Distribution patterns of SOC/TN content and their relationship with topography,vegetation and climatic factors in China's north-south transitional zone

• 作者: ZHANG Junhua ZHU Lianqi LI Guodong ZHAO Fang QIN Jingting
• 来源期刊: 地理学报（英文版）
• 年，卷（期）: 2022,（4）
• 所属期刊栏目: Research Articles
• 页码范围: 645-662
• 页数: 18页
• 语种: 英文
• DOI: 10.1007/s11442-022-1965-x

摘要

The spatial distributions and variation mechanism of key soil indices in the Qin-ling-Daba Mountains are important indicators for the identification of the transitional effect and regional characteristics of the north-south transitional zone in China.This manuscript ana-lyzes the spatial variations in soil organic carbon(SOC)and total nitrogen(TN)and corre-sponding relationships with major geographical factors based on spatial analysis and geosta-tistics considering data obtained from the Second National Soil Survey.The results indicate that the spatial distributions of the SOC and TN contents are consistent,and three high-content areas,one secondary high-content area and one low-content area are observed.High content values are located in the high-altitude regions of the Qinling-Daba Mountains and mountainous areas to the west of the Jialing River,the low-content area occurs on the north slope of the Qinling Mountains,and the secondary high-content area mainly encom-passes both sides of the Hanjiang River and regions in the Qinling-Daba Mountains at alti-tudes below 1000 m.The SOC and TN contents vary between the above two ranges,with the gradual increase in content revealing a horn-shaped pattern.Considering the spatial varia-tions and functions of vegetation,topography and climate factors,it is found that the SOC/TN range in the secondary high-content area remains consistent along the 1000 m contour line,the upper limit of the transitional mountain altitudinal belt,the 0℃isotherm line in January and the 24℃isotherm line in July.This region constitutes the main body of the transitional zone between the subtropical and warm temperate zones,and the northern boundary is roughly distributed along the Dujiangyan-Maoxian-Pingwu-Wenxian line to the west of the Jialing River and the 1000 m contour line on the southern slope of the Qinling Mountains,while the southern boundary occurs along the Dujiangyan-Beichuan-Qingchuan line to the west of the Jialing River and the 1000 m contour line on the northern slope of the Daba Mountains.SOC/TN spatial variation provides a reference for the demarcation of the sub-tropical and warm temperate zones,and further identification of the soil processes and eco-logical effects in typical regions can help reveal multidimensional transitional characteristics and variation mechanisms.