On The Characteristics Of Typical Soils In Xiangxi Area Of Hunan And Their Attributions In Chinese Soil Taxonomy

Soil is the material basis for human existence and the important source of wealth.It is also the means of production for human development and utilization.In order to solve the complex problems encountered in soil research,the first thing is to correctly understand the soil,that is,to make a unified classification and nomenclature of the soil.Nowadays,soil taxonomy is the mainstream trend in international soil classification.Soil classification in China is at an important stage of the transformation from genetic soil classification to taxonomic soil classification.Therefore,this paper conducts field investigation and indoor analysis on typical dry land soil and typical paddy soil with four kinds of parent materials in Western Hunan,studies their soil-forming environment,profile morphological characteristics and physicochemical properties,identifies diagnostic horizon and diagnostic characteristics of soil profiles according to "the keys to Chinese soil taxonomy(3rd edition)",and determines the senior taxon of chinese soil taxonomy.The nomenclature of basic taxa of Chinese Soil Taxonomy is determined according to “criteria for establishment of soil family and soil series in Chinese soil taxonomy”.its attribution in Chinese soil taxonomy is finally determined,and the current Chinese soil taxonomy system is verified,supplemented and improved.The results show that:(1)According to the classification principles and methods of the keys to Chinese Soil Taxonomy(3rd edition),typical dry land soils with weathered limestone,slate shale,sandstone and purple gritstone in Western Hunan were retrieved.The main diagnostic horizon were ochric epipedon,umbric epipedon,argic horizon and cambic horizon,and so on,the diagnostic characteristics and phenomena were L.C.of carbonate rocks,lithic contact,paralithic contact,humic property,alic evidence,ferric property,udic soil moisture regime,perudic soil moisture regime,thermic soil temperature regime,mesic soil temperature regime and so on;The main diagnostic horizon of typical paddy soils were: anthrostagnic epipedon,hydragric horizon,agric horizon,etc.The diagnostic characteristics and phenomena were: reclioxic features,gleyic features,gleyic evidence,fimic evidence,ferric property.anthrostagnic moisture regime,thermic soil temperature regime,etc.(2)According to the diagnostic horizon and diagnostic characteristics of typical Dryland Soils in Western Hunan,they can be divided into three orders: Luvisols,Cambisols and Entisols;five Suborders: Perudic Luvisols,Udic Luvisols,Perudic Cambisols,Udic Cambisols andOrthic Entisols;six Groups: Hapli-Perudic Argosols,Ali-Udic Argosols,Ferri-Udic Argosols,Ali-Perudic Cambosols,Ferri-Udic Cambosols and Usti-Orthic Primosols.nine Subgroups: Humic Hapli-Perudic Argosols,Typic Hapli-Perudic Argosols,Humic Ali-Udic Argosols,Typic Ali-Udic Argosols,Red Ferri-Udic Argosols,Typic Ali-Perudic Cambosols,Humic Carbonati-Udic Cambosols,Typic Ferri-Udic Cambosols,Lithic Usti-Orthic Primosols;typical paddy soil can be divided into one order: Anthrosols;one Suborder: Stagnic Anthrosols;two Groups: Fe-accumulic Anthrosols and Hapli-Stagnic Anthrosols;three Subgroups: Endogleyic Fe-accumulic Anthrosols,Typic Fe-accumulic Anthrosols and Typic Hapli-Stagnic Anthrosols.(3)According to “Chinese classification standards of soil family and soil series”,five soil families,such as electrode clayey silica mixture non-acidic mesic-Typic Hapli-Perudic Argosols(43-XX01)and so on,and five soil series,i.e.jianfu series(43-XX01)and so on,have been established for limestone soils;three soil families,such as clayey silica acidic thermic-Typic Ali-Udic Argosols(43-XX03)and so on,and three soil series,i.e.hongyanxi series(43-XX03)and so on,have been established for slate soils;two soil families,such as coarse bone loam silica mixture thermic-Humic Ali-Udic Argosols(43-XX02)and so on,and two soil series,i.e.shanmuhe series(43-XX02)and so on,have been established for sandstone soils;one soil family,such as coarse bone silica mixture non-acidic thermic-Lithic Usti-Orthic Primosols(43-XX08)and so on,and one soil serie,i.e.qingming serie(43-XX08)and so on,have been established for purple stone soils.typical paddy soil have been established for six soil families,such as Clayey loamy silica mixture non-acidic thermic-Endogleyic Fe-accumulic Anthrosols(43-XX09)and so on,and six soil series,i.e.paixiong series(43-XX09)and so on,have been established for typical paddy soil in Western Hunan;(4)By comparing the attribution of tested soils in taxonomic soil classification and in genetic soil classification,it is found that they belong to the same named soil in genetic soil classification,but they belong to different names in taxonomic soil classification,even to different soil orders.Therefore,compared with the genetic soil classification in China,Chinese soil taxonomy can reflect the differences and similarities of soil properties in southern Hunan more accurately,quantitatively and objectively,avoid the problem of homonymy of different soil.