A GIS-based Modeling Approach for Fast Assessment of Soil Erosion by Water at Regional Scale, Loess Plateau of China

The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of precipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units （FAUs） to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. Arclnfo GIS was used to integrate all essential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau.

Driving forces and their interactions of soil erosion in soil and water conservation regionalization at the county scale with a high cultivation rate

Soil erosion control based on county scale Soil and Water Conservation Regionalization(SWCR)is an essential component of China's ecological civilization construction.In SWCR,the quantitative analysis of the spatial heterogeneity and driving factors of soil erosion among different regions is still lacking.It is of great significance for soil erosion control to deeply examine the factors contributing to soil erosion(natural,land use,and socioeconomic factors)and their interaction at the county and regional levels.This study focused on a highly cultivated area,Hechuan District of Chongqing in the Sichuan Basin.The district(with 30 townships)was divided into four soil and water conservation regions(Ⅰ-Ⅳ)using principal component and hierarchical cluster analysis.The driving factors of soil erosion were identified using the geographical detector model.The results showed thatⅰ)the high cultivation rate was a prominent factor of soil erosion,and the sloping farmland accounted for 78.4%of the soil erosion in the study area;ⅱ)land use factors demonstrated the highest explanatory power in soil erosion,and the average interaction of land use factors explained 60.1%of soil erosion in the study area;ⅲ)the interaction between natural factors,socioeconomic factors,and land use factors greatly contributes to regional soil erosion through nonlinear-enhancement of double-factor enhancement.This study highlights the importance of giving special attention to the effects of land use factors on soil erosion at the county scale,particularly in mountainous and hilly areas with extensive sloping farmland and a high cultivation rate.

Synthesis Analysis of Soil Erosion for Three-River Headwater Region Based on GIS

In this paper,based on the common soil erosion model,the Three-River Headwaters region was select for study object. GIS methods are applied to conduct Semi-quantitative assessment for different types of soil erosion,and some results are concluded. The water erosion occurs in High Mountain and extra-high mountain of Yushu,Nangqian,Banma and Jiuzhi County in the southeast and south of the Three-River Headwaters region. The degree of erosion is prone to topography,precipitation,river and human activity. The freeze-thaw erosion mainly distributes in the northwest of the Three-River Headwaters region. The area of middle and above middle erosion degree accounts for roughly 50%.

Effects of ecological soil and water conservation measures on soil erosion control in China’s typical regions:A meta-analysis

[Background]As one of the most serious environmental issues in the world,soil erosion causes water pollution,reservoir siltation,soil productivity decline,thus threatens agricultural systems and even affects global climate.The benefits of ecological soil and water conservation measures(ESWCMs,such as micro basins tillage and contour tillage)are widely understood,including runoff and soil loss reducing to a certain extent when compared with traditional tillage.While few studies have focused on China’s different soil types and erosion characteristics.[Methods]We reviewed literature from Web of Science,Scopus,and China National Knowledge Infrastructure using terms like“Conservation practice”“Contour tillage”“Runoff”“Sediment”“Erosion”and“China”and retained literatures based on criteria such as natural or simulated precipitation,runoff or soil loss data,reported replications and statistics,recorded factors like location and slope,and at least two data pairs per group.Ultimately,49 literatures were selected to quantify the impacts on different ESWCMs and identify the slope and precipitation for the greatest runoff and sediment reduction by calculating the log response ratio(LRR).[Results]The three regions’soil and water conservation benefits varied due to the differences in climate,terrain,and soil properties:1)ESWCMs applied in the black soil region of Northeast China were the most effective in reducing runoff and soil loss(66.65%runoff and 75.83%sediment),followed by those applied in the purple soil region of Southwest China(39.98%runoff and 58.30%sediment)and loess soil region of Northwest China(16.36%runoff and 32.44%sediment).2)Micro basins tillage(MBT)(71.79%runoff and 87.03%sediment)no-tillage with mulch(NTM)(17.30%runoff and 32.51%sediment),collecting soil to form a ridge with no-till(CSNT)(55.78%runoff and 71.36%sediment reduction)were the most efficient soil and water conservation measures in controlling water erosion in the black soil of Northeast China,the loess soil region of Northwest China and the purple soil region of Southwest China,respectively.3)The slope gradients ranged from 0-3°,>3°-5°and>10°-15°(0-3°:97.09%;>3°-5°:74.62%;and>10°-15°:39.41%)caused the largest reduction of runoff in the black soil region of Northeast China,the loess soil region of Northwest China,and the purple soil region of Southwest China.Meanwhile,the effects of sediment reduction were the most obvious,ranging from 0-3°,>10°-15°,and>20°-25°(0-3°:89.32%;>10°-15°:75.94%;and>20°-25°:67.25%).4)The effect of ESWCMs under rainstorms was the most obvious in the black soil region of Northeast China.The effect on runoff reduction under light rain in the purple soil region of Southwest China was the most obvious,but it failed to pass the significance test in sediment reduction.[Conclusions]The results provided optimal conservation tillage measures for three regions,different slopes and different rainfalls,and provided data support for reducing regional soil and water loss in China.

