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Northwest A&F University (2020)

The Dynamic of Soil Water and Shelterbelt Plants Photosynthetic and Stem Flow under Saline Drip Irrigation in Taklamakan Desert


Titre : The Dynamic of Soil Water and Shelterbelt Plants Photosynthetic and Stem Flow under Saline Drip Irrigation in Taklamakan Desert

Auteur : 刘娇;

Grade : Doctoral Dissertation 2020

Université : Northwest A&F University

Résumé partiel
Artificial vegetation planting is one of the most effective methods for ecological reconstruction and desertification control in sand areas.Water is a key factor affecting the structural stability and maintain normal function of desert ecosystems,and also the biggest limiting factor of restricting vegetation growth.It plays an important role in wind sheltering and sand fixation.In the soil-plant-atmosphere continuum(SPAC),transpiration is the main route for plant water dissipation,participates in and affects the material cycle and energy flow of the ecosystem,and is influenced by biophysical and environmental processes at the interface between soil,vegetation and atmosphere.As a basic unit of physiological metabolism and substance accumulation,photosynthesis is sensitive to changes in the external environment and is an important link in analyzing the response of plant growth and metabolism to the environment.The Taklamakan Desert,located in northwest China,is the second most mobile desert in the world.The Desert Highway Shelterbelt through it can effectively prevent and control sandstorm erosion.This study was located in the hinterland of the Taklamakan desert.Field water control experiments were used to study 1)the soil moisture dynamics of the shelter forest under different irrigation treatment ;2)Transpiration characteristics and water use characteristics of Calligonum mongolicum(C.)and Haloxylon ammodendron(H.)under different irrigation treatments ;3)Photosynthetic adaptation mechanism of Calligonum mongolicum and Haloxylon ammodendron under different irrigation treatments ;4)The suitability and feasibility of water-saving irrigation system for the shelterbelt in the Taklamakan desert.The results are :(1)The soil moisture dynamicsAt the vertical depth,the 0-100cm soil layer can be divided into three layers according to the change characteristics of soil water content,the soil water rapid layer(0-30cm),the middle variable layer and the relatively stable layer.The lower limit of the middle variable layer and the upper limit of the stable layer are closely related to the irrigation amount,plant type and plant root growth condition,and should be distinguished according to the actual situation.In terms of time scale,the change of soil moisture in shallow layer(0-60 cm)after irrigation can be divided into rapid decline period(1-9 d),slow decline period(9-19 d)and relatively stable period(19-39 d).After irrigation,the soil moisture content in 60-200 cm decreased slowly,and the rate of decline were significantly lower than that in the depth of0-60 cm.Soil moisture under 200 cm had replenishment to the soil moisture in the 60-200cm range.The water storage capacities of 0-100 cm soil were in cubic polynomial relation with the number of days 1-9 days after irrigation,and the fitting results R2 were all above0.88.From the average water content of 0-300 cm in the soil from May to September,the soil moisture content planting C.and H.under the 10-day irrigation cycle were W3>W1>W2,under the 20-day and 40-day irrigation cycle were W3>W2>W1.Irrigation amount,plant type,atmospheric factors,plant root growth status et al.all have an impact on soil water change.In May to July,plants grew rapidly and air temperature increased gradually,which belongs to the net consumption period of soil water ;in July to September,plant growth rate slowed down and temperature decreased,which belongs to the net storage period of soil water.

Mots clés : The Taklamakan desert road shelter; Calligonum mongolicum; H.ammodendron; Saline drip irrigation; Water stress; Soil moisture dynamics; Soil storage; Photosynthetic; Stem flow;

Présentation (CNKI)

Page publiée le 9 juin 2021