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

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.

Effects of water and salt for groundwater-soil systems on root growth and architecture of Tamarix chinensis in the Yellow River Delta,China

To test the patterns of the root morphology and architecture indexes of Tamarix chinensis in response to water and salt changes in the two media of the groundwater and soil,three-year-old T.chinensis seedlings were chosen as the research object.Groundwater with four salinity levels was created,and three groundwater level(GL)were applied for each salinity treatment to measure the root growth and architecture indexes.In the fresh water and brackish water treatments,the topological index(TI)of the T.chinensis roots was close to 0.5,and the root architecture was close to a dichotomous branching pattern.In the saline water and saltwater treatments,the TI of the T.chinensis roots was large and close to 1.0,and the root architecture was close to a herringbone-like branching pattern.Under different GLs and salinities,the total root length was significantly greater than the internal link length,the external link length was greater than the internal link length,and the root system showed an outward expansion strategy.The treatment with fresh water and a GL of 1.5 m was the most suitable for T.chinensis root growth,while the root growth of T.chinensis was the worst in the treatment with saline water and a GL of 0.3 m.T.chinensis can adapt to the changes in soil water and salt by regulating the growth and morphological characteristics of the root system.T.chinensis can adapt to high-salt environments by reducing its root branching and to water deficiencies by expanding the distribution and absorption area of the root system.

Spatial Distribution of Soil Salinization Based on GIS in Tianjin Binhai New Area

The distribution of soil salinization was investigated based on GIS and field sampling in Tianjin Binhai New Area. The results showed that the average soil total salt content was 0.818%, with an average pH of 8.43, and the average CI and Na＋ contents were 0.27% and 0.22%, respectively. Presenting zonal distribution feature, the soil total salt content increased gradually from west to east of Binhai New Area. Statistics on the distribution areas of different salinization degrees showed that the area of non-salinzed soils only accounted for 3.18% of the total area; with an area of 107.43 km2, mild saline soil accounted for 6.34% of the total area; the area of moderate saline soil was 173.51 km2, accounting for 10.24%; and the area of sal- inzed soils was 217.36 km2, accounting for 12.82% of the total soil area. The area of saline soils （total salt content 〉0.6%） was 1 142.8 km2, accounting 67.42% of the total land area in Binhai New Area. And the areas for the soils with total salt content of 0.6%-1.0%, 1.0%-1.5%, 〉1.5% were respectively 388.47, 411.82, 342.51 km2, accounting for 22.92%, 24.3%, 20.21% of the total area.

A Spectral Index for Estimating Soil Salinity in the Yellow River Delta Region of China Using EO-1 Hyperion Data

Soil salinization is one of the most common land degradation processes. In this study, spectral measurements of saline soil samples collected from the Yellow River Delta region of China were conducted in laboratory and hyperspectral data were acquired from an EO-1 Hyperion sensor to quantitatively map soil salinity in the region. A soil salinity spectral index (SSI) was constructed from continuum-removed reflectance (CR-reflectance) at 2052 and 2203 nm, to analyze the spectral absorption features of the salt-affected soils. There existed a strong correlation (r = 0.91) between the SSI and soil salt content (SSC). Then, a model for estimation of SSC with SSI was established using univariate regression and validation of the model yielded a root mean square error (RMSE) of 0.986 and an R2 of 0.873. The model was applied to a Hyperion reflectance image on a pixel-by-pixel basis and the resulting quantitative salinity map was validated successfully with RMSE = 1.921 and R2 = 0.627. These suggested that the satellite hyperspectral data had the potential for predicting SSC in a large area.

Correlation Between Soil Water Retention Capability and Soil Salt Content

The soil moisture retention capability of Chao soil and coastal saline Chao soil in Shandong and Zhejiang provinces were measured by pressure membrane method. The main factors influencing soil moisture retention capability were studied by the methods of correlation and path analyses. The results indicated that < 0.02mm physical clay and soil salt content were the main factors influencing soil moisture retention capability. At soil suction of 30-50 kpa, the soil salt content would be the dominant factor.

