新疆孔雀河流域下游平原灌区土壤盐碱化改良的原则与治理措施研究     

郭健  郭琳  张兵 《地下水》2011,(4):46-48

根据孔雀河流域下游平原灌区自然地理特征,分析盐碱地形成的原因,探讨实施治理盐碱地改良利用应遵守的原则,提出以水利土壤改良为先导,配以农艺改良和生物改良等治理综合措施。以期达到盐碱地标本兼治的目的,从而实现农业可持续发展。  相似文献   

上海湖沼平原地貌分界线上地层分布特征研究   总被引：1，自引：0，他引：1  

孙莉 《上海国土资源》2011,32(4):68-72

上海湖沼平原和滨海平原地貌类型划分应遵从地貌特征,为工程应用方便,可划分地貌亚区。地貌分界线上典型的地质剖面,为湖沼平原第一硬土层与滨海平原暗绿色硬土层属于同一地质时代提供了直接证据。由于古河道、台地等古地貌特征,造就了不同地貌及地貌亚区之间地层差异。  相似文献   

Silica biogeochemical cycle in temperate ecosystems of the Pampean Plain,Argentina     

《Journal of South American Earth Sciences》2015

Silicophytoliths were produced in the plant communities of the Pampean Plain during the Quaternary. The biogeochemistry of silicon is scarcely known in continental environments of Argentina. The aim of this work is to present a synthesis of: the plant production and the presence of silicophytoliths in soils with grasses, and its relationship with silica content in soil solution, soil matrix and groundwaters in temperate ecosystems of the Pampean Plain, Argentina. We quantified the content of silicophytoliths in representative grasses and soils of the area. Mineralochemical determinations of the soils' matrix were made. The concentration of silica was determined in soil solution and groundwaters. The silicophytoliths assemblages in plants let to differenciate subfamilies within Poaceae. In soils, silicophytoliths represent 40–5% of the total components, conforming a stock of 59–72 × 10³ kg/ha in A horizons. The concentration of SiO₂ in soil solution increases with depth (453–1243 μmol/L) in relation with plant communities, their nutritional requirements and root development. The average concentration of silica in groundwaters is 840 umol/L. In the studied soils, inorganic minerals and volcanic shards show no features of weathering. About 10–40% of silicophytoliths were taxonomically unidentified because of their weathering degrees. The matrix of the aggregates is made up by microaggregates composed of carbon and silicon. The weathering of silicophytoliths is a process that contributes to the formation of amorphous silica-rich matrix of the aggregates. So, silicophytoliths could play an important role in the silica cycle being a sink and source of Si in soils and enriching soil solutions and groundwaters.  相似文献   

北京平原构造断块划分及微断块第四纪活动性探讨   总被引：4，自引：3，他引：1       下载免费PDF全文

赵勇 蔡向民  王继明张 磊刘 予吕金波 《中国地质》2015,(6):1876-1876

在对北京平原地区地质构造特征综合分析的基础上,依据近年来在活动断裂研究中遇到的问题,本文提出对北京平原区进行构造断块划分的方案。将北京平原区划分为7个"断块",即马池口—沙河、小汤山、顺义、平谷、丰台—来广营、大兴—通州及房山断块。据断块内次一级活动断裂和第四纪地层沉降发育情况,进一步可划出活动微断块,把以研究单一活动断裂重点转变为以控制微断块边界的交汇活动断裂组相互作用为中心。从而揭示出第四纪以来微断块边界交汇活动断裂组的特征、活动方式及其规律等,可为首都城市建设规划和减轻地质灾害等提供有价值的参考,为保障城市地质安全提供地质依据。  相似文献   

河北中南部平原土壤重金属元素存在形态及生物有效性分析   总被引：9，自引：3，他引：6       下载免费PDF全文

崔邢涛  王学求  栾文楼 《中国地质》2015,(2):655-663

本文以河北省中南部平原农田表层土壤为研究对象,对表层土壤中7种重金属元素的形态含量进行了统计和分析,对重金属元素的生物有效性进行了评价,并运用相关分析法,对影响重金属元素生物有效性的因素进行了研究。结果表明,研究区表层土壤7种重金属元素的有效态含量以Cd最高,达36.83%,潜在生态危害性较大;其次为Pb,达13.37%,其中碳酸盐结合态达到12.38%,由于土壤呈中性或偏碱性,Pb元素的迁移能力较弱,其潜在危害性较小;Cu、Hg、Cr、As、Zn重金属元素含量均以稳定态的含量存在,之和均在90%以上,表明其潜在危害性较小;研究区土壤重金属元素的活性系数和迁移系数大小顺序为:CdPbHgCuZnAsCr和CdHgAsCuPbZnCr,其中Cd的活性系数和迁移系数平均值分别达到0.330和0.160,展现出较强的生物活性、不稳定性和迁移能力,其他重金属元素在土壤中活性系数(Pb除外)和迁移系数均较小,生物活性较弱,在土壤中稳定存在,由土壤中向植物中的迁移能力弱;研究区不同的重金属的生物有效性与其影响因素的关系不尽相同,其主要因素是土壤重金属元素全量,其次为p H、TOC、CEC、粘粒含量等,二者关系复杂。  相似文献   

山东省汶泗河冲洪积平原地下水污染评价与安全供水对策     

徐建国  朱恒华  徐华  张卓  祁晓凡 《山东国土资源》2011,27(5)

