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.

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.

Effects of irrigation water salinity on soil salt content distribution,soil physical properties and water use efficiency of maize for seed production in arid Northwest China

In order to explore the use of groundwater resources,field experiments were conducted for three consecutive years during 2012-2014 in the Shiyang River basin of Northwest China.Irrigation was conducted using four different water salinity levels that were arranged in a split plot design.These four water salinity levels were s0,s3,s6 and s9(0.71,3,6 and 9 g/L,respectively).The soil salt content,soil bulk density,soil porosity,saturated hydraulic conductivity,plant height,leaf area index and yield of maize for seed production were measured for studying the effects of saline water irrigation on soil salt content distribution,soil physical properties and water use efficiency.It was observed that higher salinity level of irrigation water and long duration of saline water irrigation resulted in more salt accumulation.Compared to initial values,the soil salt accumulation in 0-100 cm soil layer after three years of experiments for s0,s3,s6 and s9 was 0.189 mg/cm3,0.654 mg/cm3,0.717 mg/cm3 and 1.135 mg/cm3,respectively.Both greater salt levels in the irrigation water and frequent saline water irrigation led to greater soil bulk density,but poorer soil porosity and less saturated hydraulic conductivity.The saturated hydraulic conductivity decreased with increase in soil bulk density,but increased with improvement in soil porosity.It was noted that the maize height,leaf area index and maize yield gradually decreased with increase in water salinity.The maize yield decreased over 25%and the water use efficiency also gradually declined when irrigated with water containing 6 g/L and 9 g/L salinity levels.However,maize yield following saline water irrigation with 3 g/L decreased less than 20%and the decline in water use efficiency was not significant during the three-year experiment period.The results demonstrate that irrigation with saline water at the level of 6 g/L and 9 g/L in the study area is not suitable,while saline water irrigation with 3 g/L would be acceptable for a short duration together with salt leaching through spring irrigation before sowing.

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.

Derivation of salt content in salinized soil from hyperspectral reflectance data: A case study at Minqin Oasis, Northwest China

Soil salinization is a serious ecological and environmental problem because it adversely affects sustainable development worldwide, especially in arid and semi-arid regions. It is crucial and urgent that advanced technologies are used to efficiently and accurately assess the status of salinization processes. Case studies to determine the relations between particular types of salinization and their spectral reflectances are essential because of the distinctive characteristics of the reflectance spectra of particular salts. During April 2015 we collected surface soil samples(0–10 cm depth) at 64 field sites in the downstream area of Minqin Oasis in Northwest China, an area that is undergoing serious salinization. We developed a linear model for determination of salt content in soil from hyperspectral data as follows. First, we undertook chemical analysis of the soil samples to determine their soluble salt contents. We then measured the reflectance spectra of the soil samples, which we post-processed using a continuum-removed reflectance algorithm to enhance the absorption features and better discriminate subtle differences in spectral features. We applied a normalized difference salinity index to the continuum-removed hyperspectral data to obtain all possible waveband pairs. Correlation of the indices obtained for all of the waveband pairs with the wavebands corresponding to measured soil salinities showed that two wavebands centred at wavelengths of 1358 and 2382 nm had the highest sensitivity to salinity. We then applied the linear regression modelling to the data from half of the soil samples to develop a soil salinity index for the relationships between wavebands and laboratory measured soluble salt content. We used the hyperspectral data from the remaining samples to validate the model. The salt content in soil from Minqin Oasis were well produced by the model. Our results indicate that wavelengths at 1358 and 2382 nm are the optimal wavebands for monitoring the concentrations of chlorine and sulphate compounds, the predominant salts at Minqin Oasis. Our modelling provides a reference for future case studies on the use of hyperspectral data for predictive quantitative estimation of salt content in soils in arid regions. Further research is warranted on the application of this method to remotely sensed hyperspectral data to investigate its potential use for large-scale mapping of the extent and severity of soil salinity.

