农业生态地质调查初探——以辽宁鞍山南部地区为例   总被引：1，自引：0，他引：1  

温守钦  刘洪涛  任群智  朱恩静  金成洙  王学宓 《地质与资源》2004,13(3):156-158,191

以鞍山南部地区农业生态地质调查为例,阐述了通过测定主要元素在土壤中的分布,综合评价农业生态地质背景,从而研究土地种植适宜性及土壤环境安全性和治理对策,进而讨论在辽宁省开展农业生态地质调查研究的主要内容及意义.此外,对特种经济作物南果梨专项调查表明,土壤中铁、锰、镁、钾、钴元素含量决定了南果梨的独特品质,以变辉长岩或片岩和花岗岩混合岩为成土母岩地区是南果梨生长的最佳区域.  相似文献   

Using multivariate statistical techniques and geochemical modelling to identify factors controlling the evolution of groundwater chemistry in a typical transitional area between Taihang Mountains and North China Plain     

Fei Liu  Shou Wang  Tian-Chyi Jim Yeh  Pinna Zhen  Lishu Wang  Liming Shi 《水文研究》2020,34(8):1888-1905

Identifying the key factors controlling groundwater chemical evolution in mountain-plain transitional areas is crucial for the security of groundwater resources in both headwater basins and downstream plains. In this study, multivariate statistical techniques and geochemical modelling were used to analyse the groundwater chemical data from a typical headwater basin of the North China Plain. Groundwater samples were divided into three groups, which evolved from Group A with low mineralized Ca-HCO₃ water, through Group B with moderate mineralized Ca-SO₄-HCO₃ water, to Group C with highly saline Ca-SO₄ and Ca-Cl water. Water-rock interaction and nitrate contamination were mainly responsible for the variation in groundwater chemistry. Groundwater chemical compositions in Group A were mainly influenced by dissolution of carbonates and cation exchange, and suffered less nitrate contamination, closely relating to their locations in woodland and grassland with less pronounced human interference. Chemical evolution of groundwater in Groups B and C was gradually predominated by the dissolution of evaporites, reverse ion exchange, and anthropogenic factors. Additionally, the results of the inverse geochemical model showed that dedolomitization caused by gypsum dissolution, played a key role in the geochemical evolution from Group A to Group B. Heavy nitrate enrichment in most groundwater samples of Groups B and C was closely associated with the land-use patterns of farmland and residential areas. Apart from the high loads of chemical fertilizers in irrigation return flow as the main source for nitrate contamination, the stagnant zones, flood irrigation pattern, mine drainage, and groundwater-exploitation reduction program were also important contributors for such high mineralization and heavy NO₃⁻ contents in Group C. The important findings of this work not only provide the conceptual framework for the headwater basin but also have important implications for sustainable management of groundwater resources in other headwater basins of the North China Plain.  相似文献   

云南高原渔洞水库鱼类空间分布格局及主要影响因子     

连玉喜  李昌  叶少文  李为  刘家寿  李钟杰 《湖泊科学》2018,30(6):1755-1765

鱼类控藻是常用的生物控藻技术之一，其前提需明确水体中鱼类群落结构及分布特征.为科学调整渔洞水库鱼类群落结构，制定合理的生物操纵策略，2013年7月运用Simrad EY60型分裂波束回声探测仪对该水库进行了水声学探测，在结合多网目复合刺网（网目=8.5、4.0、12.5、2.0、11.0、1.6、2.5、4.8、3.1、1.0、7.5和6.0 cm）取样的基础上，研究了水库鱼类群落结构及其空间分布特征，并初步探讨了影响渔洞水库鱼类空间分布的关键因素.调查中在渔洞水库共采集到鱼类5科12种，其平均密度为638.4±310.2 ind./1000 m³.鱼类在水库中呈不均匀分布，库首、库中、库湾及库尾鱼类密度分别为521.5±371.3、561.9±189.2、653.7±323.7和1137.1±90.4 ind./1000 m³，呈逐渐增大趋势，且库尾鱼类的平均个体要大于库首、库中和库湾；在垂直方向上，97.6%的鱼类都分布在水面以下0~10 m的水层，深度超过10 m的水层，鱼类所占比例只有2.4%；0~20 m水层鱼类的平均目标强度最大（-58.6 dB），20~40 m水层鱼类平均目标强度最小（-63.9 dB）.MRT预测模型表明影响鱼类空间分布的关键环境因子为水温和水深.基于渔洞水库的鱼类组成和空间分布特征，建议一方面加大鲢、鳙放养量，另一方面从所属水系引进中上层土著肉食性鱼类来调整鱼类群落结构，控制藻类生物量.  相似文献   

The integrated impacts of natural processes and human activities on groundwater salinization in the coastal aquifers of Beihai,southern China   总被引：1，自引：0，他引：1  

Qinghua Li  Yanpeng Zhang  Wen Chen  Shaowen Yu 《Hydrogeology Journal》2018,26(5):1513-1526

Salinization in coastal aquifers is usually related to both seawater intrusion and water–rock interaction. The results of chemical and isotopic methods were combined to identify the origin and processes of groundwater salinization in Daguansha area of Beihai, southern China. The concentrations of the major ions that dominate in seawater (Cl^?, Na⁺, Ca²⁺, Mg²⁺ and SO ₄ ^2– ), as well as the isotopic content and ratios (²H, ¹⁸O, ⁸⁷Sr/⁸⁶Sr and ¹³C), suggest that the salinization occurring in the aquifer of the coastal plain is related to seawater and that the prevailing hydrochemical processes are evaporation, mixing, dissolution and ion exchange. For the unconfined aquifer, groundwater salinization has occurred in an area that is significantly influenced by land-based sea farming. The integrated impacts of seawater intrusion from the Beibuwan Gulf and infiltration of seawater from the culture ponds are identified in the shallowest confined aquifer (I) in the middle of the area (site BBW2). Leakage from this polluted confined aquifer causes the salinization of groundwater in the underlying confined aquifer (II). At the coastal monitoring site (BBW3), confined aquifer I and lower confined aquifer II are heavily contaminated by seawater intrusion. The weak connectivity between the upper aquifers, and the seaward movement of freshwater, prevents saltwater from encroaching the deepest confined aquifer (III). A conceptual model is presented. Above all, understanding of the origin and processes of groundwater salinization will provide essential information for the planning and sustainable management of groundwater resources in this region.  相似文献   