Spatial distribution of soil moisture,salinity and organic matter in Manas River watershed,Xinjiang,China

With the classical statistical and geostatistical methods, the study of the spatial distribution and its in- fluence factors of soil water, salinity and organic matter was carried out for 0-70 cm soil layers in Manas River watershed. The results showed that the soil moisture data from all soil layers exhibited a normal distribution, with average values of 14.08%-21.55%. Geostatistical analysis revealed that the content of soil moisture had a moder- ate spatial autocorrelation with the ratios of nugget/sill ranging from 0.500 to 0.718, which implies that the spatial pattern of soil moisture is influenced by the combined effects of structural factors and random factors. Remarkable spatial distributions with stripped and mottled features were found for soil moisture in all different soil layers. The landform and crop planting had a relatively big influence on the spatial distribution of soil moisture; total soil salinity was high in east but low in west, and non-salinized soil and lightly salinized soil appeared at the northwest and southwest of the study area. Under the effect of reservoir leakage, the heavily salinized soils are widely distributed in the middle of the study area. The areas of the non-salinized and lightly salinized soils decreased gradually with soil depth increment, which is contrary to the case for saline soils that reached a maximum of 245.67 km2 at the layer of 50-70 cm. The types of soil salinization in Manas River watershed were classified into four classes： the sulfate, chloride-sulfate, sulfate-chloride and chloride. The sulfate salinized soil is most widely distributed in the surface layer. The areas of chloride-sulfate, sulfate-chloride, and chloride salinized soils increased gradually along with the increment of soil depth; the variation range of the average values of soil organic matter content was be- tween 7.48%-11.33%. The ratios of nugget/sill reduced gradually from 0.698 to 0.299 with soil depth increment, which shows that the content of soil organic matter has a moderate spatial autocorrelation. The soil organic matter in all soil layers met normal distribution after logarithmic transformation. The spatial distribution patterns of soil or- ganic matter and soil moisture were similar; the areas with high organic matter contents were mainly distributed in the south of the study area, with the lowest contents in the middle.

Water and salt movement in different soil textures under various negative irrigating pressures

supported by the National High-Tech R＆D Program of China （2013AA102901）

Variation of soil physical-chemical characteristics in salt-affected soil in the Qarhan Salt Lake,Qaidam Basin

Soil salinization has adverse effects on the soil physical-chemical characteristics.However,little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the Qarhan Salt Lake and at different soil depths in the surrounding areas.Here,we selected five sampling sites(S1,S2,S3,S4,and S5)alongside the Qarhan Salt Lake and in the Xidatan segment of the Kunlun Mountains to investigate the relationship among soil salt ion concentrations,soil physical-chemical characteristics,and environmental variables in April 2019.The results indicated that most sites had strongly saline and very strongly saline conditions.The main salt ions present in the soil were Na^(+),K^(+),and Cl^(-).Soil nutrients and soil microbial biomass(SMB)were significantly affected by the salinity(P<0.05).Moreover,soil salt ions(Na^(+),K^(+),Ca2+,Mg^(2+),Cl^(-),CO_(3)^(2-),SO_(4)^(2-),and HCO_(3)^(-))were positively correlated with electrical conductivity(EC)and soil water content(SWC),but negatively related to altitude and soil depth.Unlike soil salt ions,soil nutrients and SMB were positively correlated with altitude,but negatively related to EC and SWC.Moreover,soil nutrients and SMB were negatively correlated with soil salt ions.In conclusion,soil nutrients and SMB were mainly influenced by salinity,and were related to altitude,soil depth,and SWC in the areas from the Qarhan Salt Lake to the Xidatan segment.These results imply that the soil quality(mainly evaluated by soil physical-chemical characteristics)is mainly influenced by soil salt ions in the areas surrounding the Qarhan Salt Lake.Our results provide an accurate prediction of how the soil salt ions,soil nutrients,and SMB respond to the changes along a salt gradient.The underlying mechanisms controlling the soil salt ion distribution,soil nutrients,and SMB in an extremely arid desert climate playa should be studied in greater detail in the future.

