叶尔羌河流域土壤盐分特征研究——以喀什地区叶城县为例

土壤盐渍化问题是干旱区可持续发展和改善环境质量的战略问题之一。分析土壤盐分特征,对治理土壤盐渍化和农业可持续发展至关重要。采用统计分析法与主成分分析法研究了喀什地区叶城县土壤盐分的变化规律。结果表明,土壤盐渍化类型以硫酸盐渍土为主;盐分组成中,阳离子以K⁺和Na⁺为主,阴离子以SO₄^2-离子为主;表层的总盐、各盐分离子含量均高于其余土层 ,即土壤盐分剖面垂直分布呈现表聚性;8月份土壤剖面各土层含盐量均高于2月份;主成分分析结果表明,SO₄^2-,K⁺,Na⁺为研究区土壤盐渍化状况的特征因子。不同土地利用类型条件下,耕层土壤盐分平均值从高到低依次为旱地、盐渍地、耕地、核桃林、大棚。     

RESPONSES OF WHEAT PLANTS IN TERMS OF SOIL WATER CONTENT,BULK DENSITY,SALINITY, AND ROOT GROWTH UNDER DIFFERENT PLANTING SYSTEMS AND VARIOUS IRRIGATION FREQUENCIES

The effects of irrigation water rates and seed bed shapes on changes in soil water and salinity status, bulk density, root growth and dry matter (DM) weights of wheat plants (Triticum aestivum L.) were investigated with a split plot design in a field trial in Zahak Agricultural Research Station in Sistan, Iran in 2005. Irrigation intervals after 80 and 160 mm evaporation from class A evaporation pan were used as main plot. Flat surface, single, triple, and six-row beds with a 20 cm row space were used as subplots. Each treatment was replicated four times. Volumetric soil water content and soil electrical conductivity (EC) were measured using Time Domain Reflectometry (TDR) at 0 —20, 20 —40 and 40 —60 cm depths at nine different times during the growing season. Soil water contents were also measured at 0 —10 and 10 —20 cm depths using standard sampling rings at four different times. The three and six-row beds increased the EC of the saturated paste extract with the more frequent irrigation intervals in this coarse textured soil. Soil water content, DM, and root density were always greater with the more frequent irrigations (shorter irrigation intervals). Root density was greatest in 0 —20 cm depth with the single row bed treatment. Grain yield and root density were greatest with single row bed treatment due to the bed shape at the root development stage (possibly due to a reduced mechanical resistance). A greater soil water content by the short irrigation interval increased grain yield and root density via reducing mechanical resistance. With the loamy sand, bulk density and mechanical resistance increased rapidly after cultivation. Bed shape at root development stage might have enhanced root growth and the crop yields. Apparently, mechanical resistance was the most limiting factor with these loamy sand soils than salinity.     

根系及盐分含量对农田土壤干缩裂缝发育规律的影响

为研究不同根系含量和盐分含量土壤表面干缩裂缝的发育规律,该文提出了一套基于数字图像处理的裂缝几何参数提取方法,分析裂缝形态随含水率的变化规律。结果表明:随着含水率的降低,不同根系含量条件下裂缝面积密度和长度密度的差异显著(P0.05),裂缝发育稳定时根系含量越大,面积密度越小,长度密度越大。盐分质量分数为2.0%的土壤试样在整个干燥过程中裂缝面积密度明显比其他低盐分含量的试样高。当含水率27%时,盐分含量对土壤裂缝面积密度的影响差异明显,不同盐分含量的土壤裂缝面积密度和长度密度均差异显著(P0.05),说明盐分含量越大,稳定时土壤裂缝面积密度越大,长度密度越小。该成果对指导开裂土壤的农田灌溉具有重要的实践意义。     

