长江三峡重庆库区不同植被条件下土壤抗冲性研究

以长江三峡重庆库区典型针阔混交林、常绿阔叶林、毛竹林、灌木林及农地(对照)为研究对象,通过室内放水冲刷试验,分析探讨了森林表层与亚表层土壤的抗冲时间特性和坡度效应。结果表明:土壤抗冲性随冲刷时间延长而增强,表层土壤抗冲性为前5 min抗冲指数变化最为剧烈,亚表层土壤抗冲性为前3 min抗冲指数变化最为剧烈,典型林地土壤抗冲指数随时间变化特征为幂函数关系;林地土壤抗冲指数与坡度关系为xK e0.0755 0.0755,农地土壤抗冲性受坡度影响最为强烈,竹林土壤抗冲性受坡度影响最小;农地较林地土壤抗冲性明显降低,林地中,针阔混交林土壤抗冲性最强,森林有较好的抵抗土壤冲刷的作用。     

太行山片麻岩区坡地水土流失规律研究

通过人工模拟降雨和野外观测试验,对太行山片麻岩区坡地水土流失规律进行了研究。结果表明:雨前土壤含水量越大,产流越早;土层越厚,土壤蓄水量越大;累积地表径流量与降雨时间的对数呈显著正相关,拟合方程为W=a+blnt,相关系数均大于0 92;径流量与降雨量呈显著正相关,并且径流量随降雨量的增加呈指数形式增加,拟合方程为Y=aebx,相关系数均大于0 95;径流量随降雨强度的增大而增大,并与30min最大降雨强度呈显著正相关;地表径流量与植被覆盖度呈显著负相关关系;相同土地类型,土壤侵蚀量与坡度呈对数曲线关系,坡度越大,土壤侵蚀量也越大,拟合方程为Y=a+blnx;相同土地类型土壤侵蚀量的增量随时间的增加趋于平缓;在其他条件相同的情况下,不同土地类型的土壤侵蚀量为坡耕地>油松林地>刺槐林地>荒坡草地。     

金沙江不同林地坡面的产流产沙特征研究

为解决金沙江水土流失问题,在金沙江头塘小流域水源涵养林生态系统定位研究站内,选择典型人工林为研究对象,对4种典型生态恢复人工林类型(21年生云南松林、19年生旱冬瓜林、19年生银荆林和荒草地)的产流产沙特征进行研究。结果表明,4种林地坡面的产流量、产沙量和土壤侵蚀强度都表现出相同的大小规律,都为云南松林的最小,其次是银荆林和旱冬瓜林,荒草地的产流量、产沙量、土壤侵蚀强度都是最大的,分别为云南松林的3.05倍、6.23倍、6.29倍,说明云南松林的水土保持效果好。产流量、产沙量与降雨量都呈正相关关系,径流系数与产沙量呈正相关关系,即降雨在坡面产流时,径流系数增大,即产流量增大,产沙量也随之增大。由此可知,营造良好的人工林林分可以防止金沙江头塘小流域水土流失。     

生物埂不同植物类型下土壤分离水力学特性研究

【目的】探明川中丘陵区六棱型预制网格式生物埂不同植物类型下土壤分离能力与细沟水流水力学特性间的数学关系。【方法】野外采集生物埂坡面麦冬和韭菜2种植物根系下的原状土样(直径10 cm),以单一网格式生物埂裸坡为对照,建立室内模拟细沟(长4 m,宽0.12 m,深0.1 m),在3个坡度(15°、20°、25°)、5个流量(39.86、59.98、79.67、100.45、121.16 L/min)的完全组合条件下进行冲刷试验,探讨水力学参数(雷诺数Re、弗汝德数Fr、Darcy-Weisbach阻力系数f、曼宁系数n)与土壤分离能力间的数学定量关系。【结果】1)不同植物类型下生物埂土壤分离能力表现为麦冬(均值2.24 kg/(s·m^2))>对照(均值1.34 kg/(s·m^2))>韭菜(均值1.09 kg/(s·m^2))。2)土壤分离能力与水流流态与流型参数之间均呈幂函数正相关,其中与雷诺数Re呈极显著幂函数正相关(均值R^2=0.75,P<0.01),与弗汝德数Fr呈显著幂函数正相关(均值R^2=0.27,P<0.05)。3)土壤分离能力与水流阻力参数间的关系主要呈负相关,其中与Darcy-Weisbach阻力系数f呈显著幂函数负相关(均值R^2=0.36,P<0.05),而与曼宁系数n之间的幂函数关系不显著(均值R^2=0.16,P>0.05)。【结论】与麦冬相比,韭菜增强土壤抗侵蚀能力的效果更显著。水力学参数中,水流流态流型参数中雷诺数Re预测土壤分离能力的效果相对较好,水流阻力参数中以Darcy-Weisbach阻力系数f效果较好,总体比较,以雷诺数预测土壤分离能力效果最好。     

