This research used both geostatistics and GIS approach to compare temporal change of soil salt between 1980 and 2003, to analyze the spatial distribution of surface soil salt, to developed methods for predicting soil ...This research used both geostatistics and GIS approach to compare temporal change of soil salt between 1980 and 2003, to analyze the spatial distribution of surface soil salt, to developed methods for predicting soil salinization potential based on recent improvements to the Dempster-Shafer theory, and to develop probability maps of potential salinization in Yucheng City, China. A semivariogram model of soil salt content was developed from the spherical model, and then employing kriging interpolation the spatial distribution of salt content in 2003 was obtained utilizing data from 100 soil sampling points. Potential salinization distribution was mapped using an approach that integrated soil data of the second general survey in 1980 in Yucheng City, which included groundwater salinity, groundwater depth, soil texture, soil organic matter content, and geomorphic maps. With the support of Dempster-Shafer theory and fuzzy set technique the factors that affected potential soil salinization were characterized and integrated; and then soil salinization was predicted. Finally a prognosis map of potential salinization distribution in the research area was obtained, with higher probability values indicating higher hazards to salinity processes. The distribution of the potential soil salinization probability was a successive surface.展开更多
Soil salinization is a common phenomenon that affects both the environment and the socio-economy in arid and semi-arid regions; it is also an important aspect of land cover change. In this study, we integrated multi-s...Soil salinization is a common phenomenon that affects both the environment and the socio-economy in arid and semi-arid regions; it is also an important aspect of land cover change. In this study, we integrated multi-sensor remote sensing data with a field survey to analyze processes of soil salinization in a semi-arid area in China from 1979 to 2009. Generally, the area of salt-affected soils increased by 0.28% per year with remarkable acceleration from 1999 to 2009 （0.42% increase per year）. In contrast, the area of surface water bodies showed a decreasing trend （-0.08% per year） in the same period. Decreases in precipitation and increases in aridity due to annual （especially summer） warming provided a favorable condition for soil salinization. The relatively flat terrain favored waterlogging at the surface, and continuous drought facilitated upward movement of soil water and accumulation of surface saline and calcium. Meanwhile, land-use practices also played a crucial role in accelerating soil salinization. The conversion to cropland from natural vegetation greatly increased the demand for groundwater irrigation and aggravated the process of soil salinization. Furthermore, there are potential feedbacks of soil salinization to regional climate. The salinization of soils can limit the efficiency of plant water use as well as photosynthesis; therefore, it reduces the amount of carbon sequestrated by terrestrial ecosystem. Soil salinization also reduces the absorbed solar radiation by increasing land surface albedo. Such conversions of land cover significantly change the energy and water balance between land and atmosphere.展开更多
Extracting information about saline soils from remote sensing data is useful, particularly given the environmental significance and changing nature of these areas in arid environments. One interesting case study to co...Extracting information about saline soils from remote sensing data is useful, particularly given the environmental significance and changing nature of these areas in arid environments. One interesting case study to consider is the delta oasis of the Weigan and Kuqa rivers, China, which was studied using a Landsat Enhanced Thematic Mapper Plus （ETM＋） image collected in August 2001. In recent years, decision tree classifiers have been successfully used for land cover classification from remote sensing data. Principal component analysis （PCA） is a popular data reduction technique used to help build a decision tree; it reduces complexity and can help the classification precision of a decision tree to be improved. A decision tree approach was used to determine the key variables to be used for classification and ultimately extract salinized soil from other cover and soil types within the study area. According to the research, the third principal component （PC3） is an effective variable in the decision tree classification for salinized soil information extraction. The research demonstrated that the PC3 was the best band to identify areas of severely salinized soil; the blue spectral band from the ETM＋ sensor （TM1） was the best band to identify salinized soil with the salt-tolerant vegetation of tamarisk （Tamarix chinensis Lour）; and areas comprising mixed water bodies and vegetation can be identified using the spectral indices MNDWI （modified normalized difference water index） and NDVI （normalized difference vegetation index）. Based upon this analysis, a decision tree classifier was applied to classify landcover types with different levels of soil saline. The results were checked using a statistical accuracy assessment. The overall accuracy of the classification was 94.80%, which suggested that the decision tree model is a simple and effective method with relatively high precision.展开更多
In this paper,we reviewed the progress in the application of stable isotope techniques to the study of soil salinization.As a powerful technique,stable isotopes have been widely used in the studies of soil water evapo...In this paper,we reviewed the progress in the application of stable isotope techniques to the study of soil salinization.As a powerful technique,stable isotopes have been widely used in the studies of soil water evaporation,the dynamics of soil salinization and salt-tolerant plant breeding.The impact of single environmental factors on plant isotope composition has been the focus of previous studies.However,the impact of multiple environmental factors on plant isotope composition remains unclear and needs to be carefully studied.In order to gain insights into soil salinization and amelioration,especially soil salinization in arid and semiarid areas,it is essential to employ stable isotope techniques and combine them with other methods,such as located field observation and remote sensing technology.展开更多
Soil salinization may affect biodiversity and species composition,leading to changes in the plant community structure.However,few studies have explored the spatial pattern of soil salinization and its effects on shrub...Soil salinization may affect biodiversity and species composition,leading to changes in the plant community structure.However,few studies have explored the spatial pattern of soil salinization and its effects on shrub community structure at the ecosystem scale.Therefore,we conducted a transect sampling of desert shrublands in Northwest China during the growing season(June–September)in 2021.Soil salinization(both the degree and type),shrub community structure(e.g.,shrub density and height),and biodiversity parameters(e.g.,Simpson diversity,Margalf abundance,Shannon-Wiener diversity,and Pielou evenness indices)were used to assess the effects of soil salinization on shrub community structure.The results showed that the primary degree of soil salinization in the study area was light salinization,with the area proportion of 69.8%.Whereas the main type of soil salinization was characterized as sulfate saline soil,also accounting for 69.8%of the total area.Notably,there was a significant reduction in the degree of soil salinization and a shift in the type of soil salinization from chloride saline soil to sulfate saline soil,with an increase in longitude.Regional mean annual precipitation(MAP),mean annual evapotranspiration(MAE),elevation,and slope significantly contributed to soil salinization and its geochemical differentiation.As soil salinization intensified,shrub community structure displayed increased diversity and evenness,as indicated by the increases in the Simpson diversity,Shannon-Wiener diversity,and Pielou evenness indices.Moreover,the succulent stems and leaves of Chenopodiaceae and Tamaricaceae exhibited clear advantages under these conditions.Furthermore,regional climate and topography,such as MAP,MAE,and elevation,had greater effects on the distribution of shrub plants than soil salinization.These results provide a reference for the origin and pattern of soil salinization in drylands and their effects on the community structure of halophyte shrub species.展开更多