Monitoring Soil Salt Content Using HJ-1A Hyperspectral Data: A Case Study of Coastal Areas in Rudong County, Eastern China

Hyperspectral data are an important source for monitoring soil salt content on a large scale. However, in previous studies, barriers such as interference due to the presence of vegetation restricted the precision of mapping soil salt content. This study tested a new method for predicting soil salt content with improved precision by using Chinese hyperspectral data, Huan Jing-Hyper Spectral Imager(HJ-HSI), in the coastal area of Rudong County, Eastern China. The vegetation-covered area and coastal bare flat area were distinguished by using the normalized differential vegetation index at the band length of 705 nm(NDVI705). The soil salt content of each area was predicted by various algorithms. A Normal Soil Salt Content Response Index(NSSRI) was constructed from continuum-removed reflectance(CR-reflectance) at wavelengths of 908.95 nm and 687.41 nm to predict the soil salt content in the coastal bare flat area(NDVI705 < 0.2). The soil adjusted salinity index(SAVI) was applied to predict the soil salt content in the vegetation-covered area(NDVI705 ≥ 0.2). The results demonstrate that 1) the new method significantly improves the accuracy of soil salt content mapping(R2 = 0.6396, RMSE = 0.3591), and 2) HJ-HSI data can be used to map soil salt content precisely and are suitable for monitoring soil salt content on a large scale.

Soil Organic Carbon Contents and Stocks in Coastal Salt Marshes with Spartina alterniflora Following an Invasion Chronosequence in the Yellow River Delta,China

Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.

An experimental study of salt expansion in sodium saline soils under transient conditions

Salt expansion in sulfate saline soils that are widely distributed in northwestern China causes serious infrastructural damages under low-temperature conditions. However, the mechanism of salt expansion under low temperatures is not clear. In this study, we conducted a series of cooling experiments combined with salt crystallization to study this mechanism, and employed an ionic model to calculate the supersaturation ratio of the solution. During the experiments, the strength and the process of salt expansion were examined under different cooling rates and various crystal morphologies. The relationship between temperature and supersaturation ratio under transient conditions was also considered. Results indicate that the initial supersaturation ratio of a sodium sulfate solution is closely related to environmental conditions, and that this ratio decreases with slowing the cooling rates and stabilizing the crystal forms. Higher initial supersaturation ratios lead to an increased non-steady-state zone, resulting in less salt expansion. On the other hand, chloride ion content has a distinct influence on the crystallization supersaturation ratio of the sodium sulfate solution, and higher chloride ion content can inhibit salt expansion in sodium saline soils. These findings help explain salt expansion mechanisms in complex conditions such as seasonally frozen soils, and thus help search for improved methods of preventing salt expansion in sulfate saline soils.

Reducing water and nitrogen inputs combined with plastic mulched ridge-furrow irrigation improves soil water and salt status in arid saline areas,China

Plastic mulched ridge-furrow irrigation is a useful method to improve crop productivity and decrease salt accumulation in arid saline areas.However,inappropriate irrigation and fertilizer practices may result in ecological and environmental problems.In order to improve the resource use efficiency in these areas,we investigated the effects of different irrigation amounts(400(I1),300(I2)and 200(I3)mm)and nitrogen application rates(300(F1)and 150(F2)kg N/hm^(2))on water consumption,salt variation and resource use efficiency of spring maize(Zea mays L.)in the Hetao Irrigation District(HID)of Northwest China in 2017 and 2018.Result showed that soil water contents were 0.2%-8.9%and 13.9%-18.1%lower for I2 and I3 than for I1,respectively,but that was slightly higher for F2 than for F1.Soil salt contents were 7.8%-23.5%and 48.5%-48.9%lower for I2 than for I1 and I3,but that was 1.6%-5.5%higher for F1 than for F2.Less salt leaching at the early growth stage(from sowing to six-leaf stage)and higher salt accumulation at the peak growth stage(from six-leaf to tasseling stage and from grain-filling to maturity stage)resulted in a higher soil salt content for I3 than for I1 and I2.Grain yields for I1 and I2 were significantly higher than that for I3 and irrigation water use efficiency for I2 was 14.7%-34.0%higher than that for I1.Compared with F1,F2 increased the partial factor productivity(PFP)of nitrogen fertilizer by more than 80%.PFP was not significantly different between I1F2 and I2F2,but significantly higher than those of other treatments.Considering the goal of saving water and nitrogen resources,and ensuring food security,we recommended the combination of I2F2 to ensure the sustainable development of agriculture in the HID and other similar arid saline areas.

