【摘要】 为了解南方红壤丘陵区樟树林地土壤水分变化规律,对0—100 cm不同深度的土壤水分与温度以及相应气象要素连续l年的观测,并基于土壤水分平衡法计算蒸散量,研究土壤水分的时空变化、蒸散量变化和对降水的响应。结果表明:(1)观测期土壤水分的季节变化可划分为丰水期(3—6月)、耗水期(7—10月)和补水期(11月—次年2月);(2)土壤体积含水量由浅至深表现为增长型,稳定性增强,且垂向变化具有显著季节差异;(3)非降水日林地蒸散量的季节变化表现为耗水期(3.28 mm/d)>丰水期(1.83 mm/d)>补水期(1.0 mm/d),蒸散量日内变化呈现白天强、夜间弱的特征,日蒸散量与日均气温、VPD、太阳辐射均呈极显著正相关;(4)土壤水分干季比湿季对降水响应更强烈,湿季9 mm、干季3 mm的降水使最大下渗深度达10 cm,土壤水分开始接受补给。林地土壤水分受降水和蒸散发影响,具有显著时空分异。更多还原

【Abstract】 To understand the dynamics of soil water in Cinnamomum camphora forest in the red soil hilly region of south China, soil moisture and temperature in 0—100 cm soil layer and meteorological factors were observed in the entire year. Evapotranspiration was calculated based on soil moisture balance method. The temporal and spatial variations of soil moisture, evapotranspiration and their response to precipitation were studied. The results showed that:(1) the seasonal variation of soil moisture during the observation could be divided into three stages, i. e. water-rich period(from March to June), water-consuming period(from July to October) and water-replenishing period(from November to following February);(2) soil bulk water content increased from shallow to deep, and its stability increased, and its vertical variation had significant seasonal difference;(3) the seasonal variation of forest land evapotranspiration in non-precipitation days decreased in the sequence: water-consuming period(3.28 mm/day)>water-rich period(1.83 mm/day)>water-replenishing period(1.0 mm/day); the diurnal variation was characterized as strong change on daytime and weak change at night. Daily evapotranspiration was significantly positively correlated with daily average temperature, VPD and solar radiation;(4) the response of soil moisture to precipitation in dry season was stronger than that in wet season; the precipitation of 9 mm in wet season and 3 mm in dry season made the maximum depth of infiltration reach up to 10 cm, and thus, soil moisture could be replenished. Soil moisture in forestland was significantly affected by precipitation and evapotranspiration, and presented the significant spatiotemporal distribution.更多还原