Irrigation and Salinity: a Perspective Review of the Salinity Hazards of Irrigation Development in the Arid Zone

Irrigation development in the arid zone almost alwayshas to deal with not only secondarysalinity but also with primary and fossilsalinity. In many cases, irrigationdevelopment brings about large scalechanges in the local geohydrological regimewhich often result in mobilization of saltsstored in the underlying substrata. Thisprimary and fossil salt mobilization hasbeen found to be one of the principalcauses of rivers salinization in irrigatedbasins in the arid zone. The paperhighlights this hitherto insufficientlyrecognized salinity hazard and discussesrelated control measures and strategies.     

高盐度难降解工业废水生化处理的研究

通过逐步提高有机负荷和盐浓度的方法 ,驯化出耐高浓度盐污泥 ,在进水NaCl浓度为( 2 6 8～ 4 72 )× 1 0 4mg·L- 1之间时 ,系统的单位污泥负荷较低 ,只有 0 32kgCOD·kgVSS- 1·d- 1,保持反应器较高的污泥浓度可使容积负荷达到 1 6kgCOD·m- 3·d- 1,COD和苯乙酸去除率可以达到95 %以上。驯化后的污泥能适应瞬时盐浓度变化冲击。     

盐碱对小麦生理的影响

采用室内水培试验的方法,模拟内蒙古河套灌区具有代表性的三种盐碱土,测试分析了小麦苗期长势、叶绿素、胡萝卜素、光合活性、叶肉细胞等生理指标,得出小麦在不同盐分条件下生长的耐盐标准和死亡样值以及不同类型的盐碱土对小麦的危害程度,从而为盐碱地改良治理,确定冲洗脱盐标准和规划作物种植结构提供了可靠的技术指标和理论依据。     

Salinity and sodicity influences on infiltration during surge flow irrigation

The interactive influences of water quality and surge-flow irrigation (intermittent application of water) on infiltration into a bare loam soil, packed into a long metal flume, were measured with a laboratory recirculating infiltrometer devised for the experiments. Cumulative infiltration and final infiltration rates were measured over three irrigation episodes using synthetic waters of different qualities. Four water-quality combinations of low and high salinity levels (i.e., electrical conductivity, EC=1.5 and 7.5 dS/m) and low and high degree of sodicity [i.e., sodium adsorption ratio in the range of 5-10 and 25-35 mmol^1/2 l^-1/2] were tested. Results showed that surge-flow cumulative infiltration of low saline waters - especially during the first irrigation episode - was lower than the corresponding continuous-flow cumulative infiltration. Conversely, it was higher for high saline and high saline-sodic waters. Effects of the water-quality treatments on final infiltration rate were similar to and in agreement with the effects on cumulative infiltration. However, the range of the final infiltration rates among surge-flow treatments was larger than with the continuous-flow treatments. Overall, infiltration was higher with surge-flow application of high saline and high saline-sodic waters than with the continuous-flow treatment. The observed contrasting results for the surge effect with the low saline, high saline, and high saline-sodic water-quality treatments were attributed to soil consolidation, formation of a depositional seal layer, and the different levels of irrigation water salinity and sodicity. It was concluded that the "surge effect" phenomena (reduction in soil infiltration caused by surge flow) under brackish (saline, sodic, and saline-sodic) water application was not pronounced and had adverse effects, in comparison to the low saline-sodic water application. Consequently, from theory, practical application of surge-flow irrigation under these circumstances, from viewpoints of infiltration reduction and irrigation efficiency improvements, is questionable.     

