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1.
山西是水土流失比较严重的地区,河流含沙量一般较大,对推移质泥沙估算,目前还没有比较理想的方法,通过对水文站和水库大量系列实测资料进行了分析,运用沙量平衡原理分析,提出了山西不同河流推移质的计算参数。  相似文献   

2.
研究小流域泥沙的产生与搬运机制,是水土保持学和河道工程学学科既古老而又全新的课题,有很多科学工作者进行立题研究。但对河流泥沙运动的研究并不多,特别有关推移质的情况,因观测困难,没有取得有效的研究成果。2008年日本京都府立大学松村和树等对泥沙产生与搬运作用进行实地观测。观测内容:裸地坡面泥沙输移量、积雪产生泥沙及影响、河水混浊度、径流量及推移质流量、推移质运动状态等。通过对多沙流域有关产生泥沙—漂流—搬运等连续的流动,进行综合研究,揭示了推移质拖曳力与推移质平均移动速度的关系。其观测方法可行,试验结果可信。此项研究将为有关多沙河流推移质的研究起到借鉴或推介作用。  相似文献   

3.
风沙活动、降雨和人类活动是干旱-湿润过渡区影响粗泥沙(d>0.05mm)入黄的几个重要因素。粗泥沙输沙量的变化取决于全沙输沙量和粗泥沙在全沙中所占的比例。基于悬移质输沙量和泥沙粒径构成、降雨量、沙尘暴日数和水土保持面积等数据,分析了粗泥沙输沙量与影响因素之间的关系,利用Arc-GIS和SPSS软件定量分析了影响无定河流域代表自然过程的风水两相作用和人类活动对粗泥沙输沙量的影响,并通过回归分析确定了不同影响因素对全沙输沙量和粗泥沙比例的贡献。结果表明,影响全沙输沙量的主要因素是降雨量和水土保持措施,而影响粗泥沙比例的是风沙活动和水土保持措施。利用二元回归分析确定了各因素的贡献比例,认为降雨量的减少和人类活动对全沙量减少的贡献相当,人类活动对粗泥沙比例降低的贡献高于风沙活动的作用。  相似文献   

4.
河流向下游输送泥沙的结果是引起河床上升……使海岸线后退。2008年日本学者近藤玲次等人实施了不同水深条件下的推移质和悬移质观测研究,以把握泥沙流量和洪水中的泥沙粒度随时间变化的形态。其结果:泥沙量与流量呈正相关关系。即流量增加1个等级,泥沙流量增加3~4个等级。以悬移质冲刷量占总泥沙流量的50%以上,多数为80%以上,很少接近100%。悬移质超过推移质。分散推移的量超过悬移质,有趋近迹象。  相似文献   

5.
风水两相变化对黄河中游支流粗泥沙的影响   总被引:1,自引:0,他引:1  
基于黄河中游河口-龙门区间实地考察和对1964—1989年的实测资料进行时空变化分析,结果发现:该区水力、风力变化对河流产出的粗泥沙的量和质的变化具有一定的分异控制作用,水力对河流的输沙量的变化起主导作用,而风力对粗泥沙占全沙的百分比变化起主导作用。随着降雨量的减少和风沙活动的减弱,黄河中游河流输沙量和粗沙比有不同程度的减少,输沙量减少明显,减沙比在50%~70%之间,而粗沙比的变化要小得多,减少量在10%~20%之间。  相似文献   

6.
1995年康定城区洪灾成因分析   总被引:1,自引:0,他引:1  
谢洪  钟敦伦 《山地研究》1997,15(2):129-131
分析洪灾成因:长时间连续降雨和随后而至的暴雨,是山洪成灾主要因素:特殊的水系结构使洪峰流量和城区河流汇合处叠加:山洪的功能大,挟带泥沙和冲蚀能力强,泥石流,滑坡,崩塌强烈活动,为山洪提供大量泥沙,推移质;人类经济活动不当,加大了灾害损失。  相似文献   

7.
黔西北炼锌地区河流重金属污染特征   总被引:15,自引:0,他引:15  
黔西北地区铅锌矿的开发导致了后河严重的重金属污染。为此对河流水体、悬浮物和沉积物中重金属及其沿河流的分布规律进行了研究。结果表明,土法炼锌及其下游铅锌选矿都对河流造成污染,特别是选矿厂的尾矿直接注入河道,使河流沉积物中滞留有较多硫化物矿物。河流重金属的搬运迁移以悬浮质或泥沙推移等机构搬运为主。河流水体环境化学性质对沉积物中硫化物的氧化作用及其重金属向水体的释放起到一定抑制作用,但流水的淘洗和支流的混入过程等水文地球化学条件改变时可使氧化矿物表面的重金属释放返回水相,成为溶解态重金属。沉积物是河流重金属潜在的二次污染源。  相似文献   

