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Organic fertilization improves soil fertility and ameliorates the deleterious effects of accumulated salts in soil for sustainable agricultural production. This research was carried out on thirteen-year-old Mexican lime trees to study the effect of humic acid (HA), applied as soil (10, 20 or 30 mL·tree−1) and foliar (0.1 or 0.2%) applications, on soil fertility, tree growth, productivity and fruit quality. The experiment was conducted during the 2020 and 2021 seasons in a randomized complete block design of twelve treatments with three replicates with two trees each. Soil and foliar applications of HA were performed once and twice a month in Marsh, May and July, respectively. HA enhanced the soil's N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B availability and microbial activity, in addition to improved tree growth, canopy size, leaf chlorophyll and nutrient contents with reduced proline levels. The total yield and number of fruit per tree were increased with increased HA levels. Fruit weight, juice and soluble solids were also increased. The best results were achieved with the combined soil (30 mL·tree−1) and foliar (0.2%) applications of HA, which indicated a great potential to alleviate the effects of salinity stress on Mexican lime growth and productivity. [ABSTRACT FROM AUTHOR]

Despite studies focusing on soil substrates (carbon and nitrogen) and heavy metal availability, the impact of diversified parent materials in arid alkaline regions has received little attention. To reveal the influence of parent material, we investigated four different parent materials: fluvio-marine, Nile alluvial, lacustrine, and aeolian deposits. We assessed the effect of soil parent materials through selected soil physical and chemical properties, such as clay content, bulk density, pH, and available phosphorus (AP). The Tukey HSD test (SPSS ver. 23) was used to assess the soils derived from these different sediments. Using the R "glmulti" package, we examined this effect in a model of mixed-effects meta-regression. The sum of Akaike weights for models that contained each element was used to estimate the importance of each factor. The average contents of soil organic carbon (SOC) and total N in alluvial deposits were greater (p < 0.001) than those of marine, aeolian, and lacustrine deposits. A multivariate analysis in arid regions revealed that parent material, soil pH, and the availability of P had the greatest effects on SOC concentration, whereas clay content, available P, soil pH, parent material, and bulk density had the greatest effects on soil total nitrogen. The average content of Fe in the aeolian deposits was greater (p < 0.001) than those of marine, alluvial, and lacustrine deposits, without any significant differences between the latter two deposits. We found that the highest average contents of zinc (Zn), manganese (Mn), and copper (Cu) were recorded in alluvial deposits, with significant differences between other deposits. Soil parent material was the major factor impacting soil iron (Fe) content, along with clay content and soil pH. However, soil bulk density was the most important factor controlling soil Zn and Mn contents, while SOC drove Cu content. This study will help in developing a more accurate model of the dynamics of soil substrates and availability of heavy metals by considering readily available variables, such as parent materials, soil pH, soil bulk density, and clay content. [ABSTRACT FROM AUTHOR]

Soil degradation and low productivity are among the major agricultural problems facing farmers of the newly reclaimed agricultural area in the Nile Delta region, Egypt. High content of clay and silt characterizes the soil texture of all farms in the area, while farmers still rely on the traditional mole drainage (MD) system to reduce the salinity of the farm soil. We present a comparison of innovative geo-resistivity methods to evaluate mole drains and the salinity affected clay soils. Geoelectrical surveys were conducted on three newly reclaimed farms to image the subsurface soil drainage conditions and to evaluate the efficiency of using the traditional MD systems in these heavy clay environments. The surveys included measuring the natural spontaneous potential (SP), apparent resistivity gradient (RG), and electrical resistivity tomography (ERT). Integrating the results of the three methods reduced the ambiguous interpretation of the inverted ERT models and allowed us to determine the subsurface soil structure. The inverted ERT models were suitable for locating the buried MDs and delineating the upper surface of the undisturbed clay beds. The proximity of these layers to the topsoil reduces the role played by MDs in draining the soil in the first farm and prevents the growth of deep-rooted plants in the second farm. Time-lapse ERT measurements on the third farm revealed a defect in its drainage network where the slope of the clay beds opposes the main direction of the MDs. That has completely obstructed the drainage system of the farm and caused waterlogging. The presented geo-resistivity methods show that integrated models can be used to improve the assessment of in situ sub-surface drainage in clay-rich soils. [ABSTRACT FROM AUTHOR]

