应用SWR技术研究垂柳茎体含水率

Measurement of Stem Water Content of Salix Babylonica Using Standing Wave Ratio Principle

应用驻波率(SWR)技术对垂柳茎体含水率进行了较长期的监测,验证了SWR技术可以用来定量监测乔木茎体的含水率。实验结果如下:①对垂柳茎体含水率的日变化观测结果表明,在晴天茎体含水率呈下降趋势,下降范围为7%～4%,下午又基本恢复到起始状态;阴雨天茎体含水率的日变化范围较小,为4%～2%;②茎体含水率季节性变化观测结果表明,垂柳茎体含水率具有周期性变化的规律,变化范围为18%～10%;③受根部土壤水分和叶片蒸腾耗水的均衡作用,垂柳茎体含水率基本保持在一定的范围内变化;④不同深度的土壤水分变化情况不同,深度为35cm的土壤传感器水分变化最剧烈,受降水、根系吸水和近地面空气层影响也最大,而离地表越深,土壤水分变化越小。

This paper studies the feasibility of measuring changes of the stem water content using SWR （Standing Wave Ratio, SWR） principle. In our experiment, salix babylonica tree was exposed to natural conditions. The results show that： （1） the diurnal change of the stem water content decreases from 7% to 4% in sunny days, and is recovered in the afternoon; while in rainy days the change is small, from 4% to 2%; （2） the seasonal change ranges from 18% to 10%; （3） the root-zone soil water content has a little influence on the stem water content; （4） the root-zone soil water content changes with the height from the surface of the root-zone soil.