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
Parent rock Parent rock Parent rock, also referred to as substratum, refers to the original rock from which something else was formed. It is mainly used in the context of soil formation where the parent rock (or parent material) normally has a large influence on the nature of the resulting soil. For example,clay soil is derived from shale while sandy soil comes from the weathering of sandstones. The term is also used in the context of metamorphic rocks where again the parent rock or protolith refers to the original rock before metamorphism takes place. Parent rocks can be sedimentary, igneous or metamorphic.