On The Attribution Of The Paddy Soil Profiles Of Soils In Eastern Hunan In Chinese Soil Taxonomy

China's paddy soil has about 30 million hectares,of which 93% in the southern rice area,paddy soil in food production occupies a primitive position.Paddy soil is very important grains and commercial crops in our country,it is also a variety of economic crops production base.It has very important guiding significance for the production and crop distribution by exploring the classification in the Chinese Soil Taxonomy,finding the index of basal classification,establishing representative basal soil styles and commenting on the performance of soil series under the similar parent soils.(1)This essay,based on the principles for soil classification,gives higher classification of 27 typical soil profiles in eastern Hunan Province.By analyzing the diagnostic horizons and diagnostic characteristics,it identifies that the 27 profiles belongs to the order of Anthrosols,the suborder of Stagnic Anthrosos,3 groups of Gleyi-Stagnic Anthrosols,Fe-accumulic-Stagnic Anthrosols and Hapli-Stagnic Anthrosols,and 3subgroups Typic-Gleyi-Stagnic Anthrosols,Typic Fe-Accumulic-Stagnic Anthrosols and Typic Hapli-Stagnic Anthrosols.(2)Based on the higher categories of soil classification,this essay gives soil family classification to the soil profiles according to several quantitative indicators such as the soil temperature,the size and level of soil particles in soil control sections,the mineralogical soil types,calcaric property and acid-base property,and divides them into 11 soil families.(3)Then,on the basis of soil families,it divides the soils into 27 soil series according to the indicators of solum thickness,specific soil depth and thickness,surface soil texture,rock debris,nodules and intrusive,Anthrosol turbulent layers and soil colors.(4)There are no direct corresponding relations between generic classification and soil taxonomy,and the classification standards are not the same.The soil taxonomy gives detailed classifications based on the genetic classification.Compared with genetic classification,soils with same or similar material origin in the same region has stronger classification ability in soil taxonomy in terms of basic category of soil classification.Therefore,soil taxonomy classifies the basic soil types in a more direct and quantitative way,and provides direct guidance for the utilization of local agricultural production and corps allocations.(5)Soil genetic classification focuses on the soil-forming condition and the prediction of soil-forming process,but it ignores the soil properties.Therefore,it is easy to classify the same stagnic anthrosols with the same parental materials at different developmental stage into the same groups or subgroups.Soil taxonomy,based on quantitative diagnostic horizons and diagnostic characteristics,performs better in the basic soil classification,and presents the differences of the development process and the material composition in a more sensitive way.So it can better instruct the production practice.(6)On the basis of the classification standards for soil families and soil groups in the Chinese soil taxonomy,the differences of particle size and texture level are the sensitive indicators under the similar parent-soil or parent materials.The texture level and particle size has great significance in the basic classification of stagnic soils under the similar parent material condition in the same area.