The Hotan Prefecture of Xinjiang Uygur Autonomous Region,China belongs to arid desert climate,with significant soil salinization issues.The study selected six rivers in Hotan Prefecture(Pishan,Qaraqash,Yurungqash,Cell...The Hotan Prefecture of Xinjiang Uygur Autonomous Region,China belongs to arid desert climate,with significant soil salinization issues.The study selected six rivers in Hotan Prefecture(Pishan,Qaraqash,Yurungqash,Celle,Kriya,and Niya rivers)to explore the spatial distribution of soil salinization in this area and its underlying mechanisms.Sampling was conducted along each river's watershed,from the Gobi in the upper reaches,through the anthropogenic impact area in the middle reaches,to the desert area in the lower reaches.Soil physical-chemical indicators,including total soluble salts,pH,K+,Na+,Ca2+,Mg2+,SO42-,Cl-,CO32-,HCO3-,organic matter,available nitrogen,available phosphorus,and available potassium,were tested,along with the total dissolved solids of surface water and groundwater.The results revealed that the soil water and nutrient contents in anthropogenic impact area were higher than those in Gobi and desert areas,while the pH and total soluble salts were lower than those in Gobi and desert areas.The ions in the soil of the study area were primarily Cl-,SO42-,K+,and Na+,and the ion concentration of soil salt were positively correlated with surface water and groundwater.Overall,the study area exhibited low soil water content,low clay content,infertile soil,and high soil salinization,dominated by weak to moderate chloride-sulfate types.Compared with Gobi and desert areas,the soil in anthropogenic impact area had higher soil water content,lower pH,lower soluble salts,and higher nutrients,indicating that human farming activities help mitigate salinization.These findings have practical implications for guiding the scientific prevention and control of soil salinization in the arid areas and for promoting sustainable agricultural development.展开更多
Soil salinization seriously restricts the development of agricultural production,the sustainable use of land resources,and the stability of the ecological environment.In order to objectively reveal the research status...Soil salinization seriously restricts the development of agricultural production,the sustainable use of land resources,and the stability of the ecological environment.In order to objectively reveal the research status of soil salinization,CiteSpace software was used to conduct data mining and quantitative analysis on research papers on soil salinization from 2008 to 2023 in China National Knowledge Infrastructure(CNKI)and Web of science databases.The data sources were transformed into visual graphs by reproducing clustering statistics from aspects such as publication volume,authors,keywords,and publishing institutions.In addition,this paper also combined the actual needs and cutting-edge hotspots in relevant research in China,and proposed and analyzed the limitations and future development trends of soil salinity monitoring research in China.This has important practical significance for comprehensively grasping the current research status of salinization,further clarifying and sorting out the research ideas of salinization monitoring,enriching the remote sensing monitoring methods of saline soil,and solving the actual problems of soil salinization in China.展开更多
With the environmental deterioration caused by the advance of climate change, soil salinization is a serious and growing global problem. Currently about 7% of the world＇s land surface is threatened by salinization. C...With the environmental deterioration caused by the advance of climate change, soil salinization is a serious and growing global problem. Currently about 7% of the world＇s land surface is threatened by salinization. China is a country whose soils are severely affected by this problem, which, due to its extensive area, and wide distribution poses a serious threat to regional agricultural development. In this review, we summarize the framework for soil salinization research in China over the past 70 years, assess the weaknesses of existing research in both a domestic and international context, highlight the trends and key findings of global research about saline soils over the past 30 years, and propose six major fields and directions for future research on saline soil.展开更多
Monitoring the dynamics of soil salinization is of great importance for agricultural production.This study selected Yucheng County,a typical county on the Huang-Huai-Hai Plain(HHHP)of China,as the study area and evalu...Monitoring the dynamics of soil salinization is of great importance for agricultural production.This study selected Yucheng County,a typical county on the Huang-Huai-Hai Plain(HHHP)of China,as the study area and evaluated the spatial and temporal variation of soil salinization.Three methods,consisting of principal component analysis(PCA)transformation,tasseled cap(TC)transformation,and optimal band combination(OBC),were used to extract information from an early Landsat multispectral scanner(MSS)image from 1984,and their advantages were compared.In addition,OBC was used on a thematic mapper(TM)image from 2009.An iteratively self-organizing data analysis algorithm was used together with prior knowledge of likely classifications to interpret the MSS and TM images for data classification.Finally,a transfer matrix method was used to assess the spatial and temporal variability of soil salinization and analyze the driving factors of soil salinization.Compared to PCA transformation and OBC,TC transformation was a more effective method for extracting soil salinization information from the MSS sensor.The results indicate that a soil area of approximately 298 km^2was affected by salinity in 1984 in Yucheng County,of which 5.40%,11.96%,and 12.75%were classified as being subject to slight,moderate,and severe salinization,respectively.In 2009,the saline area was reduced to only 146 km^2,of which 10.70%and 3.75%were characterized by slight to moderate salinization and no severe salinization,respectively.The saline land decreased at an average rate of 6 km^2per year.This decrease was probably a result of lower groundwater depth,increased organic fertilizer or crop straw in soil,changed land use type,and increased vegetation coverage.展开更多
Soil inorganic carbon(SIC)is an important reservoir of carbon(C)in arid,semi-arid,and semi-humid regions.However,knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C(SOC)under differ...Soil inorganic carbon(SIC)is an important reservoir of carbon(C)in arid,semi-arid,and semi-humid regions.However,knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C(SOC)under different land use types in the semi-humid region,particularly in coastal zones impacted by soil salinization.We collected 170 soil samples from 34 profiles across various land use types(maize-wheat,cotton,paddy,and reed)in the middle-lower Yellow River Delta(YRD),China.We measured soil pH,electrical conductivity(EC),water-soluble salts,and SOC and SIC contents.Our results showed significant differences in both SOC and SIC among land use types.The dry cropland(maize-wheat and cotton)soils had significantly higher SOC and SIC densities(4.71 and 15.46 kg C m^(-2),respectively)than the paddy soils(3.28 and 14.09 kg C m^(-2),respectively)in the 0–100 cm layer.Compared with paddy soils,reed soils contained significantly higher SOC(4.68 kg C m^(-2))and similar SIC(15.02 kg C m^(-2))densities.There was a significant positive correlation between SOC and SIC densities over a 0–100 cm soil depth in dry cropland soils,but a negative relationship in the paddy soils.On average,SOC and SIC densities under maize-wheat cropping were 15%and 4%lower,respectively,in the salt-affected soils in the middle-lower YRD than the upper YRD.This study indicated that land use types had great influences on both SOC and SIC and their relationship,and salinization had adverse effect on soil C storage in the YRD.展开更多
