Ecological Regionalization of Suitable Trees, Shrubs and Herbages for Vegetation Restoration in the Farming-Pastoral Zone of Northern China

To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-farming and over-grazing, the suitable trees, shrubs and herbages were examined, screened and identified under the guidance of four principles of taking precedence for ecological conservation, being beneficial to economic production, matching species (trees, shrubs and herbages) with the site, and giving consideration to the integrity of local administrative division. According to the key ecological factors that determine species growth and distribution in the zone, i.e., the lowest daily mean temperature in a year, annual accumulated temperature, and water regimes represented by the moist index, the ratio between annual rainfall and accumulated temperature (>0 degreesC), as well as the soil type influenced by climate, surface substances and landform, the farming-pastoral zone was regionalized into seven parts: ( I) Western Songliao Plain and Da Hinggan Mountain Region; (II) Upper Liaohe River Sandy Region; (III) Mid-Eastern Nei Mongol Plateau and Northwestern Heibei Mountain Region; (IV) Luliang, Taihang and Yanshan Mountain Region; ( V) Ordos Plateau Sandy Region; (VI) Northern Shaanxi to Eastern Gansu Loess Plateau Region; and (VII) Mid Gansu to Eastern Qinghai Plateau Loess Region. And the suitable trees, shrubs and herbages for each region were selected and tabularly introduced in detail.

Optimizing groundwater recharge plan in North China Plain to repair shallow groundwater depression zone, China

The North China Plain is one of the main grain producing areas in China. However, overexploitation has long been unsustainable since the water supply is mainly from groundwater. Since 2014,the South-to-North Water Diversion Project's central route has been charted to the integrated management of water supply and over-exploitation, which has alleviated the problem to a certain extent. Although the Ministry of Water Resources has made many efforts on groundwater recharge since 2018 most of which have been successful, the recharge has not yet been sufficiently focused on the repair of shallow groundwater depression zones. It still needs further optimization. This paper discusses this particular issue,proposes optimized recharge plan and provides the following recommendations:(1) Seven priority target areas are selected for groundwater recharge in alluvial and proluvial fans in the piedmont plain, and the storage capacity is estimated to be 181.00×10~8 m~3;(2) A recharge of 31.18×10~8 m~3/a is required by 2035 to achieve the repair target;(3) It is proposed to increase the recharge of Hutuo River, Dasha River and Tanghe River to 19.00×10~8 m~3/a and to rehabilitate Gaoliqing-Ningbailong Depression Zone;increase the recharge of Fuyang River, Zhanghe River and Anyang River to 7.05×10~8 m~3/a and rehabilitate Handan Feixiang-Guangping Depression Zone;increase the recharge of Luanhe River by 0.56×10~8 m~3/a and restore Tanghai Depression Zone and Luanan-Leting Depression Zone;moderately reduce the amount of water recharged to North Canal and Yongding River to prevent excessive rebound of groundwater;(4) Recharge through well is implemented on a pilot basis in areas of severe urban ground subsidence and coastal saltwater intrusion;(5) An early warning mechanism for groundwater quality risks in recharge areas is established to ensure the safety. The numerical groundwater flow model also proves reasonable groundwater level restoration in the depression zones by 2035.

Tensile Fractures and in situ Stress Measurement Data Constraints on Cretaceous-Present Tectonic Stress Field Evolution of the Tanlu Fault Zone in Shandong Province,North China Craton

Tectonic stress fields are the key drivers of tectonic events and the evolution of regional structures.The tectonic stress field evolution of the Tanlu fault zone in Shandong Province,located in the east of the North China Craton(NCC),may have preserved records of the NCC’s tectonic history.Borehole television survey and hydraulic fracturing were conducted to analyze the paleo and present tectonic stress fields.Three groups of tensile fractures were identified via borehole television,their azimuths being NNW-SSE,NW-SE and NE-SW,representing multiple stages of tectonic events.Hydraulic fracturing data indicates that the study region is experiencing NEE-SWW-oriented compression and nearly-N-Soriented extension,in accordance with strike-slip and compression.Since the Cretaceous,the orientation of the extensional stress has evolved counterclockwise and sequentially from nearly-NW-SE-oriented to NE-SW-oriented and even nearly N-S-oriented,the stress state having transitioned from strike-slip-extension to strike-slip-compression,in association with the rotating and oblique subduction of the Pacific Plate beneath the NCC,with the participation of the Indian Plate.

