杉木人工林水量平衡和蒸散的研究

 本文根据我们严密设计的小集水区径流场连续6年的水文测定数据，进行了杉木人工林水量平衡和蒸散的研究。结果表明：集水区年平均降雨量1065.5mm， 在林冠作用面降雨量的分配中，林冠截留雨量264.6mm，截留率24.8%；穿透过林冠层的雨量799.82mm，树干径流量1.08mm，分别占降雨量的75.1%和0.1%。林内降水到达林地时，在枯枝落叶层这个作用面上净降水进行再分配，其中，地表径流量9.27mm，地下径流量203.00mm，总径流系数0.199。土壤蓄水量月变化较大，但年变化很小，占降雨量的1.2%。系统水量最大的输出是蒸散，每年以气态形式返回大气的水量866.03mm，占降雨量81.3%。在蒸散的水量中，林冠截留雨量的直接物理蒸发量为264.6mm，占总蒸散量的31.6%。

STUDIES ON WATER BALANCE AND LAWS OF EVAPOTRANSPIRATION IN A CHINESE FIR PLANTATION

On the basis of the data collected from observation in six consecutive years water balance and evapotranspiration were studied. The results indicate that precipitation is 1065.5mm/year in the small watershed; that the crown-interception is 264.6mm/year, i.e. 24.8% of the total precipitation; that precipitation through crown is 799.82mm/year, i.e. 75.1% of the precipitation; that water stemflow is 1.08mm/year, about 0.1% of the precipitation; that water output in the form of runoff is 212.27mm/year of which the ground water is 203.00mm/year and surface runoff is only 9.27mm/year, thus total runoff coefficient is 0.199. On consecutive measurements of 6 years. The monthly change of soil moisture is great, but the change between years is only ±12.80, which is 1.2% of precipitation in the output of water from the ecosystem,evapotranspiration is greatest (866.03mm/year), which is 81.3% of precipitation. Of this amount,the evaporation crown-intercept is 264.6mm/year,about 31.6% of total evapotranspiration.