Armstrong Research and Demonstration Farm
Research has been conducted at the ISU Armstrong Research Farm, Lewis, Iowa, to study potassium (K) fertilization rates and placement methods on corn and soybean grain yield, K uptake, and soil-test K values. However, no research has investigated K recycling to the soil by maturing plants and crop residue until the next crop is planted. The amount and the timing of the K recycled to the soil should have a significant impact on soiltest K values, and should explain a great deal of usually very high soil-test K temporal variability. Therefore, plots of several field K trials at this farm were used to investigate these issues.
Iowa State University
Mallarino, Antonio P.; Oltmans, Ryan R.; and Havlovic, Bernard J., "Potassium Uptake and Recycling to the Soil in Corn and Soybean" (2013). Iowa State Research Farm Progress Reports. 1862.