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Advances in heat‐pulse methods: Measuring near‐surface soil water content
Author(s) -
Zhang Xiao,
Ren Tusheng,
Heitman Joshua,
Horton Robert
Publication year - 2020
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.1002/saj2.20150
Subject(s) - gravimetric analysis , water content , soil water , soil thermal properties , volumetric heat capacity , soil science , environmental science , pulse (music) , materials science , heat transfer , heat transfer coefficient , field capacity , chemistry , geotechnical engineering , thermodynamics , optics , geology , physics , organic chemistry , detector
Soil water content (θ) influences physical, chemical, and biological processes in the soil. Near‐surface θ (<1‐cm depth) is particularly important for surface energy partitioning, but few techniques are available for near‐surface in situ θ measurements. Heat‐pulse sensors can be used to determine the soil volumetric heat capacity, which is linearly related to θ. Here we describe the principles and procedures of determining near‐surface in situ θ with a heat pulse sensor. The main limitations and potential errors associated with the method are also presented. When ambient soil temperature drift and the soil–air interface effects are addressed, the error in the heat‐pulse‐determined θ is greatly reduced. For an example, data series with θ data determined by gravimetric initial θ and heat‐pulse‐based change in θ (Δθ), results agree well with gravimetric θ values, yielding a coefficient of determination of 0.95. We conclude that heat‐pulse sensors are useful tools for continuously and nondestructively determining near‐surface θ of non‐shrink–swell soils.