艾比湖湿地不同植物群落下土壤水盐空间变异性

以艾比湖湿地为研究区,运用传统统计学和地统计学相结合的方法对4种典型植物群落下土壤水盐含量变化进行了研究。结果表明:(1)4种植物群落中,碱蓬群落、盐节木群落和梭梭群落土壤含盐量呈中等变异,而芦苇群落土壤水盐则呈现较强的差异性(2)随着土层深度的增加,盐节木群落和梭梭群落中土壤含水量差异性不大,碱蓬群落和芦苇群落则呈下降趋势,而对于土壤盐分,除梭梭群落外,其余3种植物群落各土层盐分呈降低趋势,且表层盐分含量相对较高(3)在空间结构性分析中,不同植物群落下土壤含水量和盐分在一定区域范围内空间特结构性显著,能较好地满足高斯模型分布,由于受气候、距湖距离、湖面积波动及土壤类型等因素作用,4种植物群落中土壤含水量和盐分均具有较强的空间自相关性(4)对土壤水盐含量变化的相关性分析中,4种植物群落下土壤水盐含量与其关联性都相对较小,其中碱蓬群落和芦苇群落呈正相关关系,盐节木群落和梭梭群落呈负相关关系。总体来说,碱蓬群落和芦苇群落土壤水盐总变异趋势大于梭梭群落和盐节木群落,说明距湖远近对土壤水盐空间变化有一定的影响。     

基于土壤光谱特征的宁夏银北地区盐碱地盐分预测研究

对宁夏回族自治区银北地区盐碱地野外土壤表层光谱反射率和土壤全盐及盐分进行定量分析,筛选出各土壤盐分指标的敏感波段,然后采用全回归和逐步回归的方法建立各盐分的预测模型。结果表明：表层土壤高光谱反射率r,及其平滑去嗓处理后的值R,lg(R)与全盐含量呈极显著正相关关系,1/R,lg(1/R)与全盐呈极显著负相关关系,(R)'和〔lg(1/R)〕'在特定单波段处表现较佳;土壤表层光谱反射率与CO₃^2-的相关性最强,其次是SO₄^2-;土壤光谱反射率与Na⁺的相关性在各种变换方法下均较强,其次为Mg²⁺,与Ca²⁺的相关性最弱。基于R的逐步回归方程为全盐含量预测的最佳模型;基于土壤光谱反射率拟合土壤CO₃^2-的准确度略高于对土壤HCO₃^-;敏感波段估测土壤SO₄^2-含量的决定系数明显高于其他阴离子;采用〔lg(1/R)〕'逐步回归得到的方程拟合土壤Na⁺,K⁺和Mg²⁺含量相对于其他变换方式效果更理想。预测模型中对土壤全盐和Na+的模型精度较高,预测能力强;光谱对土壤SO₄^2-和Mg²⁺的预测能力也较强;对土壤Cl^-和Ca²⁺的预测稳定性、预测能力和精度都较差。     

激光平地改善土壤水盐分布并提高春小麦产量

为了促进激光平地技术的应用与推广,在河套灌区以普通畦田为对照,分期、分段测定了激光平地畦田0～80 cm土层土壤水分、土壤盐分及春小麦生长状况。结果表明,从渠口到畦尾,激光平地畦田不同地段的土壤水分在春小麦生长的不同时期无显著差异,但从拔节期开始,上层土壤盐分逐渐升高;普通畦田从三叶期开始,上层土壤水分、盐分逐渐提高,且显著或极显著高于激光平地。普通畦田从三叶期开始,激光平地从拔节期开始,从渠口到畦尾,春小麦的生长状况逐渐变差,千粒质量、产量均逐渐降低,但激光平地的春小麦千粒质量、产量高于普通畦田。激光平地改善了畦田的土壤水分、盐分分布,促进了畦田中后段的春小麦生长,提高了畦田中后段的水分利用率及产出率。     

Effect of nutrient solution salinity and ionic concentration on parsley (Petroselinum crispum Mill.) essential oil yield and content

