科尔沁草地棵间土壤蒸发

Research of Soil Evaporation of Horqin Grassland

利用小型Lysimeter对科尔沁草地的土壤蒸发（包括裸地土壤蒸发和棵间土壤蒸发）进行测定,并利用微气象观测获得相关气象数据,分析了气象因子对土壤蒸发的影响.研究结果表明,观测期间（5～9月）,裸地和棵间土壤蒸发随时间均呈减小趋势,裸地土壤蒸发高于棵间土壤蒸发;随着叶面积指数（LAI）增大,棵间与裸地土壤蒸发的比值（α）呈减小趋势,其回归方程为α=1-0.0306LAI1.2358;裸地土壤蒸发强度随光合有效辐射和净辐射的增大而按指数关系增大,且土壤含水量越高增大幅度越大;相关分析表明,土壤蒸发与饱和水汽压差、光合有效辐射、净辐射、风速极显著相关;逐步回归分析得到棵间土壤蒸发和裸土蒸发、叶面积指数的线性回归关系,回归方程是Eg0.510Ec-0.320LAI＋1.151.

Micro-lysimeters was used to measure soil evaporations of Horqin grassland （including e- vaporations of bare soil and under grass soil）. Meteorological data were measured synchronously, influence of meteorological factors on soil evaporation was analyzed. The results showed that the soil evaporations decreased with time and the evaporation of bare soil was higher than that under grass soil during the obser- vation period （May to September）. With the leaf area index increasing, the ratio a of soil evaporation under grass to bare soil evaporation decreased and was less than 1, and the regression equation was a= 1--0. 0306LAI. Bare soil evaporation intensity increased with photosynthetic active radiation or net radiation, fitting expo- nential relationships, and the more soil moisture, the greater the increment. Correlation analysis showed that soil evaporation was significantly correlated to vapor pressure difference, photosynthetic active radia- tion, net radiation as well as wind speed. By stepwise regression analysis, linear relationship between soil evaporation under grass and bare soil evaporation and leaf area index was found and the regression equation was Eg=0. 510Ec-0. 320LAI＋1. 151.