Monitoring of matrix flow and bypass flow through the subsoil in a volcanic ash soil
Monitoring of matrix flow and bypass flow through the subsoil in a volcanic ash soil
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DOI：
10.1080/00380768.2000.10409131
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发表时间：
2000-09-01
影响因子：
2
通讯作者：
Sakayori, T
中科院分区：
文献类型：
--
作者：
Hasegawa, S;Sakayori, T
利用达西定律计算了火山灰土壤中 1 米深度的每日基质流量，使用达西定律计算了未受干扰岩心样品的不饱和导水率可以表示为土壤含水量的唯一函数。在玉米（Zea mays L.）大白菜（Brassica pekinensis Rupr.）田中，通过安装在90厘米和110厘米深度的张力计从土壤吸水力获得水力梯度，并通过时域反射计（TDR）从土壤含水量换算出水力电导率，全年每30分钟监测一次，用该方法获得的基质流量代替水平衡方程来估算旁路流量以及月和年蒸散量， 1997 年年降雨量为 989 毫米，蒸散量估计为 730 毫米，尽管半个齿轮期间出现向上的基质流，但 1 米深度的净基质流向下 164 毫米。年内两次暴雨期间，水平衡法确定的下降流量超过了下降基质流量，两次流量相差63毫米，被认为对应于旁路流量。绕流流量仅占年降雨量的6.4%。通过在田间应用非饱和达西定律，可以很好地监测基质流量，并通过引入水平衡方程来量化月蒸散量和旁路量。
Daily matrix flow at 1-m depth in a volcanic ash soil was calculated during a period of one year using Darcy's law, Unsaturated hydraulic conductivity of undisturbed core samples could be expressed as a unique function of the soil water content. Hydraulic gradient obtained from soil water suction by a tensiometer installed at 90- and 110-cm depths, and hydraulic conductivity converted from the soil water content by time domain reflectometry (TDR) were monitored every 30 min throughout a year in a maize (Zea mays L.) Chinese cabbage (Brassica pekinensis Rupr.) field, The matrix flow obtained by this method was substituted for the water balance equation to estimate the bypass flow, and monthly and annual evapotranspiration, Annual rainfall in 1997 was 989 mm and evapotranspiration was estimated to be 730 mm, Net matrix flow at 1-m depth was 164 mm downward even though upward matrix flow occurred during half of the gear. Downward flow determined by the water balance method exceeded the downward matrix flow during two heavy rain events in the year and the difference between the two flows was 63 mm, which was considered to correspond to a bypass flow. The bypass flow accounted for only 6.4% of the annual rainfall. Matrix flow was well monitored by the application of unsaturated Darcy's law in a field, and monthly evapotranspiration and bypass how could be quantified by the introduction of the water balance equation.