Artemisia sieberi Besser occurs in many parts of the Irano-Turanian floristic region, which is mostly distributed throughout the Iranian plateau, especially in Iran. This study aimed to identify the effect of the soil and topography variables on A. sieberi distribution. We used canopy cover data to fit models using generalized additive models (GAMs). The results showed that the response pattern of A. sieberi along with the gradient of soil clay, soil saturation moisture, soil nitrogen and soil acidity followed the monotonic increase model, and its canopy cover percentage augmented by increasing the values of the factors. Conversely, the A. sieberi canopy cover percentage decreased by increasing the amount of soil sand, bare soil and the geographic aspect. The A. sieberi responses are in contrast to the niche theory. The relationship between the species response pattern and the gradients of soil silt, soil salinity, lime percentage, organic carbon, altitude, land slope, litter, gravel percentage, stone percentage, mean annual precipitation and mean annual temperature followed a unimodal model (consistent with the niche theory). The optimal growth limits for these factors were 32%, 1.75 ds/m, 35%, 1.3%, 2000 m, 43%, 10%, 32%, 250 mm and 15 °C, respectively. Our results highlight that environmental factors, such as soil texture, amount of soil lime, mean annual precipitation, altitude and land slope, had quantifiable effects on the performance of A. sieberi. Our findings could provide useful information for improvement, restoration and conservation programs. However, a further comprehension of the species–environment relationship is needed to predict the effects of climate change on the species habitat. [ABSTRACT FROM AUTHOR]

Water scarcity is becoming a global problem. The shift from traditional irrigation systems to deficit irrigation increased soil salinity, particularly in clay soils. The use of magnetized water (MW) and biostimulants can induce plant resistance to drought and salinity stress. To assess the role of MW and proline (P) on 'Taifi' pomegranate shrubs' growth, productivity, and fruit quality under such conditions, a split-plots experiment was conducted for two seasons using three irrigation levels (100%, 75%, and 50%), based on the crop water requirements (CWR), and four treatments including foliar spray of tap water (control) and P, irrigation with MW, and MW + P. The most pronounced effect was referred to MW + P at 75% CWR that improved shrubs' chlorophyll content and nutritional status, reduced endogenous proline content, and enhanced vegetative growth with minimum consumptive water use (CWU), optimum water use efficiency (WUE), maximum water productivity (WP), utmost yield and average fruit weight, lowest percentage of fruit cracking, and fairly good total soluble solids (TSS), vitamin C and anthocyanin contents. Overall, MW + P at 75% CWR improved the resistance mechanism of pomegranate shrubs in saline clay soils, plus improving the growers' net profit. MW generally reduced soil salinity, expressed as reduced pH, EC, Na+, and Ca2+ values. [ABSTRACT FROM AUTHOR]

Designing advanced methods of corrosion protection and increasing the bearing capacity of pile foundations on saline clayey soils is a priority geotechnical task in Kazakhstan. The formation of a suffusion-resistant waterproof shell was achieved by silicatization of a borehole before concreting, by the installation of a mold into the borehole and the impregnation of a sodium silicate solution into the space between the mold and the soil under pressure. After coagulation of the silicate solution, the mold was removed and the formed shell was filled with corrosion-resistant concrete. Full-scale static pile load tests were conducted in the construction site "Retaining wall on Mount Koktobe" in Almaty. The bearing capacity of the piles with the protective silicate shell exceeded the bearing capacity of an ordinary pile by 2.5 times on average without wetting the site, and 3.2 times after prolonged wetting. The numerical model had a close relationship with the average experimental curve obtained when conducting six static pile load tests with the protective shell. A large economic effect of the developed piling technology with a protective shell was achieved, with a significant reduction in the cost of piling, equal to 27.85%. [ABSTRACT FROM AUTHOR]

