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Characterizing the Effect of Increased Phosphorus and Potassium on Seedling Diseases and Sudden Death Syndrome of Soybean in Ohio

Eyre, Meredith M
http://rave.ohiolink.edu/etdc/view?acc_num=osu1468589286

Abstract Details

2016, Master of Science, Ohio State University, Plant Pathology.
Soil fertility may affect the development of soybean diseases, including those caused by soil borne pathogens. Though increased phosphorus and potassium levels have the potential to enhance crop productivity and profitability, secondary effects on pathogens may prove detrimental to overall plant health. Fertility recommendations serve to define optimum levels and require periodic revision to balance nutrient demands of modern cultivars and economic yield response with the associated increases in production costs, environmental considerations, and potential disease development. Fertility recommendations for soybean in the Tri-State area of Ohio, Michigan, and Indiana have not been updated in over 20 years, despite dramatic yield increases and other changes in the industry. As part of a larger collaboration working to re-evaluate current recommendations, this study assessed the effects of higher than recommended rates of phosphorus and potassium on seedling disease and sudden death syndrome disease (SDS) development in soybean through both field and greenhouse trials. Treatments above the recommended rates in the form of 112 kg/ha diammonium phosphate (DAP), 112 kg/ha potash, 112 kg/ha DAP and 112 kg/ha potash, and a nontreated control were applied to 5 field sites with seedling disease history and no differences in stand nor yield occurred. However, a significantly higher number of plants affected by damping-off was observed in plots treated with potassium than the other treatments at one location (p= 0.041). Furthermore, a trend occurred in two intensively surveyed fields in that higher than recommended rates of phosphorus, potassium, and phosphorus plus potassium seemed to increase the number of oomycetes, as more isolates were recovered from plots that had been treated with fertilizer than the nontreated control. More than 15 different oomycete species were recovered from both fields. In greenhouse assays, lower root weights occurred in plants which received fertilizer in 2 of 3 greenhouse trials. When the same treatments were applied to field soils naturally infested with Fusarium virguliforme, the addition of phosphorus and potassium applied separately significantly reduced SDS disease index at one of two locations (p= 0.052). The significant difference detected at this site may be due to lower baseline potassium levels and higher soybean cyst nematode (SCN) counts. Furthermore, in the presence of SCN and SDS, phosphorus and phosphorus plus potassium applied at levels higher than currently recommended enhanced yields, suggesting these additions may decrease disease pressure or compensate for the biotic stress. Clear trends were not observed in greenhouse trials with SDS infested soil amended with any of the fertility treatments. These trends are worth further investigation in continued field trials and greenhouse trials modified to use inoculated soil with fertility applied incrementally under consistent conditions. Future field studies which examine the effects of higher fertility on SDS should prioritize fields with low base levels of potassium and high SCN counts, as preliminary work suggests applying phosphorus and potassium at rates higher than currently recommended may enhance yield under these conditions.
Anne Dorrance, PhD (Advisor)
Steven Culman, PhD (Committee Member)
Terry Niblack, PhD (Committee Member)
Pierce Paul, PhD (Committee Member)
171 p.
Plant Pathology

Recommended Citations

Citations

  • Eyre, M. M. (2016). Characterizing the Effect of Increased Phosphorus and Potassium on Seedling Diseases and Sudden Death Syndrome of Soybean in Ohio [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468589286

    APA Style (7th edition)

  • Eyre, Meredith. Characterizing the Effect of Increased Phosphorus and Potassium on Seedling Diseases and Sudden Death Syndrome of Soybean in Ohio. 2016. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1468589286.

    MLA Style (8th edition)

  • Eyre, Meredith. "Characterizing the Effect of Increased Phosphorus and Potassium on Seedling Diseases and Sudden Death Syndrome of Soybean in Ohio." Master's thesis, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468589286

    Chicago Manual of Style (17th edition)

osu1468589286
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This open access ETD is published by The Ohio State University and OhioLINK.