Properties And Taxonomy Of Soils Developed From Volcanic Ejecta Under The Influence Of Different Factors

Compared with other countries,the research on volcanic ash in China is relatively weak,and the research on its characteristics is insufficien.Chinese scholars only systematically classified and classified volcanic ash soils under humid climate conditions,and did not involve volcanoes in semi-arid regions.The soil samples collected from the semi arid region of the Inner Mongolia Autonomous Region,Chifeng-Hexigten Banner Dali,Datong volcano in Shanxi Province,Wudalianchi volcano in Heilongjiang Province of semi humid region,the morphological,physical,chemical and mineralogical characteristics were compared according to different soil forming factors,according to the Keys to Chinese soil Taxonomy(3^rd Edition)and the Keys to Soil Taxonomy(12^th Edition),this paper provides a scientific basis for further revising and perfecting the systematic classifycation of China's volcanic ash soil.Research shows:The soil?A?layer has a deeper color,and the soil color of the B layer is lighter than that of the A layer,and the variation of the overall color of the section is gradually shallow from the upper,the soil is loose,the texture is thinner,and the soil is loam or sandy loam.The texture of the lower part of the soil is close to the upper layer,and the texture is to the loamy sandy soil or sand.Transition.In the semi humid area,the rock and mineral debris are less and the debris is smaller in the soil of the semi humid area,and the rock and mineral debris of the soil in the semi-arid area are large and the debris is larger.Some test sections in semi-arid area have lime reaction,and there is no lime reaction in the test section of semi humid area.The soil in the semi humid area is neutral or acidic,and the soil in semi-arid area is neutral or alkaline.The tested soil is salt based saturated soil.There are calcium deposits in some soil profiles of the Datong Volcanic Group in the semi-arid area.The results of selective leaching of all tested soils showed Al_p<Al_d<Al_o,all of which contained amorphous minerals such as dialite and iron ore.Influenced by climatic conditions and the grain size of the parent material,the volcanic ash matrix of the semi humid area is developed into volcanic ash or embryonic soil,and the clastic matrix of the volcano is developed into embryonic form,and the volcanic ash matrix of the semi arid area is developed into embryonic form,and the volcanic clastic matrix is developed into embryonic or new soil,and no volcanic ash is formed.Under the same climate conditions,the development degree of the soil is higher in the semi humid area,and the development degree of the soil is higher in the semi arid area.Advanced classification of soil tested according to the Keys to Chinese soil Taxonomy(3^rd Edition),all tested soils were retrieved into three soil classes,four subclasses,six soil types and seven subclasses.The seven subtypes are the common simple dry-shaped soil,the common simple and humid rudiment soil,the common cold and humid rudiment soil,the normal arid normal Neo-soil,the lime arid normal new soil,and the dark,simple cold volcanic ash soil.It is suggested that the following revision of the Keys to Chinese soil Taxonomy?3^rdd Edition?should be revised as follows:adding a subclass of droughts in the embryonic form,setting up a calcic drought earth and simply raising two soil types,and setting up three subsoil and three subsoil subsoil class.It is suggested that Amorphic,Ferrihydritic and Glassy should be added to the mineralogy search section.