在对汶泗河冲洪积平原水文地质条件和污染源现状进行阐述的基础上,对不同含水岩组无机组分指标进行了分析,表明浅层孔隙水和部分地区岩溶裂隙水无机组分含量大幅增高,深层孔隙水无机物含量则变化不大。在有机污染方面,浅层孔隙水有机物检出率26.8%,但含量很低,远未达到饮用水标准限值;岩溶裂隙水有机物检出率46.7%,检出率相对较高,局部地段有机物超标;深层孔隙水有机物基本未检出。该区地下水污染评价结果表明,浅层孔隙水和岩溶裂隙水无机污染呈面状污染特征,且污染程度较重,而有机污染则呈现点状污染特征,且污染程度总体较轻。对研究区地下水污染现状,提出了地下水安全供水对策。  相似文献   

Groundwater–surface water interactions in a lowland watershed: source contribution to stream flow     

Vijay M. Vulava  Timothy J. Callahan  Martin L. Jones 《水文研究》2012,26(21):3195-3206

The lower coastal plain of the Southeast USA is undergoing rapid urbanisation as a result of population growth. Land use change has been shown to affect watershed hydrology by altering stream flow and, ultimately, impairing water quality and ecologic health. However, because few long‐term studies have focused on groundwater–surface water interactions in lowland watersheds, it is difficult to establish what the effect of development might be in the coastal plain region. The objective of this study was to use an innovative improvement to end‐member mixing analysis (EMMA) to identify time sequences of hydrologic processes affecting storm flow. Hydrologic and major ion chemical data from groundwater, soil water, precipitation and stream sites were collected over a 2‐year period at a watershed located in USDA Forest Service's Santee Experimental Forest near Charleston, South Carolina, USA. Stream flow was ephemeral and highly dependent on evapotranspiration rates and rainfall amount and intensity. Hydrograph separation for a series of storm events using EMMA allowed us to identify precipitation, riparian groundwater and streambed groundwater as main sources to stream flow, although source contribution varied as a function of antecedent soil moisture condition. Precipitation, as runoff, dominated stream flow during all storm events while riparian and streambed groundwater contributions varied and were mainly dependent on antecedent soil moisture condition. Sensitivity analyses examined the influence of 10% and 50% increases in analyte concentration on EMMA calculations and found that contribution estimates were very sensitive to changes in chemistry. This study has implications on the type of methodology used in traditional forms of EMMA research, particularly in the recognition and use of median end‐member water chemistry in hydrograph separation techniques. Potential effects of urban development on important hydrologic processes (groundwater recharge, interflow, runoff, etc.) that influence stream flow in these lowland watersheds were qualitatively examined. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Non-point source pollution in Indian agriculture: Estimation of nitrogen losses from rice crop using remote sensing and GIS     

Abha Chhabra  K.R. ManjunathAuthor VitaeSushma PanigrahyAuthor Vitae 《International Journal of Applied Earth Observation and Geoinformation》2010

The paper presents a detailed understanding of nitrogenous fertilizer use in Indian agriculture and estimation of seasonal nitrogen loosses from rice crop in Indo-Gangetic plain region, the ‘food bowl’ of the Indian sub-continent. An integrated methodology was developed for quantification of different forms of nitrogen losses from rice crop using remote sensing derived inputs, field data of fertilizer application, collateral data of soil and rainfall and nitrogen loss coefficients derived from published nitrogen dynamics studies. The spatial patterns of nitrogen losses in autumn or ‘kharif’ and spring or ‘rabi’ season rice at 1 × 1 km grid were generated using image processing and GIS. The nitrogen losses through leaching in form of urea-N, ammonium-N (NH₄-N) and nitrate-N (NO₃-N) are dominant over ammonia volatilization loss. The study results indicate that nitrogen loss through leaching in kharif and rabi rice is of the order of 34.9% and 39.8% of the applied nitrogenous fertilizer in the Indo-Gangetic plain region. This study provides a significant insight to the role of nitrogenous fertilizer as a major non-point source pollutant from agriculture.  相似文献   

基于生态需水的石羊河北部平原生态保障技术研究     

程玉菲  王军德  李元红  金彦兆  胡想全 《冰川冻土》2014,36(3):724-731

针对石羊河流域日益严峻的生态环境问题,选择干旱区生态需水计算为切入点,以变异理论为基础,利用Mann-Kendall非参数检验的方法确定石羊河北部平原区地下水位恢复的目标年,用生态功能区划方法划分生态功能区,利用达西定律、阿维里扬诺夫公式计算了地下水恢复及生态目标条件下的生态需水量,并提出了相应的生态保障措施. 结果表明：石羊河北部平原区划分为5个生态功能亚区及16个三级区,地下水位恢复的目标年份为1977年,地下水恢复到1977年的生态需水量为 55.95×10⁸~74.10×10⁸ m³,2015年和2020年生态目标条件下的生态需水分别为1.66×10⁸ m³和1.80×10⁸ m³. 考虑到地下水恢复的缓慢性和现实性,建议优先考虑设定目标条件下的植被正常生长生态需水,其次通过继续压缩人均耕地面积和灌溉定额的方式保证地下水恢复.  相似文献   

淮北平原浅层地下水中铁和锰的空间差异性及影响因素     

刘进  许光泉 《煤田地质与勘探》2010,38(2):46-49

通过常规和地统计学分析,查明淮北平原浅层地下水中铁锰含量的空间差异性,得出变异函数图符合指数模型,二者都由结构性因素引起。对其空间分布特征进行分析表明,铁、锰在空间呈现相同的分布趋势,超标区主要分布在地势低洼地和低山丘陵区,其含量与岩土成分、地下水所处的氧化还原环境、地下水径流条件、酸碱性等有关。   相似文献