毛竹林地土壤水土流失的初步研究

采用人工模拟降雨装置,对毛竹林地土壤流失进行了试验,结果表明:林地坡度是影响林地土壤流失的主要因子,坡度在30耙陨鲜?极易造成林地土壤冲刷;地表覆盖能有效地降低地表径流中的泥沙含量;大雨、陡坡、全垦造成的水土流失非常严重.     

坡度及旅游干扰对土壤粒度特征的影响

以天马山土壤粒度特征为研究对象,通过室外调查与室内试验相结合,分析了不同坡度对土壤粒度特征的影响以及受旅游干扰后土壤粒度特征的变化。结果表明:研究区土壤粒度组成以黏粒为主,粉粒次之,砂粒最低;粒度特征受旅游干扰影响后呈现出分选性变差,偏度多为极负偏,峰态值普遍偏高。不同坡度的平均粒径不存在显著差异;分选系数、偏度、峰度之间均存在显著性差异。相关分析证明分选系数与偏度呈显著正相关关系,与峰度呈极显著的负相关。表明土壤粒度分选性越差,偏度值越小,峰度值越趋向窄峰态。受旅游干扰后土壤粒度频率分布曲线均发生明显变化,由对称的单峰曲线向复杂的多峰曲线转移。说明在旅游干扰下粒度特征存在多成因组分,且平坡较陡坡更易受到旅游干扰的影响。     

电导法测定甘肃临泽小泉子地区土壤含盐量探讨

通过不同振荡时间、水土比、离子类型和含盐量４个方面,分析电导法测定小泉子地区硫酸盐渍土壤的全盐量与土壤浸出液电导率的相关性和回归关系。结果表明：水土比５：１,土样振荡时间为３、３０、６０ｍｉｎ,浸出液的电导率之间差异不显著;水土比１：１和５：１时,电导率与全盐量间相关性显著,根据本地区土壤特性,用水土比５：１为宜,当全盐量〈１４０ｇ／ｋｇ时,用电导法测定本地区全盐量,建议一般选方程Ｙ＝２．９６８Ｚ     

人工降雨条件下不同坡度红壤坡面迳流泥沙变化特征研究

在人工模拟降雨强度为1.44 mm/min的条件下,研究了不同坡度(β)红壤近似裸地坡面迳流、泥沙的变化特征,研究结果表明:①地表迳流量随坡度的增大而迅速增加。②当β≤23°时,土壤侵蚀量随坡度的增大而迅速增加;当25°≤β≤40°时,土壤侵蚀量随坡度变化较小。③坡面土壤侵蚀的临界坡度则介于23°~25°之间。④坡度与侵蚀量关系可用函数表示为:S=199.1×L1.65×tan1.4β(0°≤β≤23°)。     

凤阳山枯落物水文特性研究

采用网格结合模拟降雨研究方法,对凤阳山枯落物水文特性进行了研究。结果表明,在一定的雨强和降水量条件下,枯落物层中产生的径流量与坡度有着密切关系,坡度越大,产生的径流量越大;渗流在降雨结束后的延续时间与坡度有着密切关系,坡度越大,渗流延续时间越长;径流在降雨结束后的延续时间与坡度有着密切关系,坡度越大,径流延续时间越长;一般情况下,渗流较径流先产生、后结束;产生渗流的面积与坡度关系密切,坡度越大,产生渗流的面积越大;不同坡度位置产生渗流的时间随着降雨点坡向距离(以下简称为距离)的增加呈线性变化关系;实验表明,临界坡度约为30°;随着坡度的增加,产生渗流的距离变长;渗流主要集中在降雨点附近,该区域的渗流量所占总渗流量的比例随着坡度增加而减少。     

尾矿料的渗透性试验

渗透系数是直接影响尾矿坝浸润线埋深及稳定性的重要参数之一.分别对取自尾矿坝区的4种尾矿料进行颗粒分析试验、原状土与重塑土渗透试验、尾矿浆水渗透试验,分析了颗粒级配、孔隙比及时间对尾矿料渗透系数的影响.试验结果表明,由于重塑土不再具有分选性,其渗透系数比相近孔隙比的同类原状土大;经过80 min后,4种尾矿浆的渗透系数K20都趋向于同一个值.     

