Study On Rainfall Interception Capability Of Three Turfgrasses In Beijing Region

Rainfall interception by the turfgrass has important effect on water use efficiency, lawn maintenance and management. In this paper, the interception capability of three turfgrasses was measured through wet-absorption method and simulation method, and based on the grey system theory, a grey correlation analysis on factors influencing interception was made. The result showed that:Both leaf area and leaf number had remarkably effect on the canopy interception for the individual grass. The canopy interception and interception rate increased with the mowing height. the capability of canopy interception was Festuca arundinacea> Poa pratensis> Zoysia sinica Hance. For Zoysia sinica Hance and Poa pratensis, the interception varied from different turf established years, the difference between growth years was significant with increased mowing height(P<0.05),but it had an insignificant effect on Festuca arundinacea.The turfgrass which grow many years is particularly easy to form thatch, and thatch has great capability to intercept water. The thickness of Poa pratensis thatch reach to 1.96cm, the interception can reach to 10.1mm; the thatch of Festuca arundinacea only 0.78cm,but it can intercept 3.8mm water. The ratio of thatch and canopy interception of Zoysia sinica Hance, Festuca arundinacea and Poa pratensis was 7.04, 2.97, 9.42. For the whole turfgrass,the capability of three turfgrass interception was Poa pratensis>Zoysia sinica Hance>Festuca arundinacea.Under the same condition, the interception decreased with increasing rainfall intensity, Compared with strong precipitation, the turfgrass can intercepted much water under little intensity precipitation. In the process of one rainfall the thatch can divided into three section: The quickly changing phase(The interception increased rapidly with the rainfall increasing), the gradually changing phase(the increasing trend slowed down),and the stationary phase(the interception keep stable with increasing rainfall).A grey correlation analysis on factors influencing turfgrass interception was made. For Zoysia sinica Hance, the influencing priority of analyzed factors was rainfall intensity> temperature > precipitation>wind speed. For Festuca arundinacea, the priority was rainfall intensity> temperature = wind speed> precipitation. For Poa pratensis, the priority was rainfall intensity> temperature >precipitation >wind speed.