Study On Root Characteristics Of Main Grassland Community In Loess Hilly Region

In this paper,the distribution characteristics of the root systems of the five major grassland plant communities,such as Thymus mongolicus Ronn community,Artemisia frigida Willd community,Potentilla acaulis L community,Stipa bungeana Trin community,Lespedeza davurica community,were studied in the area of the loess hilly region of Northwest China.The tensile strength of thyme community,Artemisia frigida community,Potentilla acaulis L community and Stipa bungeana Trin community was studied.This research provided reference for the restoration of grassland vegetation and slope protection in loess hilly areas,as well as the prevention and control of soil erosion in this area.The results showed that:(1)The root distribution of the Stipa bungeana Trin community and the Lespedeza davurica community was vertical.Thymus mongolicus Ronn,Artemisia frigida Willd,and Potentilla acaulis L community are horizontally distributed.(2)In all the five communities,the comparation between the total root biomass was as follow:sPotentilla acaulis L community>Artemisia frigida Willd community>Thymus mongolicus Ronn community>Lespedeza davurica community>Stipa bungeana Trin community.Among them,the root biomass of thyme,Stipa bungeana Trin and Lespedeza vurica community was mainly amassed in the underground 30 cm.The root biomass of Artemisia frigida Willd community and Potentilla acaulis L community is mainly concentrated in the underground 20 cm soil layer.The biomass difference in each community was not significant under 30 cm soil layer.The relationship between the soil depth and the root biomass of the five communities were showed a power function distribution.The natural logarithm of the soil depth of the five communities was linear with the natural logarithm of the root biomass.(3)Principal component analysis of root parameters showed that root surface area and root diameter were the parameters which affected the root configuration of Thymus mongolicus Ronn community and Artemisia frigida Willd community.The number of root bifurcations and average diameter are the main parameters affecting the root architecture of Potentilla acaulis L community.Root length and root surface area are the main parameters affecting the root architecture of Lespedeza davurica community and Stipa bungeana Trin community.In all the five communities,root biomass,root surface area and root length density reached extremely significant levels,and the three parameters were related in pairs.(4)The soil water content had obvious effects on the root parameters of Thymus mongolicus Ronn,Stipa bungeana Trin communities,but not on the Artemisia frigida Willd community,Lespedeza davurica community and the Potntilla acaulis L community.(5)In the Thymus mongolicus community,Artemisia frigida Willd community,Potentilla acaulis L community,and Stipa bungeana Trin community,the tensile strength of roots increased with the stronger root diameter,and the root strength of community decreased with the increase of stronger diameter..The tensile strength of the roots of the community is Thymus mongolicus community>Artemisia frigida Willd community>Stipa bungeana Trin community>Potentilla acaulis L.The comparation total roots pull were as follow:Potentilla acaulis L community>Artemisia frigida Willd community>Thymus mongolicus community>Stipa bungeana Trin community.