8.
湖南武水流域泥沙颗粒特性及分形规律研究   总被引:1,自引:0,他引:1  
流域土壤流失的泥沙颗粒及其分布与流域土壤有关,影响流域土地质量和输沙过程。以武水流域天然河道的53次降雨径流输沙过程实测资料为基础,运用R-R(Rosln-Rammler)粒径分布函数法分析了泥沙颗粒级配特性及其分形规律。结果表明,流域多年均悬移质泥沙颗粒组成为粘粒11%、粉粒51%、细砂粒32%和粗砂粒6%,以粉粒和细砂粒为主体,占83%。1981年以后,悬移质泥沙颗粒中粘粒和粉粒含量相对减少,悬移质泥沙颗粒呈变粗的趋势。悬移质泥沙颗粒组成具有分形特征,分形维数D与小于0.005 mm粉粒及粘粒含量呈较显著相关,与中值粒径相关性较差。流域推移质泥沙颗粒中值粒径平均为0.874 mm,推移质泥沙以砂、石砾为主。推移质泥沙颗粒组成具有分形特征,分形维数D与小于0.3 mm细砂及粉粒含量呈显著相关。流域泥沙级配及其变化,有利于分析泥沙来源,采取相应的治理措施,控制泥沙。  相似文献   

9.
菲律宾吕宋省中部Magat流域,目前正在开展一系列的造林效益评价.这项研究的一部分内容是在流域内对河流进行监测并调查该流域内泥沙输送情况.其采用的方法是“巢形”流域的研究方法.沿着Magat河选择三个监测站,按着测站的顺序,使流域面积逐渐增加.在每个测站,均用泵取样测量含沙量.在收集和分析泥沙样品时要区分河床上的悬浮推移质(粗砂)和冲泻质(淤泥).在将每个测站分离出的粗砂和淤泥划分等级,并从水文曲线得出每年的输沙量和1986年一段期间的产沙量.  相似文献   

10.
天然河流挟带的泥沙直接影响到河流的发展变化,并给人类开发利用水资源带来了许多问题。为了解决泥沙问题,达到兴利除害的目的,首先必须掌握足够的泥沙资料,了解其主要来源,并研究其运行规律。本文分析了河流泥沙的来源,以汾河上游宁化水文站的多年测验资料为例,论述了高含沙水流泥沙的分布特性,并对河流泥沙的测验工作提出了改进建议。  相似文献   

11.
水氮耦合对苹果光合特性和果实品质的影响   总被引:5,自引:0,他引:5  
通过不同灌水量和施氮处理,研究水氮耦合对红富士苹果光合特性及品质的影响。结果表明:红富士苹果的光合特性在不同水肥组合下的变化不同,其光合作用存在明显的“午休”现象。中水高肥和高水高肥的肥水组合对光合速率的保持有一定的作用。低水中肥的肥水组合的蒸腾速率最低,保水效果最好。中度水分供应条件下,施用较多的氮肥可以提高气孔导度利于光合的进行。肥水管理以灌溉量5250m3/hm2、氮肥施用量600kg/hm2方案能获得较高的品质效益。  相似文献   

12.
圆叶决明的栽培技术及其防蚀培肥的功效   总被引:2,自引:0,他引:2  
经多年种植结果表明,圆叶决明具有覆盖率高、固氮率高、适应性和抗逆性强等特点,是山地茶果园水土流失地套种的先锋作物,本文阐述了圆叶决明的特征特性、栽培技术以及防治水土流失、培肥地力的作用。  相似文献   

13.
14.
Soil was subjected to a variety of treatments so as to provide a series of materials with different organic residues. These preparations were inoculated with an aqueous extract of untreated soil, then incubated at 20°C with atrazine or linuron and rates of herbicide degradation were followed. The rates were lowest when virtually all the organic matter had been removed by peroxidation. The most rapid break-down occurred in samples which had been successively extracted with ethanol + toluene, hot water, dilute acid and dilute alkali. It is suggested that the organic residue left after this sequence contained hydrolysed materials that were easily metabolized and hence could support the most active microbial population. There was no relationship between extent of adsorption and decomposition rate.  相似文献   