Quantitative retrieval of soil salt content based on measured spectral data

Choosing the Minqin Oasis, located downstream of the Shiyang River in Northwest China, as the study area, we used field-measured hyperspectral data and laboratory-measured soil salt content data to analyze the characteristics of saline soil spectral reflectance and its transformation in the area, and elucidated the relations between the soil spectral re-flectance, reflectance transformation, and soil salt content. In addition, we screened sensitive wavebands. Then, a multiple linear regression model was established to predict the soil salt content based on the measured spectral data, and the accuracy of the model was verified using field-measured salinity data. The results showed that the overall shapes of the spectral curves of soils with different degrees of salinity were consistent, and the reflectance in visible and near-infrared bands for salinized soil was higher than that for non-salinized soil. After differential transformation, the correlation coefficient between the spectral reflectance and soil salt content was obviously improved. The first-order differential transformation model based on the logarithm of the reciprocal of saline soil spectral reflectance produced the highest accuracy and stability in the bands at 462 and 636 nm; the determination coefficient was 0.603, and the root mean square error was 5.407. Thus, the proposed model provides a good reference for the quantitative extraction and monitoring of regional soil salinization.

Influence of Salt Content on Soil Microbial Biomass Carbon

Soil salinization has become a global issue. Saline and alkaline arable land was taken as research object in this paper and four salt gradients were set(S1: 0.1%; S2:0. 5%; S3:0.9%; S4:1.3%). Through the addition of different substrates( CK: no addition of substrate; N: addition of nitrogen source; C: addition of glucose,C + N: addition of glucose and nitrogen source) to soil,it analyzed the influence of salt content on the soil microbial biomass carbon( SMBC) for the purpose of surveying the response mechanism of soil carbon turnover to salt stress. Results indicated that after addition of different substrates,the SMBC in high salt content(S3 and S4) is obviously lower than that in low salt content( S1 and S2). The decline rate of S3 and S4 is 5. 4% and 14. 2% for no addition of substrate; the decline rate is 9.0% and 24.0% for addition of nitrogen source; the decline rate is 11.5% and 28.0% for addition of carbon source; the decline rate is 19.5% and 39.5% for addition of carbon source + nitrogen source. Compared with no addition of substrates,addition of nitrogen source could not increase the SMBC. Addition of carbon source and carbon + nitrogen can significantly increase the SMBC,and the increase in low salt content soil( 80.0%- 81.0% and 58.0%- 59.0%) is obviously higher than high salt content soil( 52.0%- 69.0%and 34.0%- 50.0%). Generally,when the soil salt content is low( 0.5%),the influence of different substrate treatment is little on the SMBC,and increasing the soil salt content can obviously reduce the SMBC.