不同水盐胁迫对番茄生长发育和产量的影响研究

【目的】探究番茄植株对不同水盐胁迫情景的响应,为合理制定盐碱化土壤下的灌溉制度提供科学依据。【方法】以粉欧宝番茄品种为研究对象,开展水盐对番茄生长发育影响的盆栽试验。试验采用完全随机布置,设置3个水分水平(W1-充分灌溉、W2-1/2的W1灌水量、W3-干旱复水)和2个盐分水平(S1-无盐和S2-0.3%含盐量),每个处理4个重复,测定了番茄耗水、干物质和产量指标,分析了不同水盐胁迫对番茄植株生长发育与产量的影响。【结果】与充分灌溉W1相比,W2水平的番茄植株耗水、干物质、植株含水率、叶质量、产量、单果质量显著减少。W3水平的植株耗水量和叶茎比显著减少,但单株干质量与鲜干比所受影响不大;单果鲜质量与干质量显著减小,但坐果率提高导致产量有所增加。盐分处理的番茄植株耗水量、单株干质量、鲜干比、叶茎比、果实总产量、单果鲜质量与干质量均小于无盐处理。水分胁迫显著影响叶片生长和单个果实发育,盐分胁迫抑制植株的生长发育及产量形成。【结论】干旱复水与无盐处理组合(W3S1)下番茄植株表现出了较好的生长发育状况和产量水平,可用于最优调亏灌溉制度的制定。     

Salinity sensitivity of sorghum at three growth stages

Summary The relative salt tolerance of two sorghum cultivars [Sorghum bicolor (L.) Moench., cvs. Northrup King 265 and Asgrow Double TX] at three different stages of growth was determined in a greenhouse experiment. Plants were grown in sand cultures irrigated four times daily with modified Hoagland's solution. A nonsaline solution and six solutions salinized with NaCl and CaCl₂ (2: 1 molar ratio) provided treatments with osmotic potentials (_s) ranging from –0.05 to –1.05 MPa. The saline treatments were imposed for 30 days beginning at either Stage 1, 4, or 7 as defined by Vanderlip and Reeves (Agron J. 64:13, 1972). The 30-day stages are referred to here as the vegetative, reproductive and maturation stages although the first stage may have included initial panicle differentiation. Both cultivars were most sensitive to salinity during the vegetative stage and least sensitive during maturation. Based on a nonlinear least-squares analysis, grain yield reductions of 50% were predicted at _s=–0.68, –1.02, and –1.14 MPa for NK265 and at –0.62, –1.00, and –1.10 MPa for Double TX when salinized during the vegetative, reproductive, and maturation stages, respectively. Although salinity had no significant effect on mean kernel weights, significant growth stage effects and interaction indicated that kernels were heaviest for plants salinized during the vegetative stage. Stover yields were significantly reduced by salination during the vegetative stage but were unaffected when plants were salinized during the maturation stage. Salination during the reproductive stage also decreased stover yield of Double TX but the effect was smaller than that during the first stage. Stover yield of NK265 was unaffected by salinity at this stage.Mineral analysis of the first leaf below the flag leaf at harvest indicated that both cultivars tended to exclude Na from the upper leaves. Ca and Cl concentrations increased with increased salinity in plants salinized during the maturation stage but salination in earlier stages decreased Ca concentration of this upper leaf at harvest and had no effect on the final Cl concentration. Phosphate and K concentrations decreased when plants were salinized during the third stage but increased when plants were salinized during the vegetative and reproductive stages. Mg was unaffected by salinization during the first and last stage but decreased when plants were salinized,during the reproductive stage. An extensive data base now exists which describes the salt tolerances of many different crops (Maas and Hoffman 1977; Maas 1986). These data express yield responses as a function of the average salt concentration in the rootzone. Generally, these data apply only if salinity is fairly uniform from the seedling stage to maturity. Except for germination, little information exists on the tolerances of crops at different stages of growth. Such information could be invaluable to optimize the use of limited water resources. Knowledge that crops are more tolerant during some stages of growth will improve new strategies for utilizing saline drainage waters (Rhoades 1984).Several studies indicate that tolerances do change as the crop develops and matures, but none of these studies completely separated the effects of duration of treatment from the stage of growth that the crop was treated (Ayers et al. 1952; Kaddah and Ghowail 1964; Kovalskaia 1958; Lunin et al. 1961 a, 1961 b; Maas et al. 1983; Ogo and Sasai 1955; Piruzyan 1959; Verma and Bains 1974). Comparisons of sensitivity during specific phenological stages are confounded when treatment periods are of unequal duration.This study was initiated to determine the sensitivity of grain sorghum [Sorghum bicolor (L.) Moench] to salinity during three 30-day periods of growth. Francois et al. (1984) recently reported that sorghum is a moderately salt-tolerant crop. In field plot tests, grain yields of two cultivars decreased 16% per unit increase in salinity (electrical conductivity of saturated soil extracts from the rootzone) above 6.8 dS/m. They further reported that both cultivars were significantly more tolerant at germination than at later stages of growth. Soil water salinities above 8.2 dS/m delayed germination but full germination occurred within 10 days at salinities up to 22 dS/m. Treatments in the present study were designed to assess plant growth and yield responses to 30-day exposures to salinity beginning at either the 2-leaf stage, at the beginning of rapid culm elongation, or after anthesis.     