Numerical Experiments for the influence of the Transition Zone Migration on Summer Climate in North China

As the position of the transition zone changes obviously, that is, as the transition zone migrates to the north or the south from present position, it affects water or heat balance between the land and the atmosphere in a considerable degree and has a profound influence on climate in North China. The experiment results in this paper indicate whether in the dry case or in the wet case of the large-scale climatological background field, the surface air temperature in a wide range of the transition zone migration and its surrounding decreases as the transition zone migrates northward. Moreover, the net upward fluxes of the surface long wave radiation and the sensible heat decrease, and the evaporation to the atmosphere increases. As the transition zone migrates southward, the results are opposite. This kind of significant thermal forcing between the land and the atmosphere can excite secondary circulation or circulation cells, which interact with the large-scale circulation systems, changing the atmospheric motion, affecting the water vapor transportation and consequently having an effect on the precipitation.

Earthquake-controlling Processes of Detachment Zones in Eastern North China

The basin-and-range area in eastern North China is known for frequent occurrence of earthquakes, their great magnitudes and heavy losses thereby incurred. Seismic studies in the past usually emphasized the intersections, inflexions and branches of the faults. However, the intensities of many great earthquakes in this area do not show linear distribution, and the epicenters are horizontally dispersed at certain depths instead of along the strike of faults. Based on the sub-mantle plume studies made by authors in the past decade, it is thought that there exists an uplifted sub-mantle plume under the fault depression area in North China. The uplifting and intrusion of mantle materials caused the upper crust to be faulted, while low-velocity and high-velocity layers are alternatively distributed in the middle crust under the influence of the mantle and the lower crust. The middle and lower crust materials were detached from the top of the sub-mantle plume to the surroundings while the sub-mantle plume materials were detached outward. When the detached middle and lower crust come to the boundary of fault basins in the upper crust, they will be obstructed by the orogenic zone and the detachment will go slower. The shearing between them will cause the stress to accumulate and release alternatively, so that earthquakes occurred frequently in the areas of sub-mantle plume and its surroundings.

Preliminary Study on Two Newly-Generated Seismotectonic Zones in North and Southwest China

In previous seismotectonic studies,the emphasis was placed on the inherited active fault zones.In the recent tectonic stage that essentially keeps in step with the current regional geologic environment and the stress field,however,there are also some newly generated fault zones.By studying the seismicity in North and Southwest China,it has been known that the NE-trending Tangshan-Hejian-Cixian and NW-trending Tengchong-Gengma-Lancang seismic zones are just two newly generated fault zones.As distinguished from the inherited fault zones,they are called the newly generated seismotectonic zones.This paper deals with the existence of these two seismogenic zones from their seismicity and geological structures,gives a preliminary analysis of their characteristics,and shows their significance.

THE POSSIBILITIES AND REALITIES ON THE REMANAGEMENT OF DESERTIFIED LANDS IN THE TRANSITIONAL ZONE BETWEEN THE DRY-FARMING AREA AND THE GRAZING AREA IN NORTH CHINA

The desertification process is rapidly developing at present and 61.5% of the land area in the zone are already desertified.Among the desertified lands, 26.9% are seriously desertified, 25% most seriously desertified and 47.4% are the lands where desertification is under way. They are caused by over-reclamation for farming, over-grazing, unreasonable collection of firewood,the destruction of vegetation and the misuse of water resources. Under the ecological environment in semi-arid zone,the degraded environment process possesses the ability of restoring to its original status as soon as the interruption of excessive human activities are eliminated. The fencing- and-self-cultivating method is an effective measure adopted universally in semi-arid zone to cure the desertified lands.The desertified lands can be readjusted and controlled easily if other controlling measures are supplemented. The fundamental ways to control desertification are to utilize rationally the resources, to readjust the existing

Structural Relationships along a Neoarchean Arc-Continent Collision Zone, North China Craton

The Archean North China Craton is composed of the Western Block,Eastern Block and the intervening Central Orogenic Belt.A 4-10 km wide and 85 km long tectonic mélange belt informally called the Zanhuang tectonic

Structure of the mantle transition zone in the central and western parts of the North China Craton using the receiver function 3D Kirchhoff migration method

