Eco-hydrological effect of the canopy,litter and soil of a eucalyptus plantation in South China

The hydrological function is one of the important ecological functions of forest.To understand the eco-hydrological effects of eucalyptus plantation,we studied the canopy interception,rainfall redistribution and water-retaining capacity of litter and soil based on fixed field observation and measurement of laboratory in Gaoyao,Zhaoqing City,Guangdong Province,China.The results indicate that among the cumulative gross rainfall(2016.7mm)generated during the period from Apr.2006 to Apr.2007,throughfall,stemflow and canopy interception account for 85.70%(1728.4mm),3.62%(72.9mm),and 10.68%(215.4mm),respectively.The stemflow can be produced only when the precipitation is more than 3.93 mm.The throughfall and stemflow are distinctly positive related to the precipitation(P0.01)and the values of the interception ratio to gross rainfall have a distinctly negative relationship to the precipitation(P0.05).The value of interception ratio to gross rainfall keeps generally steady when the precipitation is more than 20 mm.The results also show that the water-capacity of litter is 4.27mm,and among the total 4.27mm,the capacity from the part of leaves(2.54 mm)is the best among all kinds of components of litter.The maximum water-capacity of the soil layer from 0 to 100 cm depth is 470.06 mm,and the non-capillary water-capacity accounts for 20.90%(98.22mm)of the total.Both of the total and non-capillary porosities show a decreasing trend with the increasing of soil depth.The initial and steady infiltration rates in the surface(0-10 cm)are 25.03 mm·min-1 and 8.83 mm·min-1 respectively,and also decrease with the increasing of soil depth.