1) unsaturated soil hydraulic conductivity
非饱和土壤水力传导度
2) unsaturated conductivity
非饱和水力传导度
1.
A less laborious,and simpler technique for the determination of soil water characteristic curve and unsaturated conductivity is described.
介绍一种通过室内短柱蒸发试验测定原状土或扰动土土壤水分特征曲线和非饱和水力传导度的方法,该法需用的设备简单,测试容易。
3) soil unsaturated conductivity
非饱和土壤导水率
1.
In order to calculate the soil unsaturated conductivity of three different kinds of soil types on loess plateau under different temperature conditions,the quantitative experiments have studied the relations between characteristic curve and temperature factors, the relations between wetting front infiltrating speed,the water content of wetting front and average water content seperately.
为计算黄土高原3种土壤不同温度下的非饱和土壤导水率,采用土壤水分动力学方法和数值模拟,利用室内试验分别对3种土壤在不同温度下的土壤水分特征曲线,湿润峰下渗速率以及湿润峰湿度与湿润剖面平均湿度的关系进行了定量研究。
4) saturated soil hydraulic conductivity
饱和水力传导度
1.
The results show: ①In about 1 000-year chronological scale,the bulk density and the saturated soil hydraulic conductivity of the surface layer(0~20 cm) significantly reduced with the increase of land reclamation year,at the same time,soil porosity,stability of aggregates,silt content significantly increased.
结果表明:①在约1 000 a的时间尺度上,随绿洲土壤开垦年限的增加,表层(0~20 cm)土壤容重与饱和水力传导度随时间显著降低,与此同时,土壤孔隙度、团聚体稳定性、粉粒含量显著增加。
5) saturated hydraulic conductivity
土壤饱和导水率
1.
Bulk density,saturated soil moisture content,saturated hydraulic conductivity,and soil water characteristics are essential soil parameters related to infiltration,evaporation,soil erosion and pollutants movement.
土壤容重、土壤饱和含水率和土壤饱和导水率,以及土壤水分特征曲线是与土壤水分入渗、蒸发、土壤侵蚀及污染物运移有关的重要的土壤水分参数。
6) soil saturated hydraulic conductivity
土壤饱和导水率
1.
Effects of grassland vegetation restoration on soil saturated hydraulic conductivity in mountain area of southern Ningxia
宁南山区草地植被恢复方式对土壤饱和导水率的影响
2.
Effects of vegetation rehabilitation on soil saturated hydraulic conductivity in Ziwuling Forest Area
子午岭植被恢复对土壤饱和导水率的影响
3.
The soil saturated hydraulic conductivity Ks of BSC and three types of control(no any crust,physical crust and removed BSC) were measured by tension infiltrometer to explore the effects of BSC on soil water infiltration and conductivity.
结果表明:与无结皮土壤相比,两种类型生物结皮均可极显著降低土壤饱和导水率;与去除生物结皮土壤相比,两种类型生物结皮对土壤饱和导水率的降低均不显著;与有物理结皮发育的土壤相比,地表生物结皮对土壤饱和导水率的降低不显著,而地上生物结皮对土壤饱和导水率的降低显著。
补充资料:土壤水力传导度
土壤水力传导度
hydraulic conductivity of soil
土壤水力传导度的测定方法较多,饱和土壤的渗透系数常用达西试验装置测定。非饱和土壤水力传导度常用垂直土柱入渗法,水平短土柱法,瞬时剖面法等方法测定。但这些方法均假设土壤各向同性,故在田间运用中有一定的局限性。turang shull.chuandaodu土壤水力传导度(hydraulie eonduetivityof 5011)单位水力梯度下,土壤水流通量。其量纲为〔L尹‘〕,常用厘米/秒或米/日表示,亦称导水率,是分析土壤中水流运动的重要参数。 根据达西定律,一维垂直土壤水流运动方程为: ~,‘口功一一八戈胡— d之式中q为土壤水的通量;z为垂直坐标;0为土壤体积含水率;K(a)为土壤水力传导度,当土壤为非饱和时,为e的函数;当土壤饱和时,是与土壤含水率无关的常数,记作凡功为土壤的总水势,包括重力势和基质势两部分,即当之向下为正时: 梦一功m一之式中砂。为基质势。 在土壤处于饱和状态时,土壤水力传导度常称为渗透系数。由于土壤饱和时,所有孔隙都充满了水,且都可以导水,所以土壤的水力传导度最高。在非饱和土壤中,有些孔隙是充气的,土壤的横断面上导水孔隙减少,水力传导度降低。同时,在吸力增加时,最先排出的是大孔隙中的水分,其余土壤水分在较小孔隙中流动,而水在孔隙中流动的速度又是随孔径的减小而减小,因此,非饱和土壤水力传导度也随之降低。另外,当大孔隙中水排出后,它就成为水流流向相邻孔隙的障碍,这也是非饱和土壤水力传导度降低的一个原因。由于上述缘由,土壤水从饱和过渡到非饱和时,土壤水力传导度将急剧降低。当吸力从零增加到0.1兆帕(l巴)时,土壤水力传导度可以降低几个数量级(有时降低到饱和时数值的1/100000)。 土壤水力传导度与含水率或吸力有密切关系,以一个非饱和的水平土柱为例,当水流在吸力作用下流动时,若土柱两端的吸力水头保持恒定,则水通量是稳定的。若土柱很短,使两个观测点的距离较小,可计算出土样的某一平均吸力时的平均水力传导度(即 △X_,_,、,:.~一~__、.___、__.。。.___K-Q巍之。其中“肋水平距离,么瓜为两观测点的吸力差)。 在同一平均吸力时,通量与吸力梯度成正比。可是,通量和吸力梯度关系直线的斜率随不同的平均吸力而变(见图1)。在饱和土壤中则相反,土壤水力传导度一般不随水势或压力的数值而变。 不同质地土壤水力传导度与吸力的关系如图2所示。图2表明,虽然沙质土在非饱和时水力传导度Ksl高于粘质土饱和时的水力传导度K。2。
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