Timely monitoring of soil water-salt dynamics within cropland by hybrid spectral unmixing and machine learning models

Soil salinization and water scarcity are main restrictive factors for irrigated agriculture development in arid regions.Knowing dynamics of soil water and salt content is an important antecedent in remediating salinized soils and optimizing irrigation management.Previous studies mostly used remote sensing technologies to individually monitor water or salt content dynamics in agricultural areas.Their ability to asses different levels of crop water and salt management has been less explored.Therefore,how to extract effective diagnostic features from remote sensing images derived spectral information is crucial for accurately estimating soil water and salt content.In this study,Linear spectral unmixing method(LSU)was used to obtain the contribution of soil water and salt to each band spectrum(abundance),and endmember spectra from Sentinel-2 images.Calculating spectral indices and selecting optimal spectal combination were individually based on soil water and salt endmember spectra.The estimation models were constructed using six machine learning algorithms:BP Neural Network(BPNN),Support Vector Regression(SVR),Partial Least Squares Regression(PLSR),Random Forest Regression(RFR),Gradient Boost Regression Tree(GBRT),and eXtreme Gradient Boosting tree(XGBoost).The results showed that the spectral indices calculated from endmember spectra were able to effectively characterize the response of crop spectral properties to soil water and salt,which circumvent spectral ambiguity induced by water-salt mixing.NDRE spectral index was a reliable indicator for estimating water and salt content,with determination coefficients(R2)being 0.55 and 0.57,respectively.Compared to other models,LSU-XGBoost model achieved the best performance.This model properly reflected the process of soil water-salt dynamics in farmland during crop growth period.This study provided new methods and ideas for soil water-salt estimation in dry irrigated agricultural areas,and provided decision support for gover-nance of salinized land and optimal management of irrigation.

Straw interlayer improves sunflower root growth:Evidence from moisture and salt migration and the microbial community in saline-alkali soil

A straw interlayer added to soil can effectively reduce soil salinity effects on plant growth,however,the effects of soil moisture,salt and microbial community composition on plant growth under a straw interlayer are unclear.A rhizobox study was conducted to investigate the role of straw interlayer thickness on soil moisture,salt migration,microbial community composition,as well as root growth in sunflower.The study included four treatments:Control(no straw interlayer);S3(straw interlayer of 3.0 cm);S5(straw interlayer of 5.0 cm);S7(straw interlayer of 7.0 cm).Straw interlayer treatments increased soil moisture by 8.2–11.0%after irrigation and decreased soil salt content after the bud stage in 0–40 cm soil.Total root length,total root surface area,average root diameter,total root volume and the number of root tips of sunflower plants were higher under straw interlayer treatments than in the control,and were the highest under the S5 treatment.This stimulated root growth was ascribed to the higher abundance of Chloroflexi and Verrucomicrobia bacteria in soil with a straw interlayer,which was increased by 55.7 and 54.7%,respectively,in the S5 treatment.Addition of a straw interlayer of 5 cm thickness is a practical and environmentally feasible approach for improving sunflower root growth in saline-alkali soil.

Increased salinity and groundwater levels lead to degradation of the Robinia pseudoacacia forest in the Yellow River Delta

Forest degradation is a worldwide problem,although its causes vary due to geographical and climatic differences and man-made causes.In recent years,the Robinia pseudoacacia forest in the Yellow River Delta has suffered severe degradation.The causative mechanisms were investigated in the field over two years,and the results show that increased forest degradation was reflected by increased tree mortality,high leaf and soil sodium salt levels and groundwater depth.Average tree diameters decreased,and leaf chlorophyll and soil microbial contents decreased.Redundancy discriminate analysis(RDA)showed that degradation of the forest was correlated positively with soil salt content,but negatively with groundwater depth.Correlation analysis showed that 0.79%–0.95%soil salt content and above 1.20 m groundwater depth caused the death of R.pseudoacacia trees due to localized anthropogenic economic activities,such as rice farming,that disrupted the original water–salt balance.Measures are recommended to prevent further degradation and restore degraded forests.