Gully Erosion Regionalization of Black Soil Area in Northeastern China

Gully erosion is the frequent and main form of soil erosion in the black soil area of the northeastern China, which is one of the most important commodity grain production bases in China. It is encroaching upon the fertile farmland there. Regionalization of gully erosion can reveal the spatial distribution and regularity of the development of gully erosion. Based on the eco-geographical regional background features of the black soil area, this study combined the regionalization with influencing factors of the development of gully erosion. GIS spatial analysis, geostatistical analysis, spatial statistics, reclassification, debris polygon processing and map algebra methods were employed. As a result, the black soil area was divided into 12 subregions. The field survey data on type, length, volume and other characteristics indicators of gully erosion were used to calibrate the results. Then the features of every subregion, such as where the gully erosion is, how serious it is, and why it happens and develops, were expounded. The result is not only an essential prerequisite for gully erosion surveys and monitoring, but also an important basis for gully erosion prevention.

Regions and Their Typical Paradigms for Soil and Water Conservation in China

China is experiencing conflicts between its large population and scarce arable land,and between a demand for high productivity and the severe soil erosion of arable land.Since 1949,China has committed to soil and water conservation(SWC),for which eight regions and 41 subregions have been developed to improve the environment and increase land productivity.To obtain information from the regional planning and strategies for SWC and to explore whether SWC practices simultaneously contribute to soil conservation,ecosystem functioning,and the livelihoods of local farmers,and to summarize the successful experiences of various SWC paradigms with distinct characteristics and mechanisms of soil erosion,this paper systematically presents seven SWC regions(excluding the Tibetan Plateau region)and 14 typical SWC paradigms,focusing on erosion mechanisms and the key challenges or issues in the seven regions as well as on the core problems,main objectives,key technologies,and the performance of the 14 typical paradigms.In summary,the 14 typical SWC paradigms successfully prevent and control local soil erosion,and have largely enhanced,or at least do not harm,the livelihoods of local farmers.However,there remain many challenges and issues on SWC and socioeconomic development that need to be addressed in the seven SWC regions.China,thus,still has a long way to go in successfully gaining the win-win objective of SWC and human aspects of development.

Analysis on Status and Development Trend of Wind Erosion in Black Earth Region of Northeast China

In this paper,areas and main factors of wind erosion in black earth region of Northeast China were systematically analyzed,as well as the development trend of wind erosion in black earth region of Northeast China.In addition,development trend of wind erosion in black earth region of Northeast China was analyzed from the aspects of the geographic position,climatic change law in recent 40 years and effects of northeast sand land desertification on wind erosion in black earth region,which had provided references for the research and prevention of wind erosion in soil of black earth region of Northeast China.

