Submitted to: Fluid Fertilizer Foundation Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 1, 2006
Publication Date: February 1, 2006
Citation: Karlen, D.L., Kovar, J.L. 2006. No-till corn response to banded K on Des Moines lobe soils. In: Fluid Fertilizer Foundation Symposium Proceedings. Fluid Feritlizer Forum 2006, February 12-14, 2006, Scottsdale, AZ. 2006 CD-ROM
Potassium (K) was identified as a limiting factor for no-till (slot-plant) and ridge-till (till-plant) corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] in a long-term tillage and crop rotation study at the Iowa State University (ISU) Agronomy and Agricultural Engineering Research Center (AERC). This report summarizes two years of research comparing 30 lb K2O/A broadcast, dry band or liquid band applications with a control (0 lb/A K). The treatments were applied to the same plots each year, thus providing us with three site-years of response data for corn and one for soybean. Pre-treatment soil-test status, plant nutrient concentrations and yield were monitored. Sodium-saturated cation exchange membranes were used to monitor positional availability of the K treatments. The soil-test data confirmed K stratification after several years of reduced tillage and that K saturation was less than 2% for both the continuous corn and rotated blocks. Although not always statistically significant, whole plant and leaf tissue K concentrations were always lower in check plots compared to those receiving K and the concentrations for almost all of the samples were at or below the level considered to be low for the various plant parts. Sodium-saturated exchange membranes were useful tools for characterizing the positional bio-availability of the K. Check-plot yields were significantly lower than those in plots receiving K except for broadcast treatments on the rotated block where the response to K was still positive. The 2005 data also showed a 16% yield penalty for continuous corn. Overall, this study confirms that K is a limiting nutrient at this site and that more attention must be given to it, especially if corn residues are to be harvested for biofuels production.