and not suitable for human consumption and community uses. Finally, this study will help develop sustainable groundwater resources in the coastal region and a fresh groundwater supply plan in saline-prone areas.