●Bacterial richness declined but fungal richness increased under salinization.●Bacteria did not become interactively compact or facilitative under salinization.●Fungi exhibited more compartmentalized and competitiv...●Bacterial richness declined but fungal richness increased under salinization.●Bacteria did not become interactively compact or facilitative under salinization.●Fungi exhibited more compartmentalized and competitive patterns under salinization.●Fungal stability showed steeper increases under salinization than bacterial stability.Soil salinization is a typical environmental challenge in arid regions worldwide.Salinity stress increases plant convergent adaptations and facilitative interactions and thus destabilizes communities.Soil bacteria and fungi have smaller body mass than plants and are often efficient against soil salinization,but how the stability of bacterial and fungal communities change with a wide range of soil salinity gradient remains unclear.Here,we assessed the interactions within both bacterial and fungal communities along a soil salinity gradient in the Taklamakan desert to examine(i)whether the stability of bacterial and fungal communities decreased with soil salinity,and(ii)the stability of which community decreased more with soil salinity,bacteria or fungi.Our results showed that the species richness of soil fungi increased but that of soil bacteria decreased with increasing salinity in topsoils.Fungal communities became more stable under soil salinization,with increasing compartmentalization(i.e.,modularity)and proportion of competitions(i.e.,negative:positive cohesion)as salinity increased.Bacterial communities exhibited no changes in modularity with increasing salinity and smaller increases in negative:positive cohesion under soil salinization compared to fungal communities.Our results suggest that,by altering interspecific interactions,soil salinization increases the stability of fungal not bacterial communities in extreme environments.展开更多
This paper analyzes the impacts of physical background and human activities on secondary soil salinization in arid Hetao Plain,overviews the adopted amelioration strategies,and suggests the corresponding strategies de...This paper analyzes the impacts of physical background and human activities on secondary soil salinization in arid Hetao Plain,overviews the adopted amelioration strategies,and suggests the corresponding strategies dealing with water shortage in the Yellow River.展开更多
Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH...Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH_(3)volatilization were measured using the open static chamber method(sponge sampling),alongside the distribution of^(15)N and NO_(3)^(-)-N concentrations in layers,in a 30-cm soil column experiment with vermicompost addition after incorporation of^(15)N-labeled urea in the upper layer(0-10 cm)of a saline-alkali soil.Destructive sampling was conducted on days 20 and 60 of the column experiment to investigate the influencing factors of NH_(3)volatilization and^(15)N/NO_(3)^(-)retention,respectively.The results showed that the addition of vermicompost to saline-alkali soil decreased cumulative NH_(3)volatilization by 45.1%,decreased the^(15)N concentration in the bottom layer(20-30 cm)by 17.1%,and increased the^(15)N concentration in the upper soil by 48.7%.Vermicompost regulated the abundances of amoA,amoC,and nxrA genes,which can decrease NH_(3)volatilization by converting substrate NH_(4)^(+)to NO_(3)^(-).Additionally,Ca^(2+)adsorption is enhanced(increased by 6.2%)by increasing soil cation exchange capacity(increased by 20.6%),thus replacing the adsorption of Na^(+)(decreased by 13.8%)and decreasing the desorption of NH_(4)^(+).Vermicompost enhanced the adsorption of NO_(3)^(-)by increasing Ca^(2+)and Mg^(2+)and decreasing Cl-by 30.4%in the upper soil.This study concluded that vermicompost addition can inhibit N loss by reducing NH_(3)volatilization and improving^(15)N/NO_(3)^(-)retention in saline-alkali soils.展开更多
The application of modified biochar has been proven to be a novel and promising strategy to improve saline-alkali soil.However,the effect of iron-modified biochar(FB)on the chemical properties of saline-alkali soil at...The application of modified biochar has been proven to be a novel and promising strategy to improve saline-alkali soil.However,the effect of iron-modified biochar(FB)on the chemical properties of saline-alkali soil at different depths remains unclear.Therefore,we designed a soil column and divided it into three consecutive parts(i.e.,topsoil,middle soil,and subsoil)to explore the amelioration effects of biochar on saline-alkali soil chemical properties and bacterial communities along a depth gradient in the treatments amended with 0.5%(weight/weight)pristine biochar(PB),1%(weight:weight)PB,0.5%(weight:weight)FB,and 1%(weight:weight)FB and without biochar(control,CK).The results showed that soil chemical properties were significantly improved with 1%FB application,while the amelioration effect of FB was different between the topsoil and subsoil.The activities of extracellular enzymes significantly increased in the topsoil and base cations decreased in the subsoil in the FB treatment compared with CK.Moreover,the abundances of halophilic taxa were higher in the subsoil than in the topsoil,especially for Bacteroidetes and Deinococcota.Furthermore,the abundances of beneficial bacteria(e.g.,c_Alphaproteobacteria,Sphingomonas,and Pontibacter)in saline-alkali soil increased in the FB treatment compared with CK.Our results suggest the ameliorative effect of FB on soil properties and bacterial communities along a soil depth gradient,providing a novel strategy for improving saline-alkali soil with biochar.展开更多
This study aims to investigate the combined use of multi-sensor datasets(Landsat 4–5&8 OLI satellite imagery,spatial resolution=30 m)coupled with field studies to evaluate spatio-temporal dynamics of soil saliniz...This study aims to investigate the combined use of multi-sensor datasets(Landsat 4–5&8 OLI satellite imagery,spatial resolution=30 m)coupled with field studies to evaluate spatio-temporal dynamics of soil salinization along the coastal belt in West Bengal,India.This study assesses soil salinization by mapping the salinity and electrical conductivity of saturation extract(ECe)and utilizing spectral signatures for estimating soil salinity.The SI change(%)was analyzed(2021–1995),categorizing increases in salinity levels into 5%,10%,and 50%changes possibly due to salt encrustation on the soil layers.The land use land cover(LULC)change map(2021–1995)demonstrates that the study area is continuously evolving in terms of urbanization.Moreover,in the study area,soil salinity ranges from 0.03 ppt to 3.87 ppt,and ECe varies from 0.35 dSm^(-1)to 52.85 dSm^(-1).Additionally,vulnerable saline soil locations were further identified.Classification of soil salinity based on ECe reveals that 26%of samples fall into the nonsaline category,while the rest belong to the saline category.The Spectral signatures of the soil samples(n=19)acquired from FieldSpec hand spectrometer show significant absorption features around 1400,1900,and 2250 nm and indicate salt minerals.The results of reflectance spectroscopy were crossvalidated using X-ray fluorescence and scanning electron microscopy.This study also employed partial least square regression(PLSR)approach to predict ECe(r^(2)=0.79,RMSE=3.29)and salinity parameters(r^(2)=0.75,RMSE=0.51),suggesting PLSR applicability in monitoring salt-affected soils globally.This study’s conclusion emphasizes that remote sensing data and multivariate analysis can be crucial tools for mapping spatial variations and predicting soil salinity.It has also been concluded that saline groundwater used for irrigation and aqua-cultural activities exacerbates soil salinization.The study will help policymakers/farmers identify the salt degradation problem more effectively and adopt immediate mitigation measures.展开更多
Salinized soil is an important reserved arable land resource in China.The management and utilization of salinized soil can safeguard the current size of arable land and a stable grain yield.Salt accumulation will lead...Salinized soil is an important reserved arable land resource in China.The management and utilization of salinized soil can safeguard the current size of arable land and a stable grain yield.Salt accumulation will lead to the deterioration of soil properties,destroy soil production potential and damage soil ecological functions,which in turn will threaten global water and soil resources and food security,and affect sustainable socio-economic development.Microorganisms are important components of salinized soil.Microbial remediation is an important research tool in improving salinized soil and is key to realizing sustainable development of agriculture and the ecosystem.Knowledge about the impact of salinization on soil properties and measures using microorganisms in remediation of salinized soil has grown over time.However,the mechanisms governing these impacts and the ecological principles for microbial remediation are scarce.Thus,it is imperative to summarize the effects of salinization on soil physical,chemical,and microbial properties,and then review the related mechanisms of halophilic and halotolerant microorganisms in salinized soil remediation via direct and indirect pathways.The stability,persistence,and safety of the microbial remediation effect is also highlighted in this review to further promote the application of microbial remediation in salinized soil.The objective of this review is to provide reference and theoretical support for the improvement and utilization of salinized soil.展开更多
