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1.
地表径流对荒漠灌丛生境土壤水分空间特征的影响   总被引:3,自引:2,他引:1  
李小军 《中国沙漠》2012,32(6):1576-1582
土壤水分是干旱区多尺度生态水文过程的关键影响因素和驱动因子,其时空格局是生态、水文、气象、地形等自然过程研究的重要参数。笔者研究了降水径流事件后3种不同灌丛个体尺度土壤水分空间异质性特征,结果表明,珍珠灌丛个体尺度土壤水分空间分布特征表现为灌丛边缘>灌丛内部>灌丛间裸地,驼绒藜灌丛表现为灌丛内部>灌丛边缘>灌丛间裸地,而狭叶锦鸡儿灌丛不同微生境土壤水分差异不显著。珍珠和驼绒藜灌丛同一微生境土壤水分存在坡位梯度,珍珠灌丛3个微生境土壤水分均表现为上坡位大于下坡位,而驼绒藜灌丛边缘表现为上坡位小于下坡位,其他两个微生境无明显规律;狭叶锦鸡儿灌丛土壤水分无明显的坡位梯度。3种灌丛不同微生境土壤含水量随土层深度增加的变化不明显。这说明在降水径流事件中,不同斑块的反应差异引起了地表径流的形成以及随之发生的资源再分配,从而导致了景观内土壤水分的空间异质性。  相似文献   

2.
Soil moisture is the key link between land hydrological and ecological processes which plays an important role in the terrestrial water cycle. As extreme weather events have increased in recent years, the stochastic simulation of soil moisture has gradually become the focus of ecohydrology research. Based on continuous monitoring of soil moisture data from 2008 to 2011, and historical precipitation data from 1991 to 2011, combined with the Rodriguez-Iturbe soil moisture dynamic stochastic model, soil moisture dynamics and its probability density function in a revegetated desert area was simulated. Results show that annual soil moisture dynamic changes of the revegetated desert area during the growing season complied with rainfall distribution; soil moisture probability presents a single-peak distribution in the plant rhizosphere layer (0–60 cm). The peak width in the 20 cm topsoil was wider than in other soils, and the distribution presented the strong fluctuations and multiple aggregates. The peak widths of 40 cm and 60 cm soil moisture probability distribution were small, which are in accordance with simulated results of the Rodriguez- Iturbe model. This confirms that the Rodriguez-Iturbe model has good applicability and can well simulate the statistical characteristics of soil moisture in an arid revegetated desert area.  相似文献   

3.
Li  Wei  Li  Xiaoyan  Huang  Yongmei  Wang  Pei  Zhang  Cicheng 《地理学报(英文版)》2019,29(9):1507-1526

In many arid ecosystems, vegetation frequently occurs in high-cover patches interspersed in a matrix of low plant cover. However, theoretical explanations for shrub patch pattern dynamics along climate gradients remain unclear on a large scale. This context aimed to assess the variance of the Reaumuria soongorica patch structure along the precipitation gradient and the factors that affect patch structure formation in the middle and lower Heihe River Basin (HRB). Field investigations on vegetation patterns and heterogeneity in soil properties were conducted during 2014 and 2015. The results showed that patch height, size and plant-to-patch distance were smaller in high precipitation habitats than in low precipitation sites. Climate, soil and vegetation explained 82.5% of the variance in patch structure. Spatially, R. soongorica shifted from a clumped to a random pattern on the landscape towards the MAP gradient, and heterogeneity in the surface soil properties (the ratio of biological soil crust (BSC) to bare gravels (BG)) determined the R. soongorica population distribution pattern in the middle and lower HRB. A conceptual model, which integrated water availability and plant facilitation and competition effects, was revealed that R. soongorica changed from a flexible water use strategy in high precipitation regions to a consistent water use strategy in low precipitation areas. Our study provides a comprehensive quantification of the variance in shrub patch structure along a precipitation gradient and may improve our understanding of vegetation pattern dynamics in the Gobi Desert under future climate change.

