沙尘暴的成因、危害与防治

１沙尘暴的成因沙尘暴是因强风气流对地表的冲击作用,使沙土粒脱离地表,进入气流被搬运、堆积的风力侵蚀过程;是荒漠化过程的典型表现形式,是一种风吹沙走,使得天空能见度急剧降低的灾害性天气现象。沙尘暴所形成的黑色云团———沙尘壁高度可达３００～５００ｍ,距...     

黄河下游引黄灌区沉沙区水土流失综合防治体系研究

针对黄河下游引黄灌区沉沙区由于引沙、沉沙、弃沙造成的土壤沙化和水土流失严重这一突出问题,以小开河引黄灌区集中沉沙区为研究对象,结合自然条件、地形地貌特征、水土流失分布和特点,在水土流失分区的基础上,制定了各分区水土保持生态恢复的关键技术,建立了引黄灌区中游沉沙段"沙化工程治理及配套生物修复综合整治模式",为黄河下游引黄灌区水土流失综合防治和灌区水土保持生态建设提供了理论依据和技术参考。     

德庆县水土流失区沙渍地开发利用研究

德庆县水土流失区沙渍地开发利用研究沈家安（广东省德庆县水土保持办公室，５２６６００）沙渍地是德庆县花岗岩崩岗侵蚀的产物。崩岗侵蚀带来大量泥沙，冲入谷地覆盖农田，形成高低不平的沙渍地。在治理水土流失的同时，如何开发利用沙渍地，发展各项生产，增加经济收入...     

川中丘陵区坡地防护林侵蚀产沙特征的研究

以川中丘陵区坡地防护林林地降雨量、径流量、泥沙含量等因子测定为切入点,借助侵蚀产沙数学模型,系统分析了不同防护林类型的降雨侵蚀力与产沙、降雨强度与产沙、次降雨下产流与产沙、地表径流与产沙以及不同防护林类型产流产沙的关系,同时通过对比分析,阐述了防护林体系中不同类型的产沙侵蚀过程和水土流失规律,为川中丘陵区坡地防护林结构的调整、控制水土流失和提高防护功能具有指导作用。     

我国治理水土流失的系统思考

我国严重的水土流失造成江河泛滥、土地荒漠化、沙尘暴和生态失衡,这与我国当前重经济发展忽视环境保护有很大关系,贯彻落实科学发展观,建立水土保持的管理、投入机制,实现人与自然的和谐,是建立社会主义新农村的重要内容。本文对我国水土保持的现状以及水土流失产生的严重问题进行了探讨,分析水土保持的制约因素：管理体制、投入机制、经济发展与水土保持,并提出系统解决水土流失问题的一些建议。     

大昌汗小流域水土流失成因及其对策

府谷县大昌汗小流域是黄河中游多沙集中来源区的重点区域,属极强烈水土流失区,土壤侵蚀模数11 400t/(km2.a)。由于自然和人为因素的双重作用,水土流失严重。尤其是近年来开矿、筑路、开发区建设等开发建设类项目的增多,忽视水土保持工作,造成了严重的水土流失,严重破坏了生态环境。为防止生态环境继续恶化,在坡地、荒地、沟壑等采取修建梯田、谷坊、拦沙坝等水土保持综合措施进行治理,取得了明显的效果,流域水土保持生态防护体系初步形成,基本控制了水土流失;减少了入黄泥沙和水土流失的危害,实现了水土资源持续利用。     

区域水土流失过程及其定量描述的初步研究

水土流失是一个多时空尺度,空间尺度包括坡面、小流域和区域等层次。不同尺度具有不同的主导性过程。区域尺度水土流失过程包括了产流产沙过程,水沙物质汇集和传输过程,水土流失治理过程三个子过程,基于已有坡面、小流域和区域水土流失模型研究和区域水土流失因子试验研究成果,可以实现对区域水土流失过程的定量描述。     

东港市合隆小流域减流减沙效益分析

小流域水土流失防治措施减流减沙效果的定量评价,可为流域发展规划和治理方案的优化提供科学指导。采用SWAT模型定量分析了东港市合隆小流域水土流失治理措施的减流减沙效益。结果表明:在减流方面果园、封禁治理、保土耕作和水平梯田措施基本相当,而水平梯田较其它措施的减沙效果更加显著。     

