Soil clay loam that begins at 43% water by weight to a field capacity of 22% is six days, whereas a sand loam that is flooded to its maximum of 22% water will take two days to reach field capacity of 11% water. The available water for the clay loam might be 11% whereas for the sand loam it might be only 8% by weight. The above are average values for the soil textures as the percentages of sand, silt and clay vary. Water moves through soil due to the force of gravity, osmosis and capillarity. At zero to one-third bar
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.