Showing papers on "Soil salinity published in 2023"

Canopy temperature: as an indicator of soil salinity (a case study in Syrdarya province, Uzbekistan)

Abstract: A shift in the temperature of the canopy may signify stress in the plants. In laboratory and greenhouse trials, using canopy temperature for the measurement salt stress in certain agricultural crops was thoroughly examined; however, its potential application in landscape-level investigations employing remote sensing methods has not yet been investigated at different time series. A satellite thermography for measuring the soil salinity of agricultural areas at the provincial level was the subject of our investigation. The research area was the irrigated, semi-arid, and salt-affected agricultural land appertain to Syrdarya province in Uzbekistan, which was mostly planted with wheat and cotton. The provincial soil salinity map was considered as a ground truth data and the moderate-resolution imaging spectroradiometer satellite (MODIS) data were perceived as an indication for canopy temperature in this study. We investigated the relationships between the soil salinity, the normalized difference vegetation index, and canopy temperature, using analysis of variance. The findings indicated a strong inverse correlation between canopy temperature and soil salinity, although this relationship changed throughout the experimental years. For cotton, the highest correlation was shown in September. In comparison to the other variables looked at, canopy temperature had higher computed F values. Our findings indicate that soil salinity may be detected at the landscape level using satellite thermography in regions where crops are being grown.

Response of Contrasting Rice Genotypes to Zinc Sources under Saline Conditions

Abstract: Abiotic stresses are among the major limiting factors for plant growth and crop productivity. Among these, salinity is one of the major risk factors for plant growth and development in arid to semi-arid regions. Cultivation of salt tolerant crop genotypes is one of the imperative approaches to meet the food demand for increasing population. The current experiment was carried out to access the performance of different rice genotypes under salinity stress and Zinc (Zn) sources. Four rice genotypes were grown in a pot experiment and were exposed to salinity stress (7 dS m−1), and Zn (15 mg kg−1 soil) was applied from two sources, ZnSO4 and Zn-EDTA. A control of both salinity and Zn was kept for comparison. Results showed that based on the biomass accumulation and K+/Na+ ratio, KSK-133 and BAS-198 emerged as salt tolerant and salt sensitive, respectively. Similarly, based on the Zn concentration, BAS-2000 was reported as Zn-in-efficient while IR-6 was a Zn-efficient genotype. Our results also revealed that plant growth, relative water content (RWC), physiological attributes including chlorophyll contents, ionic concentrations in straw and grains of all rice genotypes were decreased under salinity stress. However, salt tolerant and Zn-in-efficient rice genotypes showed significantly higher shoot K+ and Zn concentrations under saline conditions. Zinc application significantly alleviates the harmful effects of salinity by improving morpho-physiological attributes and enhancing antioxidant enzyme activities, and the uptake of K and Zn. The beneficial effect of Zn was more pronounced in salt-tolerant and Zn in-efficient rice genotypes as compared with salt-sensitive and Zn-efficient genotypes. In sum, our results confirmed that Zn application increased overall plant’s performance under saline conditions, particularly in Zn in-efficient and tolerant genotypes as compared with salt-sensitive and Zn efficient rice genotypes.

Crop root system plasticity for improved yields in saline soils

Abstract: Crop yields must increase to meet the demands of a growing world population. Soil salinization is increasing due to the impacts of climate change, reducing the area of arable land for crop production. Plant root systems are plastic, and their architecture can be modulated to (1) acquire nutrients and water for growth, and (2) respond to hostile soil environments. Saline soils inhibit primary root growth and alter root system architecture (RSA) of crop plants. In this review, we explore how crop root systems respond and adapt to salinity, focusing predominately on the staple cereal crops wheat, maize, rice, and barley, that all play a major role in global food security. Cereal crops are classified as glycophytes (salt-sensitive) however salt-tolerance can differ both between species and within a species. In the past, due to the inherent difficulties associated with visualising and measuring root traits, crop breeding strategies have tended to focus on optimising shoot traits. High-resolution phenotyping techniques now make it possible to visualise and measure root traits in soil systems. A steep, deep and cheap root ideotype has been proposed for water and nitrogen capture. Changes in RSA can be an adaptive strategy to avoid saline soils whilst optimising nutrient and water acquisition. In this review we propose a new model for designing crops with a salt-tolerant root ideotype. The proposed root ideotype would exhibit root plasticity to adapt to saline soils, root anatomical changes to conserve energy and restrict sodium (Na+) uptake, and transport mechanisms to reduce the amount of Na+ transported to leaves. In the future, combining high-resolution root phenotyping with advances in crop genetics will allow us to uncover root traits in complex crop species such as wheat, that can be incorporated into crop breeding programs for yield stability in saline soils.