The scarcity of water resources in arid and semi-arid areas is considered a threat to agricultural sustainability. Therefore, approaches are needed to rationalize use of irrigation water without reducing crop productivity or degrading soil properties. The objective of this study was to investigate the effect of different organic amendments (O1 = control, O2 = compost, and O3 = vermicompost) combined with different rates of nano- zinc foliar spraying (Zn1 = 0, Zn2 = 1 and Zn3 = 2 gm/L), under irrigation supplements (I1 = 100%, I2 = 85%, and I3 = 65% of water requirements) on clay soil characteristics, on the production of Egyptian barley Giza 126. Over two successive winter growing seasons, 2018/2019 and 2019/2020, field experiments were conducted as a split-split plot design with three replications. The results show that using vermicompost is an appropriate organic amendment to improve the physical and chemical properties of soils as compared with compost. Application of vermicompost led to a reduction in soil salinity (ECe), exchangeable sodium percentage (ESP), and soil bulk density (BD), of −5.67%, −5.44%, and −2.21%, respectively; there was a significant increase in soil organic carbon (SOC), available nitrogen (A.N), and field capacity (F.C.), of 43.75%, 14.37%, and 18.65%, respectively, compared with unamended soil (O1). The maximum values for grain yield were increased by 13.2% and 14.9% in both seasons, respectively, and the irrigation water productivity of barley was increased more than compost and control. Vermicompost increased the irrigation water productivity for grain (1.69 and 1.69 kg grain m−3) and straw (1.23 and 1.17 kg straw m−3) in the first and second season, respectively. Similar trends were also observed from treatments on the water applied, stored water, and water application efficiency. Application of vermicompost and nano-Zn foliar spraying could be exploited for the development of barley growth and yield, which are enhanced under water-saving irrigation strategies. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to study the spatial characteristics and possible influencing factors of farmland soil texture and salt content in the Syr Darya River Basin. Data on the soil grain size and salt content were collected at 56 sampling sites in the southern part of the Shardara Reservoir and the left bank of the Syr Darya River irrigation area. With the methods of local spatial statistics (Getis-Ord Gi* and Moran's I), the hotspots of soil salinity and grain size in the study area were revealed, and along with the use of correlation analysis, the possible factors affecting soil salt distribution were discussed. Among the 56 soil sampling sites, sandy loam, loamy loam, and chalky loam accounted for 20%, 50%, and 30%, respectively, and mildly, moderately, and severely saline soils accounted for 80.36%, 14.28%, and 5.36%, respectively. There was statistically significant spatial autocorrelation between sand, silt, and clay content in the soils, but the spatial autocorrelation for salt content was weak. The results show that high and high-cluster areas (hotspots) with statistically significant salt content are mainly distributed in the northwest of the study area and that the hotspot distribution of salt content is mainly affected by topography (altitude), but the effect of soil texture on salt content is not significant. The control of soil salinity should prioritize low-altitude areas, especially in the northwestern region. The results are of great significance for the regulation and control of soil salinity and the sustainable utilization of soil in arid Central Asia. [ABSTRACT FROM AUTHOR]

This paper presents the application of a frequency-domain reflectometry (FDR) sensor designed for soil salinity assessment of sandy mineral soils in a wide range of soil moisture and bulk electrical conductivity, through the determination of soil complex dielectric permittivity spectra in the frequency range 10-500 MHz. The real part of dielectric permittivity was assessed from the 380-440 MHz, while the bulk electrical conductivity was calculated from the 165-325 MHz range. The FDR technique allows determination of bulk electrical conductivity from the imaginary part of the complex dielectric permittivity, without disregarding the dielectric losses. The soil salinity status was determined using the salinity index, defined as a partial derivative of the soil bulk electrical conductivity with respect to the real part of the soil complex dielectric permittivity. The salinity index method enables determining the soil water electrical conductivity value. For the five sandy mineral soils that have been tested, the relationship between bulk electrical conductivity and the real part of dielectric permittivity is essentially linear. As a result, the salinity index method applied for FDR measurements may be adapted to field use after examination of loam and clayey soils. [ABSTRACT FROM AUTHOR]

