小型人工沙棘林对砒砂岩沟道土壤有机质与水分的影响

在内蒙古砒砂岩典型地区的准格尔旗东一支沟开展了小型人工沙棘植物林水保生态效应野外试验。根据试验数据,分析与研究了沙棘植物对沟道土壤有机质及土壤含水率的影响,揭示了沙棘植物对砒砂岩沟道土壤改良及对沟道土壤水分的调控效应,可为沙棘植物治理砒砂岩地区水土流失提供理论依据。结果表明：小型人工沙棘林的土壤剖面（0～100cm）有...     

沙棘"柔性坝"对沟底土壤有机质影响的现场试验

有机质是土壤肥力最重要的组分之一,是评价土壤质量和健康状况的重要指标。2006年试验测定了种植沙棘"柔性坝"的沟道内不同位置、不同深度的土壤有机质含量,同时与东一支沟左岸一条未种植沙棘的小支沟进行了对比分析。试验结果表明:坝内有机质的垂向分布不仅与土壤的发育过程和土层结构有直接联系,而且与土壤中的水分运移过程密不可分;种植沙棘"柔性坝"的沟道内土壤的有机质含量明显高于未种植沙棘"柔性坝"的对比沟道,而且在相同时期种植的沙棘"柔性坝"内不同取样点处的有机质含量总和相当接近;种植沙棘"柔性坝"的沟道内土壤异质性不显著,但与未种植沙棘的沟道相比,土壤的空间异质性较大,建议对这一问题应采用更大的空间尺度进行深入研究。     

沙棘”柔性坝”对沟道水流含沙量及粒径沿程分布影响的试验研究

为了深入研究沙棘"柔性坝"生态措施的阻水拦沙作用,在陕西眉县野外实验基地进行了沙棘"柔性坝"拦沙试验,分析与探讨了不同种植参数对砒砂岩沟道水流含沙量及粒径分布的影响。水流含沙量及粒径分布的沿程变化表明:不同参数下"柔性坝"含沙量的总体趋势为从上游到下游是逐渐减少的。坝体的上部位置含沙量逐渐减少,到了坝体中部含沙量则会增大,最后在坝体下部部位又逐渐减少,并且当坝长适中时拦沙效果才最显著,但随着坡度的不断变陡,拦沙的效果反而降低。沙棘"柔性坝"中,沿水流方向泥沙粒径呈递减趋势,并且对于粒径大于2.5μm的颗粒泥沙具有分选效果。文中研究有助于人们深入理解沙棘柔性坝滞流拦沙作用,为沙棘柔性坝这一生态工程在砒砂岩地区的推广提供理论依据。     

古尔班通古特沙漠南缘浅层风沙土含水量空间变异

2008年5月,在古尔班通古特沙漠南缘梧桐沟区段设置200 m×50 m样地,均匀选取180个样点进行样方的植被、地形和地貌调查,并且采取表层(0～10 cm)和次表层(10～30 cm)土壤样品进行土壤含水量分析。借助地统计软件GS~+和ArcGIS地统计模块分析研究区土壤含水量在沙垄不同地貌条件下的空间变异规律。结果显示:两层土壤水分的半方差函数值拟合为指数模型;表层和次表层土壤水分的变程分别为37.8 m和21.3 m,偏基台值与基台值的比值[C/(C_0+C)]分别为75.1%和75.6%,说明两层土壤水分具有强烈的空间自相关性,也表明土壤水分的变异主要由结构性差异所引起,客观地反映了研究区土壤水分的空间格局特征。克里格插值图显示,土壤水分随地势的升高而增大,平均数分析表明,0～10 cm土壤含水量由高至低的变化趋势是:垄顶>迎风坡>背风坡>垄间地,而10～30 cm则为:迎风坡>垄顶>垄间地>背风坡。     

延安碾庄沟流域梯田与坝地土壤水分对比分析

以延安碾庄沟小流域为研究对象,对该小流域内梯田地与坝地的土壤水分特征进行分析.结果表明,梯田地与坝地的土壤水分垂直分布有着相似的特点,梯田地和坝地土壤水分的垂直变化可以分为4个层次:土壤水分剧变层;土壤水分活跃层;土壤水分次活跃层;土壤水分相对稳定层.坝地的土壤含水量高于梯田地,且不同的作物类型可以引起土壤水分的变化,说明作物类型与土壤水分状况有一定的关系.     

