Mechanism of Evapotranspiration from Forest Floor based on Soil Moisture Changes and its Evaluation Method

基于土壤水分变化的林地蒸散机理及其评价方法

• 批准号: 10660141
• 负责人: TSUCHIYA Satoshi
• 金额: $ 2.37万
• 依托单位: Shizuoka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660141/
• 关键词: Evapotranspiration; Soil Column; Soil Moisture; Forest; Richards式; 体積含水率; 土壤水分; 林床面; ソイルカラム; リイルカラム; 土壌水分フラックス

This paper examines possible evaluations on the amount of evapotranspiration separately, based on evaporation experiments with an undisturbed soil column.To evaluate the amount of water movement during infiltrating and drying, experiments were performed by using a Kuroboku column picked out under undisturbed conditions on the forest. In the experiments, the pressure heads changes and water balance of the soil column were measured. In comparison with the measured and evaluated amount of water through the upper and lower boundary, the two were in close agreement. To estimate the surface evaporation and the water uptake by pseudo-root system separately, pressure heads in the undisturbed soil column with inserting pseudo-roots on the side were measured. In consequence, the sum of the decrease of volumetric water content in each layer was in good agreement with the loss in weight of the soil column. Evaporation from the top surface of the column was evaluated as the amount of the decrease o … More f volumetric water content in the 1st layer. Water uptake by pseudo-roots was evaluated as a sum of the decrease of volumetric water content from 2nd to 6th layers of the column. Secondly, evaporation from the top surface obtained by solving Richards' equation with the unsaturated flow analysis, was evaluated as the water flux through the top boundary of the column. Water uptake by pseudo-roots was calculated as the difference in the flux between upper and lower layer at the boundary. The sum of estimated amount of evaporation and water uptake by pseudo-roots was in good agreement with the loss in weight of the soil column. Finally, the unsaturated flow analysis applied to the soil moisture changes measured in the southwest slope of Mt. Fuji. As a result, the transpiration rate was evaluated 1.7 mm/day on the average. The evaporation rate from forest floor was evaluated 1.0 mm/day on the average, and the evapotranspiration rate by trees was estimated 2.7 mm/day by adding transpiration rate and evaporation rate. Less

本文根据不受干扰的土壤柱进行了蒸发实验，对蒸散量分别进行了对蒸散量的评估。要评估浸润和干燥过程中的水运动量，使用在森林中未经扰动的条件下采摘的kuroboku柱进行实验。在实验中，测量了压力头的变化，并测量了土壤柱的水平衡。与通过上边界和下边界进行测量和评估的水量相比，两者是密切一致的。为了分别估算伪根系系统的表面经济和水吸收，测量了不受干扰的土壤柱中的压头，并测量了侧面插入伪根的压力头。因此，每一层的体积水分含量的减少与土壤柱重量的减少非常吻合。评估了从色谱柱的顶部表面蒸发，以减少O的量。评估伪根的水吸收是从柱的第二层到6层的体积水含量减少的总和。其次，通过使用不饱和流量分析求解理查兹方程获得的顶部表面蒸发，评估为穿过色谱柱顶部边界的水通量。伪根的水吸收是在边界上上层和下层之间通量的差异。伪根的估计经济和水吸收量的总和与土壤柱重量的减少非常吻合。最后，不饱和流分析应用于富士山的西南坡度测得的土壤水分变化。结果，平均评估了1.7毫米/天的蒸腾率。森林地面的经济速率平均评估了1.0毫米/天，通过增加蒸腾速率和蒸发率，估计树木的蒸散率估计为2.7毫米/天。较少的

项目成果

柏原佳明、土屋智、逢坂興宏: "土壌カラムにおける蒸発量と擬似根系による水分吸収量の分離"中森研. 48巻. 191-194 (2000)

Yoshiaki Kashihara、Satoshi Tsuchiya 和 Okihiro Osaka：“土壤柱蒸发与假根系统吸水的分离” Nakamori Lab. 48. 191-194 (2000)