Using data from the regional broadband dense temporary array deployed by the ChinArray project,we applied the three-dimensional(3D)Kirchhoff migration method of the teleseismic P-wave receiver function to investigate discontinuity structures of the mantle transition zone(MTZ)in the central and western parts of the North China Craton(NCC)using a highresolution 3D velocity model of the East Asian region.The results show that the 410-km discontinuity beneath the Datong Volcano is depressed by~10 km,indicating the presence of a high-temperature anomaly near the depth of 410 km,which is likely related to small-scale mantle upwelling caused by the dehydration of the stagnant Pacific Plate in the MTZ.The upwelling of hot material provides a heat source for surface magmatic activity.Beneath the Bohai Bay Basin,significant subsidence of the 660-km discontinuity is observed,and the transition zone here is extensively thickened.It’s suggested that the anomalies in this region are related to the stagnation of the Pacific slab in the MTZ.Although the thickness of the transition zone west of the North-South Gravity Lineament appears normal,we propose that the subducting front of the Pacific slab did not cross the gravity lineament in the NCC.In comparison,the small-scale subsidence of the 660-km discontinuity and the thickening of the MTZ observed north of the Hannuoba Volcano likely indicate that the slab crossed the gravity lineament at its turning point and remained in the MTZ.Furthermore,a local thickening of the MTZ is observed in the Dabie orogenic belt of the Qinling Mountains.This is believed to be a combined effect of lithospheric delamination into the transition zone in the lower Yangtze region and the stagnation of the Pacific Plate.

Study on Water Consumption Coefficient of People's Living and Its Regional Disparity in the North of China

By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion to different precipitation zones anddifferent periods of time. The study shows that 5-(water consumption coefficient of urban people’sliving), 5. (water consumption coefficient of ruralpeople’s living) and increase with time passing, andthe increasing extent of 5 is 1.84, 2.62, 2.84 and 2.68times respectively from the west to the east, whichresults from the total quantity of water resources andthe speed of urbanization. 5- and 5. of eachprecipitation zone increased with 5- increasing morequickly than 5., and the difference between the twoalso increased when time passed. In the past fifty years(1950-2000), the increasing extent of 5- was 1.71,2.96, 2.41 and 2.33 times respectively from the westto the east, in which 200-400mm precipitation zoneincreased more than others. Meanwhile the increasingextent of 5. is 1.55, 1.60, 1.53 and 1.64 timesrespectively from the west to the east with eachprecipitation zone increasing similarly. The change of5-is due to the speed of urbanization and the stabilityof water resources. This study provides basis forcalculating the water demand of people’s living andrevealing the impact of water demand of people’s livingon ecological drought in different zones.

Dynamic influence of Holocene characteristics on vadose water in typical region of central North China Plain

In the typical region of central North China Plain, vadose sediments are Holocene sediment strata. With samples from field drillings, the study analyzes the sedimentary characteristics of vadose zone. The study takes the content of silty sand as the basis for sedimentary environment analysis, and the content of clay and sand as the sensitive indicator for sedimentary characteristics. Combining palynology analysis, the study divides vadose zone from top to bottom into diluvia oxbow lacustrine sediments, lacustrine sediments, lacustrine and swamp sediments, weak palaeohydrodynamic lacustrine sediments and alluvial sediments. Based on the sedimentary characteristics of Holocene strata, it analyzes the changes across depth of vadose zone water potential and matrix potential, obtaining the influence of vadose zone sedimentary characteristics on the migration of water in typical region of central North China Plain.

Research on the correlation between North China earthquake and global regional strong earthquakes

Active belts of global strong earthquakes were divided into 17 seismic zones based on the principles of global plate tectonics.The seismicity index number A(b) was used to denote the yearly seismicity level.Using the stepwise regression method,an empirical formula was derived to predict the North China seismic risk in the next year by the aid of strong earthquakes in the world.

TEMPORAL SPATIAL VARIATION CHARACTERISTICS OF CRUST DEFORMATION OF ACTIVE TECTONIC BLOCKS IN NORTH CHINA

Global Positioning System (GPS) observations during four measurement campaigns from 1992 to 1999 are used in a study of the temporal and spatial variation characteristics of crustal deformation of active tectonic blocks in North China. The Euler vectors for these active blocks are determined on the basis of GPS velocities of a group relative stable points in 1992,1995,1996 and in 1996,1999 respectively. We have studied the relative motion between blocks at the boundaries and the intra block deformation field. We have also inverted the strain rate fields for these active blocks by bi cubic spline model based on the GPS velocity field. The results show that the intra block deformation rates are different from those in block boundary zones, and are also different in different periods; the deformational field is generally characterized by intra-block extension in North China.

Determination of 3-D Velocity Anomalies of the Nanbei Tectonic Zone of China Based on Local Earthquakes

: In this paper, 3-D velocity images of the crust and upper mantle beneath the Nanbei tectonic zone of China are constructed using P-wave travel time residuals of earthquakes, with the data supplied by China's seismic networks and the International Seismic Centre.