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4.
人工固沙植被区土壤水分动态及空间分布   总被引:6,自引:2,他引:4  
土壤水分是干旱区固沙植被生长发育最主要的限制因子,了解其动态变化特征对沙区人工植被建设具有重要意义。本研究利用EnviroSMART土壤水分监测系统,于2009-2013年对宁夏沙坡头地区人工固沙植被区的土壤水分动态进行连续监测。结果表明:(1)降水对土壤水分状况及动态变化有较大的影响。土壤水分总体处于过度消耗状态,在非生长季,土壤水分没有明显的回升现象。(2)生长季初期(4-5月)为土壤水分弱消耗阶段;生长旺盛期(6-8月)为土壤水分快速消耗阶段,水分变化波动较剧烈,空间异质性最强;生长季末期(9-10月)的土壤水分处于相对稳定状态。(3)土壤水分随深度增加呈“S”形变化趋势,浅层的土壤含水量明显高于其他深度,200 cm深度土壤含水量较低且年际间变化不大(1.53%~2.10%)。湿润年份土壤水分剧烈变化的土层深度为0~100 cm,而干旱年份为0~20 cm。(4)相对于干旱年份,湿润年份的土壤含水量不但较高,而且水分变化波动较为剧烈。当土壤水分较低时,其变异性会随着土壤水分含量的增加而增加。(5)试验区灌木盖度在5年间呈下降趋势,一年生草本受降水量影响年际变化较大。受降水时空分布影响的土壤水分是沙坡头人工植被演替的重要驱动力。  相似文献   

5.
In many arid ecosystems, vegetation frequently occurs in high-cover patches interspersed in a matrix of low plant cover. However, theoretical explanations for shrub patch pattern dynamics along climate gradients remain unclear on a large scale. This context aimed to assess the variance of the Reaumuria soongorica patch structure along the precipitation gradient and the factors that affect patch structure formation in the middle and lower Heihe River Basin(HRB). Field investigations on vegetation patterns and heterogeneity in soil properties were conducted during 2014 and 2015. The results showed that patch height, size and plant-to-patch distance were smaller in high precipitation habitats than in low precipitation sites. Climate, soil and vegetation explained 82.5% of the variance in patch structure. Spatially, R. soongorica shifted from a clumped to a random pattern on the landscape towards the MAP gradient, and heterogeneity in the surface soil properties(the ratio of biological soil crust(BSC) to bare gravels(BG)) determined the R. soongorica population distribution pattern in the middle and lower HRB. A conceptual model, which integrated water availability and plant facilitation and competition effects, was revealed that R. soongorica changed from a flexible water use strategy in high precipitation regions to a consistent water use strategy in low precipitation areas. Our study provides a comprehensive quantification of the variance in shrub patch structure along a precipitation gradient and may improve our understanding of vegetation pattern dynamics in the Gobi Desert under future climate change.  相似文献   

6.
A single shrub in a widely spaced shrubby area acts as a roughness element and, therefore, it can affect the distribution of the rainfall received on the ground surface surrounding it. This paper focuses on such rainfall distribution on arid hillslopes and its eco-geomorphic implications. Relatively simple methods were used to measure the rainfall around shrubs growing in a small basin that is associated with a prevailing wind direction during rain events. There was a trend toward significantly reduced rainfall onto bare soil areas located on the leeward side, compared with that on other bare soil areas along the hillslope. This may alert to another potential cause for patchiness in the hydrological response of arid hillslope systems.  相似文献   

7.
干旱人工固沙植被区土壤水分动态随机模拟   总被引:1,自引:0,他引:1  
黄磊  张志山  陈永乐 《中国沙漠》2013,33(2):568-573
土壤水分是陆地水循环过程的关键环节,是联系陆地水文过程与生态过程的纽带。随着全球极端气候事件的频繁发生,土壤水分随机模拟逐渐成为当前生态水文学研究的热点。利用2008-2011年生长季土壤湿度连续监测数据及1991-2011年日降水资料,结合Rodriguez-Iturbe土壤水分动态随机模型,模拟了沙坡头人工植被区生长季土壤水分动态与土壤湿度概率密度函数特征。结果表明:人工固沙植被区生长季土壤水分年际变化与降雨分布一致。2008-2011年生长季植物根际层(0~60 cm)土壤湿度概率分布基本呈单峰状,20 cm处的土壤水分峰的阔度较其他土层相对土壤湿度峰较宽,并且分布也出现了一定程度的跳跃。而随着土层厚度的增加,在40 cm和60 cm的土壤水分概率分布峰的阔度也较小,与Rodriguez-Iturbe土壤水分动态随机模型模拟结果一致。说明Rodriguez-Iturbe模型在干旱人工植被区也具有很好的适用性,可以对荒漠人工植被恢复区的土壤水分统计特征进行很好的模拟,为以后干旱沙区随机生态水文模型的建立奠定基础。  相似文献   