Corn yield and evapotranspiration under simulated drought conditions

Summary Measurements of corn yield and evapotranspiration (ET) were made under a wide variety of limited irrigations simulating drought conditions. Three locations were studied in two seasons. There was a strong linear relation between relative yield and ET (R² = 0.95 for dry matter yield and R² = 0.87 for grain yield) where variable irrigation was applied throughout the season as well as where irrigation was applied only at the early part of the season. Yield predictions using the model PLANTGRO (Hanks, 1974) were made from soil, crop, and climatic data. Agreement between prediction and measurements was better for relative dry matter yield (R² ranged from 0.91 to 0.99) than a relative grain yield (R² ranged from 0.93 to 0.97). The method for predicting grain yields could be improved but a relation involving seasonal estimates of relative transpiration gave good first-order predictions.Contribution from Utah State University Agricultural Experiment Station Journal Paper No 2506     

水面蒸发的盐度效应及其影响因子分析

【目的】明确滨海盐碱地水面蒸发(E)的盐度效应及其主要影响因子。【方法】于2018年5—10月设置了盐分梯度为1、3、5、10 g/L和20 g/L的水面蒸发试验。通过自制的20 cm蒸发皿获取不同质量浓度咸水的水面蒸发量,利用灰度关联分析确定了气象因子与不同质量浓度咸水蒸发量的关联程度,分别于晴天和阴天,选取关联度前三的气象因子和质量浓度(S)对水面蒸发量进行通径分析。【结果】(1)咸水质量浓度的升高会增加液面的表面张力,导致水面蒸发量降低,观测期内1 g/L咸水的累积蒸发量相比于20 g/L增加了97.66 mm;(2)水面蒸发与辐射强度(R)、风速(W_s)、饱和水汽压差(VPD)和空气温度(T_a)呈正相关关系,与相对湿度(RH)、大气压力(P_r)和质量浓度(S)呈负相关关系;(3)辐射强度是滨海盐碱地水面蒸发的主要影响因子,W_s和VPD分别于晴天和阴天对水面蒸发起到间接作用。【结论】咸水质量浓度的升高增加了水面的表面张力,造成了质量浓度高的咸水蒸发量的降低;相比于质量浓度对水面蒸发的影响,气象...     

有机硅功能肥对土壤水分运移和盐分的影响

有机硅功能肥作为一种改良盐碱地新型复合材料,具有施用简便易行、周期短、能够大面积推广等特点,有很大的应用前景.通过室内土柱试验,研究有机硅功能肥和秸秆在不同添加量下对盐碱土水分运移和电导率的影响,设置了4个施用量,分别为0.5％、1％、1.5％、2％.结果表明:随着有机硅功能肥和秸秆施用量的增加,湿润锋运移和累积入渗量...     

滴灌年限对土壤盐分分布及棉花的影响

针对新疆盐碱地的改良及土壤次生盐渍化的问题,定点监测了121团开荒应用膜下滴灌技术种植棉花从第2年到第4年连续3年的盐分变化,并与荒地盐分对比。结果表明:滴灌2年,各个土层土壤含盐量在生育期初与生育期末变化较小,积盐现象与荒地相比有所减轻;随着滴灌年限的增加,各个土层土壤含盐量均呈减少趋势;滴灌4年后各个土层土壤含盐量再分布比较明显,0～20cm土层及120～140cm土层含盐量最大,40～60cm与80～100cm土层土壤含盐量较小,棉花根系主要分布的40～60cm土层土壤含盐量最小;滴灌4年土壤含盐量基本满足种子出苗,平均成活率从6.9%,增加到94.5%,但是棉花平均株高、平均单株铃数及产量仅为正常棉花的66%、53%和57%,相对较低。对于滴灌4年后的盐碱地应继续加大水盐调控的力度。     