郯庐断裂转换段新沂地裂缝成生机理及构造意义

新沂地区处于郯庐断裂带转换段的关键部位,自20世纪70年代以来在新沂地区共发现地裂缝灾害点28处。这些地裂缝以群发的形式发育在南马陵山以西、沂河—骆马湖以东的区域内,地裂灾害影响区面积达100 km^(2)。新沂地裂缝与地层结构、地震活动、地下水开采等因素有着千丝万缕的联系,对其研究形成了多种观点。利用实地调查与勘探手段,新近查明了新沂地裂缝的基本特征,它们具有走向一致性、纵向尖灭性、局部群发性等特点,且与邻近断裂(郯庐断裂带次级断裂F3)具有高度一致性,属于区域构造控制型地裂缝。以新沂地区地质构造为原型,构建了逆断层作用下地裂缝成生物理试验模型。试验结果表明,随着逆断层断距加大而依次呈剪裂段、离层段、弯裂段等发展过程。结合新沂地区“地堑地垒地堑”组合结构,新沂地裂缝的成因机制可概括为“跷跷板”构造模型,在构造应力、自重应力、地下水波动等作用下,下沉段受挤压,上升段因抬升而弯裂,从而形成地裂缝。研究新沂地区地裂缝,对揭示郯庐断裂带“北中南”段构造变化和“深浅表”部结构联系具有重要的指示意义。

华北平原制革废水Cr(Ⅲ)和氨氮在典型包气带中迁移模拟与污染评价

【研究目的】为探明制革废水中的特征污染物铬(Cr(Ⅲ))和氨氮(NH_(4)^(+)–N)在华北平原典型包气带中的迁移规律,评价其可能产生的土壤与地下水污染风险。【研究方法】采用土柱淋滤实验研究Cr(Ⅲ)和NH_(4)^(+)–N在典型粉土中的吸附和迁移转化特征,结合Hydrus–1D建立的包气带水流和溶质运移模型,模拟预测深0.5 m渗坑中NH_(4)^(+)–N连续入渗状态下通过包气带到达地下水面所需时间及不同深度浓度值的变化规律。【研究结果】在3 cm定水头,污染液(Cr(Ⅲ)20 mg/L,NH_(4)^(+)–N 250 mg/L)定浓度持续淋滤120 d的情况下,Cr(Ⅲ)在土柱中垂向迁移距离小于10 cm,且以残渣态(73%)为主,未检出Cr(VI)。NH_(4)^(+)–N则迁移能力较强,淋滤40 d后即穿透50 cm厚粉土柱。在高含盐量(电导率为10.08 ms/cm)条件下,NH_(4)^(+)–N在粉土中的迁移主要受吸附作用控制,土-水分配系数为25.87 L/kg,未发生硝化作用。持续淋滤150 d时NH_(4)^(+)–N迁移至地下水面(18 m埋深)且浓度超过Ⅲ类地下水质量标准(0.5 mg/L,GB/T 14848–2017),在223 d完全穿透包气带,严重污染地下水。【结论】高含盐量制革废水中Cr(Ⅲ)在粉土中迁移能力较弱,且难以被氧化为Cr(Ⅵ),对地下水威胁较小。NH_(4)^(+)–N则随水流快速迁移至地下水面,严重威胁地下水安全。

Land use pattern evolution and optimization in the Farming-Pastoral Zone of Northern China

Using information about the land cover of the Farming-Pastoral Zone of Northern China retrieved from multi-temporal NOAA/AVHRR and SPOT VEGETAN images obtained in 1989, 1994 and 1999, the authors analyzed land-use pattern evolution over this 10-year period and built a land-use pattern simulation model, based on which land-use pattern evolution and optimization modeling in this region were studied. Results showed that the proposed model can effectively simulate regional land-use patterns and help improve regional ecological environments.