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）

Soil water and salt distribution under furrow irrigation of saline water with plastic mulch on ridge

Furrow irrigation when combined with plastic mulch on ridge is one of the current uppermost wa- ter-saving irrigation technologies for arid regions. The present paper studies the dynamics of soil water-salt trans- portation and its spatial distribution characteristics under irrigation with saline water in a maize field experiment. The mathematical relationships for soil salinity, irrigation amount and water salinity are also established to evaluate the contribution of the irrigation amount and the salinity of saline water to soil salt accumulation. The result showed that irrigation with water of high salinity could effectively increase soil water content, but the increment is limited com- paring with the influence from irrigation amount. The soil water content in furrows was higher than that in ridges at the same soil layers, with increments of 12.87% and 13.70% for MMF9 （the treatment with the highest water salinity and the largest amount of irrigation water） and MMF1 （the treatment with the lowest water salinity and the least amount of irrigation water） on 27 June, respectively. The increment for MMF9 was gradually reduced while that for MMF1 increased along with growth stages, the values for 17 August being 2.40% and 19.92%, respectively. Soil water content in the ridge for MMF9 reduced gradually from the surface layer to deeper layers while the surface soil water content for MMF1 was smaller than the contents below 20 cm at the early growing stage. Soil salinities for the treatments with the same amount of irrigation water but different water salinity increased with the water salinity. When water salinity was 6.04 dS/m, the less water resulted in more salt accumulation in topsoil and less in deep layers. When water salinity was 2.89 dS/m, however, the less water resulted in less salt accumulation in topsoil and salinity remained basically stable in deep layers. The salt accumulation in the ridge surface was much smaller than that in the furrow bottom under this technology, which was quite different from traditional furrow irrigation. The soil salinities for MMF7, MMF8 and MMF9 in the ridge surface were 0.191, 0.355 and 0.427 dS/m, respectively, whereas those in the furrow bottom were 0.316, 0.521 and 0.631 dS/m, respectively. The result of correlation analysis indicated that compared with irrigation amount, the irrigation water salinity was still the main factor influ- encing soil salinity in furrow irrigation with plastic mulch on ridge.

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.

Effects of salinity on the soil microbial community and soil fertility

Saline area is an important reserve resource of arable land,however,the effects of soil microorganisms on the soil fertility in saline coastal ecosystems remain poorly understood.The salinity effects on soil microorganisms,nutrient availabilities and their relationships were studied in soils along a salinity gradient.A total of 80 soil samples were collected from 16 sites at four salinity levels(non-saline soil,salt content<1 g kg^1;low salinity soil,salt content=1–2 g kg^1;middle salinity soil,salt content=2–4 g kg^1;high salinity soil,salt content>4 g kg^1).The results showed that the salinity increased soil pH and exchangeable Na percent,but decreased soil organic matter,soil exchangeable K,and soil microbial biomass.Both the abundance and community composition of soil bacteria and fungi were significantly different between the non-saline and the saline soils.The predominant genera of soil bacteria(Planctomyces and Archangium,positive for carbon fixation)and fungi(Hydropisphaera,efficient in lignin degradation)changed with the increasing soil salinity and the decreasing soil organic matter.In summary,soil salinity changed the abundances of soil bacterial,fungal,and arbuscular mycorrhizal communities and,subsequently,affected their function in saline coastal ecosystems.

Experimental research on physical properties of saline soil subgrade filler in Chaerhan region

In order to improve the engineering stability of saline soil of high chloride content in the Chaerhan salt lake region, six typical characteristics saline soil samples were selected, and tests on their primary physical properties （total salt content, specific gravity of soil, liquid limit, plastic limit, maximum dry density, and optimal water content） were conducted. The relationships among them were analyzed, a series of variation laws between salt content and these basic physical parameters were determined, and regression equations were derived. This research can improve future engineering design and construction in saline soils and can also help prevent subgrade filler from undermining subgrade stability and producing disease.