Strigolactone-Mediated Mitigation of Negative Effects of Salinity Stress in Solanum lycopersicum through Reducing the Oxidative Damage

Abstract: Soil salinity is one of the main barriers to increasing global food production as it reduces crop growth and productivity. While irrigated lands in arid climates (about 20% of total affected) are more prone to salinization, many other natural and anthropogenic factors contribute to an increase in salinity in arable lands that currently affects over 100 countries and more than one billion ha. Management of agro-ecosystems at every level, including soil, water, and the plant itself, is important in mitigating the effects of salinity. Plant hormones control cellular metabolism, and mediate plant defense response mechanisms against abiotic and biotic stresses. Foliar fertigation with plant growth regulators has been shown to improve growth and metabolism under stress conditions. Strigolactones (SLs) have emerged as a group of novel phytohormones with several functions in plant interactions with microorganisms, plant metabolism, development, and in responding to many environmental cues. The present research addressed SL (GR24) effects on growth, photosynthetic parameters, and oxidative stress in Solanum lycopersicum under salinity stress. Growth indices, photosynthesis and related attributes, antioxidant enzyme activity, and malondialdehyde (a product of lipid peroxidation) and hydrogen peroxide concentrations were compared in unstressed and salt-stressed (NaCl; 150 mM) S. lycopersicum seedlings untreated or treated with GR24 (2 µM). Improved antioxidant enzyme activity, proline (8%) and protein (14%) contents, and photosynthetic (33%) and transpiration (34%) parameters under GR24 treatment result in a significant increase in plant growth parameters, viz., shoot length (29%), root length (21%), shoot fresh weight (31%), root fresh weight (23%), shoot dry weight (26%), and root dry weight (19%). Increased chlorophyll index (14%) and stomatal conductance (16%) in GR24-applied plants under salinity stress results in improved growth and photosynthetic efficiency of S. lycopersicum. Our results add to the existing knowledge of the relatively new function of SLs in mitigating abiotic stress, particularly that of salinity stress in crop plants.

Turfgrass Salinity Stress and Tolerance—A Review

Abstract: Turfgrasses are ground cover plants with intensive fibrous roots to encounter different edaphic stresses. The major edaphic stressors of turfgrasses often include soil salinity, drought, flooding, acidity, soil compaction by heavy traffic, unbalanced soil nutrients, heavy metals, and soil pollutants, as well as many other unfavorable soil conditions. The stressors are the results of either naturally occurring soil limitations or anthropogenic activities. Under any of these stressful conditions, turfgrass quality will be reduced along with the loss of economic values and ability to perform its recreational and functional purposes. Amongst edaphic stresses, soil salinity is one of the major stressors as it is highly connected with drought and heat stresses of turfgrasses. Four major salinity sources are naturally occurring in soils: recycled water as the irrigation, regular fertilization, and air-borne saline particle depositions. Although there are only a few dozen grass species from the Poaceae family used as turfgrasses, these turfgrasses vary from salinity-intolerant to halophytes interspecifically and intraspecifically. Enhancement of turfgrass salinity tolerance has been a very active research and practical area as well in the past several decades. This review attempts to target new developments of turfgrasses in those soil salinity stresses mentioned above and provides insight for more promising turfgrasses in the future with improved salinity tolerances to meet future turfgrass requirements.