By analyzing the process of soil salt accumulation in irrigation area, and discussing the change of irrigation and drainage methods for drought transformed into water, the control scheme of soil secondary salinization...By analyzing the process of soil salt accumulation in irrigation area, and discussing the change of irrigation and drainage methods for drought transformed into water, the control scheme of soil secondary salinization in Wujiazi Irrigation Area was analyzed concretely, and the experience was summarized. After in-depth discussion, the importance of irrigation and drainage methods in the prevention and control of soil secondary salinization in irrigation areas was analyzed.展开更多
Sudden temperature drops cause soils in natural environments to freeze unidirectionally,resulting in soil expansion and deformation that can lead to damage to engineering structures.The impact of temperature-induced f...Sudden temperature drops cause soils in natural environments to freeze unidirectionally,resulting in soil expansion and deformation that can lead to damage to engineering structures.The impact of temperature-induced freezing on deformation and solute migration in saline soils,especially under extended freezing,is not well understood due to the lack of knowledge regarding the microscopic mechanisms involved.This study investigated the expansion,deformation,and water-salt migration in chlorinated saline soils,materials commonly used for canal foundations in cold and arid regions,under different roof temperatures and soil compaction levels through unidirectional freezing experiments.The microscopic structures of saline soils were observed using scanning electron microscopy(SEM)and optical microscopy.A quantitative analysis of the microstructural data was conducted before and after freezing to elucidate the microscopic mechanisms of water-salt migration and deformation.The results indicate that soil swelling is enhanced by elevated roof temperatures approaching the soil's freezing point and soil compaction,which prolongs the duration and accelerates the rate of water-salt migration.The unidirectional freezing altered the microstructure of saline soils due to the continuous temperature gradients,leading to four distinct zones:natural frozen zone,peak frozen zone,gradual frozen zone,and unfrozen zone,each exhibiting significant changes in pore types and fractal dimensions.Vacuum suction at the colder end of the soil structure facilitates the upward migration of salt and water,which subsequently undergoes crystallization.This process expands the internal pore structure and causes swelling.The findings provide a theoretical basis for understanding the evolution of soil microstructure in cold and arid regions and for the management of saline soil engineering.展开更多
The progressive failure characteristics of geomaterial are a remarkable and challenging topic in geotechnical engineering.To study the effect of salt content and temperature on the progressive failure characteristics ...The progressive failure characteristics of geomaterial are a remarkable and challenging topic in geotechnical engineering.To study the effect of salt content and temperature on the progressive failure characteristics of frozen sodium sulfate saline sandy soil,a series of uniaxial compression tests were performed by integrating digital image correlation(DIC)technology into the testing apparatus.The evolution law of the uniaxial compression strength(UCS),the failure strain,and the formation of the shear band of the frozen sodium sulfate saline sandy soil were analyzed.The test results show that within the scope of this study,with the increase of salt content,both the UCS and the shear band angle initially decrease with increasing salt content before showing an increase.In contrast,the failure strain and the width of the shear band exhibit an initial increase followed by a decrease in the samples.In addition,to investigate the brittle failure characteristics of frozen sodium sulfate saline sandy soil,two classic brittleness evaluation methods were employed to quantitatively assess the brittleness level for the soil samples.The findings suggest that the failure characteristics under all test conditions in this study belong to the transition stage between brittle and ductile,indicating that frozen sodium sulfate saline sandy soil exhibits certain brittle behavior under uniaxial compression conditions,and the brittleness index basically decreases and then increases with the rise in salt content.展开更多
Biochar and animal manure application can improve crop yields in salt-affected soil.Previous studies have primarily applied biochar and animal manure either alone or at fixed ratios,while their combined effects with v...Biochar and animal manure application can improve crop yields in salt-affected soil.Previous studies have primarily applied biochar and animal manure either alone or at fixed ratios,while their combined effects with varying combination proportions are still unclear.To address this knowledge gap,we performed a 2-a experiment(2023-2024)in a salinized cotton field in Wensu County of Xinjiang Uygur Autonomous Region of China with the following 6 treatments:control;application of biochar(10t/hm^(2))alone(BC100%);application of cow manure(10 t/hm^(2))alone(CM100%);application of 70%biochar(7 t/hm^(2))combined with 30%cow manure(3 t/hm^(2))(BC70%+CM30%);application of 50%biochar(5 t/hm^(2))combined with 50%cow manure(5 t/hm^(2))(BC50%+CM50%);and application of 30%biochar(3 t/hm^(2))combined with 70%cow manure(7 t/hm^(2))(BC30%+CM70%).By measuring soil pH,electrical conductivity,soil organic matter,available phosphorus,available potassium,and available nitrogen at 0-20 and 20-40 cm depths,as well as yield components and cotton yield in 2023 and 2024,this study revealed that soil nutrients in the 0-20 cm depth were more sensitive to the treatment.Among all the treatments,BC50%+CM50%treatment had the highest value of soil pH(9.63±0.07)but the lowest values of electrical conductivity(161.9±31.8μS/cm),soil organic matter(1.88±0.27 g/kg),and available potassium(42.72±8.25 mg/kg)in 2024.Moreover,the highest cotton yield(5336.63±467.72 kg/hm^(2))was also observed under BC50%+CM50%treatment in 2024,which was 1.9 times greater than that under the control treatment.In addition,cotton yield in 2023 was jointly determined by yield components(density and number of cotton bolls)and soil nutrients(available phosphorus and available potassium),but in 2024,cotton yield was only positively related to yield components(density,number of cotton bolls,and single boll weight).Overall,this study highlighted that in salt-affected soil,the combination of biochar and cow manure at a 1:1 ratio is recommended for increasing cotton yield and reducing soil salinity stress.展开更多
基金Project supported by the National Natural Science Foundation of China (No, 40371058), and the National Key BasicResearch Support Foundation of China (No. G1999011803)
文摘This research used both geostatistics and GIS approach to compare temporal change of soil salt between 1980 and 2003, to analyze the spatial distribution of surface soil salt, to developed methods for predicting soil salinization potential based on recent improvements to the Dempster-Shafer theory, and to develop probability maps of potential salinization in Yucheng City, China. A semivariogram model of soil salt content was developed from the spherical model, and then employing kriging interpolation the spatial distribution of salt content in 2003 was obtained utilizing data from 100 soil sampling points. Potential salinization distribution was mapped using an approach that integrated soil data of the second general survey in 1980 in Yucheng City, which included groundwater salinity, groundwater depth, soil texture, soil organic matter content, and geomorphic maps. With the support of Dempster-Shafer theory and fuzzy set technique the factors that affected potential soil salinization were characterized and integrated; and then soil salinization was predicted. Finally a prognosis map of potential salinization distribution in the research area was obtained, with higher probability values indicating higher hazards to salinity processes. The distribution of the potential soil salinization probability was a successive surface.
