Soil Facts Soil is living. There are more than 70,000 types of soil in the United States. It takes more than 500 years to form one inch of topsoil. Nearly all antibiotics used to fight our infections are obtained from soil organisms. In one gram of soil, there are over 5,000 different types of bacteria.
Soil A mixture of minerals, organic matter, water, and air, which forms on the land surface. Soil supports the growth of plants.
Soil Structure The arrangement of soil particles into clusters of various shapes that resemble balls, blocks, columns, or plates.
Soil Texture The relative proportions of sand, silt, and clay particles.
Sand The largest-sized soil particles. Sand feels gritty. Also refers to a soil texture that consists of at least 85% sand particles.
Silt Soil particles in between sand and clay in size. Silt feels like flour (smooth and velvety). Also refers to a soil texture that consists of at least 80% silt particles.
Clay The smallest-sized soil particles. Often have plate- like shapes. Feels sticky when wet. Also refers to a soil texture that consists of at least 40% clay particles.
Wetland An area of land where the soil is saturated with water, such as a marsh, swamp, or bog.
Watershed A watershed is the area of land where all of the water that is under it or drains off of it goes into the same place.
Water Cycle The earth has a limited amount of water. Water keeps going around and around and around and around in what we call the "Water Cycle".
Evaporation & Transpiration Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air. Transpiration is the process by which plants lose water out of their leaves. Transpiration gives evaporation a bit of a hand in getting the water vapor back up into the air.
Condensation Water vapor in the air gets cold and changes back into liquid, forming clouds. This is called condensation.
Precipitation Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow.
Collection When water falls back to earth as precipitation, it may fall back in the oceans, lakes or rivers or it may end up on land. When it ends up on land, it will either soak into the earth and become part of the “ground water” that plants and animals use to drink or it may run over the soil and collect in the oceans, lakes or rivers where the cycle starts all over again.