Monitoring Soil Salinity Using Machine Learning and the Polarimetric Scattering Features of PALSAR-2 Data

Abstract: Soil salinization is one of the major problems affecting arid regions, restricting the sustainable development of agriculture and ecological protection in the Kriya Oasis in Xinjiang, China. This study aims to capture the distribution of soil salinity with polarimetric parameters and various classification methods based on the Advanced Land Observing Satellite-2(ALOS-2) with the Phased Array Type L-Band Synthetic Aperture Radar-2 (PALSAR-2) and Landsat-8 OLI (OLI) images of the Keriya Oasis. Eleven polarization target decomposition methods were employed to extract the polarimetric scattering features. Furthermore, the features with the highest signal-to-noise ratio value were used and combined with the OLI optimal components to form a comprehensive dataset named OLI + PALSAR2. Next, two machine learning algorithms, Support Vector Machine (SVM) and Random Forest, were applied to classify the surface characteristics. The results showed that better outcomes were achieved with the SVM classifier for OLI + PALSAR2 data, with the overall accuracy, Kappa coefficient, and F1 scores being 91.57%, 0.89, and 0.94, respectively. The results indicate the potential of using PALSAR-2 data coupled with the classification in machine learning to monitor different degrees of soil salinity in the Keriya Oasis.

Seed Priming and Foliar Application with Ascorbic Acid and Salicylic Acid Mitigate Salt Stress in Wheat

Abstract: Ascorbic acid (AA) and salicylic acid (SA) are naturally active antioxidants that protect against plant stresses, including salinity. We studied the physiological response of wheat to AA and SA (100, 200 ppm) as well as the combined treatment of AA and SA (100 ppm) through application as both priming and foliar spray treatments under saline conditions. The results showed that wheat plants under salt-affected soils exhibited numerous physiological effects in plant metabolism, which subsequently affected the qualitative and quantitative parameters of growth and yield. Moreover, the photosynthetic pigments, antioxidant content, and yield are significantly enhanced under the combined treatment of AA and SA. In contrast, the application of AA and SA lowered the osmolytes and lipid peroxidation content under saline conditions. Accordingly, the enhancement of the mentioned parameter was related to the scavenging of the reactive oxygen species and decreasing the oxidative stress on the plant under the salinity stress. Our results explore the significance of applied AA and SA as efficacious compounds in wheat farming under saline conditions. The combined application of (100 ppm) AA with (100 ppm) SA using priming or a foliar spray can be a promising treatment for beneficent wheat growth and productivity improvement under salt-affected soil conditions.

Evaluation analysis of the saturated paste method for determining typical coastal saline soil salinity

Abstract: The electrical conductivity of saturated paste extracts (EC e ) is more widely used as the laboratory method for estimating soil salinity compared to the soil-water ratio method. However, the current saturated paste process is time consuming and mainly based on subjective experience, and the quantitative relationships among the factors influencing the saturated paste process are not clear. In order to understand and optimize the process of soil salinity determination by saturated paste method, an experiment involving the process of making saturated paste and the key factors in salt determination was carried out on coastal saline silt and sandy loam soils: amount of water added, soaking time, number of centrifugations, and soil particle size. These test factors had clear impact on soil salinity results (both EC e and mass salt content) and pH. Based on the principle of obtaining more mass salt content in this study, suitable parameters for the production of saturated slurries were proposed as follows: (1) the amount of distilled water added to the soil sample should be 2.2 times the saturated water content of the soil; (2) the equilibration time of saturated paste was reduced from 18 to 12 h; (3) only 40 % of the full salt content was obtained by one centrifugation and obtaining 80 % requires three centrifugations; and (4) 0.25–0.50 and 1–2 mm of particle-size sieving should be used to prepare samples of silt and sandy loam soils, respectively. • Suitable parameters for the laboratory production of saturated paste are proposed and a standard production process for SP is established. • The quantitative relationship between the various factors of the saturated paste production process is clarified. • The study provides a more in-depth discussion of the process of determining the salinity of saturated paste, which helps to monitor soil salinity.