Spatial Distribution and Temporal Dynamics of Soil Carbon Removal Caused by Water Erosion in China

Using water erosion data from three national soil erosion remote-sensing surveys （the first：1985-1986; the second：1995-1996; the third： 2000-2001） and carbon density data from the second national soil survey （1979-1992）, we computed soil carbon removal caused by water erosion, and analyzed its spatial distribution and temporal dynamics in China. Results revealed that the total removal of soil carbon caused by water erosion was about 74.61 Tg C y^-1 , of which 51.49 Tg C y^-1 was organic carbon, and 23.12 Tg C y^-1 was inorganic carbon. The main erosion level of the whole is moderate erosion. Among the seven erosion regions, the Southwest Karst Region had the most significant removal of soil organic carbon, which was 26.48% of the total and mainly due to its moderate erosion. In contrast, about 67.62% of the soil inorganic carbon removal occurred in the Loess Plateau Region, which mainly due to its highly intense and intense erosion. As a whole, the removals of soil carbon caused by water erosion represented a decreasing trend among the three national soil erosion remote-sensing surveys. Between the first and the second survey, soil carbon removal decreased by 11.66 Tg C y^-1 , of which 81.93% was organic carbon. Compared with that in the second survey, soil carbon removal decreased by 1.65 Tg C y^-1 in the third survey, of which 1.514 Tg C y^-1 was organic carbon, and 0.134 Tg C y^-1 was inorganic carbon.

寒区黑土侵蚀沟治理新技术研究

东北地区黑土侵蚀沟已严重威胁我国粮食安全,其绝大部分处于寒区环境,谷坊作为治理侵蚀沟的通用手段,面临寒区复杂环境威胁。针对寒区谷坊易受冻融、融雪和降雨等多因素耦合下稳定性不足的问题,提出了一种寒区黑土侵蚀沟治理新技术——生态柔性煤矸石土谷坊,该谷坊由土、滤土防冲土工合成材料、煤矸石铰接块和植被防护组成,具有就地取材、节省工期、柔性稳定、固废利用、替代石料和有利扦插等优势。文中给出设计理念、关键参数及现场应用关键技术,形成了成套工艺。研究结果表明:生态柔性煤矸石土谷坊变形值集中在-0.0518~0.0307 m之间,在允许范围内,谷坊前后沟道均无扩宽,泥沙淤积深度17~67 cm,有效减少水土流失,植被覆盖率一年增加30%,表明该谷坊具有良好的稳定性与治理效果,生态效益明显。生态柔性煤矸石土谷坊是在传统谷坊形式上做出优化和改进而形成的一种新型谷坊,此技术将生态技术与工程技术有机结合,为寒区黑土侵蚀沟治理提供了新思路和新手段。

三江源区土壤侵蚀野外调查报告

[目的]现场调查三江源区土壤侵蚀状况,旨在为该区域今后水土流失防治提供参考。[方法]调查组在2023年7月25日至8月20日,分3组分别前往青海省的果洛州、玉树州、海南州和黄南州,对上述区域的林地、草地、农田、裸地、道路、河流岸坡、山区沟谷进行了调查和分析。[结果]草地的土壤侵蚀类型最为复杂,受到风蚀、水蚀、冻融侵蚀和重力侵蚀等多营力侵蚀的共同作用,造成了其水土流失严重。此外,高原鼠害对草地破坏可能是草地侵蚀发生另一重要因素;乔木林地常在林下出现侵蚀细沟,但是由于工程护坡的作用下,发生侵蚀风险整体偏小;灌木林地所在坡面的坡脚处,受到水力侵蚀和重力侵蚀的影响较大,侵蚀风险较大;农田虽然分布面积较少,但是在田埂部分发生轻度的水蚀;对于裸地,细沟侵蚀较为剧烈,水土流失严重;值得注意的是,在道路两侧,边坡侵蚀较为严重,工程开挖导致草皮破坏,在重力的作用下发生滑塌,出现较大的裸露面,为水蚀的发生提供了条件,导致部分区域已经形成了较大的侵蚀沟网。[结论]青海省三江源区域土壤侵蚀类型复杂多样,随着人类活动的加剧,局部区域水土流失有进一步加剧的风险,亟需开展新时期的水土保持工作,需要在该区域加强土壤侵蚀基础研究,加强水土保持监测站网的布设,智能化管理等。

