Quantitative analysis of the dynamic change and spatial differences of the ecological security: a case study of Loess Plateau in northern Shaanxi Province

Using the theory and method of the ecological footprint, and combining the changes of regional land use, resource environment, population, society and economy, this paper calculated the ecological footprint, ecological carrying capacity and ecological surplus/loss in 1986-2002 on the Loess Plateau in northern Shaanxi Province. What is more, this paper has put forward the concept of ecological pressure index, set up ecological pressure index models, and ecological security grading systems, and the prediction models of different ecological footprints, ecological carrying capacity, ecological surplus and ecological safety change, and also has assessed the ecological footprint demands of 10,000 yuan GDE The results of this study are as follows： （1） the ecological carrying capacity in northern Shaanxi shows a decreasing trend, the difference of reducing range is the fastest; （2） the ecological footprint appears an increasing trend; （3） ecological pressure index rose to 0.91 from 0.44 during 1986-2002 on the Loess Plateau of northern Shaanxi with an increase of 47%; and （4） the ecological security in the study area is in a critical state, and the ecological oressure index has been increasing rapidlv.

Change Characteristics and Cause Analysis of Summer Precipitation Anomaly in Loess Plateau of Northern Shaanxi Province

[ Objective] The research aimed to study change characteristics and formation cause of summer precipitation abnormality in Loess Plateau of northern Shaanxi Province. [ Method] Based on summer precipitation data at 15 observation stations in Loess Plateau of northern Shaanxi Province and NCEP/NCAR dataset from 1961 to 2008, change characteristics of summer precipitation in the region were investigated by using linear trend estimation and composite analysis. [Result] Summer rainfall had decrease trend in most parts of northem Shaanxi Province, but had increase trend in western and southern regions. The interannual and interdecadal variations were obvious. It had a large amount of precipitation from the mid- 1970s to the mid-1990s, while summer rainfall had decrease trend after the mid-1990s and increase trend in recent years. In wet years, it was a large positive anomaly zone from western Ural Mountains to northem Lake Baikal at middle and high latitudes, indicating that there was a blocking high over the Ural Mountains, while it was negative anomaly zone from northern Okhotsk Sea to Lake Baikal. From Northwest Pacific Ocean to Bo- hal Sea Bay and North China, it was a wide range of significant positive anomaly zone, which was favorable for Westem Pacific subtropical high ex- tending westward and northward. The analysis in dry years showed opposite circulation configuration. It was ＂ -, ＋, -＂ wave train distribution in middle and high latitudes and positive anomaly zone along the Sea of Okhotsk. Western Pacific subtropical high was also by south and east. Major water vapor was from southeast direction in wet years, and abundant water vapor caused more summer rainfall in northern Shaanxi. In dry years, water vapor was from westerly tuming southerly flow. It was weaker and by east. [ Conclusion] The research provided reference for reasonable utilization of summer precipitation in the zone.

Changes in Ecosystem Service Values on the Loess Plateau in Northern Shaanxi Province,China

The Loess Plateau in northern Shaanxi Province of China covers Yulin, Yan＇an, and Tongchuan cities mainly. The kind of physiognomy is complicated and various, including the transitional region of the sand and wind, the hilly-gully fragile region, the pimple mound region from North to South. Large-scale land reclamation projects that are severely affecting these ecosystems have been implemented. In this paper, we reported an investigation to the changes in land use and ecosystem services on the Loess Plateau in northern Shaanxi Province from 1978 to 2000. We used three LANDSAT TM and/or ETM data sets to estimate the changes in the size of five land-cover/land-use categories, and we also used previously published value coefficients to estimate the changes in the value of ecosystem services delivered by each land category. Finally, we ranked the contribution of various ecosystem functions to the overall value of the ecosystem services, we have estimated that the annual value of the ecosystem services is 56.95 billon RMB yuan in the Loess Plateau in northern Shaanxi Province in 2000. In the region, from 1978 to 2000, the economic value of the fixing carbon was higher, the economic value of water conservation was the lowest, but the economic value of the NPP, fixing carbon, and supplying oxygen accounted for above ninety percent of the total value, obviously the vegetation created the biggest ecosystem service value. We can conclude that future land-use policy formulation should give precedence to the conservation of these ecosystems over uncontrolled reclamation, and that further land reclamation should be based on rigorous environmental impact analyses.

