Northeast Research and Demonstration Farm
Research has been conducted at the ISU Northeast Research Farm for many years 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 from maturing plants and crop residue until the next crop is planted. Because all plant K is soluble in water, the amount and the timing of the K recycled to the soil should have a significant early impact on soil-test 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.; Thompson, Louis B.; and Pecinovsky, Kenneth T., "Corn and Soybean Potassium Uptake, Removal with Harvest, and Recycling to the Soil" (2013). Iowa State Research Farm Progress Reports. 1950.