Effects of Artificial Vegetation Restoration on Soil Physicochemical Properties in Southern Edge of Mu Us Sandy Land

[Objective] This study aimed to investigate the artificial vegetations on soil physicochemical properties of sandy land. [Method] The soil physicochemical proper- ties in five representative lands respectively covered by Artemisia ordosica, Salix cheilophila, Hedysarum scoparium, Populus simonii and Amorpha fruticosa, all of which were planted artificially at the same year were measured in the present study, using a bare soil as the control. [Result] Artificial vegetation improved the soil physicochemical properties by different extents in the lands covered by different plants. The soil physicochemical properties such as bulk density under A. Fruticosa and H. Scoparium were improved greatly. The frequency distribution of soil particle size under artificial vegetations exhibited a bimodal curve. The average soil particle size under A. fruticosa was the smallest, and the soil was very poorly sorted. The soil nutrients in the sandy land were not significantly improved by artificial vegeta- tion. [Conclusion] Artificial vegetation has a certain impact on soil properties in sandy land, as it greatly improves the soil physical properties but not the chemical properties.

Effects of Vegetation Restoration in Different Types on Soil Nutrients in Southern Edge of Mu Us Sandy Land

In order to explore effects of vegetation on nutrients in soils, nutrients characters of soils under natural grass, closed grass, abandoned lands, forest lands returned from farmlands and fixed sandy areas in Mu Us Desert were researched. The results indicated that vegetations in varied types have different effects on organic matter, total N, available N and available P, among which the first three were all higher in soils under closed grass, forest lands returned from farmlands, and fixed sandy lands than those under natural grass and abandoned lands. This was totally contrary with contents of available P in soil. In addition, nutrients in soils at 0-20 cm were more influenced by vegetation, than those at 20-60 cm, and Caragana Korshinskii proved better in improving nutrients in soils.

Effects of the vegetation restoration years on soil microbial community composition and biomass in degraded lands in Changting County,China

We evaluated the effects of the number of years of restoration of vegetation on soil microbial community structure and biomass in degraded ecosystems.We investigated the microbial community structure by analyzing their phospholipid fatty acids then examined microbial biomass carbon and nitrogen by chloroform fumigation extraction of restoration soils over several years.The data were compared with those of highly degraded lands and native vegetation sites.The results show that the duration of vegetation on the sites substantially increased microbial biomass and shifted the microbial community structure even after only 4 years.However,microbial communities and biomass did not recover to the status of native vegetation even after 35 years of vegetation cover.A redundancy analysis and Pearson correlation analysis indicated that soil organic carbon,total nitrogen,available potassium,soil water content,silt content and soil hardness explained 98.4%of total variability in the microbial community composition.Soil organic carbon,total nitrogen,available potassium and soil water content were positively correlated with microbial community structure and biomass,whereas,soil hardness and silt content were negatively related to microbial community structure and biomass.This study provides new insights into microbial community structure and biomass that influence organic carbon,nitrogen,phosphorus and potassium accumulation,and clay content in soils at different stages of restoration.

Impact of large-scale vegetation restoration project on summer land surface temperature on the Loess Plateau, China

A large-scale afforestation project has been carried out since 1999 in the Loess Plateau of China. However, vegetation-induced changes in land surface temperature (LST) through the changing land surface energy balance have not been well documented. Using satellite measurements, this study quantified the contribution of vegetation restoration to the changes in summer LST and analyzed the effects of different vegetation restoration patterns on LST during both daytime and nighttime. The results show that the average daytime LST decreased by 4.3°C in the vegetation restoration area while the average nighttime LST increased by 1.4°C. The contributions of the vegetation restoration project to the changes in daytime LST and nighttime LST are 58% and 60%, respectively, which are far greater than the impact of climate change. The vegetation restoration pattern of cropland (CR) converting into artificial forest (AF) has a cooling effect during daytime and a warming effect at nighttime, while the conversion of CR to grassland has an opposite effect compared with the conversion of CR to AF. Our results indicate that increasing evapotranspiration caused by the vegetation restoration on the Loess Plateau is the controlling factor of daytime LST change, while the nighttime LST change is affected by soil humidity and air humidity.

