Study On Dynamics In Rainfall Interception And Dissipation Of Urban Turf Canopy

Rainfall interception is an important process,which affects the distribution of rainfall and the water use in plants.This research focused on the processes of rainfall interception,leaf water absorption and desorption,and their impact factors in several cool-season turfgrasses.Results showed that:The processes of water absorption and desorption in the leaves of Perenial ryegrass(Lolium perenne L.),Kentucky bluegrass(Poa pratensis L.) and Tall rescue(Festuca arundinacea Schreb.)were rapid in the initial stage,slow in the later stage and stable in the end.Saturated leaf water content increased with specific leaf area(SLA) linearly.Leaf cell wall content:Kentucky bluegrass＞Tall fescue＞Perennial ryegrass;leaf cuticle thickness:Tall fescue＞Kentucky bluegrass＞Perennial ryegrass.Among the factors of rainfall intensity,rainfall duration,leaf angle and leaf area,leaf area had the greatest effect on rainfall interception of Kentucky bluegrass,Perennial ryegrass and Tall fescue, followed by rainfall duration;these three turfgrasses reached their maximum amount of interception at the lowest level of leaf angle and at the highest level of leaf area.The regression equation confirmed that rainfall intensity,rainfall duration,leaf angle and leaf area had significant effect on rainfall interception.Under different Rainfall duration,rainfall interception and absorption of both Tall fescue and Kentucky bluegrass increased along with the rise of rainfall;and rainfall absorption increased with the rise of rainfall interception linearly.Under different plant densities,rainfall interception and absorption of Tall fescue and Kentucky bluegrass increased along with the rise of plant densities;and rain absorption increased linearly with the rise of rainfall interception. Water contents in thatches of Kentucky bluegrass and Red fescue(Festuca rubra L.) water declined with the increase in the depth of water infiltration under different rainfalls.The treatment of Red fescue thatch consumed significantly more water and time than that of Kentucky bluegrass thatch and the treatment without coverage of thatch when runoff happened,and its infiltration depth was significant higher than the other two treatments.The moisture of soil covered by Red fescue thatch was always higher than the other two treatments in evaporation processes of soil moisture after different rainfalls.