北京松山林地nirK型反硝化微生物群落立地及林型效应

[目的]探究北京松山林地土壤nirK型反硝化微生物群落特征及影响因子,为华北暖温带森林土壤生态系统氮循环过程和环境变化提供依据。[方法]在北京松山国家级自然保护区选择油松林、山杨林、蒙古栎林3种典型林型,分别设置3块(20 m×20 m)标准地进行调查,采集0~20 cm表层混合土样,分析土壤性质并提取土壤微生物总DNA,PCR扩增反硝化过程关键酶亚硝酸盐还原酶的编码基因nirK片段,采用第2代高通量测序分析不同林型土壤nirK型反硝化微生物群落组成和多样性,探究林型和土壤性质对反硝化微生物群落特性的影响。[结果]1)从油松林、山杨林和蒙古栎林9个土壤样本中共得到nirK基因有效序列993 401条、优质序列770 328条。3种林型土壤nirK基因共检测出7门78属,在已鉴定的微生物中各林型优势菌为变形菌门,其相对丰度在3种林型中均达50%,在油松林中最高为58.2%;优势属主要为慢生根瘤菌属、中生根瘤菌属和红假单胞菌属,总相对丰度达50%以上,其中核心菌属为慢生根瘤菌属。2) nirK型反硝化微生物α多样性分析显示,油松林Shannon(7.59±0.56)、 Simpson(0.98±0.01)、 Chao1(2 164.24±214.08)指数均显著高于山杨林(5.23±0.26、 0.89±0.02、1 650.56±136.69)和蒙古栎林(5.76±0.38、 0.93±0.02、 1 621.36±156.70)(P<0.05)。基于Bray-Curtis距离算法并采用PCoA分析显示,不同林型土壤反硝化微生物群落组间差异大于组内。3)林分因子、土壤性质与土壤反硝化微生物的冗余分析结果表明,土壤碱解氮、硝态氮和有机质等土壤性质是影响nirK型反硝化微生物群落组成的关键因子(P<0.05)。[结论]北京松山油松林、山杨林和蒙古栎林土壤nirK型反硝化微生物群落组成、多样性存在明显差异,林型与碱解氮、硝态氮和有机质等土壤性质是影响土壤nirK型反硝化微生物群落特征的重要因素。

北方岩溶区降水入渗补给系数及补给机制:以羊庄岩溶水系统为例

为建立北方岩溶区水文地质参数系列,提高岩溶地下水可采资源计算精度,笔者团队于20世纪80年代开始,在山东羊庄封闭式泉排型岩溶水系统开展了岩溶水均衡试验研究,积累了40余年的监测试验数据。根据长期野外水均衡要素观测资料,推导出裸露型、半覆盖型和覆盖型岩溶区降水入渗补给系数计算公式,建立了岩溶区降水入渗补给系数α与降水量P和地下水位埋深D的相关方程,以及可调控的最大降水入渗补给系数系列,揭示了降水入渗补给过程与α变化机制。结果表明:α随水位埋深D的改变而改变,每个降水量P段分别对应一个最大降水入渗补给系数α_(max)和最大降水入渗补给量即补给极限G_(max),相应的水位埋深便是最佳水位埋深D_(critical)。D>D_(critical)时,包气带截留量随着水位埋深的增大而增大,α<α_(max);D<D_(critical)时,地表径流量随着地下水位埋深的减小而增大,α<α_(max)。不同的降水量段对应不同的D_(critical),降水量增大时,对应的α_(max)及D_(critical)也增大。在任意水位埋深时,G_(max)为蓄满产流临界降水量与包气带最大截流量之差。本研究解决了岩溶区降水入渗补给的关键科学问题,即揭示降水入渗补给机制、建立降水入渗补给系数与降水量和水位埋深的定量关系,提升了我国北方岩溶水资源基础性研究水平。

华北一次层状云系暖区水汽和液态水分布特征

基于机载微波辐射计、地基微波辐射计和Ka波段云雷达3种遥感资料,结合FY-4A气象卫星、气象观测站、天气雷达及再分析资料,研究2021年5月15日一次华北降水性层状云系暖区的水汽和液态水分布特征。结果表明:水汽和液态水的水平分布不均,飞机平飞时机载微波辐射计探测的积分水汽含量和液态水路径起伏变化,最大值分别为4.00 cm和1.87 mm,随着暖区云顶高度和云层厚度降低,二者分别降至0.89 cm和0.13 mm。随着降水发生发展,地基微波辐射计探测的积分水汽含量和液态水路径均出现跃增,峰值分别为8.62 cm和3.85 mm,水汽变化滞后于液态水,垂直方向上液态水含量的累积区厚度、最大值及所在高度均随降水先增后减,液态水的时空演变对暖区降水及增雨作业时机和部位的判识有重要指示意义。云雷达探测的液态水含量也出现跃增,在1 km高度以下反射率因子较大、粒子下落速度及离散程度较大时段,液态水丰富,对应降水量较大,粒子碰并是暖区降水的主要机制。