长武塬区农田生态系统土壤热状况变化特征  

Variation Characteristics of Soil Thermal Regime in the Agricultural Ecosystem of Changwu Tableland

作　　者：王春风[1] 刘文兆[1,2] 朱元骏[2] 韩晓阳[3] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]中科院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100 [3]西北农林科技大学林学院,陕西杨凌712100

出　　处：《中国农学通报》2011年第18期130-134,共5页Chinese Agricultural Science Bulletin

基　　金：黄土高原土壤侵蚀与旱地农业国家重点实验室专项经费项目(10502-Z10;10502-Z10-1)

摘　　要：利用2008年长武塬区典型农田生态系统土壤热状况和太阳辐射观测资料,研究分析了地表反照率、土壤温度梯度、土壤热通量的变化特征以及热通量与净辐射之间的关系。结果表明:(1)各深度温度最小值出现在2月,2、10、20cm深度处在7月达到最大值,40、80cm深度处在8月达到最大值,冬季冻层深度达30cm多;(2)温度梯度方向分别在2—3月间和8—9月间发生改变。热季土壤温度梯度方向向下时,2～10cm平均梯度大于2～80cm平均梯度,两者均在5—6月间达到最大。冷季土壤温度梯度向上时,2～10cm平均梯度小于2～80cm平均梯度,两者均在11月下旬达到最大;(3)土壤热通量月变化趋势与土壤温度梯度变化趋势正好相反;(4)地表反照率在1月达到年最大值0.66,3—9月变化不大,在9月份达到最低值0.14,从10月份开始,上升趋势明显;(5)净辐射日变化可分为净辐射持续增强和减弱两个时间段,同一辐射强度对应的土壤热通量值相差较大,土壤热通量延迟不明显。增强时段净辐射与热通量的相关性(R2=0.76)小于减弱时段的相关性(R2=0.79)。In this study,the characteristics of soil albedo,soil temperature gradient,soil heat flux and the relationship between soil heat flux and net radiation were investigated based on the data of soil thermal regime and solar radiation in the typical agricultural ecosystem of Changwu Tableland in 2008.Results indicated that （1） the minimum temperature at different depths occurred in February,whereas the maximum temperature at the depths of 2,10,20 cm occurred in July and at the depths of 40,80 cm,in Aug.Frozen layer may come to the depth of 30 cm in winter.（2） The direction of temperature gratitude was inverted between February and March and between August and September,respectively.The average temperature gratitude in the layer of 2-10 cm was much higher than that in the layer of 2-80 cm and both of them reached the maximum between May and June.In the cold months,the temperature gratitude of the two layers increased to the maximum at the end of November.（3） The change tendency of soil heat flux was opposite to that of soil temperature gratitude.（4） Soil albedo reached the maximum value of 0.66 in January,kept steady between March and September,and decreased to the minimum value of 0.14 in September.After that,soil albedo was enhanced obviously.（5） The daily change of net radiation may be divided into two stages：continuous increase stage and continuous decrease stage.The values of soil heat fluxes with the same radiation intensity were different and the delay of soil heat flux was not evident.The correlation coefficient （R 2 =0.76） between soil heat flux and net radiation during continuous increase stage was less than that （R 2 =0.79） during continuous decrease stage.

关 键 词：温度梯度 土壤热通量 反照率 净辐射 

分 类 号：S161.2[农业科学—农业气象学]