Integrating potential distribution of dominant vegetation and land use into ecological restoration in the Yellow River Basin,China

Due to the influence of human activities such as cultivation and urban construction,the ecosystem of the Yellow River Basin(YRB)is subjected to increased vulnerability and even potential risk of destruction.Ecological restoration has led to an increase in vegetation,but excessive afforestation conversely results in low survival rate of trees,water shortages,and biodiversity loss.It is of great significance for achieving sustainable development of forests to reasonable revegetation in the region.At present,the potential distribution pattern of dominant species and their mixed forms in the basin has not been effectively studied.This study simulated the potential distribution of dominant vegetation in the YRB based on Maximum Entropy(Max Ent)and Genetic Algorithm for Rule-Set Prediction(GARP)and explored the impact of human interference on it by employing land use as the environmental filter to distinguish the regions of human activities.We further predicted the potential distribution of typically mixed forests and discussed their human interference.The main results are as follows:(1)Except for Caragana korshinskii,all models had good above performance(0.7<the mean AUC<1).Except for Caragana korshinskii,the area under the curve(AUC)for 90%of the models indicated that Max Ent performed better than GARP,and Max Ent easily lead to over-fitting while GARP predicted a wider range.(2)Except for Nitraria tangutorum,the dominant types of vegetation such as Pinus tabulaeformis,Platycladus orientalis,and Hippophae rhamnoides mainly distributed in southern Gansu,Shaanxi,and south-central Shanxi.Among them,the largest suitable area of Artemisia gmelinii and Stipa bungeana(High suitable area)were approximately 56.7×104 km2(38.8%)and 54.7×104 km2(28.5%)with the area occupied by large-scale cultivation being 17.5×104 km2(39.4%)and 18.9×104 km2(48%),respectively,which indicated human activities caused great damage to the core growth regions of these vegetation.(3)Mean temperature of coldest quarter or month mainly constrained the growth of most vegetation in the YRB in terms of temperature,while precipitation of wettest/driest month is one of the dominant factors.However,some vegetation responded differently to other meteorological factors due to niche differences.(4)Most of the mixed forests were distributed in southern Gansu,Shaanxi,and Shanxi provinces;its middle and high suitable areas were mainly concentrated in Shaanxi and southern and central Shanxi,where the cultivated land had occupied most of them.Therefore,the results showed that the restoration of herbaceous vegetation such as Artemisia gmelinii and Stipa bungeana has a high potential and it is appropriate that the measures for afforestation should be concentrated in the areas like the lower reaches of the Weihe,Jinghe,and Beiluo rivers and Luliang Mountain,where the cultivated land overlaps with the high suitable areas of the corresponding vegetation and the mixed forests with less water consumption and wide distribution,such as Caragana korshinskii-Hippophae rhamnoides,Pinus tabulaeformis-Quercus liaotungensis,and Ostryopsis davidiana-Stipa bungeana-Hippophae rhamnoides.The results of this study can provide effective guidance for mixed forest plantations and vegetation conservation in the YRB.

Measures of Vegetation Restoration in Abandoned Mined Lands

By 2004, the occupied and disturbed land area had reached 3.393 million ha by mining, of which forest land took 532 000 ha; In addition, mining also caused 3.721 million -5.316 million ha of degraded forests and woodlands. The impact of mining on environment is multi-fold and deep. Thus it is necessary and significant to approach effective methods to speed up vegetation restoration in abandoned mined lands. Phytoremediation is a relatively new technology (in the lastest decade) and the numbers of plant species have been identified to accumulate high levels of heavy metals, which implies that phytoremediation is available, practical and effective. Thereby the main procedure of ecosystem restoration in abandoned mined lands by mean of phytoremediation is discussed in the paper, such as site preparation, species selection, planting techniques, maintenance and tending methods.