8.
黑河流域荒漠区土壤水分对降水脉动响应   总被引:16,自引:5,他引:11  
 利用气象站资料,对黑河流域荒漠区降水特征及其土壤水分对降水脉动响应进行了系统研究。结果表明,荒漠区降水属于降水脉动事件,降水前后土壤水分特征存在显著差异,且随土层增加差异逐渐变小。土壤水分在降水量、土壤深度和降水前后的差异极显著,交互效应也极显著(P<0.0001),表明荒漠区土壤水分对降水脉动具有显著的响应现象。土壤水分的降水脉动响应表现为降水后土壤含水量激增,在蒸散作用下缓慢减小。降水前后土壤含水量的时间序列变异规律均能较好地拟合成变异函数的理论模型。降水前后土壤含水量随机变异均小于结构性变异,反映出荒漠区土壤水分在时间尺度上具有较强的自相关性格局。降水使土壤水分空间结构差异呈现下降趋势,在时间序列上异质性降低。  相似文献   

9.
青海湖湖东沙地不同沙丘降雨入渗研究   总被引:2,自引:0,他引:2  
降雨入渗对干旱、半干旱区土壤水分的影响很大,降雨量、降雨强度、土壤前期含水量等要素都会影响水分的入渗过程。本文通过监测青海湖湖东沙地3种类型沙丘的土壤水分和降雨情况,对区内降雨特征以及不同要素对沙丘水分入渗的影响进行了分析。结果表明:降雨量只有达到某一临界值才发生下渗,流动沙丘、固定沙丘、经治理(人工植被+麦草方格沙障)的流动沙丘发生下渗的临界降雨量分别为5.6 mm、1.6 mm、0.2 mm。水分累积入渗量随降雨量增大而增加,降雨量相同的情况下,入渗量大小表现为经治理的流动沙丘>固定沙丘>流动沙丘。当降雨量和土壤前期含水量相近时,入渗量随降雨强度的增大而增加,尤其在小降雨事件下,降雨强度是影响入渗的关键因素,大降雨事件下降雨量则成为影响入渗的决定因素。降雨量和降雨强度相近的情况下,入渗量与土壤前期含水量呈负相关关系。随着降雨量增大,入渗水分全部消耗所需要的时间逐渐增加,尤其当降雨量大于10 mm时,入渗水分消耗所需时间将随着降雨量的增大迅速增加。  相似文献   

10.
水分是干旱区生态过程中主要限制因子,降水可通过改变土壤的干湿状况直接影响土壤的生态过程,继而引起土壤碳库的变化。生物土壤结皮作为干旱区主要的地表覆盖物,其自身不但可以进行呼吸作用,还能充分利用有限的水分通过光合作用固碳,改变土壤圈与大气圈之间的碳交换通量。通过模拟0、2、5、8、15 mm降雨,利用红外气体分析仪,对腾格里沙漠东南缘人工固沙植被区主要的生物土壤结皮覆盖土壤净CO2通量进行了原位测定,探讨生物土壤结皮覆盖土壤CO2释放和光合固定CO2(吸收)共同作用下的土壤净CO2通量对模降雨的响应特征。结果表明:(1)降雨会迅速激发生物土壤结皮覆盖土壤CO2释放,降雨激发CO2释放速率和有效时间取决于降雨量,降雨量越高,激发程度越低,激增的生物土壤结皮覆盖土壤CO2释放(源)效应有效时间随降雨量的增加而延长;降雨激发的土壤碳释放总量随着降雨量的增加显著增加,且藓类结皮覆盖土壤碳释放总量显著高于藻类结皮(P<0.05)。(2)降雨引起生物土壤结皮覆盖土壤CO2吸收速率在初期呈单峰变化,后逐渐回归到降雨前的水平,随降雨量的增加,CO2吸收的效应的时间越长,峰值越高;降雨量越高,生物土壤结皮光合碳固定量越多,当降雨量增加到15 mm时,藻类结皮光合碳固定量显著低于8 mm时的碳固定量;降雨量<5 mm时,藓类结皮光合碳固定量显著低于藻类结皮(P<0.05),≥5 mm时,藓类结皮光合碳固定量显著高于藻类结皮(P<0.05)。(3)干旱荒漠地区生物土壤结皮覆盖土壤,在无降雨的干旱期表现为较低水平的净碳排放效应,不同程度降雨的初期阶段都有短暂的增加土壤碳的汇效应,且碳汇效应的时间随降雨量的增加而延长;适度的降雨会降低长期干旱藻类结皮覆盖土壤向大气的碳排放量,而过高或过低的降雨都会不同程度地增加藻类结皮覆盖土壤向大气的碳排放,降低土壤碳的储量。不论降雨量大小,降雨都会增加藓类结皮覆盖土壤更多碳向大气排放,但随着降雨量的增加,源效应逐渐减弱。降雨量≤8 mm时,藓类结皮覆盖土壤净碳排放总量显著高于藻类结皮(P<0.05),当降雨量>8 mm时,藓类结皮覆盖土壤净碳排放量显著低于藻类结皮覆盖土壤(P<0.05)。因此,干旱区在估算生物土壤结皮覆盖土壤与大气碳交换对降雨的响应规律时,应该充分考虑降雨量大小对生物土壤结皮碳固定量和土壤碳释放组分的效应,明确降雨事件大小对不同类型生物土壤结皮覆盖土壤与大气之间碳交换的作用。  相似文献   

