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International Journal of Agronomy
Volume 2012 (2012), Article ID 461894, 10 pages
Research Article

Foliar Potassium Fertilizer Additives Affect Soybean Response and Weed Control with Glyphosate

1Division of Plant Science, Lee Greenley Jr. Memorial Research Center, University of Missouri, Novelty, MO 63460, USA
2Department of Soil, Environmental and Atmospheric Science, University of Missouri, Columbia, MO 65211, USA
3Division of Plant Science, University of Missouri, Portageville, MO 63873, USA
4GBE Herbicide Field Testing Lead, Monsanto, Chesterfield, MO 63017, USA
5Division of Plant Science, University of Missouri, Columbia, MO 65211, USA

Received 12 August 2012; Accepted 25 September 2012

Academic Editor: Robert J. Kremer

Copyright © 2012 Kelly A. Nelson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Research in 2004 and 2005 determined the effects of foliar-applied K-fertilizer sources (0-0-62-0 (%N-%P2O5-%K2O-%S), 0-0-25-17, 3-18-18-0, and 5-0-20-13) and additive rates (2.2, 8.8, and 17.6 kg K ha−1) on glyphosate-resistant soybean response and weed control. Field experiments were conducted at Novelty and Portageville with high soil test K and weed populations and at Malden with low soil test K and weed populations. At Novelty, grain yield increased with fertilizer additives at 8.8 kg K ha−1 in a high-yield, weed-free environment in 2004, but fertilizer additives reduced yield up to 470 kg ha−1 in a low-yield year (2005) depending on the K source and rate. At Portageville, K-fertilizer additives increased grain yield from 700 to 1160 kg ha−1 compared to diammonium sulfate, depending on the K source and rate. At Malden, there was no yield response to K sources. Differences in leaf tissue K , S , B , and Cu concentrations among treatments were detected 14 d after treatment at Novelty and Malden. Tank mixtures of K-fertilizer additives with glyphosate may provide an option for foliar K applications.