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Inner Mongolia Agricultural University (内蒙古农业大学) 2021

Experimental Study on Carbon Isotope Characteristics of Different Plant Landscape Zones in Semi-arid Dune and Meadow

张苗苗

Titre : Experimental Study on Carbon Isotope Characteristics of Different Plant Landscape Zones in Semi-arid Dune and Meadow

Auteur : 张苗苗

Grade : Master 2021

Université : Inner Mongolia Agricultural University (内蒙古农业大学)

Résumé partiel
In order to study the characteristics of stable carbon isotope composition of the atmosphere,vegetation leaves and soil systems in the canopy of the semi-arid Sand Dune and meadow in different landscape zones and their responses to various influencing factors,in this paper,the stable carbon isotope technique was used to analyze five typical vegetation types,including semi-mobile Dune,Artemisia Halodendron,meadow corn and Reed,semi-mobile semi-fixed Dune and Caragana Microphylla Salix Gordejevii,comparing the changes of carbon content andδ13C value of each vegetation during the growing season,the effects of persistent drought and continuous rainfall on them,and using weather stations and other measured meteorological and soil environmental factors,the variation characteristics of stable carbon isotope of different vegetation and its response to influence factors were studied.The main results are as follows :(1)The range of δ13C value of Artemisia halodendron leaves in growing season is-29.62‰~-27.56‰,the range ofδ13C value of Caragana microphylla leaves is-27.33‰~-25.81‰,and the range ofδ13C value of willow leaves is-28.83‰~-25.57‰The range ofδ13C value of meadow maize leaves was-13.40‰~-12.29‰,and that of reed leaves was-27.94‰~-26.68‰,which indicated that maize was a C4 plant.The carbon content andδ13C value of leaves in different ages of vegetation were different.Compared with the old leaves and litter,the new leaves had stronger carbon fixation ability and higher water use efficiency.The carbon content of reed leaves was sensitive to the monthly average rainfall,and theδ13C value of five vegetation leaves was sensitive to the monthly average temperature and the monthly average rainfall.(2)The content of soil organic carbon in maize,Reed,Caragana Microphylla and Salix Gordejevii decreased with the increase of soil depth.The content of soil organic carbon was lower in late growth stage than in early growth stage and lower in middle growth stage than in meadow vegetation.Theδ13C values of 5 vegetation soils were all enriched with the increase of soil depth.Theδ13C values of corn,Reed,Caragana Microphylla and Salix Gordejevii soil were negative with the increase of soil water content,and the soil organic carbon content of meadow vegetation was greatly affected by soil water content,temperature and p H.

Mots clés : Stable carbon isotope ;Semi-arid dunes and meadows ;Water use Fficiency ;Soil organic carbon ;Environment factor ;

Présentation (CNKI)

Page publiée le 23 mars 2022