11.
苏打盐碱土地区不同土地利用类型的地表水分蒸渗特征   总被引:6,自引:0,他引:6  
选择东北松嫩平原西部典型地区,采用FAO56方法和实际田间定期观测相结合,分析了当地旱田和碱斑地两种主要土地利用类型地表水分蒸散和入渗特征及其对土地盐碱化的影响。结果表明:对于玉米地这样相对蒸散量比较大的旱作农田来讲,水分亏缺和盐碱化主要发生在根层,而对表层土壤,即使在偏干旱年份,仍然有足够的水分入渗量来维持盐分平衡。碱斑地随着植被的破坏,总体上表层土壤蒸发和入渗量基本平衡,但是由于土壤水分蒸发过程中盐分浓度要比入渗过程中的盐分浓度大,表层土壤依然向盐碱化方向发展。采取适当的土地利用方式,建立耗水量与该地区降雨水平相适应的植被系统是控制区域土地盐碱化发展的关键。  相似文献   

12.
荒漠灌丛树干茎流及其入渗、再分配特征   总被引:8,自引:2,他引:6  
王正宁  王新平 《中国沙漠》2010,30(5):1108-1113
运用铝箔收集法测定了荒漠灌木柠条(Caragana korshinskii Kom.)树干茎流;利用时域反射仪连续测量土壤剖面水分含量,分析树干茎流影响下柠条根际区水分入渗与再分配过程。结果表明,柠条灌丛产生树干茎流需要2.2 mm的前期降雨量,树干茎流占降雨量的7.9%,平均汇流率是89.8。土壤表层含水率对降雨过程响应明显; 当降雨量达到6 mm时,树干茎流有利于增加根际区土壤水分增量,补充深层土壤水分,对荒漠植被在干旱条件下存活起着重要作用。  相似文献   

13.
荒漠人工植被区浅层土壤水分空间变化特征分析   总被引:11,自引:1,他引:10  
潘颜霞  王新平 《中国沙漠》2007,27(2):250-256
研究土壤水分的空间变异及时间动态特征有助于在水文过程与生态格局之间建立定量的联系,由于土壤水分对整个地球系统的重要性,它的时间和空间变化日益引起水文界的广泛关注。干旱荒漠区年降水量稀少,土壤水分在整个生物过程中的作用就显得尤为重要。试验于2005年4月到10月在中国科学院沙坡头沙漠试验研究站人工植被区进行,主要观测1956年植被区表层(0—15 cm)和亚表层(15—30 cm)土壤水分的空间格局与动态分布及其相关影响因素。结果表明:人工植被区表层土壤水分含量明显高于亚表层,其空间变异程度为中等,空间分布的时间差异性显著;降雨是引起干旱沙地表层土壤水分空间变异的决定因素,植物根系是引起亚表层水分空间变异的重要因素。从不同微地形来看,土壤水分含量值表现为丘间低地>背风坡>迎风坡,变异程度丘间低地小于迎风坡和背风坡;地形是决定背风坡表层和亚表层以及迎风坡亚表层土壤水分空间分布的主要因素,而迎风坡表层土壤水分变化受风力等环境因子的影响较大。  相似文献   

