干旱区农田土壤水分地温变化规律及其相互关系

The variation rule and interrelationship of farmland soil moisture content and ground temperature in arid areas

以干旱区农田灌溉后土壤水分、地温实测数据为基础,研究了其土壤水分、地温各自的变化规律及两者的相互关系。结果表明,各层含水量之间具有高相关性,基本达到了极显著的水平。这与土壤水分灌溉时由上而下的逐渐下渗,以及蒸发时由下而上的逐层上升有密切的关系。各层地温间的相关性大,除地面温度外,其余各层地温间的相关水平为显著或极显著水平,且相邻土层地温间均呈极显著相关。土壤水分及地温剖面垂直变化特征明显,并具有动态性。土壤水分含量大时,两者的垂直变异系数小,反之变异系数大。0～20 cm、地面(0 cm)分别为剖面含水量及地温变异强度的最大层,属中等变异强度。土壤水分及温度之间的负相关性明显。地面温度是预测表层、底层土壤水分的良好指标,利用回归分析法建立的土壤水分与地温间的函数关系可为推测土壤水分提供依据。

Based on the data of irrigated farmland soil moisture content and ground temperature,this paper studied their variation rules and coupling relationships.The results showed that soil moisture content of each layer correlated significantly because the soil water infiltrated from top to bottom layer by layer when irrigation,and reversed when evaporation.The correlation of each layer ground temperature was obvious.Except for land surface temperature,ground temperature of soil layers had significant correlations especially the adjacent soil layers.The vertical variation characters of soil moisture content and ground temperature were distinct and dynamic.When it comes to high soil moisture content,their vertical variation coefficient was small;however variability became bigger when soil moisture content decreased.Both of the land surface ground temperature and soil moisture of 0～20 cm soil layer had middle variation,which is the highest variation of ground temperature and soil moisture content.Soil moisture content and ground temperature had obviously negative correlation.Land surface temperature was a good factor to forecast soil moisture content of the top and bottom soil layer.The linear regression equation of soil moisture content and ground temperature could be helpful for soil moisture content forecasting.