Effect of Biochar Application on Soil Fertility, Nitrogen Use Efficiency and Balance in Coastal Salt-Affected Soil under Barley–Maize Rotation

Abstract: Coastal lands are often affected by salinization, which leads to a deterioration of soil structure and a decrease in land productivity. As a widely used soil amendment, biochar has been proven to improve poor soil properties and promote crop growth and N adsorption and utilization. However, the effects of biochar on soil fertility, N use efficiency (NUE) and balance in coastal salt-affected soil have rarely been reported. Therefore, we conducted a field micro-plot experiment to study the improvement effects of different biochar rates (0, 13.5, 20.25 and 27 t/ha, corresponding to CK, B1, B2 and B3 treatments, respectively) on coastal salt-affected soil. The results showed that biochar application increased soil water content (SWC) in seasons with abundant rainfall but decreased SWC in seasons with strong evaporation, and the increase or decrease in SWC was greater with the increase in biochar rates. Biochar application increased soil salinity and decreased soil pH, although high rates of biochar increased soil salinity to a lesser extent, while low rates of biochar decreased soil pH most. Biochar application was able to reduce soil bulk density, while B1and B2 treatments decreased it to a higher degree. Moreover, biochar application increased soil macro-aggregates (>0.25 mm) and organic matter, while B2 and B3 treatments increased it to a higher degree. Biochar application improved soil fertility to an extent that crop grain increased yield by 2.84~19.88% in barley season and 12.27~16.74% in maize season. Meanwhile, biochar application also increased NUE because it promoted the increase of yield. In particular, the calculation of N balance between soil and plant systems suggested that biochar application could reduce the apparent N loss during crop planting, and B1 treatment was better at reducing apparent N loss. Overall, our study indicates that biochar application has great potential to improve poor physicochemical properties and N nutrient utilization in coastal salt-affected soil. More importantly, we suggest that biochar application rates should be controlled in coastal salt-affected soil.

Numerical and Experimental Study on Water-Heat-Salt Transport Patterns in Shallow Bare Soil with Varying Salt Contents under Evaporative Conditions: A Comparative Investigation

Abstract: Soil salinization is aggravated by evaporation, resulting in salt crystallizing on the soil surface. Soil salinization is harmful to agriculture and has significant implications for the engineering and construction industry. Therefore, this paper investigates water and salt transport in saline soils through comparison of numerical simulations with indoor evaporation tests. Based on Darcy's law, ideal gas law, mass conservation law, and energy conservation law, a one-dimensional transient mathematical model of coupled water-heat-salt transport is derived. The bottom of the model represents a recharge boundary condition, the sides of the soil column are insulated and impermeable, and the top serves as a heat source. The results show that the greater the salinity of the soil, the more drastic the temperature change, and at the same time, the greater the water retention of the soil. The temperature gradient along the height of the soil column provides a tremendous driving force for water-salt transport, and although the volumetric water content of the soil column at 3 ∼ 4 cm dissipates quickly, there is a gradient of increasing salt concentration towards the ends and decreasing towards the middle. The modeled results agree with the experimental data, indicating that the model can effectively simulate the water-heat-salt transport process for different saline sites under evaporation conditions. The model is essential for the improvement of saline soils and for finding new methods to prevent further soil salinization.

Saline Stress Impairs Lipid Storage Mobilization during Germination in Eruca sativa

Abstract: Soil salinization become worse in the last decades, leading to reduced crop yields, especially in the Mediterranean basin. Eruca sativa is a common species cultivated in this area with remarkable economic importance. This study aimed at investigating the effect of salinity on this plant, focusing on (i) seedling development in terms of variations in germination and growth parameters and (ii) anatomical and ultra-structural changes in the morphology of cotyledons. For this reason, seeds were treated with different salinity levels ranging from 137 to 548 mM NaCl. Seed germination was delayed by all the concentrations tested, but only above 137 mM seedling growth was impaired. Results showed a high occurrence of lipid bodies within the mesophyll cells of cotyledons of seedlings exposed to salt concentrations above 137 mM, suggesting an impairment in lipid mobilization caused by salinity during plant development. The cotyledons of treated seedlings showed reduced intercellular spaces and ultrastructural changes in chloroplasts and peroxisomes. Moreover, salt-induced autophagic processes were present in samples grown at the highest NaCl levels. Interestingly, at 137 mM NaCl, seedlings showed the highest values of mesophyll thickness and fresh weight, implying a possible mechanism of salt adaptation during germination.