Current situation and human health risk assessment of fluoride enrichment in groundwater in the Loess Plateau:A case study of Dali County,Shaanxi Province,China

This study aims to investigate the mechanisms and health risks of fluoride enrichment in groundwater in the Loess Plateau,China.By taking Dali County,Shaanxi Province,China as an example,this study obtains the following results through field investigation and the analyses of water,soil,and crop samples.(1)The groundwater can be divided into two major types,namely the Quaternary pore-fissure water and Karst water.The Karst area and sandy area have high-quality groundwater and serve as the target areas for optional water supply.The groundwater in the study area is slightly alkaline and highly saline.Meanwhile,high-fluoride groundwater is mainly distributed in the loess and river alluvial plains in the depression area of the Guanzhong Basin and the discharge areas of the groundwater,with the highest fluoride concentration exceeding seven times the national standard.(2)Fluoride in groundwater mainly originates from a natural source and human activities.The natural source refers to the fluoride-bearing minerals in rocks and soil,and the fluoride from this source is mainly controlled by natural factors such as climate,geologic setting,pH,specific hydrochemical environment,ion exchange,and mineral saturation.Human activities in modern life can be further divided into industrial and agricultural sources primarily.(3)The health risks of fluoride contamination are very high in the Loess Plateau,especially for children compared to adults.Meanwhile,the risks of fluoride exposure through food intake are higher than those through drinking water intake.The authors suggest selecting target areas to improve water supply and ensure the safety of drinking water in the study area.Besides,it is necessary to plant crops with low fluoride content or cash crops and to conduct groundwater treatment to reduce the fluoride concentration in drinking water.These results will provide a theoretical basis for safe water supply in the faulted basin areas in the Loess Plateau.

Study on the Effects of Extreme Precipitation for Seven Growth Stages of Winter Wheat in Northern Weihe Loess Plateau, China

The research on the characteristic frequency of precipitation is a great significance for guiding regional agricultural planning, water conservancy project designs, and drought and flood control. Droughts and floods occurred in northern Weihe Loess Plateau, affecting growing and yield of winter wheat in the area. Based on the daily precipitation data of 29 meteorological stations from 1981 to 2012, this study is to address the analysis of three different frequencies of annual precipitation at 5%, 50%, and 95%, and to determine the amount of rainfall excess and water shortage during seven growth stages of winter wheat at 5%, 10%, and 20% frequencies, respectively. Pearson type III curve was selected for this study to analyze the distribution frequency of annual rainfall and rainfall amount following seven growth stages of winter wheat crop in 29 stations of Northern Weihe loess plateau. As a result of our study, annual precipitation is gradually increasing from southwest to northeast of Northern Weihe loess plateau. The highest amount of annual precipitation occurred in the Baoji area and the lowest precipitation covered by the northwest area of Northern Weihe loess plateau. Moreover, the amount of rainfall of seven growth stages indicates that excessive rainfall occurs not only in the first stage (sowing to tillering) and seventh stage (flowering to ripening) but also in second stage (tillering to wintering). In the seventh stage, a large amount of excessive rainfall occurred in Changwu, Bin, Qianyang, Fengxiang, Baojiqu, and Baojixian. Moreover, water shortage is distributed in the third stage (from wintering to greening), the fourth stage (from greening to jointing), the fifth stage (from jointing to heading), and the sixth stage (from heading to flowering). Furthermore, the worst water shortages occurred in Hancheng, Heyang, Chengcheng, Pucheng, Dali, Tongchuan, and Fuping in the fourth stage (greening to jointing stage). Even though we study the crop water requirement under extreme rainfall conditions, the amount of rainwater still supply inadequate in some parts of the winter wheat growth stage. Therefore, this study provides main clues for the next step to study the irrigation water needs of winter wheat crops and to reduce agricultural risks in 29 counties in the northern loess plateau and other regions.

New Thought of Meteorological Forecasting and Warning Models of Geological Disasters in Loess Plateau of North Shaanxi

The study established daily comprehensive precipitation equations and calculated respective critical daily comprehensive precipitation value of loess-collapse disasters and landslide disasters by dint of the geological disasters and corresponding precipitation data in 47 years.Considering geological disaster risk divisions,precipitation influence coefficient and daily comprehensive precipitation,hourly rolling daily-forecasting and hourly warning fine and no-gap models on the base of high temporal and spatial resolution rainfall data of automatic meteorological station were developed.Through the verifying of combination of dynamical forecasting model and warning model,the results showed that it can improve efficiency of forecast and have good response at the same time.

