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Northwest A&F University (2019)

Effects and Mechanism of Soil Carbon and Nitrogen Sequestration Following Desertification Reversion in MU US Sand Land

Effects and Mechanism of Soil Carbon and Nitrogen Sequestration Following Desertification Reversion in MU US Sand Land

Titre : Effects and Mechanism of Soil Carbon and Nitrogen Sequestration Following Desertification Reversion in MU US Sand Land

Auteur : 哈斯尔;

Grade : Master’s Theses 2019

Université : Northwest A&F University

Résumé partiel
Desertification is one of the most serious types of land degradation phenomenon in the world at present,a lot of vegetation reconstruction and ecological restoration project had been launching in everywhere,it has an important theoritical and practical significance for understanding,practice and evaluation of desert area to explore the effect of the reversal process and mechanism.As the component of soil fertility,organic carbon and nitrogen can indicate the effect and mechanism to the restoration and desertification land management.Consequently,based on long-term field tracking survey,this article selects the typical desertification in Yulin Hongshixia sandy lands-semifixed lands-fixed lands which recovery year of 20a,30a,51a of shrubs and trees as the research object.In the process of reverse recovery of desertification,analysis of soil composition were carried out indoor,we have a research of the changes of soil total organic carbon,nitrogen,sand,silt,clay with combined organic carbon,total nitrogen,light fraction and heavy fraction with carbon nitrogen,active oxide organic carbon with the extension of projects in the recovery evolution of the characteristics,retaining ratio as well as different carbon and nitrogen components decomposition resistance stability,reveals the effect and mechanism of soil carbon and nitrogen fixed sandy in the the process of desertification reversion in study area.The main results were getted following :(1)soil total organic carbon content in 05cm of 51a shrub and 51a tree are respectively 10.7 and 11.3 times than flow sand,9.0 and 9.2 times in nitrogen.At the same time,soil total organic carbon content of different recovery year in 05cm is 1.93.4 times than in 510cm and 1020cm soil layer,1.84.0 times in tree ;soil total nitrogen content of different recovery year in 010cm is 2.24.7 times than in 1020cm soil layer,2.53.9times in tree.According to the soil particle size grouping,sand carbon,silt carbon in 05cm soil layer of 51a shrub and 51a tree are 2.5 and 2.7 times,1.8 and 2.6 times than clay carbon ;sand nitrogen,silt nitrogen in 010cm soil layer of 51a shrub and 51a tree are 1.3and 1.1 times,1.9 and 1.6 times than clay nitrogen.The density growth of sand,silt and clay carbon in 05cm soil layer of shrub soil were 0.05,0.05 and 0.02 Mg/hm2·a ;the density growth of sand,silt and clay carbon in 05cm soil layer of shrub soil were 4.4,4.0and 2.5 Mg/hm2·a.According to the light and heavy fraction,the organic carbon content of light fraction of 51a shrubs and 51a trees was 1.3 and 4.9 times respectively than heavy fraction ;the nitrogen content of light fraction of 51a shrubs and 51a trees was 0.5 and 1.6times respectively than heavy fraction.According to the active organic carbon and inert organic carbon group,the oxidative active organic carbon content of 20a shrub and 51a shrub was 2.0 and 1.2 times than that of 20a trees and 51a trees.

Mots clés : Process of reverse; Soil organic carbon; Soil nitrogen; Soil particles; Light heavy fraction;

Présentation (CNKI)

Page publiée le 22 mai 2020