Evaluation of Land Reclamation and Implications of Ecological Restoration for Agro-pastoral Ecotone: Case Study of Horqin Left Back Banner in China

The agro-pastoral ecotone has been recognized as the main distribution area of reserved land resource for cultivation. Accordingly, clarifying this assumption, as well as concerting land reclamation and ecological restoration, is important to ensure food security and environmental improvement in the agro-pastoral ecotone. We selected Horqin Left Back Banner(HLBB) as the subject of our case study. The landscape ecological security pattern of this area was determined using the minimum cumulative resistance model. Over-cultivation, quantity of reserved land resource for cultivation, and changes in landscape indexes before and after land use adjustment were then analyzed. Over-cultivation is a serious problem in the agro-pastoral ecotone. Reserved land resource for cultivation is less than that considered previously, and the area of reserved land resource for cultivation in HLBB only accounts for 11.50% of total uncultivated land. With regard to changes in landscape indexes, the adjusted land use pattern is effective for anti-desertification. The compensation standard for abandoned cultivated land should be improved and the comprehensive results of ‘Grain for Green' should be evaluated to further implement ecological restoration in the agro-pastoral ecotone.

Ecological effect of the plantation of Sabina vulgaris in the Mu Us Sandy Land,China

Vegetation restoration through artificial plantation is an effective method to combat desertification,especially in arid and semi-arid areas.This study aimed to explore the ecological effect of the plantation of Sabina vulgaris on soil physical and chemical properties on the southeastern fringe of the Mu Us Sandy Land,China.We collected soil samples from five depth layers(0-20,20-40,40-60,60-80,and 80-100 cm)in the S.vulgaris plantation plots across four plantation ages(4,7,10,and 16 years)in November 2019,and assessed soil physical(soil bulk density,soil porosity,and soil particle size)and chemical(soil organic carbon(SOC),total nitrogen(TN),available nitrogen(AN),available phosphorus(AP),available potassium(AK),cation-exchange capacity(CEC),salinity,p H,and C/N ratio)properties.The results indicated that the soil predominantly consisted of sand particles(94.27%-99.67%),with the remainder being silt and clay.As plantation age increased,silt and very fine sand contents progressively rose.After 16 years of planting,there was a marked reduction in the mean soil particle size.The initial soil fertility was low and declined from 4 to 10 years of planting before witnessing an improvement.Significant positive correlations were observed for the clay,silt,and very fine sand(mean diameter of 0.000-0.100 mm)with SOC,AK,and p H.In contrast,fine sand and medium sand(mean diameter of 0.100-0.500 mm)showed significant negative correlations with these indicators.Our findings ascertain that the plantation of S.vulgaris requires 10 years to effectively act as a windbreak and contribute to sand fixation,and needs 16 years to improve soil physical and chemical properties.Importantly,these improvements were found to be highly beneficial for vegetation restoration in arid and semi-arid areas.This research can offer valuable insights for the protection and restoration of the vegetation ecosystem in the sandy lands in China.

Ecological rebuilding and land reclamation in surface mines in Shanxi Province, China

It is well known that the mining industry produces a large amount of derelict land, and causes pollution of water loss and soil erosion as well as other environmental damage in China. As land is under pressure in China, it is now policy to restore or reclaim land despoiled by mining, the aim being to develop sustainable and healthy arable land ecosystems. This paper outlines the principles and approaches of ecological restoration, which have been adopted in Shanxi Province with reference to three typical surface mines. In the research, the principles of ecological engineering and ecological succession are considered as the critical theories of ecological restoration in mine degraded land. Meanwhile, the paper made a comparative research on main links of ecological rebuilding in three surface mines in Shanxi Province, which include new land construction, treatment of toxic substances, control of soil erosion, fertility management, irrigation, ecological planning and the establishment of legislation systems. As the research demonstrated, for successful restoration, new land construction is the fundamental framework, but it must be integrated with ecological engineering including ecological planning, the control of soil erosion and vegetation establishment and ecosystem creation in order to optimise land productivity and soil fertility. In addition, the establishment of the legislation systems and organization of administration are also indispensable aspects of ecological rebuilding in mined land.

