On The Characteristics Of Hilly Upland Soils In Eastern Hunan And Their Attributions In Chinese Soil Taxonomy

Soil classification is the symbol of soil science development.As there are shortcomings existing traditional soil genetic classification,such as ambiguous classification standards and indefinite quantity for classification indicators.To solve these problems,Soil Taxonomy characterized by quantification,systematization and standardization is necessary for the development of soil taxonomy.Therefore,the project named “The survey of soil series and the compilation of soil series records” supported by Chinese Government was conducted in 2008,and implemented the investigations to 16 provinces and directly-controlled municipalities in eastern China,such as Hei Longjiang,Hubei,Beijing,Guangdong and Hainan.In 2014,China launched the project named “the survey and the record compilation of soil series in central and western China” for the second phase.To comprehensively master the classification and distribution of the soil system in Hunan and provide identification basis for the establishment of the typical soil series classifications in Hunan,this essay,on the basis of the project of Chinese soil series survey,gives soil series study on the dry land soils in eastern Hunan,and selected four parental materials including Quaternary red clay,granite,slates and shivers,purple gravel,and purple shivers of the 33 dry land soil profiles from Changsha,Zhuzhou,Xiangtan and Yueyang.Based on the study on the soil forming environment,profile morphological characteristics and physic-chemical properties,this essay established the diagnositic horizon and diagnostic characteristics of the four parental materials as well as their classification system,identified the location of the tested sols in soil taxonomy and provided references for the soil taxonomy in Hunan Province.The main results are shown as following:(1)Based on the classification principals and methods provided by Chinese Soil Taxonomy(3rd edition),the diagnostic horizons of the Quaternary red soil,granite red soil,slate and shiver red soil,and purple soil in eastern Hunan include s Ochric epipedon,Umbric epipedon,LAC-ferric horizon,Argic horizon,Plinthic horizon and Cambic horizon;the diagnostic characteristics include L.C.of sandy deposits,ali-evidence,ferrosol evidence,water regime of udic soil and temperature regime of thermic soil.(2)According to the diagnostic horizons and diagnostic characteristics of the Quaternary red soil,it belongs to 3 orders such as argosols,ferrosols and cambosols;3 suborders such as udic argosols,udic ferrosols and udic cambosols;3 groups such as hapli udic ferrosols,ali-udic argosols and ali-udic cambosols;6 subrgoups as rhodi hapli udic ferrosols,trunic hapi-udic ferrosols,and plinthic hapli-udic ferrosols.Based on the diagnostic horizons and diagnostic characteristics of the granite red soil,it belong to 3 orders such as argosols,ferrosols,and cambosols;3 suborders like udic argosols,udic ferrosols and udic cambosols;4 groups as hapli-udic ferrosols,ali-udic argosols,acidi-udic argosols and ali-udic cambosols;and 4 subgroups as typic ali-udic cambosols,typic hapli-udic ferrosols,typic ali-udic argosols,typic acidi-udic argosols.What is more,in terms of the diagnostic horizons and diagnostic characteristics of slate red soil and shiver red soil,it belongs to 4 orders as argosols,cambosols,ferrosols and primosols;4 suborders as udic-argosols,udic-ferrosols,udic-ferrosols and orthic primosols;5 groups as acidi-udic argosols,ali-udic argosols,ali-udic cambosols,alliti-udic ferrosols and usti-orthic primosols;and 5 subgroups as typic acidi-udic argosols,typic ali-udic argosols,typic ali-udic cambosols,typic alliti-udic ferrosols and lithic usti-orthic primosols.Based on the diagnostic horizons and diagnostic characteristics of purple soil,it belongs to 2 orders such as primosols and cambosols;3 suborders as sandic primosols,udic cambosols,and orthic primosols;4 groups such as rougi-orthic primosols and ali-udic cambosols;and 4 subgroups such as typic usti sandic primosols and typic ali-udic cambosols.(3)According to the classification standards for soil family and soil series,9 soil families as clay kaolinite type with acidic and hot typic ali-udic argosols,and 12 soil series as Yantang series(43-LY01)are established for the quaternary red soil;6 soil families as clay loam and siliceous mixed type with acidic and hot typic ali-udic cambosols,and 8soil series as Tuojia series(43-CS18)are established for granite red soil;6 soil families as clay loam and siliceous mixed type with acidic and hot typic acidi-udic argosols,and 7 soil series as Gaoshen series(43-CS16)are established for red slate soil;6 soil families such as sandy siliceous mixed type acidic and hot typic usti sandic primosols and 6 soil series such as Nanyue series(43-LY02)are established for the purple soil.(4)This essay,by comparing the soil genesis classification and the location in soil taxonomy,finds out the asymmetrical relationship of the quaternary red soil clay,granite,slate and shiver red soil,purple gravel and purple shiver,especially the complex corresponding relation in the higher categories of soil classification,which is several for one or one for several,while the corresponding relation in the basic categories of soil classification is simple,which is one for one or one for several.