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Ningxia University (2018)

Canopy Hydrological Process of Caragana Intermedia in Desert Steppe

古君龙;

Titre : Canopy Hydrological Process of Caragana Intermedia in Desert Steppe

Auteur : 古君龙;

Grade : Master’s Theses 2018

Université : Ningxia University

Résumé partiel
The canopy precipitation redistribution,especially the stemflow enrichment effect,is an eco-hydrological process mechanism in which drought-bearing shrubs adapt to arid habitats.The study of the process and pattern of canopy precipitation redistribution by artificial desert Caragana trees in degraded desert grassland has important theoretical significance for elucidating the ecological and hydrological mechanism of maintaining the vegetation pattern of strip-like artificial Caragana intermediaunder the background of soil aridity.Morphological factors are usually the key factors that determine the redistribution and enrichment efficiency of canopy precipitation.From a practical point of view,morphological degradation is an external manifestation of degraded plantation associated with soil aridity ;whether and how this degradation affects the ecological and hydrological characteristics of the shrub,which has important research significance for the in-depth analysis of the stability maintenance mechanism of age plantation.In this study,the typical degraded shrubs of the strip-shaped artificial Caragana intermedia in desert steppe were selected as the object(degenerate group),and the natural shrubs of the adjacent natural scattered Caragana korshinskii community were used as the control(healthy group).Based on the comparative analysis of shrub morphological structure,the research work of the canopy precipitation and redistribution patterns,penetration rain and its spatial distribution,sap flow and its relationship with morphological factors,and stemflow hydrological statistical model construction were carried out respectively.The main findings and conclusions are as follows :(1)Morphological characteristics of Caragana intermediaCompared with the scattered middle caragana,the morphological degradation of Caragana intermedia is obvious.Statistical analysis showed that the crown width,base diameter,branching angle,branch length,leaf area,and crown area of Caragana intermedia in the degraded group were significantly lower than those in the healthy group,However,on the shrub scale,the diameter and number of branches were larger than that of the healthy group.The cluster analysis of the branch-scale morphological structure index factors showed that the 33 morphological and structural factor indicators of the healthy group can be generally divided into three categories,namely the overall branch attribute index,the graded branch attribute and the leaf component index group.The inverted trapezoidal structure parameters are related to various types of indicators,and are relatively decentralized,and have a high integrated indication value,which can be seen as a miniature of the entire branch.The degraded group can also be generally grouped into three categories,including the indicator of the internal structure of the branch,the leaf area group and the branch quantity index group.Relatively speaking,the effect of morphological degradation on the morphological structure of branches is still quite obvious:First,the connection between the twig members and leaf members is weakened.

Mots clés : Caragana intermedia; Canopy hydrological process; Stemflow hydrological model; Morphological degradation; Desert steppe;

Présentation (CNKI)

Page publiée le 16 mai 2019