不同氮肥条件下盐分处理对小麦生长的影响分析

以盆栽为试验条件,研究了不同氮肥条件下土壤盐分含量对冬小麦生长特性及产量的影响.结果表明:高盐胁迫导致小麦株高降低,分蘖能力下降,生物量及有效叶面积减少,有效穗数,每穗粒数减少,千粒重降低,产量下降.高盐胁迫处理与对照差异显著,低盐胁迫处理与对照差异不显著.在相同盐分胁迫下,施氮量与小麦性状及产量呈正相关关系,小麦株高、叶面积及产量等指标随着施氮量的增加表现增大趋势.     

聚丙烯酰胺对盐渍化土壤水肥保持及产量的影响

对河套地区盐渍化土壤施用聚丙烯酰胺(PAM)后保水性、保肥性及最优产量下的水、肥及PAM的施用量组合进行了研究。采用正交试验设计对水、肥及产量各自特性进行详细分析,在整个生育期内研究了PAM施用层的含水率、土层深度为0~100cm的土壤碱解氮的动态变化规律及最优产量下所对应的各施用量的最佳组合。试验结果表明:经PAM处理的盐渍化土壤在其PAM施用层能够保持一定的水量,且随着PAM施用量的增加而增加;施用PAM处理的盐渍化土壤在PAM施用层能够保持一定的碱解氮且不易使碱解氮下移,未施PAM的4个灌水处理在不同程度上均下移至40cm左右,表明施用PAM明显抑制了氮素深层移动效应,起到了控制氮素淋失、防止土壤贫瘠的作用;而对于产量的分析,通过正交试验处理及SPSS主效应分析选取3因素最佳的施用量为:灌水量1 800m3/hm2、肥料为600kg/hm2、PAM量为18.75kg/hm2,可见PAM施用对盐渍化土壤节水、保肥效果明显,且PAM施用可对产量产生显著影响。该成果可用于指导盐渍化土壤合理的灌水量、施氮量及施用PAM后可显著提高葵花产量。     

盐分胁迫对油菜生长特性和产量的影响

为了确定紫色土地区油菜微咸水灌溉的安全使用质量浓度,采用盆栽试验,研究了不同矿化度微咸水对油菜生长和产量的影响。试验采用3种微咸水,NaCl溶液、CaCl2溶液以及二者矿化度1∶1混合溶液,矿化度设置为0.6、1、3、5、7g/L,共15种处理。结果表明,适宜矿化度的微咸水可以促进油菜生长;3种微咸水灌溉促进生长的适宜矿化度不同,NaCl溶液、CaCl2溶液以及矿化度1∶1混合溶液处理,最适矿化度分别为3.92、1.63和2.64g/L;矿化度超过7.06、3.99和4.78g/L时,油菜的形态和产量均受到严重影响。采用3.92g/L矿化度NaCl的微咸水灌溉,苗期、蕾薹期、开花期、成熟期土壤水分分别为70%θf~80%θf、75%θf~85%θf、70%θf~80%θf、60%θf~65%θf是紫色土地区微咸水灌溉油菜的适宜模式。     

利用NDVI指数识别作物及土壤盐碱分布的应用研究

利用监督分类、NDVI指数等遥感影像处理方法,在黄河上游的宁夏青铜峡灌区开展识别作物及土壤盐碱分布的应用研究。基于LANDSAT卫星遥感影像,依据NDVI指数推断作物及土壤盐碱分布,得到灌区作物及土壤盐碱分布状况和相应的估算结果。研究结果表明,灌区上、下游之间在作物长势上存在着较大差异,北部地区明显低于南部,土壤盐碱分布差别是造成该差异的主要原因之一。受盐碱影响的作物面积在年度内随气候条件的改变呈现出明显的季节性变化,灌区年内受土壤盐碱危害的面积约为100000hm2,近1/3的作物面积受到程度不一的土壤盐碱化影响,且灌区下游的盐碱地面积及盐碱化程度均高于上游。     

