Sustainable Irrigation with Brackish Groundwater in Heilonggang Region, China     

Jin Menggui  Zhang Renquan  Gao Yunfu 《中国地质大学学报(英文版)》1998,9(1):2

ＢＡＣＫＧＲＯＵＮＤＡＮＤＳＩＧＮＩＦＩＣＡＮＣＥＯＦＳＡＬＩＮＥＷＡＴＥＲＵＴＩＬＩＺＡＴＩＯＮＨｅｉｌｏｎｇｇａｎｇｒｅｇｉｏｎ,ａｓｅｍｉ－ａｒｉｄａｒｅａｗｉｔｈ５００－６００ｍｍａｎｎｕａｌｐｒｅｃｉｐｉｔａｔｉｏｎ,ｌｉｅｓｉｎｔｈｅＥａ...  相似文献   

喷灌条件下土壤水分空间分布特性研究   总被引：9，自引：0，他引：9       下载免费PDF全文

李久生  雷志栋 《水科学进展》1998,9(1):7-14

分别在火山灰土和砂壤土两种土壤上进行了不同喷灌均匀系数和灌水量的土壤水分空间分布试验。对土壤干容重空间分布规律的研究表明,干容重在空间的随机分布可用正态分布来表示。为了确定喷灌洒水量和土壤含水率的空间结构,分别计算了它们的半方差和自相关函数。结果指出,喷灌洒水量的相关距离为h～6m,该距离随风速呈增大趋势;灌水停止4h后的土壤含水率的相关距离为5～6m,喷灌均匀系数对该距离无明显影响。田间试验还表明,喷灌洒水在土壤中的分布要比其在地表的分布均匀得多,土壤水分空间分布的均匀性主要取决于土壤初始含水率的均匀程度和灌水量。  相似文献   

浅论马鞍山地区的膨胀土     

简河清 《世界地质》1998,17(3):83-85

膨胀土由于粘土矿物含量较多,在一定气候条件下其体积随含水量的增加而膨胀,随含水一的减少而收缩,以膨胀土为地基的低层建筑物常常成群开裂,笔者首次报道了马鞍山地区的膨胀土,并对该区膨胀土的分布,成因,评价方法和防治措施等提出了初步看法。  相似文献   

土流变学研究现状与趋势   总被引：1，自引：0，他引：1  

王常明 《世界地质》1998,17(4):33-37

土流变学是研究土流变性的科学,包括宏观力学和微观结构两个研究方面。其中就这两方面阐述了国际土流变学的研究现状和我国土流变学研究水平,并对今后的研究趋势作了展望。  相似文献   

香港大屿山残坡积土的残余强度试验研究   总被引：8，自引：1，他引：7  

戴福初  李焯芬 《工程地质学报》1998,6(3):223-229

粘性土的残余强度是边坡稳定性评价、桩基与土的相互作用机理研究及填土边坡设计中的重要参数。本文在综述大量文献的基础上,结合香港大屿山火山岩风化残坡积土的残余强度试验研究,分析了残余强度的测试方法和影响残余强度的因素。研究结果表明,残余强度与有效法向应力间具有明显的非线性关系;与单剪测试结果相比,多级剪测试结果明显偏高。  相似文献   

A source of bias in rates of surface soil movement as estimated from marked particles     

Nel Caine 《地球表面变化过程与地形》1981,6(1):69-75

When estimated from measurements of introduced tracer particles, the rate of surface soil movement tends to be greater than the natural rate for equivalent particles on the same site. This consistent overestimation is greatest in the period following tracer introduction and leads to a measurement bias that may be as high as 300 per cent. The magnitude of the bias decreases with time, as the tracer is incorporated into the surface material, but remains detectable statistically for more than a year on some low-angle sites.  相似文献   

Dating of post-glacial landforms in the central howgills     

A. M. Harvey  F. Oldfield  A. F. Baron  G. W. Pearson 《地球表面变化过程与地形》1981,6(5):401-412

Little is known of Holocene landform development in Upland Britain. This paper describes a site at Middle Langdale in the Howgill Fells of Cumbria where large, but now stabilized and inactive gullies cut through periglacial material. At the base of the gullies large debris cones have buried earlier alluvial sediments on the valley floor. On these sediments and buried by the debris cones is a well-developed organic soil from which two ¹⁴C dates have been obtained in an attempt to estimate the age range of the soil. These dates range from 2580±55 years BP for the fine particulate fraction from the base of the organic horizon to 940±95 years BP for fossil rootlets from the uppermost organic layer, immediately below the overlying debris cones. The pollen evidence suggests that the valley floor site was initially dominated by alder carr and later by a Juncus marsh with birch, alder and hazel nearby. The pollen, from the surrounding upland area suggests woodland on the valley sides, dominated by oak and elm that was later replaced by a more open environment rich in heath species and in which disturbed ground species were present. The magnetic evidence indicates a stable local environment during soil formation but shows a sudden inwash of unweathered debris at the top of the buried soil. The evidence suggests that the valley floor was geomorphologically stable throughout the period of soil formation, although there was a local change in valley floor vegetation and a reduction of woodland cover on the valley sides at sometime during the period. The evidence then points to major geomorphological changes; a wave of soil erosion, gully development and debris cone deposition, perhaps following the Scandinavian introduction of sheep farming in the tenth century A.D.  相似文献   

农业气象试验站温室土壤温度控制系统     

马丽  万长健 《南京气象学院学报》1998,21(4):750-754

采用８０３１,８２７９,８２５５,ＡＤＣ０８０９,２８６４,６２６４等芯片组成一实用的温室土壤温度控制系统。由键盘输入温室土壤的上,下限温度,通过ＡＤＣ０８０９对温室土壤温度进行采样,并实时显示土壤温度。当土壤温度超越上,下限时,系统报警,并进行自动处理。  相似文献   

陆面生态过程的一维数值模拟     

杨志勇  朱平  蒋瑞宾 《气象》1998,24(4):3-10

建立了一个研究大气、植被、土壤相互作用的传播模式。模式是由多层大气模式、多层土壤模式和植被模式通过界面上能量、水汽传输平衡方程耦合而成。对植被和土壤的不同性质,进行了一系列的数值试验。结果表明,不同的植被覆盖以及降水等因子会对大气、植被、地表界面上能量、水汽传输以及热状态产生显著的影响。此模式还可以耦合进中尺度模式用以研究非均匀区域陆面过程和大气的相互作用。  相似文献   

小麦出苗至抽穗期土壤湿度预报及喷灌量计算     

辛玉善  杨锡勤  宋秀焕 《气象》1998,24(11):50-53

以黑龙江省８５０农场的资料进行分析,５至６月份小麦出苗、拔节至抽穗阶段,经常出现干旱,是需水关键期,对产量影响极大。所以利用麦田土壤湿度资料,建立经验公式,对土壤墒情进行预测预报,从而获得最佳喷灌时间及喷灌量,为节约用水、计划用水提供了可靠依据。  相似文献