Soil texture know the percentages of sand, clay, and silt in your soil sample, the triangle can be used to determine which of the twelve soil types you have. To do this, find your percentage of sand along the bottom of the triangle. Then follow the slanted line up to the left until you reach your percentage of clay. Where that point is will tell you what soil type you have. For example, if your soil is 70 percent sand and 10 percent clay then your soil is classified as a sandy loam. The same method can be used starting on any
Duplex soil is highly variable, with the top-soils ranging from coarse sand to clay loam and the subsoils from light to heavy clay. Some duplex soils are distinguished by the presence of an A2 bleached horizon, a character also used as a diagnostic key for the distinction between these type of soils. The diagnostic properties used by Northcote for the definition of duplex soils consider only the soil texture (texture contrast and type of boundary between horizons A and B) and the colour is used for their differentiation (i.e. brown, red and yellow duplex soils). Under the Australian Soil Classification they can