The growth and essential oil (EO) production of parsley were evaluated in response to salinity and nutrient solution concentrations in a soilless culture. Parsley plants that were 60 days old were potted in a coconut fiber and peat moss medium and were treated with four different nutrient solutions, including T1, T2, T3 and T4. The T1 nutrient solution was the standard, the T2 and T3 solutions contained incremental macronutrient concentrations with an electrical conductivity (EC) of up to 2.2 and 3.2 dS m^?1, respectively, and the T4 solution was the same as T2 but with sodium chloride (NaCl) and an incremental macronutrient concentration with an EC of 3.2 dS m^?1. Next, these plants were grown for 90 days in a greenhouse with natural daylight in Nador, Morocco. Shoot and root growth significant decreased with increasing EC. However, the salinity that resulted from the addition of NaCl did not affect plant growth in the nutrient solutions. The optimum obtained growth and EO production were 1.2 and 2.2 dS m^?1, respectively. Consequently, the optimum EC value (based on the EO production) of parsley in the soilless culture was 1.2–2.2 dS m^?1.     

Effects of different levels of soil salinity on yield attributes,accumulation of nitrogen,and micronutrients in Brassica spp.

The present study was conducted to assess the effect of soil salinity on yield attributes as well as nutrient accumulation in different plant parts of seven Brassica cultivars from two different species raised in pot culture experiment with two levels of salinity treatments along with control corresponding to soil electrical conductivity (EC) values of 1.65 (S₀), 4.50 (S₁) and 6.76 (S₂) dS m^?1. The experiment was consisted of twelve replications in a completely randomized design. Imposition of salinity stress affected various yield attributing characters including plant height, which ultimately led to severe yield reduction. However, tolerant cultivars, CS 52 and CS 54 performed better under salt treatment showing lesser yield loss. Salinity stress reduced the nitrogen (N) content in leaves of the Brassica plants, which reflected in decreased seed protein content. Reduced accumulation of iron (Fe), manganese (Mn) and zinc (Zn) was observed in leaf, stem and root at flowering and post-flowering stages, while CS 52 and CS 54 showed less reduction than susceptible cultivars under salinity stress.     

青海黄河沿岸土壤盐分特征及影响因素研究

应用常规统计学方法和典范对应分析方法,研究青海黄河沿岸不同程度盐渍化土壤各属性特征及其数量关系,探讨了土壤属性与环境因子之间的关系。结果表明:非农地土壤属中度、重度盐渍化土壤和盐土;随盐渍化程度增强,土壤阳离子从镁钙盐型转变为钠盐型;土壤阴离子从硫酸盐型转变为氯化物型;除Ca~(2+)与Cl~-、K~+相关性不显著外,其他各离子浓度之间显著正相关;有机质与pH值显著负相关;电导率与各离子浓度极显著正相关,与总盐浓度的相关性高达0.91;土壤各粒级含量及分形维数与各离子浓度、电导率、总盐浓度之间相关性不显著。土地利用类型能够很好地指示土壤盐渍化水平,盐渍化程度同时受微地形影响。土壤盐碱化与沙化是两个相关的土壤退化过程。     

内蒙古杭锦旗北部盐碱田温湿盐动态与生产利用

为探析水-热-盐关系以及植被对盐碱田改良的意义,利用2008年8月2日-8月6日在内蒙古杭锦旗黄河灌区盐碱田进行的试验观测数据,主要通过方差分析与典型相关分析方法对3个样地(裸地、紫花苜蓿地和玉米地)土壤温度(0-30cm土层)、湿度(0-20cm土层)、盐度(0-100cm土层)的动态变化进行了分析。结果表明,3个样地的温(度)-湿(度)-盐(度)动态基本呈现裸地苜蓿地玉米地的格局;0-5cm地温与耕作层(0-20cm)的土壤水分具有显著相关关系,是0-30cm土层内地温驱动水盐动态的主要热力因子;植物能够减少土壤表层积盐,并可以降低碱化度;苜蓿地比玉米地具有更低的钠吸附比值。在盐碱地区选择耐盐碱牧草品种开展草田轮作,有益于盐碱土壤的改良与利用。