沙棘植物柔性坝坝体变形初步分析

本文基于2005年在内蒙古准格尔旗西召沟小流域对已植的沙棘柔性坝进行野外调查,从植物生长角度对沙棘柔性坝坝体进行了纵向、横向、垂向(即沙棘柔性坝坝长、坝宽、坝高)的变形分析。对于沙棘柔性坝的坝长变化,主要从沙棘根系蘖苗萌生出发,分析得出其每年扩展约1m;柔性坝坝宽受沟宽限制,其发展趋势为扩展至满沟;柔性坝坝高变化采用三次函数和Logistic型函数两种具有“S”形特征的曲线进行拟合分析,经对比其变化过程服从Logistic型生长函数,并结合Logistic函数对沙棘植物柔性坝坝高的变化进行了具体意义的探讨。     

黄土丘陵沟壑区沟道造地土壤水分时空变异特征

基于Van Genuchten模型测定土壤水动力学参数,采用定点监测方法,在沟道中不同位置以及对照坡面进行土壤水分观测,分析了延安市典型治沟造地项目沟道造地土壤水分的时空变异特征,阐明治沟造地工程对沟道土壤水分的影响。结果表明：（1）土壤水力学参数在沟道土层深度为40 cm附近发生了显著改变,0~40 cm土层土壤容重1.12 ~1.25 g·cm^-3,导水率达到40 mm·min^-1以上,入渗能力强,同时饱和含水率较大,40 cm以下土层土壤容重在1.5 g·cm^-3左右,导水率在1.25~1.41 mm·min^-1之间,入渗速率明显减小;（2）沟道土壤水分显著大于对照坡面,其季节变化稍滞后于降水的季节变化,整个生长季在15.76%~21.91%间波动,高出对照坡面5%左右,垂直分布随土层深度的增加而增加,表层最低,为15.07%,160 cm土层最高,为22.84% ,深层土壤含水量优势更加显著;沟道土壤水分变异系数在0.131~0.234之间,相比较坡面,沟道表层以下土壤水分存在较强的空间异质性,100 cm以下土层变异系数在0.2左右,土壤水分变化活跃;（3）沟口土壤含水量显著高于沟头,土层深度40 cm以下的土壤含水量长期达到甚至超过田间持水量。通过治沟造地工程水分综合调控体系,沟道能够为作物生长提供水分充足的生境条件,提高水资源利用效率的同时改善农业生态环境。     

黄土区坡沟系统容重、饱和导水率和土壤含水量变化分析

切沟是黄土高原侵蚀沟的重要类型之一,对流域水文、植被、地貌和生态等地表过程具有深刻影响。为明确土壤物理参数对切沟地形、坡位和深度的响应,在陕北黄土高原选择典型切沟,根据其走向设置沟道、沟缘及坡面3条样线,对40个样点按照10 cm深度间隔采集0~30 cm各土层原状土样,利用定水头法和烘干法对土壤容重、饱和导水率和土壤含水量进行测定并分析。结果表明:(1)地形对容重、饱和导水率和土壤含水量具有显著或极显著影响,3个参数随坡位自下而上均呈波浪式变化趋势;沟缘和坡面位置容重随坡位上升总体呈微弱减小趋势,沟缘表层坡下土壤含水量较其他坡位明显偏低;(2)沟缘和坡面位置不同土层深度饱和导水率及容重的大小变化规律与沟道恰好相反;(3)对于各土层深度而言,沟缘和坡面土壤含水量均与沟道内差异显著,且沟缘土壤含水量总是低于坡面。以上结果表明,切沟分布改变了土壤容重、饱和导水率和土壤含水量在坡面的空间格局,在黄土区坡沟系统内不同地形条件对相关土壤物理参数的影响不应忽视。     

宁夏河东沙区浅层风沙土土壤含水量季节变化及空间分布特征

为探讨宁夏河东沙区典型沙漠化治理区风沙土土壤含水量的变化规律,选取了研究区表层及30cm深度的风沙土,采用烘干法及TDR300对土壤含水量进行监测,研究结果显示:1)表层土壤含水量4月底、5月底、6月底平均值较高,7月底土壤含水量最低,8月底和9月底逐渐开始增加.30cm的土壤含水量平均值4月底、8月底及9月底较高,5-7月相对较低.10cm和30cm的土壤含水量均属中等变异,且前者变异系数大于后者.2)不同时间的表层土壤含水量及30cm深处的土壤含水量均表现出强烈的空间自相关.30cm的空间变异程度低于10cm的.而表层土壤含水量空间自相关性较强.3)不同时间的表层土壤含水量的空间分布明显不同.不同季节的30cm的土壤含水量空间异质性较相似,6月底、7月底、8月底和9月底空间分布图相似,4月底和5月底,研究区北部土壤含水量空间分布有差异,其它区域空间分布斑块也很相似.30cm处的土壤含水量空间分布基本表现为南部低地与西部坡中部土壤含水量较高,坡中部偏东区域及坡上部土壤含水量较低.     