14.
干旱区防护林营造方式对沙漠化土地恢复能力的影响研究   总被引:19,自引:8,他引:11  
通过对防护林体系营造方式对沙漠化土地的恢复和重建能力的研究,发现固氮灌木树种对沙漠化土地肥力恢复的作用十分显著。采用工程措施与生物措施相结合的组合造林技术是恢复沙漠化土地肥力最有效的方法。在沙漠化土地上营造乔、灌混交防沙阻沙林带,可以明显地提高土壤的有机质和氮素水平。建立农田防护林网可以有效地改善土壤水环境和物理性质,并能增加土壤微生物,使土壤微生物的种群数量较荒漠化土地有较大幅度提高。土壤微生物的数量分布与种植植物的种类和人为经营强度有关。草田轮作是干旱区改土培肥的好形式,新开发荒漠地以第一年农作物+第二年牧草+第三年农作物的轮作制度较好。  相似文献   

15.
额济纳绿洲不同植被覆盖下土壤特性的时空变化   总被引:3,自引:1,他引:2  
额济纳绿洲地处干旱内陆河地区。在分析额济纳绿洲土壤特性的基础上,以不同植被类型下的土壤作为分析对象,根据观测的土壤含水量数据及环境因子的观测数据,研究了额济纳绿洲土壤水分的时空变化规律,分析了土壤水分变化与环境因子之间的关系,建立了土壤含水量与环境因子之间的回归模型。研究结果表明,土壤剖面土壤类型及结构差异较大,土壤类型的差异主要受成土条件的制约和外部自然环境的影响,戈壁地区与其他几种植被类型下的土壤差异最为显著;土壤类型及结构的差异,土壤容重变化的特性及土壤水势、土壤含水量的变化,直接影响着植被的生长和分布;额济纳绿洲不同植被类型下的土壤含水量变化差异显著;土壤含水量的季节变化分析表明,土壤剖面中不同层的土壤含水量变化也存在着一定的差异,可以分成不同的稳定变化层,急剧变化层和相对稳定层;土壤含水量的日变化受环境因子的影响较为明显,空气温湿度、土壤温度及地下水水位埋深是影响土壤含水量最为显著的因素。  相似文献   

16.
巴丹吉林沙漠南部高大沙丘包气带水分空间分布特征研究   总被引:3,自引:1,他引:2  
水是影响沙漠生态系统的主要因子,决定着多年生植物的种类和数量。受恶劣的自然条件和研究手段限制,目前对沙漠地区包气带水分时空动态变化的研究相对薄弱。以巴丹吉林沙漠南部湖泊密集区为研究对象,通过随机采样和同一坡向剖面采样,综合运用DCCA和地统计学分析方法,揭示0~10 m较深层包气带沙丘水分的空间变化规律和局部控制因子对包气带水分的影响。结果表明,0~10 m沙丘包气带水分变化曲线呈指数、对数和对数正态分布3种类型,分别受地下水或下伏黏土层的毛管作用、湖心距和综合地形因子控制;影响沙漠包气带水分空间变化的主要局部控制因子与小流域的研究结果差异显著。地形、植被等局部控制因子影响对数分布型包气带水分的深度为表层1 m,而影响对数正态分布型的深度为3~4 m;沙丘水分随相对湖面高程空间变化差异显著,而空间相关距离则不显著。  相似文献   

17.
 通常认为极干旱区土壤水分来源于降水、大气或凝结水,深埋区不存在潜水蒸发。然而通过使用拱棚法初步证明在极干旱深埋区存在潜水蒸发,而潜水是土壤水分的重要来源。为了进一步求证土壤水分来源,开挖200 cm×200 cm×200 cm的土坑,完全隔绝与下层土壤及四周的水分联系,回填后监测土壤10、30、50、100、150 cm的空气温湿度;同时设置与四周隔绝但底面联通的对照坑。27 d后都模拟25 mm降雨。监测发现模拟降雨前联通土壤的水分含量、空气相对湿度、绝对湿度都明显高于隔绝土壤。1 a后远离降雨时土壤水分的检测发现隔绝土壤水分含量低于联通对照,但因隔绝土壤处于潜水蒸发漫溢的相同气象环境,其湿度不会无限下降。隔绝对比实验反演证明深埋极干旱区存在潜水蒸发。  相似文献   

