The Response Of Functional Characters Of Main Species To Root Cutting And Fertilization Measures In Leymus Chinensis Mowing Steppe

In order to improve the environment of mowing grassland,it is necessary to take improvement measures for degraded mowing grassland.In this study,the typical degraded grassland was taken as the research object,and the improvement and cultivation measures of root cutting & fertilization were selected.The individual functional characteristics of the main population were taken as the evaluation index.By comparing with mowing,the improvement measures were evaluated,and the optimum cultivation technology of degraded grassland was found,which provided a scientific basis for the improvement and cultivation of degraded grassland.The main results are as follows:1.Root cutting & fertilization increased stem diameter,leaf nitrogen content and decreased leaf C/N of the three populations.Leymus chinensis reduced the total leaf length and number,Stipa grandis increased the clump width,and Cleistogenes squarrosa decreased the clump width and plant height.Root-cutting & fertilization measures restrain the negative effects of cutting by increasing the stem diameter of three main populations,while increasing the content of elements in plant stems and leaves,reducing the traits of whole plant,stem and leaf to regulate and maintain the above ground biomass of the population.Root cutting & fertilization reduced the stoichiometric characteristics of the main populations,indicating that the uptake ofnitrogen and phosphorus elements(N,P)in the main populations was promoted and the limitations of N and P were alleviated.2.The sensitivities of plant functional traits of L.chinensis population were enhanced by root cutting & fertilization,while those of S.grandis and C.squarrosa population decreased.Stem diameter was a sensitive index of cutting root &fertilization for L.chinensis and C.squarrosa populations,and total leaf length was a sensitive index for S.grandis population.3.Root cutting & fertilization can change the trade-off relationship of plant functional traits under mowing treatment.Under the treatment of root cutting &fertilization,the functional traits of the three populations were mostly synergistic,and the trade-off relationship was significantly increased under the treatment of mowing control.Under mowing,when the available resources of plants are limited,they will balance and allocate their functional traits.However,after root cutting & fertilization,the resource limitation was improved,and the relationship between traits was also changed.