嘉陵江李子口小流域侵蚀产沙模型初探

到目前为止,国内外对土壤侵蚀产沙模型已经进行了大量的研究,建立了大量的土壤侵蚀产沙模型,从嘉陵江流域、李子口小流域的基本情况（尤其是水土流失现状）入手,结合长江流域侵蚀产沙模型研究情况,初步探讨了李子口小流域侵蚀产沙模型。     

河龙区间减沙效益与水土流失治理度的关系

 研究黄河中游河龙区间水土保持措施减沙效益与水土流失治理度的关系。结果表明:1)河龙区间减沙效益与水土流失治理度呈正相关关系。二者关系可以按照治理度与减沙效益取值范围的不同,明显分为减沙效益高值区和减沙效益低值区2个区,其单位治理度的减沙效益基本相等。减沙效益低值区的治理度小于15%时,基本没有减沙效益。“两川两河”要想取得10%以上的减沙效益,治理度应超过30%。2)河龙区间减沙效益与水土流失治理度关系分为减沙效益高值区、减沙效益中值区和减沙效益低值区3个区后,减沙效益高值区的治理度提高10%,减沙效益可以提高约8%;减沙效益中值区的治理度提高10%,减沙效益提高8%;减沙效益低值区的治理度提高10%,减沙效益只能提高3.4%。因此,构筑减少黄河粗泥沙的第一道防线,建议首选位于减沙效益低值区的窟野河和皇甫川流域。     

黄土高原水蚀风蚀交错带和神木试区的环境背景及整治方向

黄土高原土壤侵蚀最强烈地区出现于年降水量为400mm左右的水蚀风蚀交错地带,本区气候变化剧烈,植被稀疏,土壤侵蚀全年进行,为典型的脆弱生态环境区。春季风蚀强烈,夏秋暴雨侵蚀频繁,两者交替进行,相互促进,年均侵蚀模数多在10000t/km²以上,境内的晋陕蒙煤田开发区为强烈侵蚀的中心,又为黄河下游河床粗泥沙的主要来源区。鉴于治黄和煤田开发的紧迫需要,神木试区即设于该地区,建立该试区进行环境整治的试验示范研究具有广泛的实际指导意义。综合分析神木试区的优势和劣势。以小流域为单元,探讨工副业与农业相结合,生态效益与经济效益同步发展,农林牧副业生产走向商品化,走向市场的新途径。     

降雨类型对褐土横垄坡面土壤侵蚀过程的影响

雨型是影响土壤侵蚀过程的重要因子之一,而影响效应与耕作措施密切相关。目前,雨型对横垄坡面土壤侵蚀过程的影响机制尚不清楚。该文以褐土横垄坡面为研究对象,设计了平均雨强和降雨量相同的4种雨型(增加、减弱、增加-减弱和减弱-增加型),采用可同时调节垄向和坡面坡度的土槽进行模拟降雨,研究各个雨型下不同侵蚀阶段的产流产沙特征。结果表明:雨型间的径流量和侵蚀量在细沟间和细沟侵蚀阶段均差异显著,且差异在细沟阶段体现的更为明显。雨型间径流量的大小顺序为增加-减弱型减弱型减弱-增加型增加型,侵蚀量则为增加-减弱型减弱-增加型减弱型增加型。给定雨强下(30、60或90 mm/h),径流量、径流贡献率和侵蚀量贡献率均随降雨过程中雨强发生时序的延迟而增加,而单位径流侵蚀量呈相反趋势;雨型间给定雨强同一发生时序下的径流量和侵蚀量及其它们对总径流量和总侵蚀量的贡献率均差异显著。4种雨型下,幂函数均能很好的描述细沟间和细沟侵蚀阶段内产沙率与径流率间的关系,且方程中的指数均低于2,但雨型间幂函数方程中的指数存在明显差异。以上研究结果有助于深入理解褐土垄作系统下的土壤侵蚀机理,并为横坡垄作的合理利用提供科学指导。     