15.
16.
Asulam reaching the soil either directly as spray drift or as rain washings from bracken fronds would, due to its rapid mobility in soil, be expected to leach down the soil profile into the drainage water and thereby contaminate streams and water catchments. The mobility of asulam in soil is influenced by pH, where undissociated asulam will leach less rapidly than the associated form (asulam pKa 4·82). This is particularly relevant in the case of bracken as it can grow satisfactorily over a wide range of pH values (3·6 – 7·6). Adsorption coefficients expressed as Kd values [(μg asulam/g soil)/(μg asulam/ml solution)] were 2·54, 1·94 and 0·96 at pH readings of 4·0, 4·3 and 4·9 respectively. Another factor involved, the breakdown of asulam, was shown to be temperature dependent, 30·95, 7·65 and 2·50% remaining after 28 days at 5, 18 and 25°C respectively, thus underlining the influence of geographical regions and climatic conditions on asulam behaviour.  相似文献   

17.
选用8个不同基因型的甘蔗,即粤糖86-368、新台糖16号、农林8号、拔地拉、割手密和从甘蔗杂交后代F1中选出的3株种茎的无性系(单株)。在甘蔗伸长初期,测定其 2节间至 8节间的长度、茎径,同时取 3、 5、 8节间,测定其可溶性蛋白质、细胞壁离子型结合蛋白质、细胞壁共价型结合蛋白质及可溶性总糖的含量。结果表明:从 2节间到 8节间,不同基因型的节间长度的变化极为相似,除割手密外,其它基因型甘蔗的节间长度都在 6节达到最长;但其茎径在 6节间以后仍保持稍微的增粗。从 3节间到 5、 8节间,所有基因型的三类蛋白质含量都逐渐下降,而可溶性总糖含量都逐渐提高。其中,三个节间较粗的基因型即拔地拉、粤糖86—368和无性系3号,其三类蛋白质含量相对较高,而可溶性总糖含量相对较低。  相似文献   

18.
The properties, hydrological features, and genesis of the solods occurring in the Baraba Lowland and Priobskoe Plateau were studied. Methods for determining the hydromorphism degree are considered; the features of the similarity and differences between the solods and other soils with textural profile differentiation are shown. Depending on the reasons for the waterlogging, the solods should be divided into two groups: the solods of groundwater waterlogging and the solods of surface waterlogging. Criteria for their discrimination are suggested: the ratio between the contents of the clay fraction in the parent rock (or in the B2 horizon) and that in the A2 horizon, the changes in the pH values along the soil profiles, and the content of nonsilicate iron compounds. The solods studied are shown to be formed under the conditions of a stagnant-percolative regime and gleying. This circumstance is an obligatory and sufficient reason for the formation of the light-colored acid eluvial (A2) horizons. According to some basic properties of the soil solid phase (the acidity, the total chemical composition, and the clay pattern in the eluvial part), the gleyed solods are close or identical to the gleyed soddy-podzolic and gleyed chernozem-like podzolic soils. At the same time, the solods differ from the gleyed chernozem-like podzolic soils by their thicker A1 (or Ap) horizon and their higher humus content (5–7%).  相似文献   

19.
党的十七届六中全会提出了要推动文化创意产业成为国民经济的支柱性产业。图书馆拥有丰富的文献资源和信息服务能力,在为文化创意产业项目提供信息服务的同时,应提升自身形象,谋求更大发展。  相似文献   

20.
Limited information on the effect of glyphosate (N-phosphonomethylglycine) on soil microorganisms justified an inquiry into the response of soil actinomycetes, bacteria and fungi in terms of their respiration, and sensitivity of isolates. Low concentrations of glyphosate had little effect on total populations of these organisms during the 214-day experiment, while high concentrations initially increased actinomycete and bacterial numbers by 2 and 1case12 logs, respectively. The stimulation was followed by a decline and fluctuation showing a gradual increase in numbers. The respiration rates of the soil microbiota in soil suspensions, showed some irregular stimulation and retardation with up to 10 μg glyphosate ml?1. In contrast high doses suppressed O2 uptake by the microbiota. Fungi were the least affected. Pronounced inhibition of actinomycete and bacterial respiration was in agreement with the results from isolate replication. The results indicated both stimulation and inhibition of O2 uptake by some organisms within these groups. In contrast to some reports of limited, short-term inquiries these results showed considerable effects of glyphosate on soil microorganisms.  相似文献   

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