Sulfur Recommendations for Wheat in Ohio
In the March 3, 2009 issue of the OSU CORN Newsletter, Keith Diedrick discusses sulfur applications on winter wheat.
Sulfur deficiencies are most likely to occur in soils that are coarse textured (sandy) with very low organic matter. In replicated research done in Ohio over the years (as well in our neighboring states), wheat grain quality and yield improvements are rarely and inconsistently realized when sulfur (as ammonium sulfate or gypsum) was supplemented in the system. Most yield improvements in wheat seem to be due to using the varieties adapted to your fields, planting date, and nitrogen rates. In most Ohio soils, sulfur is in sufficient levels to avoid limitation of yield. Unless you have coarse-textured, very low OM soils where it is economically beneficial, we do not recommend applying sulfur fertilizers to soft red winter wheat in Ohio. Full CORN Newsletter story available here: http://corn.osu.edu/story.php?setissueID=282&storyID=1678
In 2004 a local research project was conducted at Farm Focus to examine the addition of sulfur topdress in wheat. This study is set up with two different nitrogen topdress rates with and without sulfur for a total of four treatments. The treatments are 60 lb./A nitrogen, 60 lb./A nitrogen with 20 lb./A sulfur, 90 lb./A nitrogen, and 90 lb./A nitrogen with 20 lb./A sulfur. The nitrogen only treatments were applied using 28% UAN liquid fertilizer. The treatments with sulfur had THIO-SUL (26% sulfur solution, 2.87 lb. sulfur/gal.) added at a rate of 7 gallons per acre, and the amounts of 28% UAN liquid fertilizer were adjusted to compensate for the nitrogen available in THIO-SUL. Based on the yield differences from this trial, it would appear the sulfur did improve nitrogen efficiency at the lower rate of application, but had no effect on the higher rate of nitrogen application. If nitrogen was not a limiting factor for yield at the higher 90 lb./A application rate, then a difference in yield from the addition of sulfur at this higher rate would not be expected. Full study available here: http://farmfocus.osu.edu/Sulfur_NRate-Wheat-04.pdf
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Edit 04/09/09: On the subject of adding formaldehyde to wheat topdress, below is a quote from Robert Mullen:
We tried this years ago in North Dakota (no real scientific study), and it still burned the wheat when urea formaldehyde was applied. The key to N application this time of year that really influences the injury seen is air temp and humidity. Higher temps and lower humidity increase burn. Burn this time of year is not really a serious issue and it is unlikely to decrease yield, but it is tough for a producer to look at. The only real concerns with burn are if the flag leaf has emerged.