Water vapour transport in a soil column in the presence of an osmotic gradient
Water vapour transport in a soil column in the presence of an osmotic gradient
复制标题
存在渗透梯度的情况下土壤柱中的水蒸气传输
DOI：
10.1016/j.geoderma.2017.11.031
复制
发表时间：
2018
期刊：
影响因子：
6.1
通讯作者：
H. Fujimaki
中科院分区：
文献类型：
--
作者：
S. M. Mahdavi;M. Neyshabouri;H. Fujimaki
在干旱半干旱区，由于水源获取和土壤盐渍化问题，农业向新区域的扩展受到了限制。了解地下土壤中水分和能量的运输过程对于理解这些地区农业实践对环境和经济的影响至关重要。本研究旨在：(a)评估水分、温度和渗透梯度下水蒸气运动对盐存在下水分和能量平衡的相对重要性；(b)评估估算30分钟间隔蒸发的温差法。试验在沙土柱中进行，土柱埋于田间，孔隙体积为50 g/L NaCl溶液灌溉。柱旁埋有3个风干沙地参考柱。土柱1、5、10 cm深度土壤含水量、温度、电导率以及土柱、风干土柱表面温度；并对5 cm深的气瓶进行温度监测。结果表明，近96%的蒸汽转移是由温度梯度引起的。虽然渗透效应对蒸汽运动的影响小于3%，但在目前的工作中仍然大于水分梯度效应。水汽通量对总水汽通量的贡献为5%。蒸汽通量输送的热量显著，在1 ~ 5 cm深度占总热流的45%，在5 ~ 10 cm深度高达30%。用微分法估算的累积蒸发量与能量平衡方程的观测值相差小于5%。
In arid and semi-arid regions because of water access and soil salinity problems extending of agriculture to a new area has been faced with restriction. Knowledge of the transport process of moisture and energy in subsurface soil is vital to understanding the environmental and economic impact of agricultural practices in these areas. This study was conducted to: (a) assess the relative importance of water vapour movement under moisture, temperature and osmotic gradients on moisture and energy budget in the presence of salts, (b) evaluate the temperature differential method to estimate evaporation in 30 minute interval. The experiment was conducted in a sandy soil column that was buried in the field and irrigated with a pore volume of 50 g/L NaCl solution. Three reference air-dried sandy soil cylinders were buried beside the column. Water content, temperature and electrical conductivity of soil water in depths of 1, 5 and 10 cm of the column as well as surface temperature of soil column and air-dried soil cylinders; and temperature of 5 cm depth in air-dried cylinders were monitored. The result showed that nearly 96% of vapour transfer was due to temperature gradient. Although the osmotic effect on vapour movement was less than 3%, nevertheless still was more than moisture gradient effect in current work. The contribution of the water vapour flux to the total moisture flux was 5%. The heat transported by vapour flux was significant and accounted for 45% of total heat flux in 1–5 cm depth and up to 30% at 5–10 cm depth. The observed difference between estimated cumulative evaporations using the differential method and energy balance equation was less than 5%.