盐渍土路基含盐量的演化规律研究

虽然目前针对盐渍土的研究比较多,但基本上都集中在项目勘察设计及建设期,对利用盐渍土填筑的路堤中含盐量随时间变化的规律,国内外研究还比较少。为了探究盐渍土路基填料中含盐量随时间的变化规律,为改建项目中盐渍土路基设计提供理论支撑,本文依托巴基斯坦罗赫里至木尔坦段既有铁路提速改造项目,通过现场调查及大量现场试验,对比分析既有路基填料及两侧原状土中含盐量,总结出盐渍土路基变化规律。结果表明:采用盐渍土填筑的路堤,路基填土中含盐量随着时间推移逐渐降低,逐渐过渡为非盐渍土;对于新建路基采用盐渍土填筑时,采用加宽路基面、放缓路堤坡率等工程措施,同时优先安排施工,静置浸润后,可有效降低路基填料中含盐量,直接采用盐渍土填筑路基既节约工程投资,又能确保路基的安全稳定。

Influencing factors of compressive strength of solidified inshore saline soil using SH lime-ash

Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.

不同改良剂对土壤盐渍化特性及燕麦生物排盐作用的影响

为探讨不同土壤改良剂在旱区盐渍土上的应用效果,通过单因素随机区组试验,以不施改良剂(T0)为对照,探究粉煤灰(T1)、生物炭(T2)、普通有机肥(T3)、糠醛渣(T4)、蚯蚓粪(T5)、腐殖酸(T6)六种改良剂单施以及分别使用单施用量的1/2进行不同改良剂粉煤灰+有机肥(T7)、粉煤灰+糠醛渣(T8)、生物炭+糠醛渣(T9)、蚯蚓粪+腐殖酸(T10)配施对土壤盐渍化特性和燕麦盐分积累的影响。结果表明,与T0处理相比,T1~T10处理下土壤Na^(+)、HCO_(3)^(-)、Cl^(-)和SO_(4)^(2-)含量分别降低37.18%~67.83%、35.25%~78.10%、45.16%~69.51%和6.60%~13.94%,K^(+)、Ca^(2+)和Mg^(2+)含量均增加;土壤全盐含量和钠吸附比(SAR)分别降低8.41%~15.97%和41.94%~69.70%;施用改良剂后土壤的pH值不同程度降低,T1、T2处理因改良剂自身的碱性导致土壤pH值降低效果不显著,T3~T10处理的土壤pH值较T0处理降低了5.09%~8.61%。改良剂配施对土壤Na^(+)、HCO_(3)^(-)、Cl^(-)、SO_(4)^(2-)含量、全盐含量及SAR、pH值的降低程度均优于单施,其中T7处理的降低效果最好。施用改良剂提高了燕麦的干草产量、地上部分的含盐量和盐分积累量。除T6处理外其他处理的燕麦盐含量较T0处理增加了1.43%~3.52%;T1~T10处理的燕麦盐分积累量增加了14.92%~34.64%,且盐分积累量增加幅度亦表现为配施大于单施。施用改良剂加速了耕层土壤的脱盐,T1~T10处理的脱盐率是T0处理的5~9倍,T7处理的脱盐率较T1~T5处理提高了4.99%~7.41%。综合来看,供试改良剂的单施及四种配施均具有降低试区盐渍土耕层土壤的盐度和碱化度的作用,且提升了燕麦的生物排盐作用;以粉煤灰与普通有机肥配施对耕层土壤盐渍化程度的降低效果最好。

含泥量对砂类硫酸盐渍土工程特性的影响分析

为了明确含泥量对砂类硫酸盐渍土的盐胀和力学特性的影响,人工配制了不同细粒土含量的砂类硫酸盐渍土,在1%和3%(质量分数,下同)含盐量单向冻结盐胀试验的基础上,选取了细粒土含量为5%、15%、30%和40%的砂样进行常温、低温三轴剪切试验。研究结果表明:此试验条件下,不同级配砂类硫酸盐渍土的冻结温度为-0.7~-0.1℃,当砂样孔隙溶液浓度在冻结温度之上达到饱和时,降温过程中会首先生成盐结晶;1%含盐量条件下,高细粒土含量(≥30%)砂样的起胀温度在4~9℃之内,而低细粒土含量砂样的起胀温度在0℃附近,3%含盐量砂样的起胀温度为20~23℃;试验含水率和细粒土含量通过影响土体中自由水的含量对盐冻胀产生显著影响。在力学特性方面,随着细粒土掺量的增加,砂类硫酸盐渍土的抗剪强度表现出先增大后减小的趋势,细粒土由增强摩擦转变为颗粒间的“润滑”作用;此外,冻结后砂土转变为承载能力更强的“土-盐-冰骨架结构”,抗剪强度大幅提高,并呈现出明显的脆性破坏特征,由于冻结砂土受相对温度的影响,随着含盐量的增加,破坏应力呈先减小后增大的趋势。

