초록

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Abstract ▼ AI-Helper

Soil temperature is one of the important environmental factors which control all the physical, chemical and biological processes in soil including germination and root growth of plants and other organisms living in the soil ecosystem. Soil water and nutrient availability and mobility are temperature...

Soil temperature is one of the important environmental factors which control all the physical, chemical and biological processes in soil including germination and root growth of plants and other organisms living in the soil ecosystem. Soil water and nutrient availability and mobility are temperature dependent. Soil temperature change is depended primarily upon energy exchange in soil surface, meteorological variance and physical properties of the soils which are closely related to heat transfer mechanism. In this study physical properties including bulk density, soil texture and organic matter content were measured and thermal diffusivity on the soils was calculated. Soil samples from the 66 meteorological stations under the Korea Meteorology were collected and the physical parameters were measured. To obtain relationship between thermal diffusivity and soil water content a heat probe thermal diffusivity measurement apparatus was designed and used in this experiment. According to the survey on soil physicsal properties on the 66 meteorological stations, the 52% of the surface soil texture were sandy loam and laomy sand or sand, 38% were loam and silty loam, and 10% were clay loam and silty clay loam. The bulk density which was closely related with thermal properties showed average of $1.41g/cm^3$ for sandy soils, $1.33g/cm^3$ for loam and silty loam soils, and $1.21g/cm^3$ for clay loam and silty clay loam soils. The apparent thermal diffusivity of the upper layer from 0 to 30cm ranged from 1.16 to $8.40{\times}10^{-3}cm^3/sec$ with average of $3.53{\times}10^{-3}cm^3/sec$. The apparent thermal diffusivities of the Jeju soils of which organic matter contents were high and the bulk densities were low were near $2{\times}10^{-3}cm^3/sec$. The thermal diffusivity of snow measured in Chuncheon ranged from 0.822 to $2.237{\times}10^{-3}cm^3/sec$. The damping depth calculated from the thermal diffusivity ranged from 5.92 to 13.65cm for daily basis and 124 to 342cm for yearly basis. The significant regression equation to estimate thermal diffusivity with bulk density and soil water content was obtained by the heat probe in laboratory.