砒砂岩区沙棘人工林生态系统服务功能评价指标权重初探

沙棘人工林是晋陕蒙砒砂岩区主要的退耕还林树种之一,在砒砂岩区生态环境治理中发挥着重要作用。通过理论分析、频度分析、专家咨询法构建了砒砂岩区沙棘人工林生态系统服务功能评价指标体系,运用AHP法、G1法、变异系数法确定各指标权重值,应用博弈论综合赋权法将主、客观权重进行组合,得到综合权重。结果表明:土壤侵蚀模数、土壤固氮速率、根系土壤层蓄水量、土壤固钾速率、植物物种丰富度等指标权重较大;应用博弈论综合赋权法可以更全面和客观地解决权重的确定问题,结果合理可行,方法具有通用性,可为综合评价砒砂岩区沙棘人工林生态系统服务功能提供依据。     

黄土丘陵沟壑区不同土地类型的土壤水分特性

在黄土丘陵沟壑区燕沟流域,于2002～2006年定位监测不同类型土地不同坡位、坡向的土壤含水量,对土壤含水量的动态变化进行了系统分析.结果表明:不同土地类型的土壤含水量差异明显,坝地最高,平均19.83%,川台地次之,平均17.21%,梯田平均16.34%,坡地最低,平均15.04%,土壤含水量与年降雨量呈正相关,相关系数为0.68;土壤含水量月变化动态呈现"单谷"曲线,7月份最低;不同坡位的土壤含水量变化趋势为随坡位升高,土壤水分含量递减;不同坡向的土壤含水量变化趋势为阴坡>阳坡.     

基于微地形和土地覆被的土壤水分空间变异性——以玛纳斯河流域绿洲为例

采用经典统计学和地统计学方法,对玛纳斯河流域绿洲0～70 cm土层土壤水分的空间异质性及其影响因子进行研究.结果表明:各层土壤水分均符合正态分布.从变异系数看,均属于中等变异,变异系数介于0.293～0.371,其中表层水分变异程度最高,达到0.371;0～10 cm,10～20cm,20～30 cm和30～50 cm...     

Effect of Pisha sandstone on water infiltration of different soils on the Chinese Loess Plateau

The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studied the one-dimensional vertical infiltration of water in three experimental soils, created by mixing Pisha sandstone with sandy soil, irrigation-silted soil, and loessial soil, at mass ratios of 1:1, 1:2, 1:3, 1:4, and 1:5. Our objective was to compare water infiltration in the experimental soils and to evaluate the effect of Pisha sandstone on water infiltration. We assessed the effect by measuring soil bulk density(BD), porosity, cumulative infiltration, infiltration rate and saturated hydraulic conductivity(Ks). The results showed that Pisha sandstone decreased the infiltration rate and saturated hydraulic conductivity in the three experimental soils. Cumulative infiltration over time was well described by the Philip equation. Sandy soil mixed with the Pisha sandstone at a ratio of 1:3 had the best water-holding capacity. The results provided experimental evidence for the movement of soil water and a technical support for the reconstruction and reclamation of mining soils in the Pisha sandstone area.     

Effect of Pisha sandstone on water infiltration in different soils on the Chinese Loess Plateau

The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studied the one-dimensional vertical infiltration of water in three experimental soils, created by mixing Pisha sandstone with sandy soil, irrigation-silted soil, and loessial soil, at mass ratios of 1:1, 1:2, 1:3, 1:4, and 1:5. Our objective was to compare water infiltration in the experimental soils and to evaluate the effect of Pisha sandstone on water infiltration. We assessed the effect by measuring soil bulk density (BD), porosity, cumulative infiltration, infiltration rate and saturated hydraulic conductivity (Ks). The results showed that Pisha sandstone decreased the infiltration rate and saturated hydraulic conductivity in the three experimental soils. Cumulative infiltration over time was well described by the Philip equation. Sandy soil mixed with the Pisha sandstone at a ratio of 1:3 had the best water-holding capacity. The results provided experimental evidence for the movement of soil water and a technical support for the reconstruction and reclamation of mining soils in the Pisha sandstone area.     