Effects of bile salts and divalent cations on the adsorption of norfloxacin by agricultural soils

The effects of bile salts （sodium cholate and sodium deoxycholate, 0-20 mmol/L）, divalent cations （Ca^2＋, Mg^2＋, Cu^2＋ and Zn^2＋, 0-20 mmol/L） or pH （3.0-10.0） on the adsorption of norfloxacin by three selected soils （Paddy_H, Paddy_G and Red_J） were systematically studied. Soil adsorption of norfloxacin follows a pseudo second-order kinetics model, and the maximum adsorption capacity has been determined from the nonlinear fit of the Langmuir isotherm model to be 88.8, 88.1 and 63.0 μmol/g for the adsorption onto Paddy_H, Paddy_G and Red_J, respectively. The results indicate that norfloxacin has a high adsorption affinity for the agricultural soils tested and that the organic content of these soils have at least a slight influence on this adsorption. The adsorption of norfloxacin to soils was strongly dependent on pH and exhibited a maximum at approximately pH 6. The presence of divalent cations prominently suppressed the adsorption of norfloxacin by paddy soils, which followed an order of Cu^2＋ 〉 Mg^2＋ 〉 Ca^2＋ 〉 Zn^2＋, and by red soil, which followed an order of Cu^2＋ 〉 Zn^2＋ 〉 Ca^2＋ 〉 Mg^2＋. The adsorption of norfloxacin （by the soils studied） sharply decreased as the amount of bile salts was increased. For uncharged norfloxacin at environmentally relevant pH values, such factors as soil type, exogenous divalent cations and macromolecules significantly altered the environmental fate and transport of norfloxacin between aquatic and soil interfaces.

Nutrient Accumulation and Distribution in Cotton Promoted by Removal of Mulch Film

Plastic film mulching affects changes in nutrient contents in soil and absorption and utilization of nutrients in plants were by changing hydrothermal condition of soil.The temporal and spatial variation of the total soil salt and nutrient contents with mulch film removed at three different times during the early cotton growth stage and its effects on nutrient absorption and accumulation in cotton plants were studied over 2015-2017.The film removal treatments reduced salt accumulation in normal rainfall year(2017).Film removal increased contents of soil organic matter,the total phosphorus and available potassium at the end of growth stage,increased contents of soil hydrolyzable nitrogen and the total nitrogen in the surface soil layer(0-10 cm),and increased the total nitrogen contents in the deep soil layer(40-50 cm).Film removal increased accumulation of nitrogen and phosphorus nutrients in cotton plants in 2017 and accumulation of nitrogen,phosphorus and potassium nutrients in cotton plants in heavy rainfall year(2016).These experimental results indicated that removal of mulch film at an appropriate and targeted time in the bud stage of cotton promoted nutrient absorption.

Effects of irrigation level and method on soil salt balance and crop water use efficiency in arid oasis regions

Fresh water resource scarcity and soil salt accumulation in the root-zone are two key limiting factors for sustainable agricultural development in the oasis region of arid inland basin, northwest China. The aim of this study was to explore an appropriate irrigation scheme to maintain sustainable crop cultivation in this region. The effects of four irrigation levels (full irrigation, mild deficit, moderate deficit, and severe deficit) and three irrigation methods (border, surface drip and subsurface drip) on soil water and salt dynamics, highland barley (Hordeum vulgare L.) yield, and crop water use efficiency were studied by field plot experiments. The results showed that soil salt in 0-100 cm profile was accumulated under all experimental treatments after one season of highland barley planting, but the accumulated salt mass decreased with the decrease of the lower limit of irrigation. Salt mass in 0-100 cm soil profile under subsurface drip irrigation was 16.8%-57.8% and 2.9%-58.4% less than that under border and surface drip irrigation, respectively. The grain yield of highland barley decreased first and then increased with the decrease of the lower limit of irrigation under surface drip and subsurface drip irrigation, but it was on the contrary under border irrigation. Mean grain yield for all irrigation levels under subsurface drip irrigation was 5.7% and 18.8% higher than that under border and surface drip irrigation, respectively. Water use efficiency increased with the decrease of the lower limit of irrigation, and the averaged water use efficiency of all irrigation levels under subsurface drip irrigation was 11.9% and 14.2% higher than that under border and surface drip irrigation, respectively. Considering economic benefit and irrigation water requirement, subsurface drip irrigation with the lower limit of irrigation of 50%-55% field capacity is suggested for highland barley planting in the arid oasis region.