October 9-15 is Earth Science Week (www.earthsciweek.org). Every year, Earth Science Week encourages students and the public to explore the natural world around them and learn about the geosciences. This year's theme is Our Ever-Changing Earth. Humans depend on the Earth for many resources – air, water, food, fuel, trees, metals – but we often forget about one of the most important natural resources: soil! Just like water and air, soil is an important and limited resource. Consider this:
- 75 percent of the Earth is covered in water – oceans, lakes, rivers and streams.
- 25 percent is dry land area, but half of that is desert, swamp, polar and mountainous regions where conditions are too hot, too cold or too high in elevation to be productive.
- Of the remaining area (about 12 percent), nine percent is too flood-prone, too poor-quality or too hot for food production. The remaining three percent represents the area of Earth developed by humans. Just a small fraction of this area is made up of soil that we depend on for food and other uses.
Scientists estimate that we are losing soils 10 to 40 times faster than they can be replaced – 60 percent of soils are washed into our rivers, streams and lakes where they can decrease channel depth, increase potential for flooding and smother aquatic wildlife habitat. You can help control erosion at home by using mulch to cover garden beds and other areas of exposed soil. Planting ground-cover plants or small shrubs will also help stabilize soil.
(Sources: Oklahoma Cooperative Extension Service, Division of Agriculture Sciences and Natural Resources, in cooperation with Oklahoma Department of Agriculture, Food and Forestry and Oklahoma Department of Education. "Ag in the Classroom: How Much Soil is there?" https://www.soils.org/files/about-soils/earth-science-week-2007.pdf; Smithsonian National Museum of Natural History. "Dig It! The Secrets of Soil." http://forces.si.edu/soils/index.html; EPA Office of Wetlands, Oceans, and Watersheds. "Watershed Tips." epa.gov/owow)
