Comparative Study On Characteristics Of Water Physiological Ecology Of The Main Turf-weed Populations

There is an investigation of seasonal characteristics of ruderals inturf-grass—Violaprionantha,Digitaria ischaemum,Geranium sibiricumand Potentilla anserine, which in three different management levels lawnfrom April to November in 2005. From July to October in 2006, by usingthe diminutive evapo-pervasion, there is a study of fight a droughtcharacteristic of Viola prionantha and ruderals in durative droughtcondition. And we also make an analysis of effects for growth anddevelopment of turf-grass in different irrigation time.Extensive administer is a necessary condition of a mass ofViolaprionantha,Digitaria ischaemum and Geranium sibiricum's happen;Potentilla anserine is primary ruderal population in good manage levellawn(especially in ascendant irrigation condition).Poa pratensis is longer survival time than Violaprionantha underpersistent drought, soil water use method trends stable type, soil moisturecontent shows linear downward trend; Potentilla anserine and Geraniumsibiricum population are shorter survival time, soil water use methodtrends frequent consumption, soil moisture content shows decline concave curve; Digitaria ischaemum population is intermediate type.Three types of plant day transpiration in early survival days represent:frequent consumption＞intermediate type＞stable type, all populationstranspiration decrease and remain very low level survival late. Forvarious plants, utilization efficiency of soil moisture in different layersare: surface layer＞middle-level＞under layer, Which Potentilla supina,Potentilla anserina are better than Poa pratensis L. and Viola prionanthapopulation in three layers.Under the management of every 4 days irrigation frequency, all plantpopulations under drought stress suffer no or a little hurt. Under themanagement of every 8 days irrigation frequency, drought stress whichusually appears after irrigation for 4 to 5 days have different effects onthe four plants in summer. Symptoms appears earliest in the Poapratensia L. population under drought stress and which last for longest.All populations grow normally in autumn. Under the management ofevery 12 days irrigation frequency, they have serious effect on all the fourplant populations. The drought stress has a significant effect on the lesseffect on the Viola prionantha Bunge population. The coverage of Poapratensia L. population is less than 40％during the process. So wesuggest: every 4 days irrigation frequency is suitable in summer, every 8days irrigation frequency from the mid ten days of August to the mid tendays of September, after the mid ten days of September, every 12 daysirrigation frequency is suitable.