Soil salinity and sodicity effects of wastewater irrigation in South East Australia

Although ‘sewage farming’ or wastewater irrigation started in Australia in the latter parts of the 19th century, it was in the late 1960s that a considerable interest was revived in arid and semi-arid parts of the world due to scarcity of alternative water sources and the urgency to increase local food production. The practice has manifold benefits in the form of water conservation, nutrient recycling, surface and ground water pollution prevention. But for arid and semi-arid regions like many parts of Australia, while wastewater irrigation can be an attractive solution to irrigation water problems, it might not be the ideal solution for the common soil types encountered in these regions. Due to characteristic low rainfall, high evaporation and low leaching, these soils tend to have higher salt accumulations. This paper examines the soil salinity and sodicity effects of wastewater irrigation in soil types typical to South Eastern Australia and takes the soils of Western Treatment Plant (WTP) as a case study to highlight these issues.     

Evaluating the Impact of Irrigation and Drainage Policies on Agricultural Sustainability

Farmers in the Broadview Water District in central Californiahave been improving irrigation practices in response to risingirrigation water prices and reductions in water supply since1989, when incentive policies were first implemented to reducethe volume of subsurface drain water generated in theDistrict. The average salinity of water deliveries hasincreased, over time, as the District has recycled largeamounts of drainage water to achieve regional restrictions ondrainage water discharge. We review irrigation and drainageactivities in Broadview since 1986 with an emphasis on thesustainability of crop production when drainage discharge islimited. Average cotton yields in Broadview have declined inrecent years, both nominally and in comparison with averageyields reported for the large county in which Broadview islocated. Average tomato yields in Broadview have increased inrecent years, but county-wide yields have exceeded Broadviewyields with greater frequency than in the late 1980s. Theseobservations suggest that average crop yields in Broadview maybe starting to reflect the increasing salinity of soil andwater resources, which may be due in part to persistentrestrictions on drainage water discharge.     

基于指示Kriging的土壤盐渍化风险与地下水环境分析

土壤盐渍化是制约干旱区农业发展的主要障碍,而浅埋地下水区域的地下水环境是影响土壤盐渍化的直接因素.为调控合理的地下水埋深和矿化度,以防控区域盐渍化,以河套灌区永济灌域为研究区,运用指示Kriging法比较了春灌前和生育期不同阈值条件下土壤表层含盐量、地下水埋深和矿化度的概率分布,从概率空间分布的角度研究了不同时期防治土...     

基于多源数据融合的盐分遥感反演与季节差异性研究

为提高多光谱盐分遥感反演的精度,利用实测高光谱与多光谱进行数据融合,并分析了不同季节盐分遥感的差异性。以河套灌区永济灌域为研究区域,以实测光谱仪测定的土壤高光谱数据和Landsat-8 OLI多光谱数据为基础,通过光谱变换和多元逐步回归方法筛选特征波段和特征光谱指数,构建了春、秋两季土壤盐分多光谱、高光谱反演模型,并利用特征光谱指数的线性回归构建了高-多光谱数据融合反演模型。结果表明:高光谱的反射率总体比多光谱高36.83%,春季反射率比秋季平均高23.78%。利用模型中最优变量特征光谱指数对多光谱模型与高光谱模型进行融合,高多光谱融合反演模型训练集和验证集R2平均值分别为0.651和0.635,RMSE平均值分别为2.44 g/kg和2.49 g/kg,精度明显高于对应的多光谱反演模型,其中训练集、验证集的R2平均值分别提高了36.19%和35.64%,RMSE平均值分别降低了34.28%和41.72%。春季多光谱、高光谱和融合反演模型的精度均高于秋季,其中训练集R2平均值比秋季模型分别提高了6.03%、6.05%和4.40%,验证集R2平均值分别提高了19.07%、12.21%和1.75%。构建的高多光谱融合模型反演灌域春秋两季平均盐分含量分别为6.05、5.97 g/kg,平均相对误差分别为9.65%和10.68%,总体上该区域春季土壤主要为重盐化土,秋季土壤主要为中盐化土。     

伊犁察南灌区土壤盐分时空变异特征与运移机理研究

以伊犁河谷察南灌区为研究区,运用磁感式电导率快速获取技术及室内分析相结合手段,通过构建盐分解译模型,获取2015年及2016年秋季0~30 cm、30~60 cm、60~100 cm土壤盐分含量。对土壤各土层进行了盐渍化分级统计和半方差函数分析及空间插值分析。对研究区高程信息进行提取,并通过调查河流影响范围对河流进行缓冲区分析。旨在构建适用于研究区及同类型灌区磁感式盐渍土地快速精量诊断评估与利用规划技术体系,了解干旱、半干旱区灌溉农田土盐时空变异特征,并对土盐时空运移机理进行研究。初步研究表明,相比于2015年秋季,2016年秋季研究区非盐化土面积显著减小,中度盐化土面积显著增加,非盐化土、轻度盐化土呈现向中度盐化土演变的趋势;研究区土壤盐分呈现向中部及东部区域运移的趋势,盐化土面积增加,且盐分含量均值增大;另外,在空间大尺度范围上,河流是影响土盐运移的主要影响因素,在局域小尺度范围内,地势是影响土盐运移的主要影响因素。     