Current Status and Development Trend of Soil Salinity Monitoring Research in China

Abstract: Soil salinization is a resource and ecological problem that currently exists on a large scale in all countries of the world. This problem is seriously restricting the development of agricultural production, the sustainable use of land resources, and the stability of the ecological environment. Salinized soils in China are characterized by extensive land area, complex saline species, and prominent salinization problems. Therefore, strengthening the management and utilization of salinized soils, monitoring and identifying accurate salinization information, and mastering the degree of regional salinization are important goals that researchers have been trying to explore and overcome. Based on a large amount of soil salinization research, this paper reviews the developmental history of saline soil management research in China, discusses the research progress of soil salinization monitoring, and summarizes the main modeling methods for remote sensing monitoring of saline soils. Additionally, this paper also proposes and analyzes the limitations of China’s soil salinity monitoring research and its future development trend, taking into account the real needs and frontier hotspots of the country in related research. This is of great practical significance to comprehensively grasp the current situation of salinization research, further clarify and sort out research ideas of salinization monitoring, enrich the remote sensing monitoring methods of saline soils, and solve practical problems of soil salinization in China.

Assessment and mechanism analysis of plant salt tolerance regulates soil moisture dynamics and controls root zone salinity and sodicity in seasonally irrigated agroecosystems

Abstract: Soil water deficit and saline-alkaline stress impose severe constrains to agriculture and vary across different salt-tolerant crops. Yet, the effects and mechanisms of plant salt tolerance on long-term soil water budget and future root zone (both primary and secondary) salinization and alkalization trends under changing environments in irrigated agroecosystems have not been fully understood, particularly driven by seasonal irrigation practices and stochastic climate conditions. Here, we introduce a robust species-dependent soil water, salinity, and sodicity coupled model that enables explicitly simulation to the feedback between evapotranspiration and salinity being shaped by plant salt tolerance and saturated hydraulic conductivity as affected by salinization and alkalization in seasonally irrigated agroecosystems. Using this model in conjunction with field comprehensive measurements from a typical arid inland river basin in Northwest China, we find that the species-dependent model performed well in simulating the root zone moisture (s), salinity (Cs) and sodicity (Ex) dynamics as driven by seasonal irrigation and random precipitation under different salt-tolerant crops, with average consistency measure (CM) reaching to 0.825 ± 0.017, 0.819 ± 0.027 and 0.728 ± 0.033, respectively. Stochastic simulations indicate that plant salt tolerance plays a predominant role in regulating the feedback of vegetation on soil water budget and root zone salinity and sodicity levels over time in seasonally irrigated agroecosystems. In contrast to salt-sensitive species, salt-tolerant plants seems to exhibit higher efficiency in water extraction from soil, with higher evapotranspiration rates, less frequent leaching events and greater capillary upflow fluxes, thereby lowering soil moisture and boosting salinization and alkalization in the root zone, particularly in arid climates. Sensitivity analysis revealed that plant salt tolerance, together with climatic forcing and anthropogenic perturbations, can significantly modulate the soil water balance and determine the possible trends of root zone salinization and alkalization in future, thus controlling potential risks of soil degradation related to reducing soil hydraulic conductivity Ks(Cs, Ex) in irrigated agroecosystems. Notably, since Ks(Cs, Ex) decreases with plant salt tolerance increases, salt-resilient species have the potential to exacerbate soil degradation. Our results emphasize the importance of comprehensively considering plant salt tolerance for assessing the sustainability of agricultural management practices and environmental protection measures, as well as proposing adaptive strategies under global changes.

Investigation of the spatial and temporal variation of soil salinity using Google Earth Engine: a case study at Werigan–Kuqa Oasis, West China