Variation Characteristics of Sunshine Hours and Its Reason Analysis over Loess Plateau of Shaanxi

[Objective] The research aimed to study variation characteristics of sunshine hours over Loess Plateau of Shaanxi during 1961-2010.[Method] By using the climate tendency rate,climate trend coefficient and linear correlation,the temporal and spatial variation characteristics of sunshine hours in Loess Plateau of Shaanxi in recent 50 years were analyzed.Moreover,the main reason for inducing variation of sunshine hours in the zone was discussed.[Result] In recent 50 years,the variation of annual sunshine hours in Loess Plateau of Shaanxi mainly presented decrease trend.The decrease zones were mainly located in windy desert region along the Great Wall line,central loess hilly region,most areas of plateau remains region and most areas of arid plateau region in north Weihe River.The increase zones were mainly located in west and northeast plateau remains region,southwest plateau remains region,some areas of arid plateau region in north Weihe River.Seen from four-season variation trend,except in spring,the sunshine hours in other seasons presented varying decrease trends.The decrease amplitude in summer was 24.34 h/10 a,and was the most significant.The second one was-16.62 h/10 a in winter.The decrease amplitude in winter was 3.55 h/10 a,and was unobvious.Seen from spatial variation,the annual sunshine hours presented significant increase trend in Mizhi of loess hilly region and significant decrease trend in Dingbian,Shenmu of windy desert region along the Great Wall line,Qingjian,Yanchuan of plateau remains region,Longxian,Fengxiang,Chunhua and Hancheng of arid plateau region in north Weihe River.There was no obvious variation trend in other research zones.The annual and four-season sunshine hours all presented negative correlations with rainfall,relative humidity,total cloud amount,low cloud amount,water vapor pressure and fog days.The sunshine hours presented positive correlation with visibility.The correlation coefficients between sunshine hours and relative humidity,rainfall,total cloud amount,water vapor pressure,fog days and visibility were all bigger in each region.[Conclusion] The research provided basis for analyzing climate variation over Loess Plateau of Shaanxi.

Characteristics of Wind Speed Profiles under Complex Terrain Conditions in Loess Plateau

To reveal the changing characteristics of wind speed with altitude in under complex terrain conditions in Loess Plateau in Northern Shaanxi, based on the complete data of wind speed profiles of six wind towers in the region in a year, the diurnal, monthly, and seasonal variations of wind shear index of the wind towers as well as the changes of wind shear index with wind speed under complex terrain conditions were studied. The results showed that the wind shear index of each wind tower was positive, showing that wind speed tended to increase with the rising of altitude in most areas of Loess Plateau in Northern Shaanxi; terrain had obvious effects on wind speed profiles. The wind shear index of the wind towers was small during the day and large at night; the differences between day and night in the wind shear index of various wind towers were different; there were obvious seasonal variations in the wind shear index of the wind towers under different terrain conditions. With the increase of wind speed, the wind shear index of each wind tower increased firstly and then decreased, but the peaks of wind shear index of various wind towers ap- peared in different wind speed ranges. When wind speed varied from 3 to 12 m/s, wind shear index was larger than the comprehensive wind shear index of the wind towers, which is beneficial to the improvement of power generation of a wind power plant. Wind shear index can be used to assess wind resources of a wind power plant.

The Cave Dwellings in Northern Shaanxi

Cave dwellings (or Yaodong in Chinese) are a unique style of traditional houses on the Loess Plateau of westerncentral China. They exhibit rich folk customs and a flavor of the surrounding environment. The soil of the Loess Plateau is thick and compact, making it the ideal place for building caves that are sturdy enough to last hundreds or even thousands of years without collapsing. Most cave dwellings have straight walls and low arched ceilings, with the walls reinforced with grass and mud. Cave dwellings are comfortable to live in, being cool in the summer and warm in the winter. Being cut into the mountain, the architecture blends in quite well with the surrounding natural environment, while the rust exterior exhibits the beauty of ingenuity.

