Effects Of Mowing Management On Plant Community Structure And Soil Carbon Sequestration In Reed Wetland Of Yellow River Delta

The coastal wetlands of the Yellow River Delta are rich in vegetation resources of Phragmites australis.As the dominant species of coastal wetlands,Phragmites australis has a strong carbon sequestration capacity and important economic value and ecological functions.As a common management method of wetland reeds,mowing can promote the self-regulation and virtuous circle of plant communities,and mowing plays an important role in the growth and development of reeds,optimizing and improving the wetland ecological environment.Different cutting management methods will lead to differences in reed growth and reed community.However,at present,it is not clear about the influence of mowing management on reed community and soil carbon sequestration characteristics in the Yellow River Delta wetland.Therefore,this paper selects the reed communitythe in Yellow River Delta wetland as the research object,through field observatexperimentsment and indoor analysis,studies the effects of different cutting management methods on reed growth and plant community characteristics,clarifies the effects of cutting management methods on the content of carbon,nitrogen and phosphorus and stoichiometric ratio of reed,expounds the response of soil organic carbon components and enzyme activities in reed wetland to cutting management methods,and reveals the effects of cutting management methods on reed community and soil carbon fixation characteristics.Therefore,based on the field experiment of a 5-year cutting management experiment,the plant height,base diameter,aboveground and underground biomass of reed were measured through quadrat investigation,the relative frequency,relative covera,ge and important value of plant community were investigated,and the species diversity of plant community was calculated.The stoichiometry of reeds was measured by plant sample collection,and the effects of different cutting management methods on the stoichiometry of reeds were discussed.The effects of soil physical and chemical properties,soil organic carbon storage and components,and soil enzyme activity were determined by soil sample collection,and the correlation between soil physical and chemical properties,soil carbon components,and soil enzyme activity was analyzed to clarify the mechanism of soil carbon retention affected by different cutting management methods.The results were as follows:(1)Mowing management can effectively improve the coverage,density,base diameter,reed root,stem,and leaf biomass,and reduce the root-shoot ratio of reed.Among all treatments,the treatment of cutting in March but not returning to the field could significantly increase the basal stem,densit,y and root biomass the reed.These results indicated that cutting management could promote the growth of reed and effectively increase the biomass of reed.(2)The C content in the stem and leaf of Phragmites australis was not significantly affected by cutting,and the cutting management mode significantly increased the N and P contents in the reed root,stem,and leaf.Cutting management significantly reduced root c/n,c/p;The C/N ratio of that stemis reducede,and the C/P is remarkably reduced by the cut management mode in March;Cutting back to the field in December and cutting management in March reduced leaf C/N.The cutting management mode cay increase the content of N and P in the reed,stimulate the compensatory growth of the reed,increase the absorption capacity of plants for N and P,and promote the growth of the reed.(3)Cutting management changed the structure of the reed community and reduced the diversitythe of reed community,and increased the rimportancemportant value of reethe d in reed wetland and the coverage and densitythe of reed.The reduction of diversity was the smallest in the treatment of cutting without returning to the field,which maintained the species diversity of higher reed community than other methods.Cutting management in March could be used as a restoration or protection measure to maintain the diversity of the reed plant community and iitsease the importatoe of the reed plant community.(4)Cutting significantly increased the organic carbon in the 0–10-20 cm and 10–20 cm soil layers of the reed plant community and affected significantly the increase in the content of soluble organic carbon,microbial biomass carbon,particulate organic carbon and the proportion of organic carbon.The soil enzyme activity was significantly affected by the cutting treatment.The cutting and returning treatment had a significant positive correlation with the increase in soil sucrase,urease,and alkaline phosphatase.The increase in soil enzyme activity was conducive to the accumulation of soil organic carbon.These results indicated that reed-cutting management could be taken as an effective management measure to improve soil carbon sequestration of reed communities in coastal wetlands of the yellow river delta and provide a theoretical basis for the restoration and management of degraded wetlands.