基金supported by the National Basic Research Program of China (Grant No.2009CB723904)the National Natural Science Foundation of China (Grant No. 41105076)+1 种基金the National Key technology R & D program (Grant No. 2012BAC22B04)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05090201)
文摘Soil salinization is a common phenomenon that affects both the environment and the socio-economy in arid and semi-arid regions; it is also an important aspect of land cover change. In this study, we integrated multi-sensor remote sensing data with a field survey to analyze processes of soil salinization in a semi-arid area in China from 1979 to 2009. Generally, the area of salt-affected soils increased by 0.28% per year with remarkable acceleration from 1999 to 2009 （0.42% increase per year）. In contrast, the area of surface water bodies showed a decreasing trend （-0.08% per year） in the same period. Decreases in precipitation and increases in aridity due to annual （especially summer） warming provided a favorable condition for soil salinization. The relatively flat terrain favored waterlogging at the surface, and continuous drought facilitated upward movement of soil water and accumulation of surface saline and calcium. Meanwhile, land-use practices also played a crucial role in accelerating soil salinization. The conversion to cropland from natural vegetation greatly increased the demand for groundwater irrigation and aggravated the process of soil salinization. Furthermore, there are potential feedbacks of soil salinization to regional climate. The salinization of soils can limit the efficiency of plant water use as well as photosynthesis; therefore, it reduces the amount of carbon sequestrated by terrestrial ecosystem. Soil salinization also reduces the absorbed solar radiation by increasing land surface albedo. Such conversions of land cover significantly change the energy and water balance between land and atmosphere.
基金supported by the National Natural Science Foundation of China (40861020, 40961008)Huoyingdong Education Fund, China (121018)Natural Science Foundation of Xinjiang Uygur Autonomous Region, China (200821128)
文摘Extracting information about saline soils from remote sensing data is useful, particularly given the environmental significance and changing nature of these areas in arid environments. One interesting case study to consider is the delta oasis of the Weigan and Kuqa rivers, China, which was studied using a Landsat Enhanced Thematic Mapper Plus （ETM＋） image collected in August 2001. In recent years, decision tree classifiers have been successfully used for land cover classification from remote sensing data. Principal component analysis （PCA） is a popular data reduction technique used to help build a decision tree; it reduces complexity and can help the classification precision of a decision tree to be improved. A decision tree approach was used to determine the key variables to be used for classification and ultimately extract salinized soil from other cover and soil types within the study area. According to the research, the third principal component （PC3） is an effective variable in the decision tree classification for salinized soil information extraction. The research demonstrated that the PC3 was the best band to identify areas of severely salinized soil; the blue spectral band from the ETM＋ sensor （TM1） was the best band to identify salinized soil with the salt-tolerant vegetation of tamarisk （Tamarix chinensis Lour）; and areas comprising mixed water bodies and vegetation can be identified using the spectral indices MNDWI （modified normalized difference water index） and NDVI （normalized difference vegetation index）. Based upon this analysis, a decision tree classifier was applied to classify landcover types with different levels of soil saline. The results were checked using a statistical accuracy assessment. The overall accuracy of the classification was 94.80%, which suggested that the decision tree model is a simple and effective method with relatively high precision.
基金supported by the National Basic Research Program of China (2009CB825101)the National Natural Science Foundation of China (41071032)the West Light Foundation of the Chinese Academy of Sciences (2009)
文摘In this paper,we reviewed the progress in the application of stable isotope techniques to the study of soil salinization.As a powerful technique,stable isotopes have been widely used in the studies of soil water evaporation,the dynamics of soil salinization and salt-tolerant plant breeding.The impact of single environmental factors on plant isotope composition has been the focus of previous studies.However,the impact of multiple environmental factors on plant isotope composition remains unclear and needs to be carefully studied.In order to gain insights into soil salinization and amelioration,especially soil salinization in arid and semiarid areas,it is essential to employ stable isotope techniques and combine them with other methods,such as located field observation and remote sensing technology.
基金financially supported by the National Natural Sciences Foundation of China(42330503,42171068)the Third Xinjiang Scientific Expedition Program(2022xjkk0901)the Tianshan Talent Training Program(2023TSYCLJ0048).
文摘Soil salinization may affect biodiversity and species composition,leading to changes in the plant community structure.However,few studies have explored the spatial pattern of soil salinization and its effects on shrub community structure at the ecosystem scale.Therefore,we conducted a transect sampling of desert shrublands in Northwest China during the growing season(June–September)in 2021.Soil salinization(both the degree and type),shrub community structure(e.g.,shrub density and height),and biodiversity parameters(e.g.,Simpson diversity,Margalf abundance,Shannon-Wiener diversity,and Pielou evenness indices)were used to assess the effects of soil salinization on shrub community structure.The results showed that the primary degree of soil salinization in the study area was light salinization,with the area proportion of 69.8%.Whereas the main type of soil salinization was characterized as sulfate saline soil,also accounting for 69.8%of the total area.Notably,there was a significant reduction in the degree of soil salinization and a shift in the type of soil salinization from chloride saline soil to sulfate saline soil,with an increase in longitude.Regional mean annual precipitation(MAP),mean annual evapotranspiration(MAE),elevation,and slope significantly contributed to soil salinization and its geochemical differentiation.As soil salinization intensified,shrub community structure displayed increased diversity and evenness,as indicated by the increases in the Simpson diversity,Shannon-Wiener diversity,and Pielou evenness indices.Moreover,the succulent stems and leaves of Chenopodiaceae and Tamaricaceae exhibited clear advantages under these conditions.Furthermore,regional climate and topography,such as MAP,MAE,and elevation,had greater effects on the distribution of shrub plants than soil salinization.These results provide a reference for the origin and pattern of soil salinization in drylands and their effects on the community structure of halophyte shrub species.
基金This research was supported by the Tianfu Yongxing Laboratory Organized Research Project Funding(2023KJGG05)the Geological Survey Project of Xinjiang Uygur Autonomous Region Geology and Mineral Exploration and Development Bureau(XGMB202356).