控制排水对大棚土壤盐分的影响

用定期取土样测定其电导率的方法,监测大棚控制排水2个月后不同深度的土壤盐分变化。结果表明,土壤盐分脱减量与地下水埋深为正相关关系,控制排水能有效地控制地下水埋深,影响土壤盐分的变化,且随着控制深度的加大,地下水埋深增大,土壤盐分脱减量变大。控制排水对于减轻渍害威胁和控制土壤盐分积累有明显的效果。     

Salinity distribution in paddy root zone under subsurface drainage

One-dimensional convective dispersion solute transport model was solved by Crank–Nicholson finite difference scheme and was applied over the flow domain of subsurface drained paddy fields laid with tile drain at different spacings. The flow domain was divided into a number of stream tubes to predict salinities at different distances from drain centre, at different depths from the ground surface and at different times after the initiation of the operation of the subsurface drainage system. The sub division of the flow domain into a number of stream tubes was done for two purposes, viz. (i) to enable estimation of pore water flow velocity more appropriately with respect to the flow area within a stream tube and (ii) to enable comparison of predicted salinities with the observed values which were available within some of the stream tubes. The initial and the boundary conditions in solving one dimensional equation were based on the field investigated salinity values. In the solute transport model there are two essential input parameters, viz. the pore water velocity and the dispersion coefficient. The pore water velocity was calculated by dividing the Darcian velocity by the drainable porosity. The dispersion coefficient was fitted by trial and error till the average absolute deviation between the predicted and the observed salinities became minimum.     

土壤盐分空间异质性的指示克里格阈值研究

阈值的合理选择是应用指示克里格法(Indicator Kriging,简写IK)进行风险评价的关键。以禹城市0～20 cm耕层土壤盐分空间变异性为例,利用GIS和GS+探讨了不同土壤盐分阈值下,盐分的空间结构、预测精度(均方根误差,RMSE)和预测风险的变化规律。结果表明,①随着阈值的增加,盐分的空间异质性受随机因素的...     

磁化微咸水矿化度对土壤水盐运移的影响

采用300 mT磁感应强度恒定磁水器对不同矿化度微咸水(0.14、2、3、4、5 g/L)进行磁化处理,并进行一维垂直土柱入渗试验,研究磁化微咸水矿化度对土壤水盐运移的影响。结果表明:微咸水磁化处理后,土壤入渗速率及湿润锋迁移速率显著降低,湿润体含水率显著提高;微咸水矿化度对磁化效果具有显著影响,磁化微咸水矿化度为3 g/L时,相同入渗时间累积入渗量和湿润锋深度相对减少量最大,湿润体含水率相对增加量最多。磁化微咸水入渗对Philip和Green-Ampt入渗公式参数有显著影响,相同矿化度的磁化微咸水土壤吸渗率S、饱和导水率K_s及湿润锋处吸力hf均小于未磁化微咸水;磁化与未磁化微咸水相对吸渗率ΔS及相对饱和导水率ΔK_s与矿化度之间均呈现较好的二次多项式关系,在矿化度为3 g/L时,相对吸渗率ΔS及相对饱和导水率ΔK_s均达到最大。磁化微咸水能够提高土壤持水能力,相同土层深度的土壤含水率显著增加;微咸水磁化处理后,脱盐率显著提高,土层深度0~20 cm磁化微咸水脱盐率均大于未磁化微咸水,矿化度为3 g/L的磁化微咸水磁化脱盐强度最大,相对脱盐效果更好。     

基于GIS的土壤盐分空间变异及盐分监测样点合理布设研究

在GIS技术支持下,采用经典统计学和地统计学方法对山东省房寺镇0～20 cm土壤盐分空间变异及其监测合理采样数量进行了研究.结果表明,研究区域土壤盐分属中等强度变异,受结构因素和随机因素的共同作用,土壤盐分具有中等强度的空间相关性;Kriging插值分析表明,土壤盐分的空间分布受微地形、气候和河流水入渗的影响,在地势较...