Pedology
Pedology is the study of soils in their natural settings. No matter how big or how small of an area you plan to grow on, you should always have a soil management plan.
Testing can be done every 3-years and is a great way to optimize crop production, diagnosis plant health issues, save money and energy by applying the necessary amounts of fertilizers, improve nutritional balance and much more.
If you are looking for county fair quality, testing allows for growers to determine the availability of each nutrient listed below. Pay close attention, soil should maintain a pH in the optimum range of 6.0 to 7.0
Phosphorus
Potassium
Magnesium (Mg)
Calcium (Ca)
Soil pH
Lime Index
Organic Matter
CEC Soil Type
*Note, there are additional tests out there that can test for soil and water contaminants.

There are plenty of private companies as well as universities that offer soil testing.