关键词: 土壤水分, 麦田土壤－大气界面, 波文比, 水热传输, 土壤水势

Abstract: Soil-wheat-atmosphere continuum is conceptualized as the interface between soil and atmosphere in winter wheat field, with canopy and soil surface being top and bottom boundary respectively. The depth of the interface is defined as the function proportional to (green) leaf area index. Based on the experiments conducting at Luancheng Agro-ecologic Experimental Station, Chinese Academy of Sciences, from April to June, 1996, the effects of soil moisture and soil-atmosphere interface on water-heat transfer in winter wheat field are analyzed. Soil moisture plays an important role in latent and sensible heat transfer. The drier the soil, the higher the sensible heat flux and the smaller the latent heat flux, and vice versa. This feature is especially remarkable when soil is wet. When soil is very dry, the depth of the interface dominates the two ransfers. For soil heat transfer at land surface, the depth of the interface is a more prominent influential factor than soil moisture. The analysis shows that the relationship between leaf water potential and atmosphere potential with the soil moisture matric potential at 60 cm depth is closer than the relationship between the two potentials with the soil moisture matric potentials at the other depths of soil. The soil layer of top 60 cm is a good index to study the effects of soil moisture and soil-atmosphere interface on water-heat transfer. It is also shown that the change of soil moisture potential acts as a macroscope of the variation of the water movement within the interface and above the interface.

Key words: soil moisture, soil-atmosphere interface in winter wheat field, water and heat transfer Bownen Ratio, Soil moisture potential