Utilisation of geospatial technology for characterization, classification and mapping of forest soils of central Brahmaputra valley zone of Assam

Typical pedons representing major landforms of Central Brahmaputra Valley Zone of Assam viz., rolling uplands, hill side slopes, alluvial plain, peidmont plains, hillocks and inselbergs developed from shale, quartzite, granite, gneiss and alluvium deposited by rivers occurring under forest cover were characterized, classified and assessed using geospatial technology, field survey and laboratory analysis. The soils were slightly deep to very deep, poorly drained to well drained, strongly acidic to slightly acidic in reaction, organic carbon content varied from low to high. Exchange sites were dominated by Ca2+ and Mg2+ followed by K+ and Na+. CEC ranges from 0.1 to 15.66 Cmol(P+)/kg and base saturation varies from 14.56 to 73.20%. The soils were low to high in available N, low in available phosphorus and medium to high in available potassium content. The soils were classified as Aeric Endoaquents, Dystric Eutrudepts, Fluventic Dystrudepts, Fluventic Eutrudepts, Oxic Dystrudepts, Oxyaquic Dystrudepts, Typic Kanhapludalfs and Typic Udorthents. The soils were having hyperthermic temperature regime, mixed mineralogy and aquic to udic moisture regime. Alfisols were found to be the most dominant soil (57%) followed by Entisols (31%) and Inceptisols (12%). The study revealed that soil properties like profile development, texture, structure, colour, soil acidity, CEC, base saturation, etc. were influenced by landform.