Effects of land use changes for ecological restoration on soil moisture on the Chinese Loess Plateau:a meta-analytical approach

Soil moisture is an important resource for plant growth on the arid and semi-arid Loess Plateau of China where the‘‘Grain for Green’’project was launched in 1999,but there has been no systematic evaluation of soil moisture from the effects of ecological restoration at a regional scale.We systematically assessed 63 published studies during 2000-2015,including 2050 observations at 68 sites on the Loess Plateau with the aim of determining soil moisture changes and the factors influencing those changes.We found that,after land use conversion,soil moisture decreased by 17%in the upper 100 cm soil layer and that tree plantations and shrub lands appeared to cause soil moisture depletion which became increasingly serious with soil depth.The decrease of soil moisture was significantly influenced by the planting species in all restoration types(tree plantations,shrub lands,and grasslands).We also found that tree plantations and grasslands converted from farmlands consumed more soil moisture than from wasteland(including bare land,abandoned land and wild grasslands).Artificial restoration led to significant soil moisture reduction,but natural restoration had little effect on soil moisture.Therefore,natural restoration should be an alternative restoration practice on the Loess Plateau.These results will provide helpful information for artificial afforestation and planning ecological restoration campaigns for policy makers on water-limited regions.

Comparative Study on Riparian Vegetation Buffers in Different Land Uses

This study focused on riparian vegetation buffer zones on the basis of low influence development(LID) and landscape restoration. Three types of land were selected to conduct comparative study. The types are buffers in urban districts,buffers in rural areas,and buffers in natural regions. These types basically reflect major ecological issues in different landuses. The follow conclusions were drawn:(1) there are different ecological issues in these 3 types,making the functions of buffers different.(2) The 3 types demand different ecological issues to be solved: Type A,functionally-diverse riparian landscape should be planned to enrich recreational activities and improve river's condition. Type B,agricultural areasource pollution needs to be cut down to sustain the stability of water conservation and ecological system. Type C,eco-conservation and various habitats for creatures are required.(3) Different planning methods were used respectively in the 3 types,construction methods were proposed for each type correspondingly and expressed in graphical ways in expectation of being instructive to the construction of eco-riparian landscape.

Impact of Land Reclamation on the Vegetal Cover of Bayelsa State, Nigeria

The study examined the impact of land reclamation on vegetal cover in Bayelsa State.For the purpose of this study,both quantitative and quali­tative research methods were adopted.Field observations,questionnaire survey and landsat imagery of land cover changes in the year 1986 and 2018 were generated from the global ground cover facility stream.The time series study design and supervised classification of the image processing were adopted to determine the impact of land reclamation on vegetal cover of the study area.It was therefore recommended that recovery of land will make strategic urban planning initiatives sustainable in overcrowded areas and institutions should also put in place laws and strategies to regulate rec­lamation activities across the region and also geo-spatial skills should be put in place to help quantify the dynamics,trends and rate of reclamation induced land cover change in the environment.

Effect of Land Cover Change on Soil Phosphorus Fractions in Southeastern Horqin Sandy Land, Northern China

In the past 50 years, large areas of the Horqin sandy land were afforested to prevent desertification. Although the afforestation policy appears successful, many people now doubt whether it is suitable to plant trees with high density on the poor soils in semiarid regions. Little is known about the impacts of afforestation on the sandy soil properties, although the evaluation of these impacts is fundamental to judge the rationality of afforestation policy. Soil phosphorus （P） fractions, acid phosphomonoesterase activities, and other soil chemical properties were compared among five adjoining typical ecosystems on poor sandy soils in southeastern Horqin sandy land. The ecosystems studied are natural elm savanna, degraded grassland, Mongolian pine （Pinus sylvestris var. mongolica） plantation, Chinese pine （Pinus tabulaeformis） plantation, and mixed plantation of Mongolian pine and poplar （Populus simonii）. The results showed that organic P dominated soil P （47%-65%） was the principal source of available P. The degradation of elm savanna to grassland significantly reduced soil pH and resulted in an overall reduction in soil fertility, although slightly increased labile inorganic P. Grassland afforestation had no significant influence on soil pH, organic carbon, and total N but significantly reduced total P. Impacts of grassland afforestation on soil P fractions depended on tree species. Natural elm savanna had higher soil P conserving ability than artificial plantations. Therefore, with the aim of developing a sustainable ecosystem, we suggested that vegetations with low nutrient demand （particularly P） and efficient nutrient cycling would be more suitable for ecosystem restoration in the semiarid region.