Characteristics of runoff and sediment generation of forest vegetation on a hill slope by use of artificial rainfall apparatus

We studied the impact of forest vegetation on soil erosion,surface runoff, and sediment generation by using field simulated rainfall apparatus. We measured runoff and sediment generation of five 4.5 × 2.1m runoff plots (a bare soil as a control; two Pinus tabulaeformis forestplots and two Platycladus orientalis forest with row spacing of 1 m × 1m and 1.5 m × 1.5 m, respectively) in Beijing Jiu Feng National ForestPark under three rainfall intensities (0.42, 0.83, 1.26 mm per minute).Forest vegetation significantly reduced soil erosion and sediment yield.Mean total runoff volume in the four tree stand plots was 93% of that inthe control plot, demonstrating the limited effectiveness of forest vegetation in runoff control. With increasing rainfall intensity, runoff reductionin forest plots declined from 28.32% to 2.1%. Similar trends in runoff coefficient and the relationship between runoff volume and rainfall duration was observed. Mean total sediment yield and mean sediment yield reduction rate under different treatments was 55.05% and 43.17% of those in the bare soil control plot, respectively. Rainfall intensity playedan important role in runoff and sediment generation processes, and had agreater impact on runoff than on soil erosion and sediment generation.When considering several factors in runoff and sediment transport processes, the P. tabulae form plot with row spacing at 1 × 1 m had a greater effect on soil and water conservation than did other forested plots.     

松华坝水源区迤者小流域径流和泥沙变化特征

通过实地观测、实验分析及数据处理,对松花坝水源区迤者小流域的径流和泥沙进行了初步研究,通过探究径流和泥沙变化特征来揭示该区水土流失的原因,以采用合理的方法治理该区水体流失。结果表明：松花坝水源区迤者小流域5～10月的降雨量最大,降雨是产生径流和泥沙的主要因素,但不是唯一因素,降雨、径流、泥沙之间存在着正相关的关系,如8月4日降雨深度达到39．4mm,径流总量达到88．12m^3,产沙量达到150．68kg。又如9月19日降雨深度只有0．2mm,径流总量只有0．22m^3,产沙量也只有0．01kg。降雨具有周期性和随机性,而径流和泥沙的日变化规律和降雨历时、采样时间及土地利用类型有很大的关系。我们只能分析径流和泥沙的大致变化趋势,而无具体的变化规律。     

芦花冲小流域多功能防护林水土保持效益监测

采用坡面径流场和三角形-梯形复合测流堰方法,观测了芦花冲小流域多功能防护林林地的径流、泥沙及土壤物理性质变化。结果表明多功能防护林体系的水土保持效果明显,不同造林模式林地同对照比较,坡面径流量减少17.75%~77.41%,泥沙流失量减少55.24%~89.83%,土壤容重减少3.00%~30.30%,土壤总孔隙度增加12.67%~75.55%。应用世行多功能防护林造林模式营造林3~4a后,林地的水土流失可以得到基本控制。     

紫色土丘陵区不同耕作模式土壤抗冲性对比分析

基于径流小区定位观测研究,分别研究紫色土丘陵区坡耕地不同耕作模式(横垄、顺垄、混合耕作)和不同土层(0～15 cm、15～30 cm)对土壤径流冲刷过程中径流含沙量及抗冲指数的变化特征的影响,以及影响因素的内在关系。研究结果表明:(1)在整个冲刷过程中,不同土层土壤表面径流泥沙流失量呈递减趋势,最后基本趋于稳定;(2)在整个冲刷过程中,径流泥沙流失量总体表现为0～15 cm土层>15～30 cm土层,这主要与土壤剖面特性有关,而农业耕作和根系的影响占次要地位;(3)在各种耕作模式中,抗冲指数的大小均表现为0～15 cm土层<15～30 cm土层,且后者分别是前者的2～3倍。     

黄河三角洲湿地刺槐林水文效益和生长量与气候因子的关系(英文)

