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In both the World Reference Base for Soil Resources (WRB) [1] and the USDA soil taxonomy, [2] a Histosol is a soil consisting primarily of organic materials.They are defined as having 40 centimetres (16 in) or more of organic soil material starting within 40 cm from the soil surface.
A soil family category is a group of soils within a subgroup and describes the physical and chemical properties which affect the response of soil to agricultural management and engineering applications. The principal characteristics used to differentiate soil families include texture, mineralogy, pH, permeability, structure, consistency, the ...
Intrazonal soils have more or less well-defined soil profile characteristics that reflect the dominant influence of some resident factor of relief or parent material over the classic zonal effects of climate and vegetation. There are three major sub-types, two of which have two further sub-types each.
Annex 1 is a field guide. It provides all field characteristics (including their definitions) needed for WRB classification and some additional general field characteristics. The characteristics are explained with many figures, and a flow chart is offered for hand texturing. Annex 2 lists the laboratory methods.
The World Reference Base for Soil Resources (WRB) defines "sapric" (sa) as a histosol having less than one-sixth (by volume) of the organic material consisting of recognizable plant tissue within 100 cm of the soil surface.
Soil texture triangle showing the USDA classification system based on grain size. For soil resources, experience has shown that a natural system approach to classification, i.e. grouping soils by their intrinsic property (soil morphology), behaviour, or genesis, results in classes that can be interpreted for many diverse uses.
"She fell off the growth chart and wasn't gaining weight. She wasn't growing in height." "She just wasn't getting the nutrition she needed. She was very weak, lethargic and sleeping a lot."
The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size of a soil. The classification system can be applied to most unconsolidated materials, and is represented by a two-letter symbol. Each letter is described below (with the exception of Pt):