三峡库区茶园坡面土壤水分空间分布特征及对降雨补给的响应

利用高频率(5 min)的土壤水分探针和自动气象站监测三峡库区典型茶园坡面与林地坡面的土壤水分变化过程及其对降雨的响应,明确了林地和茶园土壤水分变化的规律,揭示了土地利用方式和微地形对土壤水分和降雨储蓄的影响机制。结果表明：(1)在时间上,茶园和林地土壤含水率随降雨量的变化而改变,土壤含水率随土层深度呈现“W”型和“S”型变化。土壤含水率年内变异系数随着土层深度的增加而降低,表层土壤(10 cm)含水率为中等变异水平(10%

Spatial Distribution Characteristics of Soil Moisture on Tea Garden Slope and Its Response to Rainfall Replenishment in the Three Gorges Reservoir Area

High frequency (5 min) soil moisture probes and automatic weather stations were used to monitor the soil moisture change process and its response to rainfall on typical tea garden slopes and woodland slopes in the Three Gorges Reservoir Area. The regularity of soil moisture change in woodland and tea garden was clarified, and the impact mechanism of land use patterns and microtopography on soil moisture and rainfall storage was revealed. The results indicated that:(1) The soil moisture of the tea garden and woodland varied with the rainfall, and the soil moisture of woodland and tea garden varied with the depth in W and S shape, respectively. The annual variation coefficient of soil moisture decreased with the increasing of soil depth. The change of water content was at moderate level (10% < CV < 100%) in surface soil (10 cm), while it was at a weak variation level (0< CV < 10%) in deep soil (20-120 cm). (2) Furthermore, the results of One-way ANOVA showed that sand content in tea garden was significantly greater than that in woodland (p<0.05), while the clay content was less than that in woodland. The specific surface area of sand particles was small, and the water retention was poor. Therefore, the water storage capacity of each slope of woodland was obviously greater than that of tea garden. (3) The influences of slope position on soil moisture in woodland and tea garden were similar. Specifically, the seasonal variation of soil moisture on upper slope was smaller than that on middle and lower slopes, and was most evident in the 80-120 cm soil layer. The water content of the 80-120 cm soil layer on the upper slope was relatively stable, while it changed dramatically on middle and lower slopes. The impact of slope position on water storage recharge was shown as the recharge amount on the lower slope was greater than that on the middle and upper slopes. (4) Pearson correlation analysis showed that the soil water supplementary amount and rainfall were in a significant (p<0.01) positive correlation in tea garden and woodland. And the linear regression results showed that the determination coefficient R was greater than 0.81 except for the upper slope of tea garden, indicating a good fit between soil water supplementary and rainfall. These results could provide reference for the rational utilization of rainfall resources on tea garden slopes and regional soil erosion control in mountainous and hilly areas.