One current challenge for agricultural production in water-limited environments is to develop agronomic management practices that can overcome soil constraints and provide an economic return to the grower in both the short and long-term. The degree of soil compaction is obtained by measuring soil strength using a soil penetrometer with soil having cone index readings of >1500 kPa having restricted root growth. The soil constraints acidity/aluminum (Al) toxicity, compaction, water repellency, salinity, and poor nutrition result in reduced crop grain yield in these environments. [Extracted from the article]

Simple Summary: In anthropogenic activities, flooded paddy field is one of those events that emits CH4 and that comes the necessity of leveling down CH4 production from soil so the study on mechanisms of CH4 production in paddy soil is vital. This study was conducted for an aim of investigating CH4 influential factors in wide range of soil texture in paddy soil in Thailand and interrogating a model for predicted CH4 production potential map. Our result showed that soil carbon and sandy soil are the important factors generating CH4 production. To be exact, soil carbon works as a provider that implements an energy to soil microorganism to anoxically produce CH4 and sandy soil, that carries less iron oxide, accelerates the CH4 production. In conclusion, CH4 production in paddy field under flooding period is triggered when large amount of soil carbon exists, and the reduction being processed quickly due to a smaller number of iron oxide in the soil, especially sandy soil. The knowledge of factors influencing CH4 production brings about a better crop and water management. Further than that, predicted map of CH4 production potential can be utilized to identify whereabout of highly emitted CH4 production potential, which attention should be paid. It is well known that submerged soils emit high levels of methane (CH4) due to oxygen deprivation and free iron oxide causing a quick reduction. However, there are other soil properties that control the reduction processes in soil, especially the amount of soil organic carbon (SOC). This study aimed to investigate the major factors controlling CH4 production potential (CH4PP) in Thai paddy fields. Two provinces, Ayutthaya, a clay soil region, and Khonkaen, a sandy soil region, were selected to represent a wide range of soil textures. Soil characteristic analysis pre- and post-incubation, and weekly gas detection in an incubation experiment over two months, was conducted. Stepwise multiple regression analysis was employed to analyze major soil factors controlling CH4PP. For the regional prediction of CH4PP, a map dataset of Ayutthaya and Khonkaen by the Land Development Department, Thailand, and a soil texture map (with intersected point data using the soil property map in ArcGIS) by OpenLandMap, were used. CH4PP was correlated with 1:10 pH, Fe2+, and water-soluble organic carbon (WSOC) measured after incubation. Although CH4PP showed no significant correlation with any soil properties measured before incubation, CH4PP was correlated with SOC, 1:10 electrical conductivity (EC), exchangeable ammonium (ExNH4), and sand content. It was thought that SOC and ExNH4 were related to organic matter decomposition, 1:10 EC was related to SO42− reduction and sand content was related to free oxides. Predicted regional CH4PP was similar in Ayutthaya and Khonkaen, although SOC, ExNH4 and 1:10 EC was higher, and sand content was lower in Ayutthaya than in Khonkaen. In both regions, the distribution of CH4PP corresponded to SOC, and CH4PP was lower with lower sand content and higher 1:10 EC. In clayey Ayutthaya, higher CH4PP was observed in the area with higher ExNH4. This indicates that soil properties other than soil texture and SOC influence CH4PP in the paddy fields in Thailand. [ABSTRACT FROM AUTHOR]

