Application of Cosmic-ray Neutron Method in Soil Moisture Measurement on Complex Underlying Surface

doi:10.3969/j.issn.1000-6362.2020.01.004

Abstract

Abstract: The cosmic-ray neutron method is a mesoscale and non-contact method for measuring soil moisture with the observation scale as between point measurement and remote sensing monitoring. The measuring point was located on the mountainous terrain with significant soil heterogeneity. This study used the cosmic-ray neutron method under complicated terrain as the oven-drying method being the standard comparison, while the frequency domain reflection method being the continuous comparison. This study indicated that the result of the cosmic-ray neutron method is accurate on complex underlying surface. The determination coefficient of linear equation（R2）, root-mean-square error（RMSE）, Nash-Sutcliffe efficiency coefficient（NSE）between the value of soil moisture content measured by the cosmic-ray neutron method and the truth value represented by the multi-point mean value of the oven-drying method was 0.8717, 0.0159kg·kg-1 and 0.854, respectively. The cosmic-ray neutron method and the frequency domain reflection method were completely consistent with the trend of soil moisture change in a longer time series, and the sensitivity of the cosmic-ray neutron method was better than the frequency domain reflection method in response to changes of soil moisture caused by precipitation. In summary, the cosmic-ray neutron method can be applied to soil moisture measurement on complex underlying surfaces with the advantage of being undisturbed by soil heterogeneity and higher ability on reflecting the average soil moisture on the mesoscale.

Key words: Complex underlying surface, Cosmic-ray neutron method, Oven-drying method, Frequency domain reflectometry, Soil moisture

WU Qiang，HE Kai-li，LUO Zi-zi，DU Ai-jun，LIU Liang，TANG Yun-hui. Application of Cosmic-ray Neutron Method in Soil Moisture Measurement on Complex Underlying Surface[J]. Chinese Journal of Agrometeorology, 2020, 41(01): 34-42.

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