Eolian evidence from the Chinese Loess Plateau: the onset of the Late Cenozoic Great Glaciation in the Northern Hemisphere and Qinghai-Xizang Plateau uplift forcing

On the basis of a newly-constructed record of magnetic susceptibility (SUS) and the depositional rate change of eolian loess-red clay sequences in the last 7.2 Ma BP from the hea Plateau, together with a cornperison of a record of °18O values from the equatorial East Pacific Ocean and eolian Quartz flux variations fmm the North Pacific Ocean, the evolutiomuy process of the Late Cenozoic Great Glaciation in the Northern Hemisphere can be divided into three stages: the arrival stage around 7.2–3.4 Ma BP, the initial stage at about 3.4—2.6 Ma BP, and the Great Ice Age since 2.6 Ma BP. The evolution of the East Asian monsoon is characterized by paid winter and summer monsoons, and it is basically composed of the initial stage of weak winter and summer monsoons, the transitional stage of simultaneous increase in intensity of winter and summer monsoons, and the prevailing stage of strong winter and week summer monsoons, or weak winter and strong summer monsoons. The Late Cenowic global tectonic uplift, paaicdarly the Qinghai-Xizang Plateau uplift and the associated CO2 concentration variation, controls the dng processes of the onset of Great Glaciation and the long-term changes of East Asian monsoom climate in the Northern Hemisphere to a large extent. The accelerating uplift of the Qinghai-Xizang Plateau between 3.4 and 2.6 Ma BP provided an important driving force to global climiatic change.

Magnetic properties of Jiaxian red clay sequences from northern Chinese Loess Plateau and its paleoclimatic significance

Detailed rock magnetism investigation of the Jiaxian red clay sequences indicated that there are common magnetic mineralogy properties in red clay and loess-paleosol sequences from the Chinese Loess Plateau as well as the marked properties of themselves, magnetic min-erals mainly with magnetite, maghemite, hematite, and possibly limonite/goethite contributing to the magnetic behavior. Meanwhile, it is found that the strong paleosol in red clay sequences has a lower coercivity and higher content of ultra-fine ferrimagnetic grains than that of the weak pa-leosol, which is similar to loess and paleosol in upper Wucheng Loess sequences, and indicates that humid conditions and relatively strong pedogenesis play a significant role in the increase of ultra-fine magnetic minerals and transformation of the magnetic minerals. This suggests that, like Quaternary loess-paleosols, the change of characteristics of paleoclimatic conditions of the late Tertiary red clay deposits is fluctuant. In addition, the results of magnetic hysteresis properties show that the applied saturated field for samples from the Jiaxian red clay sequences is higher than that of the samples from eastern and southern Chinese Loess Plateau. It is obviously shown that there exist more hard magnetic minerals and relatively weak biochemical processes in the Jiaxian red clay sequences on northern Chinese Loess Plateau. We conclude that the paleocli-matic environment is different between northern and eastern/southern Chinese Loess Plateau, and it should be more arid in northern Chinese Loess Plateau.

Quantifying the vertical distribution pattern of land-use conversion in the loess hilly region of northern Shaanxi Province 1995–2015

The mountainous and hilly region plays an important role in ecological safety and production in China. However, recent studies have poorly characterized the parallel structure of land use in the valleys of the mountainous and hilly region using topographic factors(e.g.elevation, slope, aspect). Here, the loess hilly region of northern Shaanxi Province is used as a representative case area to analyze the vertical distribution pattern of land-use conversion using the relative elevation concept and the HAND index. The differences in the vertical structure of land-use conversion between absolute elevation and relative elevation were compared. We found that the classifications of absolute and relative elevation had similar proportions of each relative elevation grade in each absolute elevation grade. Cropland,woodland, and grassland were distributed evenly in each grade of absolute/relative elevation,while water body, built-up land and unused land were more likely to spread in low grades of relative elevation than those of absolute elevation. The land-use conversion(i.e. loss of cropland and gain in woodland and built-up land) showed an apparently stepped distribution with relative elevation classification, suitable for revealing vertical distributions of land-use conversion in the loess hilly region. Cropland transformed to woodland was mainly distributed in high grade of relative elevation, decreasing with a decrease in grades, while built-up land transformed from cropland and grassland was mainly distributed in low grade of relative elevation, decreasing with increases in grades. The grade of relative elevation where cropland transformed to woodland descended with the implementation of the Grain for Green Project. Our results suggest that it is better to analyze the vertical distribution of land-use conversion with relative elevation classification in hilly regions.