黄土高原水蚀风蚀交错区不同生物结皮类型对土壤有机碳及其转化的影响

[目的]黄土高原水蚀风蚀交错区是典型的脆弱生态系统,该区域生物结皮广泛分布,生物结皮在土壤有机碳积累与转化发挥着关键作用,然而,生物结皮演替及微生物对土壤有机碳转化相关酶类的影响规律尚不明确。[方法]研究土壤有机碳-微生物-碳转化相关酶在生物结皮不同演替类型的变化规律,并运用SEM模型分析了三者之间的相互关系。[结果](1)生物结皮演替显著增加土壤有机碳含量和碳转化相关酶活性,且它们在结皮层(0-2 cm)中的含量均显著高于裸沙和2—5 cm土层(p<0.05);(2)结皮层细菌、真菌和放线菌数量在藓结皮中最高,其中放线菌、真菌数量在生物结皮演替呈显著增加趋势,结皮层中的细菌和真菌数量显著高于2—5 cm土层,但2—5 cm土层放线菌数量高于结皮层(藓结皮除外);(3)SEM模型表明,土壤有机碳、碳转化相关酶活性和微生物数量之间均呈现显著相关性。[结论]生物结皮的演替对土壤有机碳的积累为碳转化相关酶类和微生物提供丰富基质,促进微生物和酶活性提高,微生物对碳转化相关酶类起着重要的驱动作用,对维持生物结皮的碳平衡发挥着关键作用。

基于中国水土保持区划的江苏省植被盖度监测点布局

植被盖度是土壤侵蚀监测与评价的重要因子。植被空间分异性是影响植被盖度分布的主要因素。以江苏省为研究区,以全国水土保持区划的三级区为控制单元,采用多源数据空间分析、分层抽样和野外调查相结合的方法,分析植被类型、林种与树种的空间分异性,提出植被盖度监测点布局方案。结果表明:1)鲁中南低山丘陵土壤保持区(Ⅲ-4-2t)、黄泛平原防沙农田防护区(Ⅲ-5-3fn)及淮北平原岗地农田防护保土区(Ⅲ-5-4nt)地带性植被为栎类落叶林;江淮丘陵岗地农田防护保土区(V-1-2nt)、江淮下游平原农田防护水质维护区(V-1-1ns)、沿江丘陵岗地农田防护人居环境维护区(V-1-5nr)以及太湖丘陵平原水质维护人居环境维护区(V-1-4sr)北部地带性植被从含有常绿灌木的落叶阔叶林演变为常绿落叶阔叶混交林;V-1-4sr南部地带性植被为常绿阔叶林;2)研究区用材林占53.45%,其次为防护林和经济林,分别占26.06%和13.10%,各水土保持三级区林种、树种的比例结构差异较大,自北向南用材林和防护林由杨树、侧柏等转变为马尾松、杉木、香樟以及以麻栎、栓皮栎、枫香、青冈等为优势树种的阔叶混交林等,经济林由苹果、梨、板栗、银杏等转变为茶、桃、柑橘等;3)基于水土保持三级区林种与树种的空间分异性,以17个县(区)为抽样区获取96个抽样监测点,通过野外调查确定49个植被盖度监测点,涵盖各区划的主要林种与树种。研究结果可为江苏省开展植被盖度监测提供技术支撑,也可为其他区域布设植被盖度监测点提供借鉴。

中国东北黑土区土壤复合侵蚀研究进展与展望

土壤复合侵蚀是在2种及以上侵蚀营力交互作用或耦合作用下发生的侵蚀现象。东北黑土区多营力复合侵蚀具有时空交替和叠加的特征。近年来,黑土区土壤复合侵蚀研究在发生机理及对土壤退化的作用等方面取得了一定的进展。基于前人研究成果,系统总结了冻融作用下的土壤水蚀或风蚀、耕作与水力复合侵蚀、风水复合侵蚀以及多营力复合侵蚀在发生机理和研究方法等方面的研究现状,归纳了研究中存在的主要问题,提出了今后在复合侵蚀机制与模拟试验方法等研究中需要解决的关键科学问题以及应关注的试验模拟技术、定量评估方法,以期为未来东北黑土区土壤复合侵蚀研究提供参考。

