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.

ZHANG Junhua;ZHU Lianqi;LI Guodong;ZHAO Fang;QIN Jingting

Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions(Henan University),Ministry of Education,Kaifeng 475004,Henan,China;College of Geography and Environmental Science,Henan University,Kaifeng 475004,Henan,China

地理学报（英文版）

[1]ZHANG Junhua;ZHU Lianqi;LI Guodong;ZHAO Fang;QIN Jingting-.Distribution patterns of SOC/TN content and their relationship with topography,vegetation and climatic factors in China's north-south transitional zone)[J].地理学报（英文版）,2022(04):645-662

Daba,geosta,tistics,Jialing,encom,Hanjiang,alti,Maoxian,Wenxian,Qingchuan

Distribution,patterns,SOC,TN,their,topography,vegetation,climatic,factors,China,transitional,spatial,distributions,key,soil,indices,Mountains,important,indicators,identification,regional,characteristics,This,manuscript,lyzes,variations,organic,carbon,total,nitrogen,corre,sponding,relationships,major,geographical,analysis,considering,data,obtained,from,Second,National,Soil,Survey,results,indicate,that,contents,consistent,three,high,areas,secondary,observed,High,values,located,altitude,regions,Qinling,mountainous,west,River,occurs,slope,mainly,passes,both,sides,tudes,below,vary,between,above,two,ranges,gradual,increase,revealing,horn,shaped,Considering,functions,climate,found,remains,along,contour,line,upper,limit,altitudinal,belt,isotherm,January,July,constitutes,body,subtropical,warm,temperate,zones,northern,boundary,roughly,distributed,Dujiangyan,Pingwu,southern,while,Beichuan,provides,reference,demarcation,further,processes,logical,effects,typical,can,help,multidimensional,mechanisms

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