文摘The Hotan Prefecture of Xinjiang Uygur Autonomous Region,China belongs to arid desert climate,with significant soil salinization issues.The study selected six rivers in Hotan Prefecture(Pishan,Qaraqash,Yurungqash,Celle,Kriya,and Niya rivers)to explore the spatial distribution of soil salinization in this area and its underlying mechanisms.Sampling was conducted along each river's watershed,from the Gobi in the upper reaches,through the anthropogenic impact area in the middle reaches,to the desert area in the lower reaches.Soil physical-chemical indicators,including total soluble salts,pH,K+,Na+,Ca2+,Mg2+,SO42-,Cl-,CO32-,HCO3-,organic matter,available nitrogen,available phosphorus,and available potassium,were tested,along with the total dissolved solids of surface water and groundwater.The results revealed that the soil water and nutrient contents in anthropogenic impact area were higher than those in Gobi and desert areas,while the pH and total soluble salts were lower than those in Gobi and desert areas.The ions in the soil of the study area were primarily Cl-,SO42-,K+,and Na+,and the ion concentration of soil salt were positively correlated with surface water and groundwater.Overall,the study area exhibited low soil water content,low clay content,infertile soil,and high soil salinization,dominated by weak to moderate chloride-sulfate types.Compared with Gobi and desert areas,the soil in anthropogenic impact area had higher soil water content,lower pH,lower soluble salts,and higher nutrients,indicating that human farming activities help mitigate salinization.These findings have practical implications for guiding the scientific prevention and control of soil salinization in the arid areas and for promoting sustainable agricultural development.
基金Supported by Jilin Provincial Department of Education Project(JJKH20230724KJ).
文摘Soil salinization seriously restricts the development of agricultural production,the sustainable use of land resources,and the stability of the ecological environment.In order to objectively reveal the research status of soil salinization,CiteSpace software was used to conduct data mining and quantitative analysis on research papers on soil salinization from 2008 to 2023 in China National Knowledge Infrastructure(CNKI)and Web of science databases.The data sources were transformed into visual graphs by reproducing clustering statistics from aspects such as publication volume,authors,keywords,and publishing institutions.In addition,this paper also combined the actual needs and cutting-edge hotspots in relevant research in China,and proposed and analyzed the limitations and future development trends of soil salinity monitoring research in China.This has important practical significance for comprehensively grasping the current research status of salinization,further clarifying and sorting out the research ideas of salinization monitoring,enriching the remote sensing monitoring methods of saline soil,and solving the actual problems of soil salinization in China.
基金National Natural Science Foundation, No.40871255 The Scientific Research Foundation of Graduate School of Nanjing University, No.2012CL14
文摘With the environmental deterioration caused by the advance of climate change, soil salinization is a serious and growing global problem. Currently about 7% of the world＇s land surface is threatened by salinization. China is a country whose soils are severely affected by this problem, which, due to its extensive area, and wide distribution poses a serious threat to regional agricultural development. In this review, we summarize the framework for soil salinization research in China over the past 70 years, assess the weaknesses of existing research in both a domestic and international context, highlight the trends and key findings of global research about saline soils over the past 30 years, and propose six major fields and directions for future research on saline soil.
基金This research was supported by the National Natural Science Foundation of China(No.41601211)the Open Fund of the State Key Laboratory of Soil and Sustainable Agriculture,China(No.Y20160007)+1 种基金the Special Fund for Agro-scientific Research in the Public Interest,China(No.200903001-01)the Talent Fund of Qingdao Agricultural University,China(No.1114344).
文摘Monitoring the dynamics of soil salinization is of great importance for agricultural production.This study selected Yucheng County,a typical county on the Huang-Huai-Hai Plain(HHHP)of China,as the study area and evaluated the spatial and temporal variation of soil salinization.Three methods,consisting of principal component analysis(PCA)transformation,tasseled cap(TC)transformation,and optimal band combination(OBC),were used to extract information from an early Landsat multispectral scanner(MSS)image from 1984,and their advantages were compared.In addition,OBC was used on a thematic mapper(TM)image from 2009.An iteratively self-organizing data analysis algorithm was used together with prior knowledge of likely classifications to interpret the MSS and TM images for data classification.Finally,a transfer matrix method was used to assess the spatial and temporal variability of soil salinization and analyze the driving factors of soil salinization.Compared to PCA transformation and OBC,TC transformation was a more effective method for extracting soil salinization information from the MSS sensor.The results indicate that a soil area of approximately 298 km^2was affected by salinity in 1984 in Yucheng County,of which 5.40%,11.96%,and 12.75%were classified as being subject to slight,moderate,and severe salinization,respectively.In 2009,the saline area was reduced to only 146 km^2,of which 10.70%and 3.75%were characterized by slight to moderate salinization and no severe salinization,respectively.The saline land decreased at an average rate of 6 km^2per year.This decrease was probably a result of lower groundwater depth,increased organic fertilizer or crop straw in soil,changed land use type,and increased vegetation coverage.
基金financially supported by the National Natural Science Foundation of China(Nos.41877028 and 41205104)a UK-China Virtual Joint Centre on Nitrogen,funded by the Newton Fund via Biotechnology and Biological Sciences Research Council(BBSRC)(No.BB/N013484/1)。
文摘Soil inorganic carbon(SIC)is an important reservoir of carbon(C)in arid,semi-arid,and semi-humid regions.However,knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C(SOC)under different land use types in the semi-humid region,particularly in coastal zones impacted by soil salinization.We collected 170 soil samples from 34 profiles across various land use types(maize-wheat,cotton,paddy,and reed)in the middle-lower Yellow River Delta(YRD),China.We measured soil pH,electrical conductivity(EC),water-soluble salts,and SOC and SIC contents.Our results showed significant differences in both SOC and SIC among land use types.The dry cropland(maize-wheat and cotton)soils had significantly higher SOC and SIC densities(4.71 and 15.46 kg C m^(-2),respectively)than the paddy soils(3.28 and 14.09 kg C m^(-2),respectively)in the 0–100 cm layer.Compared with paddy soils,reed soils contained significantly higher SOC(4.68 kg C m^(-2))and similar SIC(15.02 kg C m^(-2))densities.There was a significant positive correlation between SOC and SIC densities over a 0–100 cm soil depth in dry cropland soils,but a negative relationship in the paddy soils.On average,SOC and SIC densities under maize-wheat cropping were 15%and 4%lower,respectively,in the salt-affected soils in the middle-lower YRD than the upper YRD.This study indicated that land use types had great influences on both SOC and SIC and their relationship,and salinization had adverse effect on soil C storage in the YRD.
基金support for this work is Intergovernmental International Cooperation on Scientific and Technological Innovation as Part of National Key Research and Development Program(2021YFE0114500)the National Natural Science Foundation of China(41730638 and U1803342)+1 种基金the Agricultural Science and Technology Innovation Program(ASTIP)K.C.Wong Education Foundation(GJTD-2020-14).
