冠层郁闭度对园林复合系统中草坪蒸散的影响

Effects of Canopy Density on Turf Evapotranspiration in Compound Garden System

[目的]为北方地区园林绿地草坪的节水灌溉提供依据。[方法]以纯草坪为对照,设置郁闭度梯度为T1（0.10-0.29）、T2（0.30-0.49）、T3（0.50-0.69）、T4（0.70-0.89）,研究冠层郁闭度对颐和园园林复合系统中草坪蒸散的影响。[结果]各处理草坪蒸散量的变化规律均呈双峰型曲线。4个郁闭度梯度处理的年蒸散总量与对照均存在显著差异（P〈0.05）,T3、T4差异不显著（P〉0.05）,表明随着郁闭度梯度的增大,草坪蒸散的差异性逐渐减弱。草坪蒸散总量与郁闭度呈指数关系,蒸散量随郁闭度的增加而降低。当郁闭度达到0.60以后,蒸散量的变化趋势相对减弱。[结论]草坪蒸散量随郁闭度的增加而逐渐减少,但当郁闭度达到一定值后这种趋势将相对减弱。

[Objective] The research aimed to provide basis for the water-saving irrigation of greenbelt turf in the gardens of northern China. [Method] With pure turf as CK,the gradients of canopy density of T1（0.10～0.29）,T2（0.30～0.49）,T3（0.50～0.69） and T4（0.70～0.89） were set up to study the effects of canopy density on turf evapotranspiration of the compound garden system in the Summer Palace.[Result] The change law of turf evapotranspiration in each treatment all showed the double-peak curve.The annual evapotranspiration in the treatments of 4 gradients of canopy density all had the significant difference with that of CK（P〈0.05）and the difference between T3 and T4 was not significant（P〉0.05）,which indicated that the difference of turf evapotranspiration was gradually weakened with the increasing of canopy density gradient.Turf evapotranspiration had an exponential relationship with canopy density and the evapotranspiration was decreased with the increasing of canopy density.After the canopy density reached 0.60,the change trend was relatively weakened.[Conclusion] Turf evapotranspiration was gradually decreased with the increasing of canopy density and this trend would be relatively weakened after the canopy density reached certain value.