水盐含量及电阻率对盐渍土抗剪强度的影响

为了研究盐渍土的水盐含量及电阻率对其抗剪强度的影响,对长岭县的盐渍土进行室内试验,测量了不同深度土壤的含水率、含盐量、电阻率和抗剪强度,研究了电阻率和抗剪强度与含水率含盐量的关系。结果表明:盐渍土的电阻率随含盐量和含水率的增加而逐渐降低;经三轴剪切试验可得,内摩擦角和黏聚力均随含盐量的增加而减小,与含水率呈负相关;盐渍土的抗剪强度与电阻率之间具有良好的线性关系,抗剪强度随电阻率的增大而逐渐增大,构建盐渍土抗剪强度与电阻率之间的相关拟合公式,对实际工程应用有理论参考意义。

滨海黏质盐渍土饱和泥浆与不同土水比土壤浸提液电导率的响应关系分析

为统一和精准判定耐盐作物种植地块的土壤盐渍化程度,并针对饱和泥浆制备时饱和点的不确定性及其电导率测定的不稳定性等问题,本试验采用室内化验与统计分析方法,系统研究饱和泥浆与饱和土壤溶液两者间含水量和电导率的响应关系,以及饱和泥浆电导率、全盐含量与土水比1∶0.5、1∶1、1∶2.5、1∶3.5、1∶5土壤浸提液电导率与全盐含量的响应和换算关系。结果表明:在滨海黏质盐渍土区,利用计算田间土壤孔隙度得到的饱和土壤溶液含水量、电导率不能直接代替饱和泥浆含水量、电导率,尽管二者的响应关系达到极显著水平;饱和泥浆电导率、全盐含量分别与土水比1∶1和1∶0.5土壤浸提液的数值差异最小,且与土水比1∶0.5~1∶5间各处理土壤浸提液的相应指标均呈极显著的响应关系;饱和泥浆电导率与土水比1∶5土壤浸提液的电导率、饱和泥浆全盐含量与土水比1∶1土壤浸提液全盐含量相关性最高,可分别用最佳拟合线性模型进行换算,模型分别为ECe(mS/cm)=5.406EC1∶5-0.284 4,TSe(g/kg)=0.836 4TS1∶1-0.135 9。

土壤调理剂对滨海盐碱地土壤盐分含量及夏玉米产量的影响

研究不同类型土壤调理剂对滨海盐碱地夏玉米田0~10 cm、10~20 cm、20~30 cm和30~40 cm土层土壤盐分含量、玉米根系形态和籽粒产量的影响,为滨海盐碱地区夏玉米田适宜土壤调理剂的选用提供理论依据。试验于2022—2023年夏玉米季在山东省滨州市滨海盐碱型农田进行。采用完全随机区组设计,以不施土壤调理剂为对照(CK),设置3种不同类型的土壤调理剂,分别为硅钙钾镁型调理剂(T1)、硅钙钾镁沸石型调理剂(T2)和硅钙钾镁聚丙烯酰胺(PAM)型调理剂(T3)。研究不同类型土壤调理剂对0~40 cm土层土壤盐分含量、玉米根系形态、叶面积指数、地上部干物质积累量、氮素积累量及籽粒产量的调控效应。结果表明,与CK相比,玉米拔节期(V6)T1、T3处理20~30 cm土层土壤总盐含量和Na+含量分别降低6.88%和23.00%、28.82%和17.44%,土壤HCO3–含量分别升高10.97%、5.66%;吐丝期(R1)T2处理10~40 cm土层土壤总盐含量、Na+含量分别平均降低9.07%、14.11%,土壤HCO3–含量平均升高21.35%。土壤总盐含量降低有利于根系和地上部生长。与CK相比,吐丝期T1、T2和T3处理0~40 cm土层玉米单株平均根系长度分别提高17.56%、74.83%和33.53%;T2和T3处理单株平均根系表面积分别提高33.35%和27.44%,单株平均根系干重分别提高14.58%和11.93%。与CK相比,T1、T2和T3处理显著提高了玉米的叶面积指数,植株地上部干物质积累量以及氮素积累量,最终提高了夏玉米产量。2022年T1、T2和T3处理籽粒产量分别提高3.81%、8.22%和4.72%;2023年分别提高8.08%、18.88%和15.95%。综合分析可知,本试验条件下硅钙钾镁沸石型调理剂可有效降低玉米吐丝期土壤盐分含量,减轻盐分胁迫,促进玉米根系生长和对氮素的吸收,增加地上部氮素积累量和干物质积累量,显著增加籽粒产量,是滨海盐碱地降低盐碱胁迫促进夏玉米生长的最佳土壤调理剂类型。