文摘●Bacterial richness declined but fungal richness increased under salinization.●Bacteria did not become interactively compact or facilitative under salinization.●Fungi exhibited more compartmentalized and competitive patterns under salinization.●Fungal stability showed steeper increases under salinization than bacterial stability.Soil salinization is a typical environmental challenge in arid regions worldwide.Salinity stress increases plant convergent adaptations and facilitative interactions and thus destabilizes communities.Soil bacteria and fungi have smaller body mass than plants and are often efficient against soil salinization,but how the stability of bacterial and fungal communities change with a wide range of soil salinity gradient remains unclear.Here,we assessed the interactions within both bacterial and fungal communities along a soil salinity gradient in the Taklamakan desert to examine(i)whether the stability of bacterial and fungal communities decreased with soil salinity,and(ii)the stability of which community decreased more with soil salinity,bacteria or fungi.Our results showed that the species richness of soil fungi increased but that of soil bacteria decreased with increasing salinity in topsoils.Fungal communities became more stable under soil salinization,with increasing compartmentalization(i.e.,modularity)and proportion of competitions(i.e.,negative:positive cohesion)as salinity increased.Bacterial communities exhibited no changes in modularity with increasing salinity and smaller increases in negative:positive cohesion under soil salinization compared to fungal communities.Our results suggest that,by altering interspecific interactions,soil salinization increases the stability of fungal not bacterial communities in extreme environments.
基金funded in part by National Natural Science Fund (No. 30671722)
文摘This paper analyzes the impacts of physical background and human activities on secondary soil salinization in arid Hetao Plain,overviews the adopted amelioration strategies,and suggests the corresponding strategies dealing with water shortage in the Yellow River.
基金supported by the National Key R&D Program of China(No.2021YFD1900901)the National Natural Science Foundation of China(No.32271711).
文摘Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH_(3)volatilization were measured using the open static chamber method(sponge sampling),alongside the distribution of^(15)N and NO_(3)^(-)-N concentrations in layers,in a 30-cm soil column experiment with vermicompost addition after incorporation of^(15)N-labeled urea in the upper layer(0-10 cm)of a saline-alkali soil.Destructive sampling was conducted on days 20 and 60 of the column experiment to investigate the influencing factors of NH_(3)volatilization and^(15)N/NO_(3)^(-)retention,respectively.The results showed that the addition of vermicompost to saline-alkali soil decreased cumulative NH_(3)volatilization by 45.1%,decreased the^(15)N concentration in the bottom layer(20-30 cm)by 17.1%,and increased the^(15)N concentration in the upper soil by 48.7%.Vermicompost regulated the abundances of amoA,amoC,and nxrA genes,which can decrease NH_(3)volatilization by converting substrate NH_(4)^(+)to NO_(3)^(-).Additionally,Ca^(2+)adsorption is enhanced(increased by 6.2%)by increasing soil cation exchange capacity(increased by 20.6%),thus replacing the adsorption of Na^(+)(decreased by 13.8%)and decreasing the desorption of NH_(4)^(+).Vermicompost enhanced the adsorption of NO_(3)^(-)by increasing Ca^(2+)and Mg^(2+)and decreasing Cl-by 30.4%in the upper soil.This study concluded that vermicompost addition can inhibit N loss by reducing NH_(3)volatilization and improving^(15)N/NO_(3)^(-)retention in saline-alkali soils.
基金supported by the National Natural Science Foundation of China(No.42577377).
文摘The application of modified biochar has been proven to be a novel and promising strategy to improve saline-alkali soil.However,the effect of iron-modified biochar(FB)on the chemical properties of saline-alkali soil at different depths remains unclear.Therefore,we designed a soil column and divided it into three consecutive parts(i.e.,topsoil,middle soil,and subsoil)to explore the amelioration effects of biochar on saline-alkali soil chemical properties and bacterial communities along a depth gradient in the treatments amended with 0.5%(weight/weight)pristine biochar(PB),1%(weight:weight)PB,0.5%(weight:weight)FB,and 1%(weight:weight)FB and without biochar(control,CK).The results showed that soil chemical properties were significantly improved with 1%FB application,while the amelioration effect of FB was different between the topsoil and subsoil.The activities of extracellular enzymes significantly increased in the topsoil and base cations decreased in the subsoil in the FB treatment compared with CK.Moreover,the abundances of halophilic taxa were higher in the subsoil than in the topsoil,especially for Bacteroidetes and Deinococcota.Furthermore,the abundances of beneficial bacteria(e.g.,c_Alphaproteobacteria,Sphingomonas,and Pontibacter)in saline-alkali soil increased in the FB treatment compared with CK.Our results suggest the ameliorative effect of FB on soil properties and bacterial communities along a soil depth gradient,providing a novel strategy for improving saline-alkali soil with biochar.
基金PK thanks Banaras Hindu University(BHU)for providing the University Fellowship(R/Dev/Sch/UGC Research Fellow/2020-21/18340)and Credit Incentive to Research ScholarsPK expresses gratitude to Dr.Abhinav Yadav(IESD,BHU)for his assistance during the laboratory procedures for soil analysis.PK acknowledges the XRF facility at the Sophisticated Analytical&Technical Help Institute(SATHI)at central discovery centre,BHU,and Scanning Electron Microscopy Laboratory,Geology,BHU,for instrumental support.AB acknowledges the University Grant Commission for funding this work as a start-up Research Grant(No.F.30-431/2018-BSR)AB would also like to thank Banaras Hindu University for utilizing partial funds from the Bridge Grant(Development Scheme number 6031-A)under the Institution of Eminence(IoE)program to the University。
文摘This study aims to investigate the combined use of multi-sensor datasets(Landsat 4–5&8 OLI satellite imagery,spatial resolution=30 m)coupled with field studies to evaluate spatio-temporal dynamics of soil salinization along the coastal belt in West Bengal,India.This study assesses soil salinization by mapping the salinity and electrical conductivity of saturation extract(ECe)and utilizing spectral signatures for estimating soil salinity.The SI change(%)was analyzed(2021–1995),categorizing increases in salinity levels into 5%,10%,and 50%changes possibly due to salt encrustation on the soil layers.The land use land cover(LULC)change map(2021–1995)demonstrates that the study area is continuously evolving in terms of urbanization.Moreover,in the study area,soil salinity ranges from 0.03 ppt to 3.87 ppt,and ECe varies from 0.35 dSm^(-1)to 52.85 dSm^(-1).Additionally,vulnerable saline soil locations were further identified.Classification of soil salinity based on ECe reveals that 26%of samples fall into the nonsaline category,while the rest belong to the saline category.The Spectral signatures of the soil samples(n=19)acquired from FieldSpec hand spectrometer show significant absorption features around 1400,1900,and 2250 nm and indicate salt minerals.The results of reflectance spectroscopy were crossvalidated using X-ray fluorescence and scanning electron microscopy.This study also employed partial least square regression(PLSR)approach to predict ECe(r^(2)=0.79,RMSE=3.29)and salinity parameters(r^(2)=0.75,RMSE=0.51),suggesting PLSR applicability in monitoring salt-affected soils globally.This study’s conclusion emphasizes that remote sensing data and multivariate analysis can be crucial tools for mapping spatial variations and predicting soil salinity.It has also been concluded that saline groundwater used for irrigation and aqua-cultural activities exacerbates soil salinization.The study will help policymakers/farmers identify the salt degradation problem more effectively and adopt immediate mitigation measures.
