【摘要】 为提高田间标定效率并减少土壤空间变异对标定方程的影响,利用时域反射仪来快速标定中子水分仪。埋设中子管时边钻孔、边观测土壤岩性,同时用TDR测体积含水量。用中子仪测放射性计数,测量计数除以标准计数得到计数率比,从而得到体积含水量与计数率比关系曲线。试验结果表明:①沙壤和粉沙可以使用同一个标定方程:y=41.989x+14.989,R2=0.8539;②容重不影响标定结果,但是0~30 cm深度不适合使用中子仪测量土壤水分;③研究区内埋深30 cm以下,使用TDR标定中子仪的标定方程为:y=53.139x+10.397,R2=0.968;④TDR适用性分析表明对于研究区内的沙壤和粉沙,TDR可以直接测定其体积含水量,适合对中子仪进行标定。因此,这是一种快速有效的田间标定中子仪新方法。更多还原

【Abstract】 To improve the efficiency of field calibration and reduce the effect of soil spatial variability to the calibration equation,the time domain reflectometry(TDR)is used to calibrate neutron Probe.When laying neutron tube with the spacing of 10cm,we drilled,observed the soil lithology and measured volumetric water content with TDR at the same time.Radioactive count is measured by the neutron probe,and the relationship curve between volumetric water content and count rate ratio can be obtained.The results show that,①sandy loam and silt share the same calibration equation: y = 41.989 x + 14.989,R2=0.853 9;② bulk density does not affect the calibration results,however,it is not suitable for the use of the neutron probe to measure moisture content of the soil at the depth of 0~30 cm;③below the depth of 30 cm,the calibration equation of the neutron probe using TDR isy=53.139 x + 10.397,R2=0.968;④ the applicability analysis of TDR indicates that the volumetric water content can be directly measured by TDR for the sandy loam and silt in the study area.TDR is fit for the calibration of the neutron probe.Therefore,it is a quick effective way to calibrate neutron probes in the fields.更多还原