地理信息系统支持下的中国粮食生产潜力研究   总被引：14，自引：0，他引：14       下载免费PDF全文

党安荣  阎守邕  周艺 《遥感学报》1999,3(3):225-229,248

在地理信息系统（ＧＩＳ）及全国农业空间数据库和属性数据库的支持下,在前人关于农业生产潜力研究的基础上进行了全国粮食生产潜力的研究。作者首先论述粮食生产潜力研究进展,探讨了基于ＧＩＳ的粮食生产潜力研究方法;然后,就粮食生产潜力的土壤有效系数、土地生产潜力和社会有效系数、社会生产潜力提出了新型的计算模型,并应用机制法通过光、温、水、土、社逐级衰减,具体计算了全国分组粮食生产潜力;最后,针计算结果与实现  相似文献   

Study on Moist Potential Vorticity and Symmetric Instabilityduring a Heavy Rain Event Occurred inthe Jiang-Huai Valleys     

寿绍文  李耀辉 《大气科学进展》1999,(2)

1.IntroductionSubsequenttothe1970s,manynativemeteorologicalresearchersdiscoveredthatmesoaiscalesymmetricinstabilitydisturbanceislikelytoplayanimportantroleintriggeringandorganizingbandedconvectionandresponsibledirectlyformultiplerain--bands.Asahighly...  相似文献   

乡镇“有为政府”产业政策的逻辑与检验——基于新结构经济学视角     

李达  张绍文 《热带地理》2022,42(1):113-122

为解决乡村振兴中乡镇政府如何选择正确产业和如何制定合理产业政策2个重要问题,运用新结构经济学“增长甄别与因势利导框架”分析并提出乡镇“有为政府”产业政策演化的逻辑框架：1）选择产业,依据“两步六轨法”选择具备相似资源禀赋、约束条件的产业。2）政策制定,针对筛选出的产业制定合理的政策内容、选择适当的政策工具,以支持产业发展。以该逻辑框架为依据分析了云南省西双版纳州勐罕镇的产业现状、目标乡镇比较优势产业,发现勐罕镇领先型产业为菠萝种植业,应通过引进菠萝深度加工企业,建设营销网络、运输网络,提供市场信息支持产业发展;转进型产业为传统种植业和特色养殖业,应通过建立冷链物流等基础设施、培训农户种养能力,提高农户市场参与度;“弯道超车型”产业为酒类制造和傣药生产等,应通过联合农户开发制造技术体系,协助注册品牌商标,建设生产和成品制造基地等促进产业发展,从而完成了逻辑框架的实践检验。总体上,因势利导逻辑框架既结合实际又着眼未来,为乡镇政府的产业政策决策提供了理论指导和经验借鉴。  相似文献   

CyberGIS and spatial data science     

Shaowen Wang 《GeoJournal》2016,81(6):965-968

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Timoshenko beam solution for the response of existing tunnels because of tunneling underneath          下载免费PDF全文

Peng Li  Shou‐Ji Du  Shui‐Long Shen  Yan‐Han Wang  Hong‐Hua Zhao 《国际地质力学数值与分析法杂志》2016,40(5):766-784

An analytical solution for the deflection and internal forces of an existing tunnel because of tunneling underneath is presented. The existing tunnel is modeled as a Timoshenko beam resting on a Winkler foundation, which takes into account the contribution of shear deformation to the total deflection of the existing tunnel. The validity of the analytical solution is verified by a centrifuge test, and the merit of this analytical method is confirmed by comparison with the conventional Euler–Bernoulli beam model. Influential factors on the behavior of the existing tunnel are investigated by consideration of the variations of subgrade modulus, ground loss induced by the new tunnel construction, vertical clearance between the new tunnel and the existing tunnel, and relative existing tunnel–soil stiffness. Results show that the proposed analytical method is a valid and effective method to evaluate shearing‐induced deformation in existing tunnels with large diameters. Results also show that the pattern and the amplitude of the response of the existing tunnel are affected largely by ground loss induced by the new tunnel construction, vertical clearance between the new tunnel and the existing tunnel, and relative existing tunnel–soil stiffness. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

全球大地热流研究进展   总被引：4，自引：0，他引：4       下载免费PDF全文

郝春艳  刘绍文  王华玉  王良书 《地质科学》2014,(3):754-770

大地热流是表征地球热状态的重要地球物理参数,它记录了发生在地球深部各种作用过程和能量平衡的信息。大地热流的测量与汇编是固体地球物理学领域的基础性工作。本文对最近20年来全球大地热流研究的相关进展进行了综述,包括介绍近年来全球大地热流数据库建立和汇编情况,据此阐述了全球大地热流的分布规律及主控因素。继而重点对大陆和大洋热流研究中的若干重要概念或关键问题（如热流省、热流-生热率关系、壳幔热流配分系数、大洋岩石圈热演化模型和地下水循环等）、全球热量收支及其时空变化等方面进行了分析。最后,就全球热流汇编研究中需注意的问题以及今后的研究方向做了一些讨论。  相似文献