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vol. 5, nr. 3 (2005)
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Distribution of thermal properties of soil in a field with black fallow and grass cover
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Bogusław Usowicz1, Wojciech Marczewski2
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1 Institute of Agrophysics, Polish Academy Sciences, ul. Doświadczalna 4, 20-290 Lublin |
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2 Space Research Centre, Polish Academy of Sciences, ul. Bartycka 18A, 00-716 Warszawa |
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vol. 5 (2005), nr. 3,
pp. 745-757
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abstract:
The paper presents the results of a study on the effects of soil compaction, water content and soil temperature on the spatial-temporal distribution of thermal conductivity, heat capacity and thermal diffusivity of soil. The study was conducted on a field with bare fallow and grass cover. The thermal properties were evaluated from basic, easily measurable physical properties of soil by means of a statistical-physical model of thermal conductivity and empirical formulas for thermal capacity and thermal diffusivity. The results indicate diverse character of the spatial-temporal changes on the thermal properties of soil in the bare fallow and under grass cover. Bare fallow tended towards a more uniform temporal and spatial (within the soil profile) distribution of the properties under study compared to the soil under grass cover. The impact of soil moisture on the thermal properties dominated over the contribution of bulk density. Plants had a significant effect on the thermal properties of soil, mainly in the subsurface horizon, through differentiating effect on soil water content. The effect of temperature on the thermal properties was much less significant than that of water content and soil density. The daily cycles of soil temperature were more pronounced in the thermal properties of the bare fallow field and the grass cover in the subsurface than the deeper horizons. The bare fallow showed less gradient of thermal properties with depth, however. The magnitude of cycling achieved maximum and minimum values around the time before sunrise and sunset, respectively, on the black fallow as well as on the grass.
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keywords:
bulk density, water content, temperature, thermal conductivity, heat capacity, thermal diffusivity, soil
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original in:
Polish
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