中子仪的标定及其在坡地土壤水分测量中的应用

Field calibration of neutron probe and its application in measuring soil water content on sloping land

介绍了野外标定中子仪的方法,并比较分析了中子仪测定结果与土钻烘干法所得结果的差异。结果表明:采用分层标定的方法能够取得很好的效果,坡地土壤可以分10cm、20～30cm、40cm三个层次进行标定;由于坡地土壤物理性质的空间变异性和微地貌的差异性,中子仪法测定结果与土钻烘干法测定结果具有一定的差异;在研究降雨入渗及土壤水分再分布规律时,最好选择其它表层测量精度较高的水分测定装置。

Neutron probe is appropriate equipment for measuring soil water content continually and dynamically. The method for field calibration of neutron probe was introduced and the results measured by neutron probe and oven drying methods were compared in this paper. The results showed that neutron probe could be well calibrated at different soil layers, such as at 10, 20-30, and larger than 40 cm layers, respectively. Soil water content measured with neutron probe was a little different with that measured with oven drying method, which was caused by the variability of soil physical properties and difference of micro-topography on sloping land. Other apparatus with higher precision was needed when soil water content at upper soil layers was measured during rainfall infiltration and soil water redistribution.