According to the Soil and Conservation District of Saint Louis County (SWCDSTL), there are over 515 soil types found in Missouri. The name of each soil series is derived from the towns or landmarks near where they were first mapped and identified. No two soils are the same, although neighboring soils in the same region share a similar ability to support growing plants or building construction.
Soil by Region
The SWCDSTL notes that Kickapoo and Dockery soils are found in the northeast and north sections of Missouri, respectively. These soils are wet and heavy, cannot tolerate much watering and are prone to flooding. Leonard soil, also found in northern Missouri, and Sampsel, which is scattered throughout Missouri, are unstable because they shrink and expand, causing cracks in foundations, roads and walls. Gerald and Putnam—found in southern and northern Missouri, respectively—are wet soils that don't support things like septic systems due to their high seasonal water tables.
Menfro is the state soil of Missouri. It is commonly used to grow corn, soybeans, small grain, forage crops and specialty crops like tobacco, grapes, vegetables and fruit. Sites with Menfro soil are desirable building sites because soils are generally very deep, well drained and moderately permeable. This soil is found adjacent to the Missouri and Mississippi rivers and their major tributaries in areas that receive an annual average precipitation of 36 inches. Steeper areas support deciduous hardwood timber.
Menfro is composed of silt loam. Silt loam indicates that silt is the dominant mineral particle in this particular soil texture classification. The particles are relatively fine, smooth and floury. Silt loam contains 50 to 80 percent silt and less than 12 percent clay.
Potassium keeps trafficways in a plant operating efficiently, according to the University of Missouri Extension. A healthy plant's leaves contain about 2 percent or more potassium and contribute that potassium to the soil when it dies and decays. Soils in Missouri vary in potassium content. Soils in northwest Missouri are high in potassium because there has been little mineral leaching—washing away—over thousands of years. Soils in eastern Missouri, on the other hand, are low in potassium because of lots of weathering and removal of the potassium. As the average annual rainfall of a location increases—as is happening in Missouri—weathering increases and potassium levels are reduced.
Before gardening or beginning new construction in Missouri, it is best to have the soil tested to determine what plants or structures the ground can support. The soil test will also tell you the pH of the soil, which will help you to in choosing the right plants for the soil you have, rather than spending lots of time, money and energy to alter the soil and support plants that the pH and soil type do not favor.