The environmental impact of deposit development can be indirect and can cause combined geochemical processes in ecosystems. These must be taken into consideration under environmental forecasting and environmental risk assessment. Soil degradation in the Taiga Forest is considered, within the area of Verkhnekamskoye potash deposit (Russia), as an example of such environmental transformation. Here, the mechanism and characteristics of the anthropogenic salinisation of alluvial soils under potash deposit development are newly described. It was found that there is a strong anthropogenic impact of the potash industry on valley soils where the contaminated Na-Cl groundwater discharges or is close to the surface. The valley soils are characterised by high salinity, and the sum of toxic salts in soils has reached 26%. Alluvial gley humic clay chloride saline soil (Gleyic Fluvisols (Salic, Loamic, Technic)) and secondary solonchak on alluvial humic clay soil sulphate-chloride gypsum-containing surface-gleyed (Chloridic Gleyic Fluvic Solonchak (Hypersalic, Loamic, Technic)) were formed in hydromorphic conditions. Morphological, physicochemical and mineralogical analyses were carried out. Under hydromorphic conditions, Chloridic Gleyic Fluvic Solonchak (Hypersalic, Loamic) was described to show a hydrotroillite layer and reddish-yellow iron-rich precipitates on its surface. The top soil horizon has the highest content of iron minerals (up to 84.9%) and Fe-bearing plant residues (up to 20%). Additionally, the spongy and gel-like organic materials, as well as the siliceous remains of diatoms, are enriched in Ca, Fe, Cl, K, Na, S and P. The lower soil horizon consists of black gel-like phases and hydrogen sulphide settings with a high content of plant residues. The insoluble part of the samples contains up to 84% hydrogoethite. The sources of iron in soils and bottom sediments include the iron-enriched Sheshma sediments speckled rocks, slurry material, halite wastes and soil minerals of alluvial gley soils. [ABSTRACT FROM AUTHOR]

Soil salinization typically inhibits the ability of decomposer organisms to utilize soil organic matter, and an increase in soil clay content can mediate the negative effect of salinity on carbon (C) mineralization. However, the interactive effects of soil salt concentrations and properties on C mineralization remain uncertain. In this study, a laboratory experiment was performed to investigate the interactive effects of soil salt content (0.1%, 0.3%, 0.6% and 1.0%) and texture (sandy loam, sandy clay loam and silty clay soil with 6.0%, 23.9% and 40.6% clay content, respectively) on C mineralization and microbial community composition after cotton straw addition. With increasing soil salinity, carbon dioxide (CO2) emissions from the three soils decreased, but the effect of soil salinity on the decomposition of soil organic carbon varied with soil texture. Cumulative CO2 emissions in the coarse-textured (sandy loam and sandy clay loam) soils were more affected by salinity than those in the fine-textured (silty clay) soil. This difference was probably due to the differing responses of labile and resistant organic compounds to salinity across different soil texture. Increased salinity decreased the decomposition of the stable C pool in the coarse-textured soil, by reducing the proportion of fungi to bacteria, whereas it decreased the mineralization of the active C pool in the fine-textured soil through decreasing the Gram-positive bacterial population. Overall, our results suggest that soil texture controlled the negative effect of salinity on C mineralization through regulating the soil microbial community composition. [ABSTRACT FROM AUTHOR]

Even though the most prominent soil degradation processes are observed at arable lands, natural soils are also prone to deterioration processes, and in a greater extent over the recent years, due to global climate change, that accelerates soil erosion and the salinization processes. The observed soil degradation processes included: (1) soil salinization that is seen as salt crusts at the soil surface (Figure 2); (2) soil compaction (Figure 3), and soil erosion (Figure 4). [Extracted from the article]