Abstract: Large-scale soil salinity surveys are time-costly and labor-intensive, and it is also more difficult to investigate historical salinity, while in arid and semi-arid regions, the investigation of the spatial and temporal characteristics of salinity can provide a scientific basis for the scientific prevention of salinity, With this objective, this study uses multi-source data combined with ensemble learning and Google Earth Engine to build a monitoring model to observe the evolution of salinization in the Werigan-Kuqa River Oasis from 1996 to 2021 and to analyze the driving factors. In this experiment, three ensemble learning models, Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Light Gradient Boosting Machine (LightGBM), were established using data collected in the field for different years and some environmental variables, After the accuracy validation of the model, XGBoost had the highest accuracy of salinity prediction in this study area, with RMSE of 17.62 dS m-1, R2 of 0.73 and RPIQ of 2.45 in the test set. In this experiment, after Spearman correlation analysis of soil Electrical Conductivity (EC) with environmental variables, we found that the near-infrared band in the original band, the DEM in the topographic factor, the vegetation index based on remote sensing, and the salinity index soil EC had a strong correlation. The spatial distribution of salinization is generally characterized by good in the west and north and severe in the east and south. Non-salinization, light salinization, and moderate salinization gradually expanded southward and eastward from the interior of the western oasis over 25 years. Severe and very severe salinization gradually shifted from the northern edge of the oasis to the eastern and southeastern desert areas during the 25 years. The saline soils with the highest salinity class were distributed in most of the desert areas in the eastern part of the Werigan-Kuqa Oasis study area as well as in smaller areas in the west in 1996, shrinking in size and characterized by a discontinuous distribution by 2021. In terms of area change, the non-salinized area increased from 198.25 in 1996 to 1682.47 km2 in 2021. The area of saline soil with the highest salinization level decreased from 5708.77 in 1996 to 2246.87 km2 in 2021. overall, the overall salinization of the Werigan-Kuqa Oasis improved.

Comparing the salinity tolerance of twenty different wheat genotypes on the basis of their physiological and biochemical parameters under NaCl stress

Abstract: The climate has drastically changed over the past two decades. Rising temperatures and climate change may lead to increased evapotranspiration, specifically soil evaporation, causing water to evaporate and salt to accumulate in the soil, resulting in increased soil salinity. As a result, there is a need to evaluate methods for predicting and monitoring the effects of salinity on crop growth and production through rapid screening. Our study was conducted on 20 wheat genotypes, 10 sensitive and 10 tolerant, exposed to two salinity levels (90 and 120 mM NaCl) with the control under greenhouse conditions. Our results revealed significant differences in the genotypes’ response to salinity. Salt stress decreased chlorophyll index in sensitive genotypes but increased chlorophyll a and carotenoids in tolerant genotypes at 90 mM. Salt stress also increased protein, proline, lipoxygenase, and reactive thiobarbituric acid levels in all wheat genotypes. The study suggests that plant photosynthetic efficiency is a reliable, non-destructive biomarker for determining the salt tolerance of wheat genotypes, while other biochemical traits are destructive and time-consuming and therefore not suitable for rapid screening.

Design and performance analysis of salinity gradient solar pond under different climatic and soil conditions

Abstract: A salinity gradient solar pond (SGSP) is capable of storing a significant quantity of heat for an extended period of time. It is a great option for providing hot water at a reduced energy cost. Additionally, SGSP is used in low-temperature industrial applications such as saltwater desalination, space heating, and power generation. Solar pond thermal performance is dependent on a variety of operational variables, including the soil conditions, the climate of the particular site, the thickness of the solar pond layers, the depth of the water table, and the salt content of the pond. As such, this study examines the thermal performance of a solar pond under a variety of operational conditions. The solar pond model is used to test the thermal performance by simulating two-dimensional heat and mass transport equations. The equations are solved using the finite difference technique utilizing MATLAB® scripts. Salt distributions and temperature profiles are computed for a variety of factors influencing SGSP’s thermal performance. The main distinguishing variables influencing the thermal performance of SGSP are soil conditions, such as soil texture, types, the moisture level in soil, and water table depth. The final findings indicated that the fine sand dry soil performed better than the other soil types owing to its poor heat conductivity. The economic results indicated that the period of return (POR) of the intended system is around 2 years. The solar pond construction costs such as excavation, transportation, salt and lining, were considered based on the local prices. This modeled study extracted the greatest possible energy is 110W/m2, with the fine sand dry at 62.48°C lowest temperature. This study suggested that the climatic conditions of Lahore is better than climatic conditions of Islamabad. Additionally, deeper water tables are suggested for improved thermal performance of the pond.