研究湿地防护林水文生态效益与气候环境因子的响应是湿地生态保护与经营管理中的热点问题。本文通过自然降雨径流小区定位观测试验,定量研究了黄河三角洲湿地刺槐林地及其采伐迹地的产流产沙效果和土壤水分动态变化规律。刺槐林地与采伐迹地相比,一场降雨的径流量减少53.9%～150.8%,泥沙量减少172.8%～387.1%;刺槐林地降雨径流洪峰峰值比采伐迹地低0.8L·s-1,且径流洪峰值出现的时间比采伐迹地滞后25min;刺槐林地和采伐迹地土壤含水率随年内降水量变化分干湿两季,呈周期性变化,刺槐林地年平均含水率比采伐迹地高23.3%～25.6%,特别是雨季其含水率比采伐迹地高24.3%～29.8%。应用逐步回归分析理论和方法,建立了刺槐生态防护林高生长量与气候环境因子的回归模型,影响该地区刺槐林高生长的主导因子是光照因子,其次是水分因子,再次是热量因子。该项研究可为黄河三角湿地刺槐防护林的更新改造及其生态水文效益的定量评价提供科学依据。     

Effects of foliage and traffic intensity on runoff and sediment in skid trails after trafficking in a deciduous forest

After ground-based skidding operations, soil particles are rearranged closer together resulting in increased bulk density, reduced total porosity, and decreased infiltration capacity. The aim of the present study was to assess and quantify runoff and sediment in both leafed and leafless periods (foliage) over a 1-year duration following three levels of skidder traffic intensity (low, medium, high) performed in the Hyrcanian forests, Iran. By increasing traffic frequency, soil bulk density increased significantly, whereas total porosity decreased as compared to undisturbed (control) plots. After trafficking, runoff and sediment yield were significantly affected by foliage and traffic frequency. Regardless of foliage, mean total runoff and sediment increased with increasing traffic frequency performed on the skid trail. Mean runoff in the low, medium, and high traffic plots in the leafless period were 95.5, 54.2, and 21.7% higher than the values of runoff in the leafed period, respectively. Mean sediment yield in the low, medium, and high traffic plots in the leafless period was 7.1, 5.1, and 3.3 times higher than the values of sediment in the leafed period, respectively. Based on regression analysis, the runoff and sediment response to rainfall for the control plots and three traffic intensity classes were linear and statistically significant for both leafless and leafed periods. The total runoff in the high traffic intensity plot was 239.8 mm (62%) during the leafless period, and 38% of total runoff (148 mm) occurred during the leafed period. The sediment response to runoff over both leafless and leafed periods at all the traffic intensity classes and control plots were significantly linear. Restricting ground-based skidding operations to trail segments where the machine traffic is less than 4 (low)—9 (medium) traffic cycles can be effective to reduce runoff and sediment over compacted soil after machine-induced traffic.     

安家沟流域水土流失监测体系及分析

在水土保持综合治理措施布设中,水土流失发生的时空量分布的特征是基础的资料信息.分析了安家沟流域历史形成的水土保持监测数据关系,重点对地表坡度对径流量的影响、地表坡度对含沙量的影响、不同植被对水土保持的作用进行分析,为指导小流域的水土保持提供一定的技术依据.     

深丘区防护林体系营建前后生态效益的初步研究

通过对深丘区环境背景特征的研究，探讨了建设防护林体系的重要性，根据防护林体系的配置和观测体系的布置，以流域为单元，分层研究了防护林体系的综合效益，研究表明：营建后的防护林体系，可使坡面径流减少６２％，径流含沙量减少６９％，流域的年径流量和产沙量有显著变化，森林覆被率每增加１％，年径流深减少４．１ｍｍ，泥沙减少３．７％，但枯季径流略有增加。     

The cone index is a weak predictor of soil disturbance on forest soils of the Western Carpathians

Soil compaction is one of the primary causes of soil degradation. Predicting the soil disturbance by assessing the cone index of the soil is becoming popular, due to the simplicity of measuring it with a cone penetrometer. This paper is focused on assessing, whether the cone index is a suitable predictor of soil compaction on cambisols, luvisols, and rendzic leptosols. Overall, we measured penetration resistance, bulk density, moisture content, and rut depth on 250 locations in forests of the Western Carpatians. The mean penetration resistance of the undisturbed soil was 4.33 and 4.41 MPa in the ruts of the skid trails; the mean cone index of the undisturbed soil was 5.46 MPa; the mean bulk density of undisturbed soil was 0.95 g cm^?3; the mean moisture content of the undisturbed soil was 24%; the mean rut depth was 6 cm, and the maximal rut depth was 38 cm. Spearman’s correlation analysis showed that the relationship between the mean rut depth and the cone index was statistically insignificant, and the relationship between the maximal rut depth and the cone index was, though significant, weak (R = ?0.20).