18.
石薇  王新平  张亚峰 《中国沙漠》2018,38(3):600-609
选择腾格里沙漠东南缘人工植被区3种典型的地表覆被类型(藓类结皮、藻类结皮和流沙)土壤为对象,选取发生在7月和9月的两次降水事件,研究浅层土壤(3、5、10 cm)水分入渗与再分布过程。结果表明:浅表层3 cm深度土壤水分在降雨初期均表现为跳跃式增加,而在降雨中后期由于土壤剖面不同深度水势梯度减小,降水入渗速率降低,土壤水分仅呈现小幅波动。在两次降水事件中,藓类结皮和藻类结皮对降水入渗的阻碍作用比较显著,入渗速率表现为沙土 > 藻类结皮 > 藓类结皮;从水分再分布看,生物土壤结皮的存在致使水分再分配过程表现出明显的浅层化;降水过程结束后,结皮促进水分的蒸发损失,从而减少植被可利用水分含量。人工固沙植被区广泛发育的生物土壤结皮对降水入渗与再分布过程以及土壤水量平衡具有重要影响。  相似文献   

19.
Shallow-rooted grasses and deep-rooted shrubs dominate arid ecosystems where nitrogen is concentrated in the upper layers of the soil and water is distributed throughout. Analysis of mineral nitrogen and absorption patterns using a tracer indicated that shrubs in Patagonia absorbed nutrients from the lower, relatively nutrient-poor layers of the soil. Are they, consequently, at a competitive disadvantage with grasses that have the opposite pattern? Studies of nitrogen economy indicated that shrub and grass species have similar N-use efficiency but that they achieve it through opposite mechanisms. Shrubs have a conservative N economy absorbing annually only small fraction of their N content, whereas grasses have a more open N economy. This study about N-capture strategies in conjunction with previous studies about water-use by shrubs and grasses in the Patagonian Steppe suggest a coupling of N and water-capture strategies. Our findings have implications for the response of arid and semiarid ecosystems to global warming, nitrogen deposition, and biodiversity change. For example, climate change scenarios predict, for most arid regions, decreases in moisture availability that will result in a reduction in deep water, which in turn will reduce shrub density and result in a less conservative nitrogen economy.  相似文献   

20.
Liu  Muxing  Wang  Qiuyue  Guo  Li  Yi  Jun  Lin  Henry  Zhu  Qing  Fan  Bihang  Zhang  Hailin 《地理学报(英文版)》2020,30(6):949-968
Rainfall provides essential water resource for vegetation growth and acts as driving force for hydrologic process, bedrock weathering and nutrient cycle in the steep hilly catchment. But the effects of rainfall features, vegetation types, topography, and also their interactions on soil water movement and soil moisture dynamics are inadequately quantified. During the coupled wet and dry periods of the year 2018 to 2019, time-series soil moisture was monitored with 5-min interval resolution in a hilly catchment of the Three Gorges Reservoir Area in China. Three hillslopes covered with evergreen forest(EG), secondary deciduous forest mixed with shrubs(SDFS) and deforested pasture(DP) were selected, and two monitoring sites with five detected depths were established at upslope and downslope position, respectively. Several parameters expressing soil moisture response to rainfall event were evaluated, including wetting depth, cumulative rainfall amount and lag time before initial response, maximum increase of soil water storage, and transform ratio of rainwater to soil water. The results indicated that rainfall amount is the dominant rainfall variable controlling soil moisture response to rainfall event. No soil moisture response occurred when rainfall amounts was 8 mm, and all the deepest monitoring sensors detected soil moisture increase when total rainfall amounts was 30 mm. In the wet period, the cumulative rainfall amount to trigger surface soil moisture response in EG-up site was significantly higher than in other five sites. However, no significant difference in cumulative rainfall amount to trigger soil moisture response was observed among all study sites in dry period. Vegetation canopy interception reduced the transform ratio of rainwater to soil water, with a higher reduction in vegetation growth period than in other period. Also, interception of vegetation canopy resulted in a largeraccumulated rainfall amount and a longer lag time for initiating soil moisture response to rainfall. Generally, average cumulative rainfall amount for initiating soil moisture response during dry period of all sites(3.5–5.6 mm) were less than during wet period(5.7–19.7 mm). Forests captured more infiltration water compared with deforested pasture, showing the larger increments of both soil water storage for the whole soil profile and volumetric soil water content at 10 cm depth on two forest slopes. Topography dominated soil subsurface flow, proven by the evidences that less rainfall amount and less time was needed to trigger soil moisture response and also larger accumulated soil water storage increment in downslope site than in corresponding upslope site during heavy rainfall events.  相似文献   

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