Abstract:In order to study the effect of temperature changes on soil water characteristic curve, the water characteristic curves of red soil and paddy soil in South China were measured by high-speed centrifuge at 4, 12, 20, 28 and 36℃ respectively. The parameters were extracted by VG model, and the effects of temperature on soil equivalent pore size distribution, unsaturated hydraulic conductivity and water diffusivity were discussed. The results showed that the water contents of red soil and paddy soil decreased significantly with the increase of temperature under the same water potential (P<0.05), appearing as 4℃ > 12℃ > 20℃ > 28℃ > 36℃. The water holding capacity of red soil was significantly higher than that of paddy soil (P<0.05) at the same temperature. Under different temperature treatments, unsaturated hydraulic conductivity and water diffusivity of red soil and paddy soil showed the significant difference that the highest value was observed at 20℃ and the smallest at 36℃ (P<0.05), which indicated that the water conductivity and infiltration capacity of red soil were relatively optimal at 20℃. The unsaturated hydraulic conductivity and water diffusivity of red soil were lower than those of paddy soil at the same temperature. The saturated moisture content θs of red soil and paddy soil, the relative parameters of air intake value α, and the shape coefficient n all decreased slowly with the increase of temperature, and the fitting parameters were significantly different with the changes of temperature (P<0.05), which indicated that the parameters of soil water characteristic curve were sensitive to temperature. The results of this study could provide a reasonable reference for further exploring the effect of temperature on soil water holding capacity and water transport mechanism in southern China.