陕北黄土高原景观生态质量时空分异及驱动力分析

景观生态质量是衡量生态系统稳定度的重要指标。基于景观稳定性、景观干扰度和恢复与重建力三个层面构建景观生态质量评估模型,探究了陕北黄土高原20 a来景观生态质量及时空变化,并利用地理探测器进行了驱动力分析。结果表明:陕北黄土高原景观生态质量呈现中南部高、西部及北部低的分布特征,空间相关性和异质性显著;景观生态质量等级在中等及以上的区域面积占比由40.0%上升至63.5%,景观生态质量明显改善,并呈现先下降后上升的变化趋势;区域景观生态质量受自然因子和人为因子的共同作用,NDVI和高程是主要驱动因子,且与降水、气温、GDP和人口密度等因素交互后驱动力增强。

陕北黄土高原气象要素对植被覆盖的空间分异影响及风险探测

陕北黄土高原地处我国西北生态环境脆弱区,近年来受退耕还林(草)影响,区域植被覆盖变化显著,与气象要素的响应关系也呈现出了复杂的空间分异性和不确定性,亟待厘清。以不同地貌分区为响应单元,探究了陕北黄土高原变绿前后(1982—1992年与2005—2015年)NDVI指数的时空演化特征,分析了植被覆盖变化与气象要素之间的分异性响应关系,并透过最优参数的地理探测器模型(OPGD)探测了气象要素变化对植被覆盖演变的交互影响及风险。研究结果表明:(1)陕北黄土高原及各地貌分区在研究期内NDVI指数均呈显著上升趋势,且阶段化分异明显;各地貌区气温和实际蒸散发量在高原变绿前后趋势变化差异明显,1982—1992年主要呈不显著增加趋势,而2005—2015年则表现为不显著减少趋势;两个时期降水量的空间异质性较为显著,其中北部地区为持续增加趋势,而南部地区则由减少逆转为增加趋势。(2)不同地貌区NDVI指数与气温和蒸散发均呈正相关,且蒸散发与NDVI的相关性强于气温;相对高原变绿前,2005—2015年NDVI指数对各气象要素的响应强度均有所增大。(3)OPGD因子检测结果显示5km空间网格是评价气候变化对陕北黄土高原植被覆盖变化影响的最佳空间尺度,各地貌分区对NDVI指数变化影响最大的气象因子依次为:气温(黄土塬)、降水(盖沙黄土丘陵)、蒸散发(黄土峁状丘陵)、降水(黄土梁状丘陵)、降水(黄土宽谷丘陵)、蒸散发(风沙丘陵)、降水(土石丘陵);交互探测表明气象因子间的交互作用对NDVI指数的空间分异具有协同增强性,但不同时期各地貌区的主导交互因子略有差异。(4)风险探测发现不同实际蒸散发量对NDVI指数的影响有显著空间差异。(5)陕北黄土高原的植被覆盖变化并不能简单归因于退耕还林(草)等生态修复措施,而应是多要素耦合驱动的结果,气象要素在其中扮演了不可忽视的作用。

人水共生理念下传统窑洞聚落景观理水智慧研究——以陕北地区为例

中国传统聚落景观营建素有将人水共生作为古人聚居选址及农耕生产的理念和举措。因此,在聚落选址之初,古人对自然山水环境的寻找、观察及借用的用心程度甚至超过聚落后期的建设过程。为了更好地保护和传承半干旱区传统窑洞聚落景观理水智慧,避免本土理水营建技术的消失与断代,以陕北黄土高原区传统窑洞聚落为研究对象,从人水共生哲学思想出发,结合DIKW层次结构模型,构建传统聚落理水智慧解析路径与方法。从聚落选址布局理水智慧、人居营建理水智慧、农耕生产理水智慧和自然生态理水智慧4个方面,开展陕北传统窑洞聚落景观理水智慧的提取与体系构建。以期为当前我国半干旱地区乡村聚落生态人居景观营建和水基础设施建设提供理论与经验借鉴。