策勒绿洲外围2种植物幼苗对NaCl的生理响应

2006年8～10月,在塔克拉玛干沙漠南缘策勒绿洲外围,研究了不同浓度NaCl处理对疏叶骆驼刺(Alhagi sparsifoliaShap.)、多枝柽柳(Tamarix ramosissimaLedeb.)一年生幼苗生理状况的影响.结果表明: ① 2种植物幼苗的水势(ψ)和净光合速率(Pn)均随NaCl浓度的增加呈明显下降趋势,但下降幅度不尽一致;然而,气孔导度(Gs)和蒸腾速率(Tr)表现出相同的变化规律;②在较高NaCl浓度下,随着处理时间的增加,2种植物幼苗的ψ都呈下降趋势,而柽柳幼苗的Pn无明显变化,骆驼刺幼苗的Pn则出现进一步下降的特征;③柽柳较骆驼刺具有更强的耐盐性.     

Information extraction and dynamic evaluation of soil salinization with a remote sensing method in a typical county on the Huang-Huai-Hai Plain of China

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 km² was 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 km², 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 km² per 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.     

咸海卡拉白鱼对盐碱耐受性研究

对咸海卡拉白幼鱼进行了NaCl和NaHCO3急性和亚慢性试验。试验结果表明:24,48,96h的半致死浓度(LD50):NaCl质量浓度分别为22 61,21 66,21 24g L,碱度分别为137 55,129 02,112 23mmol L。鱼对pH耐受性范围(7d内):4 5～10 1。亚慢性试验表明:NaCl质量浓度<5g L对鱼生长无影响;NaCl质量浓度为8g L使鱼生长受抑制;NaCl质量浓度为11g L鱼存活率93%。NaHCO3碱度为0 5g L(6 47mmol L)和1g L(10 64mmol L)处理组与对照组(1 47mmol L)相比,鱼增重5 5%和7 5%;碱度为2g L(23 65mmol L)对鱼生长无影响;碱度为3g L(32 20mmol L)鱼生长受到抑制,60d死亡率5%;碱度为4g L(44 98mmol L)处理组在12d鱼死亡率100%。在盐碱双因子试验中,卡拉白幼鱼在NaCl5g L、碱度23 65mmol L(pH9 2)的水体生长良好,适宜在半咸水中生存。     

盐胁迫对大,小麦种子萌发时两种酶活性的影响

在200mmol/L NaCl处理下,大、小麦种子内α-淀粉酶活性降低,贮藏物质转化受阻,小麦比大麦更明显。分别以100,200mmol/LNaCl处理幼苗2天,大麦幼根的质膜、液泡膜微囊H~+-ATPasc活性均增大,并且随盐浓度的增加而增强;小麦在100mmol/L NaCl处理下,幼根液泡膜微囊H~+-ATPase活性增强,而在200mmol/L NaCl处理下,质膜、液泡膜微囊H~+-ATPase活性均下降。200mmol/L HaCl处理9天,大、小麦幼根质膜、液泡膜微囊H~+-ATPaso活性都下降,小麦的下降幅度大于大麦,盐胁迫对大、小麦种子萌发和幼苗生长的不同效应,主要与种子内贮藏物质的转化以及根系对离子的选择吸收及运输有关。     

人工湿地中植物对低盐度养殖废水处理效果

分别构建种植美人蕉（Canna indica）、菖蒲（Acourus calamus）和千屈菜（Luthrum salicaria）的人工湿地,开展对低盐度养殖废水处理效果的模拟研究,设置进水中的C/N/P分别为50/10/1、25/5/1、25/5/2、25/5/3,盐度分别为0.5、1.0和2.0,水力停留时间分别为1 d、2 d、3 d和4 d,测定人工湿地对总氮、总磷和化学需氧量的去除率,出水中的氨氮、硝态氮、亚硝态氮和磷酸盐含量以及3种植物的生长状况。研究表明：当HRT=4 d,盐胁迫浓度为1,C/N/P为25/5/2（COD=50 mg/L,TN=5 mg/L,TP=4 mg/L）时,人工湿地装置TN、TP及COD去除率可达90%、97%和65%;不同植物的人工湿地系统中,美人蕉-人工湿地去除效果最佳,此时美人蕉体内叶绿素（SPAD值）、超氧化物歧化酶含量较高,丙二醛含量较低,分别为40.6、1 212U/g和2.45 nmol/g,氨基酸含量为1.82 %;盐胁迫浓度为1,C/N/P为25/5/2时,人工湿地内微生物群落结构得到优化,优势菌群为变形菌门（Proteobacteria）,该菌门是污水处理中常见的功能性菌群。因此美人蕉-人工湿地能够处理低盐度养殖废水,能强化人工湿地处理效果,提高植物-微生物的协同去污和盐度耐受性,为滨海水体修复提供技术支撑。