A study on scheme of soil and water conservation regionalization in China

Regionalization of soil and water conservation is a base for the planning of soil and water conservation in China. It can provide scientific basis for constructing healthy eco-environment and regional management and development. It makes a brief review of related regionalization of study and makes clear the concept of regionalization of soil and water conservation. In this paper, based on synthetical analysis of the characteristics of eco-environments of China, the principles, indices and nomenclature of the regionalization of soil and water conservation are proposed. Through the construction of the regionalization of soil and water conservation collaboration platform and data reporting system, combined with existing soil and water conservation research, this paper uses the top-down and bottom-up and the combination of qualitative and quantitative methods to build soil and water conservation regionalization preliminary scheme, with 8 regions, 41 sub-regions and 117 sections divided in China.

Evaluation of Water Yield and Soil Erosion in the Three-River-Source Region under Different Land-Climate Scenarios

Exploring the water yield and soil conservation in the Three-River-Source region is of great significance for evaluating both the ecological stability of the Qinghai-Tibet Plateau,Yellow River basin,Yangtze River basin and Lancang River basin and the sustainable development of human society.The data sources for this study were land use/cover data from four phases(2000,2005,2010 and 2015),daily precipitation and temperature datasets,and the 1:1000000 Chinese soil database.These data were combined with vector data,such as data on settlements,roads,and rivers,along with population,economic raster datasets and CCSM4 common climate model prediction results.The Three-River-Source region was taken as the study area,and four land use/cover development scenarios and two climate change scenarios were designed based on the FLUS model and the downscaling correction method.The InVEST model was used to quantitatively simulate the water yield and soil erosion under different scenarios in the study area in 2030.The results showed the following:(1)Under different land use/cover development scenarios,grassland remained the dominant land use/cover type in the Three-River-Source region,and the area ratio was always greater than 67%.(2)Under the RCP4.5 climate scenario,the annual water yield and soil erosion increased by more than 7%and 3.9%,respectively.Under the RCP8.5 climate scenario,the annual water yield and soil erosion decreased by more than 3.3%and 1.3%,respectively.(3)Climate change played a leading role in the changes in water yield and soil erosion.Climate change contributed as much as 89.97%–98.00%to the change in water yield and 60.49%–95.64%to the change in the soil erosion modulus.However,the contribution of land use/cover changes to the change in regional water yield was only 2.00%–10.03%,and the contribution of the soil erosion modulus change was 4.36%–39.91%.Therefore,the land use development strategy in the Three-River-Source region should comprehensively consider issues such as regional development,the input of returning farmland to forest and grassland,and the resulting ecological benefits.

东北黑土区土壤侵蚀防治与水土保持策略

东北黑土地带以其丰饶的土地和充裕的自然资源而闻名,是我国关键的粮食生产区。尽管如此,水土流失问题正不断加剧,这对农业长期发展和自然环境维护构成严峻挑战。在气候条件变化和人类行为的作用下,问题更为突出。基于此,阐述东北黑土区土壤侵蚀防治的重要性,研究该地区不同类型的水土流失特点,并提出针对性的水土保持方法,以促进黑土区的可持续发展,实现资源的科学利用,保护区域生态环境。