Effects of ecological projects on vegetation in the Three Gorges Area of Chongqing, China

The construction of the Three Gorges Reservoir and the resettlement project have caused increasing contradictions between human and land,and led to the deterioration of the ecological environment. In order to ameliorate ecological environment of the Three Gorges Area, the government carried out several ecological restoration projects to improve the vegetation coverage from 1990 s. This paper aims to quantitatively analyze the impact of ecological projects on the vegetation in the Three Gorges Area of Chongqing, China. Landsat and MODIS data from 1992 to 2015 were used to estimate vegetation coverage. In addition, the land cover data of the European Space Agency(ESA) was used to explore the impact of ecological projects on land cover change. The cropland accounted for about 62% and the forestland accounted for about 34% of the total area. There was more than 90% of the study area covered with high or very high vegetation coverage.From 1992 to 2015, a total of 272.7 km;croplands were converted into forestland in the Ecological Migration Project(EMP), 795.6 km;in the Grain for Green Project(GGP), and 13.77 km;in the Ecological Restoration Zone Project(ERZP). Among the three projects, the GGP was the most powerful measure,with a contribution rate of 1.6%. The implementation of the ecological projects improved vegetation coverage, which indicated that the ecological projects measures were effective in ecological restoration.

Restoration of an Inner-City Stream and Its Impact on Air Temperature and Humidity Based on Long-Term Monitoring Data

Spatiotemporal changes in air temperature and humidity associated with the restoration of an innercity stream in Seoul, Korea, are investigated based on long-term monitoring data. The Cheonggye stream, covered under a concrete structure for 46 years, was restored in 2005 and runs 5.8 km eastward through a central region of Seoul. Long-term monitoring of the air temperature and relative humidity was made along the stream throughout the restoration and across the stream after the restoration. The area along the stream had a higher air temperature than the entire metropolitan area. The temperature anomaly between the monitoring area and the surrounding metropolitan area was 0.13℃ lower on average at the center of the stream after the restoration. The stream＇s effect on the air temperature was also evident in the temperature distribution along a street traversing the stream. The relative and specific humidities were increased due to the restoration. The restored stream modified the nearby urban climate in the opposite direction compared to urbanization. The results could be used as a model case in mitigating urban climate by a stream in future urban planning practices.

2023年土地科学研究重点进展评述及2024年展望——土地工程与信息技术分报告

研究目的:归纳分析2023年国内外土地工程与信息技术领域的研究进展,展望研究趋势。研究方法:文献分析法。研究结果:国内研究主要集中在土地综合开发模式与运行机制、全域土地综合整治的潜力机制及路径、碳中和背景下的土地复垦与生态修复、土壤—植物—微生物模式下的复垦土壤重构、国土空间生态修复差异化分区与格局构建、土地信息智能化监测技术与信息提取方法、数字化国土空间规划技术、基于GIS的土地管理技术。国外研究主要集中在农业用地土地整理模式、基于土壤改良的矿区土地复垦、土壤—植物—微生物协同修复作用机制、基于社会经济和生态指标的生态修复、土地信息监测与预测技术、基于人工智能的土地规划技术、土地管理系统优化技术。研究结论:2023年土地工程与信息技术在全域土地综合整治、土地复垦与土壤重构、国土空间生态修复、土地信息监测与管理技术等方面取得了一定进展。结合当前科技需求,2024年及未来重点关注山水林田湖草沙一体化保护和系统治理、全域土地综合整治和国土空间生态保护修复、碳中和目标下的矿区土地复垦、乡村振兴背景下的土地集约利用和低效用地治理、土地信息可视化技术和土地信息智能化处理技术。

植被类型对煤矿区复垦土壤根际微生物的影响

煤矿开采改变了矿区土壤条件、地表植被覆盖和微生物生存环境。植被由于生长条件和根际分泌物的不同,影响根际土壤微生物的组成和多样性。以山西省晋华宫煤矿复垦区侧柏、云杉、樟子松、油松、桧柏5种复垦植被为研究对象,分析其土壤理化性质、根际土壤酶活性和微生物群落结构的差异性,并计算综合土壤肥力指数以反映不同复垦植被的生态恢复效果。结果表明:不同植被对土壤物理和化学性质、土壤酶活性、根际微生物多样性和群落结构具有显著影响,樟子松林具有最高的全碳、全氮含量,为微生物提供更多的碳氮等养分,导致其具有显著高的微生物丰度和多样性;不同植被类型间微生物群落差异性显著,变形菌门、酸杆菌门、放线菌门和拟杆菌门是优势菌门,全硫、容重和碱性蛋白酶是影响土壤根际微生物群落结构的关键因子;土壤综合肥力指数表明樟子松林和云杉林优于其他植被。综上,不同植被对矿区生态恢复的效果具有一定差异,樟子松林和云杉林有助于提高根际土壤细菌多样性和土壤肥力,研究可为半干旱区煤矿复垦区生态恢复的植被选择提供科学依据。