2001—2022年陕北黄土地区地质灾害时空分布及引发因素分析

基于陕西省2001—2022年地质灾害资料,分析研究了榆林和延安22年来黄土地质灾害的时空分布规律和引发因素,并提出了防治措施建议,对陕西省乃至西北黄土高原地质灾害防治工作提供了可借鉴的依据。①在空间上重灾区呈弧形分布,主要在榆林的清涧县、绥德县、子洲县以及延安的宝塔区、安塞区、志丹县。地质灾害主要发育在丘陵区,支流两岸和河流交汇处。②在时间上主要发生在冻融季节和汛期,其中3月和7—10月是地质灾害高发期,而以7—8月为集中暴发期、产生的灾害最为严重。③降水和人工切坡是引发地质灾害发生的主要因素。④防治上,榆林、延安每年3月与汛期7—10月是重点防范期,弧形带是重点防范区,应加强巡查排查、监测预警、综合治理、宣传培训等综合防治措施;榆林前5d累计降水量在76 mm左右、预报降水量在37 mm时,延安地区前5d累计降水量在79 mm左右、预报降水量42 mm时,发出预报预警。

陕北黄土高原沟壑区文物遗产时空分布规律研究

揭示陕北黄土高原沟壑区文物遗产的分布特征,为该地区历史文化时空变迁研究与历史文化空间格局的凝炼提供借鉴。研究将文物遗产按照其所承载的内涵分为聚居型、人文型、防御型与近现代文物遗产四类,运用地理信息技术分析其空间分布特征,结合历史、文化、社会等时空变迁脉络研究陕北黄土高原沟壑区文物遗产的时空分布规律及其影响因素,指出河流道路的位置与走向对聚居型文物遗产的分布具有较大影响,自然山川的形势决定了人文型文物遗产的选址与布局,政治军事活动推动了防御型遗产“由点至带”的发展演变。

考虑降雨条件陕北Q_(2)黄土斜坡稳定性的非线性劣化研究

降雨致灾是陕北黄土斜坡最常见的灾害之一,揭示降雨对黄土斜坡稳定性影响特征有利于预防滑坡灾害的发生。通过一系列室内试验研究了降雨条件下陕北Q_(2)黄土的力学特性变化特征,并结合数值模拟分析了其对陕北黄土斜坡稳定性的影响。首先设计干湿循环试验(循环路径和次数)以模拟降雨条件(如强度、频次等);其次通过三轴剪切试验获取陕北Q_(2)黄土的力学性质的变化规律;最后以陕北地区某黄土斜坡为例,利用有限元计算并分析不同降雨条件下斜坡安全系数和塑性区的变化特征。结果表明:(1)干湿循环作用后Q_(2)黄土的抗剪强度存在非线性劣化特征。当干湿循环次数超过一定范围后,黄土物理力学性质参数劣化的边际效应减弱,并趋于稳定。(2)降雨作用下黄土斜坡的稳定性呈现出随着降雨频次或降雨强度的增加而降低的趋势。(3)Q_(2)黄土斜坡的塑性区范围随着Q_(2)黄土力学性能的不断劣化而增大,体现了降雨条件对黄土斜坡稳定性影响的非线性特征。研究结果为降雨型滑坡预防提供参考。

陕北砂黄土地区输电线路塔基边坡问题治理对策研究

陕北砂黄土具有其特殊的物理力学性质,砂黄土边坡呈现一种特殊的变形破坏方式。通过综合分析陕北砂黄土变形破坏机制及输电线路塔基边坡的治理经验,得出陕北砂黄土地区输电线路砂黄土塔基边坡问题治理的对策及建议,并给出相关的工程实例予以论证分析。

Geodetection analysis of the driving forces and mechanisms of erosion in the hilly-gully region of northern Shaanxi Province

This paper analyzes the spatial variation in soil erosion in the loess hilly-gully region of northern Shaanxi Province, China. It sums up existing research, describes the factors that drive soil erosion, and uses geodetection to investigate the factors individually and in pairs.Our results show that soil erosion in the loess hilly-gully region of northern Shaanxi is mainly hydraulic erosion. There are significant spatial differences in the severity of soil erosion in the region. Generally, it is more severe in the north and west and less severe in the south and east. Individual factor detection results show that the major risk factors affecting soil erosion are human population distribution, precipitation, land-use type, elevation, and soil type. Interactive detection results show that interacting factors play much bigger roles in soil erosion than do individual factors. Based on forced detection results from different periods of time, we can see that forest and grass coverage, urbanization, and economic development in the study area all clearly inhibit soil erosion.