Low-cost, accurate soil water sensors combined with wireless communication in an internet of things (IoT) framework can be harnessed to enhance the benefits of precision irrigation. However, the accuracy of low-cost sensors (e.g., based on resistivity or capacitance) can be affected by many factors, including salinity, temperature, and soil structure. Recent developments in wireless sensor networks offer new possibilities for field-scale monitoring of soil water content (SWC) at high spatiotemporal scales, but to install many sensors in the network, the cost of the sensors must be low, and the mechanism of operation needs to be robust, simple, and consume low energy for the technology to be practically relevant. This study evaluated the performance of a resistivity–capacitance-based wireless sensor (Sensoterra BV, 1018LE Amsterdam, Netherlands) under different salinity levels, temperature, and soil types in a laboratory. The sensors were evaluated in glass beads, Oso Flaco sand, Columbia loam, and Yolo clay loam soils. A nonlinear relationship was exhibited between the sensor measured resistance (Ω) and volumetric soil water content (θ). The Ω – θ relationship differed by soil type and was affected by soil solution salinity. The sensor was extremely sensitive at higher water contents with high uncertainty, and insensitive at low soil water content accompanied by low uncertainty. The soil solution salinity effects on the Ω – θ relationship were found to be reduced from sand to sandy loam to clay loam. In clay soils, surface electrical conductivity (ECs) of soil particles had a more dominant effect on sensor performance compared to the effect of solution electrical conductivity (ECw). The effect of temperature on sensor performance was minimal, but sensor-to-sensor variability was substantial. The relationship between bulk electrical conductivity (ECb) and volumetric soil water content was also characterized in this study. The results of this study reveal that if the sensor is properly calibrated, this low-cost wireless soil water sensor has the potential of improving soil water monitoring for precision irrigation and other applications at high spatiotemporal scales, due to the ease of integration into IoT frameworks. [ABSTRACT FROM AUTHOR]

The use of saline water for the irrigation of forage crops to alleviate water scarcity has become necessary in semi-arid and arid regions and researchers have been seeking ways to offset the harmful results of soil salinity. Soil amendments with compost, manure and other organic material provide a valuable source of plant nutrients and appear to speed up soil recovery. The aim of this study was to compare the benefits of farmyard manure and a municipal solid waste (MSW) compost (40 mg ha−1) for raising alfalfa (Medicago sativa, cv. Gabès) under salt-water irrigation. Both compost and manure improved plant mineral uptake and growth of alfalfa cultivated in clay soil. Using compost in clay soil increased the content of copper (Cu), cadmium (Cd), and zinc (Zn) in plant tissues compared to manure, while the bio-accumulation factor (BAF) of Cu, Pb and Zn was higher in plants grown with manure compared to MSW compost with salt stress. Compost addition could enhance alfalfa growth under salt stress, which depends on salt doses and can greatly improve the recovery effects in a cost-effective way, although additional amendment type should receive special attention in order to be used as a tool for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Soil salinization is a serious environmental issue that significantly influences crop yield and soil fertility, especially in coastal areas. Numerous studies have been conducted on the salinity status in Pakistan. Information about the geospatial and temporal distribution of salinity in the Sujawal district is still lacking. The present study examines the soil salinity status and the impact of seawater intrusion in the entire district from 1990 to 2017 using field and remote sensing (RS) data. In addition, 210 soil samples at different depths (0–20, 20–40, and 40–60 cm) were collected from randomly selected locations for lab measurements of physiochemical properties. The results showed that the soil texture classes were mainly fine to medium particles. The samples collected at the 0–20 cm depth were mostly dominated by three textural classes of soil: clay at 19.5%, clay loam at 25.6%, and loam at 32.9%. The electrical conductivity (EC) of 65.7% soil samples collected from the top layer exceeded the normal range. The quantitative results indicated that the exchangeable sodium percentage (ESP) ranged between 1.38 and 64.58, and 72.2% of the top layer soil samples had ESP >15, while 81.5% of soil samples were in the normal range of soil pH. Furthermore, the results indicated that the vegetation decreased by 8.6% from 1990 to 2017, while barren land and water bodies increased significantly, by approximately 4.4% and 4.2%, respectively. The extreme and high salinity classes were characterized by high contents of soluble salt on the surface in the Jati and Shah Bandar subdistricts. In addition, the soil EC values at the 0–20 cm depth were significantly correlated with the salinity index (S1). Therefore, it was concluded that more than 50% of the top layer of soil was affected by salinity due to seawater intrusion, low rainfall, climate change, and erratic river flow. It is suggested that remote sensing (RS) data are more suitable for the detection of the soil salinity status of a region and impose a lower cost compared to other conventional approaches. However, this study could provide significant knowledge to land managers, policymakers, and government officials to allow them to take action to implement salinity control measures in the study area. [ABSTRACT FROM AUTHOR]