摘要
双环入渗仪在测定田间土壤饱和导水率时被广泛采用。本文采用不同直径的双环入渗仪(内环直径分别为20 cm、40 cm、80 cm和120 cm)和不同的内外环直径比,即不同的缓冲指标(0.2、0.33、0.5和0.71),进行了16组定水头积水入渗试验,研究了双环入渗仪缓冲指标对土壤饱和导水率测定的影响。结果表明:内环直径较小的入渗仪,其累积入渗过程曲线的分布较分散;随着入渗环直径逐渐增大,分散范围逐渐缩小。另外,随着缓冲指标的逐渐增大,测定的土壤饱和导水率并没有明显的增大或减小趋势,但内环直径20 cm的入渗仪测定的土壤饱和导水率的波动最大,而80 cm和120 cm内径的双环入渗仪测定的土壤饱和导水率最稳定,并且始终非常接近。因此,相对于双环入渗仪内环大小或土壤非均质性的影响,双环入渗仪的缓冲指标对于土壤饱和导水率测定的影响要小。
The double-ring infiltrometer is widely used to measure soil saturated hydraulic conductivity. To investigate effects of ratio of the outer to the inner rings, i.e. the buffer index of double-ring infihrometer, on measurement of saturated hydraulic conductivity, 16 sets of field experiments were laid out and conducted using 16 double-ring infiltrometers with 4 inner-ring diameters （20 cm, 40 cm, 80 cm, and 120 cm） and 4 buffer indices （0. 2, 0.33, 0. 5 and 0.71）. Results show that uncertainty of the measured saturated hydraulic conductivity decreased with increasing diameter of the inner-rings. Saturated hydraulic conduetivities in the infiltrometers with an inner-ring diameter of 20cm varied in a broad range, while those in the infihrometers with inner-ring diameters of 120cm and 80cm were always close to each other and less in variation. However, no rising or falling tendency was observed for the increasing buffer indices. It is concluded that the inner-ring diameter is a more important factor to be considered than the buffer index in practice, and a larger innerring diameter, such as 80cm, is proposed as a lower limit of the inner-ring size to obtain reliable in-situ measurement of hydraulic conductivity.
出处
《土壤学报》
CAS
CSCD
北大核心
2010年第1期19-25,共7页
Acta Pedologica Sinica
基金
国家自然科学基金项目(No.90502005)
科技部863项目(No.2007AA10Z223)
中国科学院生态系统网络观测与模拟重点实验室开放基金(LENOM07YC-04)资助
关键词
土壤
饱和导水率
双环入渗仪
缓冲指标
Soil
Saturated hydraulic conductivity
Double-ring infiltrometer
Buffer index