东北黑土区土壤侵蚀研究进展与展望

东北黑土区是我国重要的商品粮生产基地,强烈水土流失导致的黑土厚度下降及土壤质量退化,直接威胁国家粮食安全。系统分析黑土区土壤侵蚀研究成果,对阻控黑土退化、维持土地生产力、保障国家粮食安全具有重要意义,论述了黑土区土壤侵蚀环境与侵蚀环境效应、土壤侵蚀过程与机理、土壤侵蚀时空变化和未来研究展望。多营力复合、缓坡长坡是黑土区独特的侵蚀环境,黑土厚度下降与坡耕地土壤质量退化是该区最典型的侵蚀环境效应。细沟间、细沟、浅沟、切沟及冻融侵蚀发育的动力机制与主控因素差异明显,输沙耗能驱动的泥沙输移对土壤分离的反馈效应是侵蚀强度沿坡长呈强弱交替的根本原因,浅沟和切沟主要发育在坡耕地,侵蚀强度受耕作方式等人类活动的显著影响。冻融侵蚀强度显著小于水力侵蚀,但可通过降低土壤抗蚀性能和促进坡面径流及壤中流发育影响水力侵蚀。土壤侵蚀类型与强度在小流域尺度上沿坡面呈明显的垂直分带特征,在区域尺度上呈南北与东西递变的纬度和经度地带性。全球气候变化可能导致黑土区水力侵蚀加强、冻融侵蚀减弱。未来亟需加强黑土厚度及土地生产力对侵蚀响应机理、复合侵蚀动力过程与耦合机制、典型侵蚀类型时空变化与主控因素等方面的研究。

Soil Erosion and Sediment Control Effects in the Three Gorges Reservoir Region, China

The Three Gorges Reservoir, the world’s largest hydropower reservoir, receives a significant sediment yield from soil erosion. Sloping farmland is the main source, exacerbated by changes in land use from relocating the inhabitants, and from engineering projects related to dam construction. Related geo-hazards, including landsliding of valley-side slopes, will further increase the sediment yield to the completed reservoir. Integrated watershed management, begun extensively in 1989, has effectively controlled soil erosion and sediment delivery to date. What is described here as the Taipinxi Mode of integrated watershed management, based on its application in the 26.14 km2 watershed of that name in Yiling District, has been successful and is recommended for the entire region. The effects of this set of erosion-mitigation measures are assessed, using experienced formulas for soil and water conservation and information from remote sensing. The amount of soil erosion, and of sediment delivery to the reservoir were reduced by 43.75–45.94 × 106 t y-1, and by 12.25–12.86 × 106 t y-1, respectively, by 2005, by which time the project had been operative for 16 years.

云南省生态功能类型区的生态敏感性

结合云南省生态功能区划,展开对全省各生态功能区的生态敏感性分析,结果表明,滇东地区水土流失较严重,石漠化敏感性强度达中度以上的区域面积超过50%;受降水量大,紫色土集中分布及地处石灰岩地带等自然地理因素的影响,云南省西南大部与东南部分地区土壤侵蚀敏感性较高;云南省的生境敏感区大多地处生态交错区,物种丰富度高,但生境脆弱,一旦破坏很难恢复。改善土地利用方式,提高农业生产技术,发展生态农业,控制农业污染,开展生态恢复等,是提高地区森林覆盖率,减少水土流失和泥石流的发生,防止石漠化加剧的主要手段。

神木水蚀风蚀交错带退耕坡地土壤水分空间变异性研究

运用统计学方法,对黄土高原神木水蚀风蚀交错带退耕坡地土壤水分空间变异性及其影响因子进行研究。结果表明:(1)土壤水分含量在垂直剖面方向表现出随深度增加,土壤水分含量呈增加趋势,在100cm土层内变异最大,在100cm以下其变化的梯度基本趋于稳定;(2)土壤水分含量沿坡长方向(即坡顶到坡下)呈波浪状递增趋势,且在各坡位变异程度不一,呈现出变异程度为坡上>坡中>坡下的趋势;(3)土壤水分含量沿垂直于坡长方向表现为:阴坡>山脊>阳坡的明显趋势,其变异程度表现为阳坡>阴坡的趋势。本文对神木水蚀风蚀交错带退耕坡地土壤水分的研究有助于了解退耕地土壤水分的变异特征,为区域环境治理和植被建设提供科学依据。