基于捐赠土壤种子库方法的沙丘植被恢复模拟实验

退化沙地土壤种子库数量不足限制了其自然恢复能力,传统的种子库添加植被恢复技术措施存在添加物种数量、配比难以确定的限制,针对上述问题,提出了捐赠土壤种子库的植被恢复方法,即从邻近植被生境相似的长期稳定群落转移包含土壤种子库的表层土壤进行受损区植被恢复的方法。该方法在受损湿地、草地和林地的恢复方面取得了较好的应用效果,但是该方法能否用于荒漠化区域的植被恢复尚未见报道。采用室内盆栽和模拟降雨相结合的实验办法,以长期稳定的固定沙丘为捐赠土壤种子库源区,以流动沙丘和半固定沙丘为受捐对象,对比分析了捐赠固定沙丘土壤种子库对流动沙丘和半固定沙丘植被恢复的效果,并模拟了降雨变化对恢复效果的影响作用。结果表明:1)捐赠土壤种子库显著提高了半固定沙丘和流动沙丘模拟处理的种子萌发数量和幼苗地上生物量,有利于促进流动沙丘和半固定沙丘向固定沙丘进行演替;2)捐赠土壤种子库方法在半固定沙丘的植被恢复效果优于流动沙丘;3)捐赠土壤种子库可以增加流动沙丘实现跨越式恢复的可能性,加快其向固定沙丘的演替进程;4)小幅度的降雨量增减对受捐区种子萌发数量和地上生物量无显著影响;5)极端降雨可以显著提高受捐区种子萌发数量和地上生物量。综上所述,在模拟实验条件下,捐赠土壤种子库技术可以有效地促进退化沙丘植被恢复,极端降雨事件对捐赠土壤种子库实施后的恢复效果影响更加显著。研究为捐赠土壤种子库在退化沙地植被恢复的野外实际应用提供了理论支持。

资源整合背景下露采转地采矿山地质环境治理方法探讨

为查明资源整合背景下楸树湾铜钼矿露采转地采矿山地质环境问题、矿区地质灾害现状及隐患、土地利用类型和各类土地的损毁及复垦情况,制定相应的矿山地质环境保护治理与土地复垦措施。通过资料收集与野外地质环境调查,对矿山生产活动造成的土地损毁与矿山地质环境影响进行综合性评估,确定保护与恢复治理分区的责任范围;从技术、经济、土地适宜性和水土资源平衡等方面提出矿山地质环境治理、修复与土地复垦措施;通过设置警示牌、防护网、修建挡土墙、排水渠、边坡复垦和表土复垦等工程技术措施,分阶段、有层次地进行修复治理。项目的有效实施消除了地质灾害隐患,避免了人员伤亡和财产损失;增加了复垦面积,提升了土地资源的综合利用率,有利于复垦区经济效益的综合提升;使因矿山开采对地质环境和土地资源的影响和破坏程度降到最低。为实施矿山地质环境保护、治理和监测及土地复垦,以及为自然资源主管部门的监管提供依据,改善矿区人居生态环境,促进区域经济的良性可持续发展。

南方滨海沙地耐盐植物种类及其生态修复应用研究进展

阐述我国南方滨海地区地理特征,把耐盐植物按照不同生活型进行划分,梳理主要耐盐植物种类,分析不同生活型下耐盐植物生活习性和种植特点。从重金属污染、有机化合物污染、土壤盐碱化、生物多样性恢复以及水体富营养化5个方面,论述耐盐植物结合其他修复材料在滨海生态修复中的作用以及应用潜力,并指出滨海盐沙地生态修复研究存在的问题。从植物耐盐性研究、耐盐植物引种筛选、新修复材料与植物结合应用和多种耐盐植物互作体系建立等方面提出了滨海盐碱生态修复研究方向,以期为滨海盐碱生态环境修复和土地可持续利用提供思路。