Soil Taxonomy And Suitabilitic Classification Evaluation Of The Representative Soils In Zunyi And Tongren Areas Of Guizhou Province

Fifty-three representative soil profiles collected from Zunyi and Tongren areas of Guizhou Province were studied for soil properties and classification.Based on field observation and laboratory physical and chemical analysis,the soil genetic characteristics in those areas were discussed.According to the requirements of "Keys to Chinese soil Taxonomic"(3rd edition),the diagnostic horizons and diagnostic characteristics in the soils were characterized,and order,suborder,group,and subgroup of the soils were identified.On these basis,both Analytic Hierarchy Process(AHP)and empirical index method were used for assessing growth suitability of the soils for plantation of tobacco,tea,tea-oil tree,and pepper.The usability of the higher classification units of the Chinese soil taxonomy in plant growth suitability of the soils was also discussed in this paper.The main results and conclusions were as follows:(1)Organic matter accumulation in the soils in the study areas was generally obvious.The soils distributed in mountain and hilly region of the study areas had characteristics of moderate desilication and allitization,and some of the soils had Argic horizon.Soil color and texture varied greatly with their parent materials.The soils-developed from alluvial deposits and diluvium had obvious Redox feature.(2)Diagnostic surface horizons of the soils in the areas mainly belonged to umbric epipedon,ochric epipedon and anthrostagnic epipedon,and main diagnostic subsurface horizons of the soils were argic,albic,cambic and hydragric horizons.Types of soil moisture regime included udic,perudic,anthrostagnic and aquic moisture regimes.Soil temperature regimes for most of the soils were thermic temperature regime,and part of them was mesic thermic temperature regime.There were lithic contact and paralithic contact for most of the soils developed from limestone or sedimentary rocks.Ferric property and calcaric property were commonly found in some of the soils.The 53 typical profiles were classified into four soil order(Athrosols,Argosols,Cambosols and Primosols),7 soil suborders,13 soil group and 17 soil subgroups.(3)The evaluation results of soil suitability showed that stagnic anthrosols and argosols were highly suitable for crops plantation,while cambosols and primosols especially were baraly suitable or unsuitable.It was found that the correlation between the higher categories in CST and the evaluation result was weak,and there was a great difference in the suitability of land-use for the same type of soil.At the same time,the evaluation results indicated that irrational land use existed in uplands of the study area.