On The Genetic Characteristics Of Upland Soils In Northern Hunan And Their Attributions In Chinese Soil Taxonomy

Soil classification is not only a reflection of the development level of soil science,but also a bridge between soil science and other disciplines,which is an urgent need for the continuous development of soil science and international integration,as well as the level of soil science.The traditional soil genetic classification is not uniform,and it is difficult to meet the international standards.A more quantitative,scientific and normative system soil taxonomy has become a trend,this essay,on the basis of the project of Chinese soil series survey,gives soil series study on the dry land soils in northern Hunan,and selected six parental materials including slate weathering,quaternary red clay,purple sand,shale weathering,river and lake sediments,sandstone and granite weathering of the 17 dry land soil profiles from Yiyang and Changde.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 six 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 slate red soil,quaternary red soil,purple soil,tidal soil,red soil of sandstone and granite in northern Hunan includes Fimic epipedon,Ochric epipedon,Umbric epipedon,LAC-ferric horizon,Argic horizon,Plinthic horizon,Cambic horizon;the diagnostic characteristics include L.C.of red sandstones shales,Paralithic contact,ali-evidence,ferrosol evidence,water regime of udic soil and temperature regime of thermic soil.(2)The diagnositic horizon and diagnostic characteristics of red soil with different maternal-development are different,so its attribution in Chinese Soil Taxonomy is also slightly different.Slate red soil belongs to 4 orders such as ferrisols,luvisols,cambisols and entisols;4 suborders such as udic luvisols,udic cambisols,udic ferrisols and orthic entisols;5groups such as fer-udic luvisols,hyp-udic luvisols,hyp-udic cambisols,hap-udic ferrisols and Usti-Orthic entisols;5 subrgoups as typic fer-udic luvisols,typic ali-udic luvisols,typic ali-udic cambosols,typic hapli-udic ferrosols and typic usti-orthic entisols.Quaternary red soil belong to 1 orders such as cambisols,1 suborders like udic Cambisols,2 groups as Fer-udic Cambisols and ali-udic Cambisols,and 3 subgroups as Red fer-udic Cambosols,typic ali-udic cambosols and plinthic ali-Udic cambosols.Purple soil,it belongs to 2 orders as cambisols and luvisols,2 suborders as udic cambisols and udic luvisols,3 groups as ali-udic cambisols,pup-udic cambisols,Fer-udic luvisols;and 3 subgroups as dystric purpli-udic cambosols,typic ali-udic cambosols and albic fer-udic luvisols.Tidal soil belongs to 1 orders such as anthrosols,1 suborders as orthic anthrosols,2 groups such as Fim-orthic anthrosols and Mum-orthic anthrosols;and 2 subgroups such as mottlic fim-orthic anthrosols and typic mum-orthic anthrosols.Red soil of sandstone and granite,it belong to 2 orders such as luvisols and cambisols;2 suborders like udic luvisols and udic cambisols;3 groups as ali-udic luvisols,fer-udic luvisols and ali-udic cambisols;and 4 subgroups as typic ali-udic luvisols,typic fer-udic luvisols and typic ali-udic cambosols.(3)According to the classification standards for soil family and soil series,5 soil families as clay loam and siliceous mixed type with acidic and hot typic fer-udic luvisols,and 5 soil series as Wenxi series(43-YIY01)are established for the slate red soil;4 soil families as clay kaolinite mixed type with acidic and hot plinthic ali-Udic cambosols,and 4 soil series as Jinpenshan series(43-YIY06)are established for the quaternary red soil;3 soil families as clay loam and siliceous mixed type with acidic and hot typic ali-udic cambosols,and 3 soil series as Liergang series(43-CD03)are established for purple soil;2 soil families as clay loam and siliceous mixed type with non-acidic and hot mottlic fim-orthic anthrosols,and 2 soil series as Damu series(43-YIY08)are established for tidal soi.3 soil families as clay loam and siliceous mixed type with acidic and hot typic ali-udic Luvisols,and 3 soil series as Fujiachong series(43-YIY03)are established for red soil of sandstone and granite.(4)This essay,by comparing the soil genesis classification and the location in soil taxonomy,finds out the asymmetrical relationship of the slate weathering,quaternary red clay,purple sand,shale weathering,river and lake sediments,sandstone and granite weathering,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.