基金the National Natural Science Foundation of China(No.42107513)the Key Projects of Natural Science Foundation of Gansu Province(No.22JR5RA051)+1 种基金the Gansu Province Science and Technology project(No.21JR7RA070)the Key Research and Development Program of Gansu Province(No.21YF5FA151).
文摘Salinized soil is an important reserved arable land resource in China.The management and utilization of salinized soil can safeguard the current size of arable land and a stable grain yield.Salt accumulation will lead to the deterioration of soil properties,destroy soil production potential and damage soil ecological functions,which in turn will threaten global water and soil resources and food security,and affect sustainable socio-economic development.Microorganisms are important components of salinized soil.Microbial remediation is an important research tool in improving salinized soil and is key to realizing sustainable development of agriculture and the ecosystem.Knowledge about the impact of salinization on soil properties and measures using microorganisms in remediation of salinized soil has grown over time.However,the mechanisms governing these impacts and the ecological principles for microbial remediation are scarce.Thus,it is imperative to summarize the effects of salinization on soil physical,chemical,and microbial properties,and then review the related mechanisms of halophilic and halotolerant microorganisms in salinized soil remediation via direct and indirect pathways.The stability,persistence,and safety of the microbial remediation effect is also highlighted in this review to further promote the application of microbial remediation in salinized soil.The objective of this review is to provide reference and theoretical support for the improvement and utilization of salinized soil.
文摘By analyzing the process of soil salt accumulation in irrigation area, and discussing the change of irrigation and drainage methods for drought transformed into water, the control scheme of soil secondary salinization in Wujiazi Irrigation Area was analyzed concretely, and the experience was summarized. After in-depth discussion, the importance of irrigation and drainage methods in the prevention and control of soil secondary salinization in irrigation areas was analyzed.
基金supported by the Open Fund of State Key Laboratory of Frozen Soil Engineering (Grant No.SKLFSE201806)the National Natural Science Foundation of China (Grant No.42177155).
文摘Sudden temperature drops cause soils in natural environments to freeze unidirectionally,resulting in soil expansion and deformation that can lead to damage to engineering structures.The impact of temperature-induced freezing on deformation and solute migration in saline soils,especially under extended freezing,is not well understood due to the lack of knowledge regarding the microscopic mechanisms involved.This study investigated the expansion,deformation,and water-salt migration in chlorinated saline soils,materials commonly used for canal foundations in cold and arid regions,under different roof temperatures and soil compaction levels through unidirectional freezing experiments.The microscopic structures of saline soils were observed using scanning electron microscopy(SEM)and optical microscopy.A quantitative analysis of the microstructural data was conducted before and after freezing to elucidate the microscopic mechanisms of water-salt migration and deformation.The results indicate that soil swelling is enhanced by elevated roof temperatures approaching the soil's freezing point and soil compaction,which prolongs the duration and accelerates the rate of water-salt migration.The unidirectional freezing altered the microstructure of saline soils due to the continuous temperature gradients,leading to four distinct zones:natural frozen zone,peak frozen zone,gradual frozen zone,and unfrozen zone,each exhibiting significant changes in pore types and fractal dimensions.Vacuum suction at the colder end of the soil structure facilitates the upward migration of salt and water,which subsequently undergoes crystallization.This process expands the internal pore structure and causes swelling.The findings provide a theoretical basis for understanding the evolution of soil microstructure in cold and arid regions and for the management of saline soil engineering.
基金supported by the National Natural Science Foundation of China(Grant Nos.42372312,and 42172299)the Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture(Grant No.JDYC20220807).
文摘The progressive failure characteristics of geomaterial are a remarkable and challenging topic in geotechnical engineering.To study the effect of salt content and temperature on the progressive failure characteristics of frozen sodium sulfate saline sandy soil,a series of uniaxial compression tests were performed by integrating digital image correlation(DIC)technology into the testing apparatus.The evolution law of the uniaxial compression strength(UCS),the failure strain,and the formation of the shear band of the frozen sodium sulfate saline sandy soil were analyzed.The test results show that within the scope of this study,with the increase of salt content,both the UCS and the shear band angle initially decrease with increasing salt content before showing an increase.In contrast,the failure strain and the width of the shear band exhibit an initial increase followed by a decrease in the samples.In addition,to investigate the brittle failure characteristics of frozen sodium sulfate saline sandy soil,two classic brittleness evaluation methods were employed to quantitatively assess the brittleness level for the soil samples.The findings suggest that the failure characteristics under all test conditions in this study belong to the transition stage between brittle and ductile,indicating that frozen sodium sulfate saline sandy soil exhibits certain brittle behavior under uniaxial compression conditions,and the brittleness index basically decreases and then increases with the rise in salt content.
基金funded by the Key Research and Development Project of Xinjiang Uygur Autonomous Region(2023A02002-2)the National Key Research and Development Program of China(2023YFD1901503)the Central Guidance Fund for Local Science and Technology Development of Xinjiang Uygur Autonomous Region(ZYYD2024CG03)。
文摘Biochar and animal manure application can improve crop yields in salt-affected soil.Previous studies have primarily applied biochar and animal manure either alone or at fixed ratios,while their combined effects with varying combination proportions are still unclear.To address this knowledge gap,we performed a 2-a experiment(2023-2024)in a salinized cotton field in Wensu County of Xinjiang Uygur Autonomous Region of China with the following 6 treatments:control;application of biochar(10t/hm^(2))alone(BC100%);application of cow manure(10 t/hm^(2))alone(CM100%);application of 70%biochar(7 t/hm^(2))combined with 30%cow manure(3 t/hm^(2))(BC70%+CM30%);application of 50%biochar(5 t/hm^(2))combined with 50%cow manure(5 t/hm^(2))(BC50%+CM50%);and application of 30%biochar(3 t/hm^(2))combined with 70%cow manure(7 t/hm^(2))(BC30%+CM70%).By measuring soil pH,electrical conductivity,soil organic matter,available phosphorus,available potassium,and available nitrogen at 0-20 and 20-40 cm depths,as well as yield components and cotton yield in 2023 and 2024,this study revealed that soil nutrients in the 0-20 cm depth were more sensitive to the treatment.Among all the treatments,BC50%+CM50%treatment had the highest value of soil pH(9.63±0.07)but the lowest values of electrical conductivity(161.9±31.8μS/cm),soil organic matter(1.88±0.27 g/kg),and available potassium(42.72±8.25 mg/kg)in 2024.Moreover,the highest cotton yield(5336.63±467.72 kg/hm^(2))was also observed under BC50%+CM50%treatment in 2024,which was 1.9 times greater than that under the control treatment.In addition,cotton yield in 2023 was jointly determined by yield components(density and number of cotton bolls)and soil nutrients(available phosphorus and available potassium),but in 2024,cotton yield was only positively related to yield components(density,number of cotton bolls,and single boll weight).Overall,this study highlighted that in salt-affected soil,the combination of biochar and cow manure at a 1:1 ratio is recommended for increasing cotton yield and reducing soil salinity stress.