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 influence 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 moderate 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 between 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 organic 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.     

Spatio-temporal variation of soil moisture in a fixed dune at the southern edge of the Gurbantunggut Desert in Xinjiang,China

Soil moisture is critical for vegetation growth in deserts. However, detailed dataregarding the soil moisture distribution in space and time in the Gurbantunggut Desert have not yet been reported. In this study, we conducted a series ofinsitu observation experiments in a fixed sand dune at the southern edge of the GurbantunggutDesert from February 2014 to October 2016, to explore the spatio-temporal variation of soil moisture content, investigate the impact of Haloxylonammodendron (C. A. Mey.) Bungeon soil moisture content in its root zone, and examine the factors influencing the soil moisture spatial pattern. One-way analysis of variance,least significant difference testsand correlation analysis were used to analyze the data. The results revealed that the soil moisture content exhibited annual periodicity and the temporal variation of soil moisture content throughout a year could be divided into three periods, namely, a moisture-gaining period, a moisture-losing period and a moisture-stable period.According to the temporal and spatial variability, the 0-400 cm soil profile could be divided into two layers: an active layer with moderate variability and a stable layer with weak variability.The temporal variability was larger than the spatial variability in the active layer,and the mean profile soil moisture content at different slope positions displayed the trend of decreasing with increasing relative heightand mainly followed the order of interdunearea>westand east slopes>slope top.The mean profile soil moisture content in the root zone of dead H. ammodendronindividuals was significantly higher than that in the root zones of adult and young individuals, while the soil moisture content in the root zone of adult individuals was slightly higher than that in the root zone of young individuals with no significant difference.The spatial pattern of soil moisture was attributable to the combined effects of snowfall, vegetation and soil texture, whereas the effects of rainfall and evaporation were not significant. The findings may offer a foundation for the management of sandy soil moisture and vegetation restoration in arid areas.     

科尔沁沙地坨甸交错区土壤水分的空间变异规律

科尔沁沙地沙丘-草甸相间地区,地貌形态多样、土地利用类型众多,从而导致土壤水分空间分布的复杂性。通过对科尔沁沙地典型沙丘-草甸相间地区的调查取样与试验分析,运用统计学理论和方法,研究土壤水分的空间变异性及其空间分布规律。结果表明：水平方向上,土壤水分总体表现为草甸地大于沙丘地,过渡带介于两者之间。就草甸地而言,植物生长越好,其土壤水分越高,保水持水性能也越好;沙丘地则与之相反,植被最稀疏的流动沙丘,其土壤含水量大于半流动半固定沙丘与固定沙丘,且有良好的储水条件。垂向上,高覆盖草甸、低覆盖草甸和农田（草甸）土壤含水量在地表下0～40 cm波动最大,40～160 cm随深度增加而递增;流动沙丘、半流动沙丘和固定沙丘土壤含水量随深度增加呈微弱加大趋势。林地、撂荒地、农田（沙丘）变化程度居中。从空间分布看,研究区中东部土壤水分偏大,且向南北两侧区域递减。     

压砂地土壤导水特性空间格局及影响因子

采用10 m×10 m网格布点的方式对宁夏压砂田0~10 cm和10~20 cm深度下土壤饱和导水率(Ks)及其相关因素的空间变异规律进行研究。经典统计结果表明:2个采样深度下土壤容重、总孔隙度和毛管孔隙度表现为弱变异,饱和含水量和土壤有机质含量表现为中等变异;0~10 cm深度下K_s表现为中等变异,10~20 cm深度下K_s表现为强变异;10~20 cm深度下土壤各种性质的平均值均大于0~10 cm深度。Pearson相关性分析可知,影响K_s的主要因素是毛管孔隙度,其次为容重、总孔隙度、饱和含水量和有机质含量。地统计结果表明,0~10 cm深度下K_s表现为纯块金效应,主要受随机性因素的影响,10~20 cm深度下K_s主要受结构性因素的影响;在2个采样深度下容重主要受随机因素的影响。从空间分布图可以看出,2个采样深度下K_s和容重存在高度的负相关关系,与饱和含水量、总孔隙度和毛管孔隙度存在高度的正相关关系。