Studies On The Population And The Biomass Changes Of The Main Weeds In Zoysia Lawns Of Hefei

The difference of environmental conditions obviously affects the growth of weeds in lawns.Digitaria sanguinalis(L.) Scop.and Cyperus rotundus L.are the dominating weeds in the better managed lawns.Eleusine indica(L.) Gaertn.mainly grows in the badly managed lawns,and Irnperata cylindrica(L.) Beauv.var.major(Ness.) C.E.Hubb.mostly appears in the average-managed lawns.The tendencies of the quantity of the four kinds of weeds present the curves with" four-peak".The seasonal changes of population-quantity all take on four-peak curves.And the curves of Digitaria sanguinalis(L.) Scop and Eleusine indica(L.) Gaertn.are similar very much.According to the characteristics of density of seasonal fluctuations and the time in which weeds growth are in biggest density,the four kinds of weeds can be divided into two categories as following,(spring)summer type,including Digitaria sanguinalis(L.) Scop and Eleusine indica(L.) Gaertn.,and autumn type,including Irnperata cylindrica(L.) Beauv.var. major(Ness.) C.E.Hubb.and Cyperus rotundus L..The sequence of average size of four kinds of plants is Irnperata cylindrica(L.) Beauv.var.major(Ness.) C.E.Hubb.＞Digitaria sanguinalis(L.) Scop＞Eleusine indica(L.) Gaertn..The seasonal tendencies of changes of individual-biomass are all one-peak curves,These quence of average speed of three kinds of plants is Eleusine indica(L.) Gaertn.＞Digitaria sanguinalis(L.) Scop＞Irnperata cylindrica (L.) Beauv.var.major(Ness.) C.E.Hubb.The tendencies of the biomass and speed of diferent weeds have great diferences,which take on several aspects as follows:(1) The sequence of average root-biomass of is Irnperata cylindrica(L.) Beauv.var. major(Ness.) C.E.Hubb.＞Digitaria sanguinalis(L.) Scop＞Eleusine indica(L.) Gaertn.. The seasonal tendencies of changes of root-biomass of three kinds of weeds are double-peak curves,which are similar very much.The sequence of average speed of three kinds of plants is Digitaria sanguinalis(L.) Scop＞Eleusine indica(L.) Gaertn.＞Irnperata cylindrica(L.) Beauv. var.major(Ness.) C.E.Hubb..(2) The sequence of average stem-biomass is Digitaria sanguinal is(L.) Scop＞Irnperata cylindrica(L.) Beauv.var.major(Ness.) C.E.Hubb.＞Cyperus rotundus L.＞Eleusine indica (L.) Gaertn..The seasonal tendencies of changes of stem-biomass of four kinds of weeds are all one-peak curves.The sequence average stem-speed of three plants is Digitaria sanguinalis Cyperus rotundus L.＞(L.) Scop＞Eleusine indica(L.) Gaertn.＞Irnperata cylindrica(L.) Beauv.var.major(Ness.) C.E.Hubb..(3) The sequence of average biomass-leaf of is Digitaria sanguinalis(L.) Scop＞Irnperata cylindrica(L.) Beauv.vat.major(Ness.) C.E.Hubb.＞Cyperus rotundus L.＞Eleusine indica (L.) Gaertn..The seasonal tendencies of changes of leaf-weight four kinds of weeds are all one-peak.The squence of average growth-speed of leaf is Eleusine indica(L.) Gaertn.＞Digitaria sanguinalis(L.) Scop＞Irnperata cylindrica(L.) Beauv.var.major(Ness.) C.E. Hubb.＞Cyperus rotundus L..(4) The sequence of average organ-biomass of four kinds of plants of sexual propagation is Cyperus rotundus L.＞Irnperata cylindrica(L.) Beauv.var.major(Ness.) C.E.Hubb.＞Digitaria sanguinalis(L.) Scop＞Eleusine indica(L.) Gaertn.,The tendencies of seasonal changes of organ-biomass of Digitaria sanguinalis(L.) Scop,Eleusine indica(L.) Gaertn., Irnperata cylindrica(L.) Beauv.vat.major(Ness.) C.E.Hubb.,Cyperus rotundus L.are all one-peak.Functions of seasonal dynamics of nutrient allocation among organs of different popolations is:(1) Digitaria sanguinalis(L) Scop.y _根=0.339538487-0.8273342152x _穗,y_根=0.455053202-0.8636854907x_叶,y _茎=0.378605949-0.16744949538x _穗(2) Eleusine indica(L.) Gaertn.y _根=0.389936403-0.7818950167x _穗,y _茎= 0.502711765-0.7384835593x _叶,y _茎=0.370096921-0.3554469183x _穗(3) Irnperata cylindrica(L.) Beauv.var.major(Ness.) C.E.Hubb.y _根= 0.498725700-1.1826991880x _穗,y _根=1.147325934-3.339585457x_叶,y_叶= 0.2186300829+0.22891832719x _穗(4)Cyperus rotundus L.y_根=1.014997930-2.4428941448x _{穗花果},y_叶=-0.01496290351+1.4428061850x _叶,y_根=0.879061130-1.4474956236x_叶The patterns of biomass allocation of four kinds of plants and their seasonal variation are largely diferent and every planth are o bvious characters.The sequence of allocation of nutrient matter of above-ground nutrient organ is Digitaria sanguinalis(L.) Scop(62.98%)＞Eleusine indica(L.) Gaertn.(57.33%)＞Irnperata cylindrica(L.) Beauv.var.major(Ness.) C. E.Hubb.(54.08%).