黄土丘陵沟壑区梯田暴雨侵蚀状况及规律分析

针对2013年延安百年不遇暴雨造成的黄土丘陵沟壑区梯田侵蚀灾害严重、水土资源利用率低等问题。选取安塞县马家沟流域曹新庄梯田作为典型研究对象,在进行野外监测的基础上,分析了梯田在百年不遇暴雨条件下的梯级侵蚀灾害发生规律。结果表明:按高程最上级梯田侵蚀轻微,依次往下梯田侵蚀面积所占百分比逐渐增大并且增加明显,上部梯田主要以面蚀为主,仅发生轻微沟蚀,下部梯田面蚀、沟蚀都比较严重。梯田侵蚀量与梯田汇水面积、地表径流量等条件有关,影响梯田侵蚀灾害发生的主要因素是地表径流量。该区2013年6—9月延安百年不遇暴雨梯田平均侵蚀模数为20 659.7 t/hm²,超过该区平均年侵蚀模数的47.6%,6—9月月降雨量侵蚀的临界值为118.8 mm。布置水沙调控措施层层拦蓄径流是保证梯田安全的重要措施。     

Dust storm erosion and its impact on soil carbon and nitrogen losses in northern China

There is increased awareness of the environmental impacts of soil carbon (C) and nitrogen (N) losses through wind erosion, especially in areas heavily affected by dust storm erosion. This paper reviews the recent literature concerning dust storm-related soil erosion and its impact on soil C and N losses in northern China. The purpose of our study is to provide an overview of the area of erosion-affected soils and to estimate the magnitude of soil C and N losses from farmland affected by dust storm erosion.According to the second national soil erosion remote-sensing survey in 2000, the area affected by wind erosion was 1.91 million km², accounting for 20% of the total land area in China. This area is expanding quickly as the incidence of heavy dust storms has greatly increased over the last five decades, mainly as a result of the intensification of soil cultivation. The economic and ecological damage caused by wind erosion is considerable. Heavily affected areas show a loss of nutrients and organic carbon in soils and the heavily degraded soils are much less productive. Compared with the non-degraded soil, the C and N contents in degraded soils have declined by 66% and 73%, respectively. The estimated annual losses per cm toplayer of soil C and N by dust storm erosion in northern China range from 53 to 1044 kg ha^− 1 and 5 to 90 kg ha^− 1, respectively. Field studies suggest that soil losses by wind erosion can be reduced by up to 79% when farmers shift from conventional soil tillage methods to no-till. Thus shifting to no-till or reduced tillage systems is an effective practice for protecting soil and soil nutrients. Our study indicates that soil conservation measures along with improved soil fertility management measures should be promoted in dry-land farming areas of northern China. As erosion is a major mechanism of nutrient withdrawal in these areas, we plead for the development of accurate methods for its assessment and for the incorporation of erosion, as a nutrient output term, in nutrient budget studies.     

山东临朐2019年“8·10”特大暴雨水土保持调查

2019年8月10日6时至12日6时,受台风“利奇马”影响,山东淄博、东营、潍坊等地区发生特大暴雨天气,造成了严重的水土流失灾害。暴雨发生后,水利部水土保持监测中心组织调查人员,运用现代技术手段对暴雨中心典型小流域进行了系统、全面的水土保持实地调查。结果表明:(1)本次特大暴雨降雨量为570.6 mm,最大24 h降雨507.6 mm,均超过历史记录;(2)本次暴雨造成严重水土流失灾害,典型小流域水蚀模数达9741 t/km^2,是多年平均值的2.4倍,梯田损毁率达5.96%,河道淤积厚度达10~30 cm,近1/3生产道路完全损毁,引起了严重的重力侵蚀,多处发生滑坡、泥石流;(3)通过对比小流域调查发现,高林草覆盖和重点工程治理分别可削减洪峰模数79%和36%,降低水蚀模数分别达80%和54%;重点治理小流域道路损毁比例减少23.9%,梯田损毁减少40.4%,重力侵蚀减少40%以上。调查摸清了本次特大暴雨径流输沙特征、土壤侵蚀状况、水土流失成灾情况、水土保持措施效益等,初步形成了科学的暴雨水土流失调查方法体系,为今后暴雨水土保持调查制度的建立提供了良好基础。     

A probabilistic approach for predicting rainfall soil erosion losses in semiarid areas

The implementation of soil and water conservation structures in semiarid areas, usually poses a difficult design problem. This is, in large part, due to the high variability of rainfall and the huge potential impact of extreme hydrologic events on structures and on the landscape in general. Magnitudes of runoff and soil loss or sedimentation rates in those environments are better not assessed by conventional modelling techniques, which tend to average out event magnitude and recurrence variability in time and space. A probability-based approach is proposed here to analyse and predict rainfall erosion losses. The maximum annual storm and its associated erosivity is used as a core element in the assessment of annual interrill and rill erosion rates. Frequency and cumulative soil loss distributions are obtained by combining verified annual and maximum daily rainfall frequency distributions with a proposed erosion algorithm. This stochastic representation of erosion permits to evaluate soil losses for the maximum annual storm, as well as annual erosion rates as a function of recurrence interval. The proposed method was verified with a short series of measured soil loss data in Cape Verde. The physical basis underlying the prediction algorithm and method in general, could be sustained by experimental data and field survey evidence. The method seems applicable to arid and semiarid ecosystems with a high seasonal concentration of precipitation and with rainfall limited to only a few major storm events.     