基于Landsat 8的节水改造背景下盐渍化土壤含盐量反演

为探明沈乌灌域节水改造后因渠道衬砌、引排水量减少引起的土壤含盐量时空分布特征及变化规律,采用区域土壤信息定点监测,结合经典统计学、空间插值以及机器学习建模反演等技术手段,利用Landsat 8卫星获取光谱数据,通过对实测土壤含盐量、光谱指数及波段反射率进行处理,运用Adaboost回归、BP神经网络回归、梯度提升树回归、KNN回归、决策树回归、随机森林回归方法构建了沈乌灌域土壤含盐量空间反演模型。采用最优反演模型对沈乌灌域土壤含盐量空间分布特征进行了遥感反演。结果表明:通过全变量单一回归法筛选出相关系数大于0.55的9个光谱因子,使用SPSS PRO软件构建6种机器学习反演模型,对比6种反演模型精度,验证集决定系数R2由大到小依次为随机森林回归、梯度提升树回归、Adaboost回归、KNN回归、决策树回归、BP神经网络回归。其中随机森林回归模型的拟合精度最佳,训练集与验证集的决定系数R2分别为0.834和0.86,说明随机森林回归模型的反演效果较好。反演结果表明:节水改造后非盐渍土面积增加391.7 km^(2),占灌域总面积的21%,中度盐渍土面积、重度盐渍土面积、盐土面积分别减少95.61、63.37、45.7 km^(2),分别占灌域总面积的5%、3%、2%。综上所述,节水改造工程完成后,沈乌灌域土壤盐渍化程度减轻,作物生长安全区面积增加,但由于渠道衬砌以及引排水量减少,土壤盐分淋洗效果减弱,土壤盐分在灌域内部运移,整体土壤环境得到改善,局部地区出现盐分聚集。

春灌定额对不同盐碱度农田水盐分布影响研究

为探究春灌定额对不同盐碱度农田土壤水盐分布的影响,确定适宜保墒洗盐的春灌定额。分别在中度盐碱地S1(5.23 g/kg)和重度盐碱地S2(8.27 g/kg)设置3种春灌定额处理(W1:1 800 m^(3)/hm^(2),W2:2 250 m^(3)/hm^(2),W3:2 700 m^(3)/hm^(2)),分析比较了春灌后至棉花播种前0~100 cm土壤水盐运移和分布情况。结果表明:春灌后14~21 d,S1W2处理71.37%的水量可保持在土体内,S2W3处理77.26%水量保持在土体内,可使农田土壤达到适宜作物生长的土壤墒情;盐分淋洗主要发生在0~60 cm土层内,0~30 cm内淋洗效果更加显著,春灌定额越大将盐分带入深层的作用越强,春灌后21 d开始出现返盐现象;春灌时间在播前21 d左右为宜,中度盐碱地春灌定额2 284.7 m^(3)/hm^(2),重度盐碱地春灌定额2 700 m^(3)/hm^(2)左右时,可达到较为良好的节水保墒洗盐效果,重度盐碱地可以根据实际情况适当提高春灌定额。研究结果可为图木舒克市不同盐碱度农田春灌提供一定的理论依据和技术参考。