When it comes to soil, Dr. Will McClain said, “We’re stuck with the soil texture we’ve been given.” The texture of a soil is determined by its mineral matter. Texture is based on the amounts of sand, silt and clay in the soil. An Agronomy Specialist with the University of Missouri Extension, McClain said it is important to know your soil, because plant species differ in their nutrient requirements. Learning what mineral nutrients you need the most and where they’re needed is the best way to save money on fertilizer.
Different areas of a farm, or field, may have differing nutrient needs. Soil testing is the best way to determine what nutrients are in the soil. If you are testing a field with one soil type, you might be able to get accuracy with only one sample. But if the field has a lot of variability, more samples may be needed. The University of Missouri recommends taking 15 to 20 cores per sample. A core is a cylindrical sample obtained by boring with a hollow drill, or a coring device. The recommended core depth is four to six inches because that is where the majority of plant roots are. Use a clean bucket because some substances, like fertilizer residue, in the bucket will show up in the soil test as very high values.
Avoid testing in areas where the animals hang out. Also avoid sampling near a limestone road. The closer you get to a chat road, the higher the pH. The measure of soil acidity is called pH. Most plants grow best in the 5.5 to 6.5 pH range.
Soil is composed of many factors. The most limiting nutrient determines the overall yield potential. A large portion of Ozarks soils are low in phosphorus. When phosphorus is added, an increase is seen in yield and root mass.
Then there’s natural fertilizer. Dr. McClain said one good way to distribute manure as fertilizer is by unrolling hay, which causes the manure to be distributed around the field. Over a period of time it will cut down on the fertilizer needed. One cow on hay for 100 days (assuming 30 lbs/day) produces 25 pounds of available nitrogen, 21 pounds of phosphate and 73 pounds of potash.
A great online tool is the website for the Center for Applied Research and Environmental Systems, and you can access that page at www.ozarksfn.com.