Tillage practices for soil and water conservation in the semi-arid zone II. Development of the basin-tillage system in wheat fields

In the northern Negev of Israel, a typical semi-arid region with a Mediterranean rainfall pattern, wheat production is limited mainly by the amount of available water. Despite the common occurrence of drought years, storm runoff coefficients for unit areas may reach 30–50% of rainfall. Runoff is the main cause of serious erosion damage consisting of soil loss, gully development and loss of productivity.The system of tied ridges or basin tillage, which effectively eliminated over 90% of runoff and erosion in fallow fields before cotton, appears to be a promising solution to the problem of both soil and water conservation in drilled crops as well. Analysis of the long-term rainfall record of the region and the predicted runoff indicates that the basin-tillage system can decrease runoff by at least 50% as compared with the conventional planting system. Experiments carried out during the 1980–1981 rainy season proved that even in a relatively dry year the basin tillage system was effective in increasing wheat yield by about 50% and eliminating erosion.     

Erosion rates on bare loamy sand soils in east Shropshire, UK

Abstract. Results from over seven years of monitoring of erosion rates on bare arable loamy sand soils at the Hilton experimental site, Shropshire, UK, are reported. On bare plots, rates are very variable; erosion during one summer convectional storm exceeded that recorded during six individual years of plot measurement. Exposure of erodible arable soils to convectional storms puts them at risk of excessive erosion. Plot erosion rates were frequently high, with rates up to 67.4 t/ha occurring during an individual storm. Rates were influenced by rainfall erosivity, slope steepness and soil organic content. Mean soil organic content on the bare plots decreased over five years by 0.08%/yr.     

水土保持措施对秃尾河径流的影响

在黄土高原地区,水土保持措施是影响流域产汇流的重要因素之一。本文采用双累积曲线、时间序列分析等方法,分析秃尾河流域降水及河川径流、暴雨洪水特征变化及其对流域水土流失治理的响应。结果表明:流域多年平均降水量406.4mm,河道多年平均径流量3.4亿m3,1977年后年径流量呈显著性减小趋势。与1977年之前相比,在水土保持措施影响下,汛期径流量占年径流量比例下降,枯水期径流量比例上升,季节分配趋于均匀。相似降水条件下,场次洪水总量、洪峰流量减少,洪水过程均化。     

基于USLE模型的重庆生态涵养发展区土壤侵蚀量估算

利用USLE模型估算渝东北生态涵养发展区土壤侵蚀量,并对研究区土壤侵蚀强度进行分级,以此为基础进一步分析不同降雨侵蚀力、坡度、土壤类型下的土壤侵蚀强度分布特征。结果表明:本研究区土壤侵蚀量大致呈东北向西南递减的趋势,东部山地土壤受侵蚀最严重,西部山间丘陵地带土壤侵蚀量相对较小,研究区平均土壤侵蚀模数为30.15t/(hm~2·a),土壤侵蚀量为10 220.85万t/a。研究区各区县土壤侵蚀分布情况可划分为三类:(1)重点预防保护区。土壤侵蚀以微度和轻度侵蚀为主,林草覆盖度较高,但有水土流失加剧的危险,代表区县是忠县、梁平、垫江;(2)重点监督区。土壤侵蚀以中度和强度侵蚀为主,土壤侵蚀相对严重,代表区县为云阳、万州、巫山、奉节、丰都;(3)重点治理区。土壤侵蚀以极强度和剧烈侵蚀为主,土壤侵蚀最严重,代表区县为巫溪、开县、城口。降雨侵蚀力为3 000~4 000(MJ·mm)/(hm~2·h·a),坡度在25°以上,土壤为石灰土、紫色土或黄褐土的地区,土壤侵蚀以强度、极强度和剧烈侵蚀为主,是水土流失治理的重点。