In fact, it would cost more to fertilize than you would get back in profits from increased yield. When soils test in the high range, applying only a small quantity of phosphorus is suggested to maintain the high fertility status. There is no economic advantage to applying phosphate to soils testing very high . The University of Missouri does not suggest applying phosphorus on soils testing very high in phosphorus. An adequate phosphorus soil test range for row crops and small grains is about 45 to 70 pounds P per acre.
Most forage crops do well in a soil testing in a range somewhat lower.
An adequate range is 40 to 60 pounds P per acre. Native warm-season grasses do well on soils testing 20 to 35 pounds of P per acre. The Cation Exchange Capacity is a measure of the soil's ability to hold certain nutrients known as cations . The CEC on the soil test report is a calculation of the exchangeable calcium, magnesium, potassium, and hydrogen measured by the soil tests. The CEC value helps technicians make the potassium and magnesium interpretations and estimate the soil texture.