Demand for potassium (K) increases with increasing soybean yield. Little research has been conducted on soybean response to K on coastal plain and piedmont soils of Virginia, especially in double-crop systems. Nineteen full-season and 14 double-crop soybean experiments were conducted in 2013 and 2014 in Virginia and northeastern North Carolina to determine full-season and double-crop soybean (with wheat straw remaining or removed) response to soil test K and K fertilizer application rates. Field moist, air dried, and oven dry soil test K extraction techniques were also compared to predict responsiveness of sites to K applications. Potassium fertilizer increased yield in five of 19 full-season experiments and one of 14 double-crop experiments. Full-season soybean yield plateaued at 88% relative yield and soil test K value of 38.8 mg K kg-1. Full-season plant K critical concentrations were 18.2 g K kg-1 for V5 and 24.6 g K kg-1 for R2. Although critical concentrations could not be determined for double-crop soybean, V5 and R2 concentrations ranged from 17.6 to 35.6 g K kg-1 or 13.2 to 28.1 K kg-1, respectively, most of which were within or above accepted sufficiency levels. Eight of 13 sites resulted in greater soil K concentrations when alternative soil drying methods were compared to air-dry methods. However, differences were not consistent and no single method was superior for these soils. More data is needed for double-crop soybean systems due to lack of response and lack of low soil test K sites in these experiments. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/56473 |
| Date | 11 August 2015 |
| Creators | Stewart, Anna Elizabeth |
| Contributors | Crop and Soil Environmental Sciences, Holshouser, David L., Thomason, Wade E., Reiter, Mark S., Frame, William Hunter |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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