To classify soils into uniform families systematically with uniform nomenclature so that they can be correlated with those in other areas, regions and countries Soil survey adopt the Internationally Common Soil Survey Manual of United States Department of Agriculture. For this purposes soil sample testing results, field studies and observation of soil inherent characteristics can evolves the nomenclature of the soil family and is done only by the experience trained personnel.
The soils of Nagaland belongs to 4 orders, 7 sub-orders, 10 great groups, 14 sub groups and 72 soil families. The 4 orders found in Nagaland are
Alfisols form in semiarid to humid areas, typically under a hardwood forest cover. They have a clay-enriched subsoil and relatively high native fertility. “Alf” refers to aluminium (Al) and iron (Fe). Because of their productivity and abundance, the Alfisols represent one of the more important soil orders for food and fiber production. They are widely used both in agriculture and forestry, and are generally easier to keep fertile than other humid-climate soils. Those in monsoonal tropical regions, have a tendency to acidify when heavily cultivated, especially when nitrogenous fertilizers are used.
Alfisols are moderately leached soils that have relatively high native fertility. These soils have mainly formed under forest and have a subsurface horizon in which clays have accumulated. Alfisols are primarily found in temperate humid and subhumid regions of the world.
Alfisols occupy 10.1% of the global ice-free land area and supports about 17% of the world’s population. The combination of generally favorable climate and high native fertility allows Alfisols to be very productive soils for both agricultural and silvicultural use.
This type of soil order is found on the western flank of the State bordering Assam. They are deep and well drained of fine to fine loamy texture. Common families of Alfisols which have been identified in Nagaland are :
(1) Fine typic Kanhapludalfs
(2) Fine loamy typic Paleudalfs
In USDA soil taxonomy, entisols are defined as soils that do not show any profile development other than an A horizon. An entisol has no diagnostic horizons, and most are basically unaltered from their parent material, which can be unconsolidated sediment or rock. Entisols are the second most abundant soil order (after inceptisols), occupying about 16% of the global ice-free land area.
Many Entisols are found in steep, rocky settings. However, Entisols of large river valleys and associated shore deposits provide cropland and habitat for millions of people worldwide.
This soil order is found on the Western and North Western part of the State on the low hill slope and narrow river valleys.
Families which have been identified under this orders are :-
(1) Fine-loamy typic Udifluvents
(2) Fine-loamy typic Udorthents
(3) Coarse-loamy typic Udorthents
(4) Fine-loamy Lithic Udorthents
(5) Coarse loamy Lithic Udorthents
Inceptisols (from Latin inceptum, “beginning”) are soils that exhibit minimal horizon development. They are more developed than Entisols, but still lack the features that are characteristic of other soil orders.
Although not found under aridic climate regimes, Inceptisols nevertheless are widely distributed and occur across a wide range of ecological settings.They are often found on fairly steep slopes, young geomorphic surfaces, and on resistant parent materials. Land use varies considerably with Inceptisols. A sizable percentage of Inceptisols are found in mountainous areas and are used for forestry, recreation, and watershed.
Inceptisols occupy an estimated 15% of the global ice-free land area
This soil dominates the entire State having fine loamy, fine clay, clay loam etc. soil textures with moderately shallow to deep soils with moderately to excessively drained. The identified families under this order are:
(1) Fine- loamy Umbric Dystrochrepts
(2) Fine loamy typic Dystrochrepts
(3) Fine Umbric Dystrochrepts
(4) Loamy , skeletal Umbric Dystrochrepts
(5) Fine typic Dystrochrepts
Ultisols (from Latin ultimus, “last”) are strongly leached, acid forest soils with relatively low native fertility. They are found primarily in humid temperate and tropical areas of the world, typically on older, stable landscapes. Intense weathering of primary minerals has occurred, and much Ca, Mg, and K has been leached from these soils. Ultisols have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors resulting from the presence of Fe oxides.
Because of the favorable climate regimes in which they are typically found, Ultisols often support productive forests. The high acidity and relatively low quantities of plant-available Ca, Mg, and K associated with most Ultisols make them poorly suited for continuous agriculture without the use of fertilizer and lime
Ultisols occupy 8.1% of the global ice-free land area and support 18% of the world’s population.
This soil is sparely scattered in all parts of the State having fine loam, clay loam and clayey texture. The families under this order which have been identified so far are :
(1) Fine Humic Hapludults
(2) Fine Typic Paleudults
(3) Fine Typic Haplohumults
(4) Fine loamy typic Hapludults
(5) Fine typic Hapludults
Inceptisols dominate the soils of the State with 66% followed by Ultisols 23.8%, Entisols 7.3% and Alfisols 2.9% of the total 16.6 million Ha. of the State Geographical Area