3/9/2009 University of Missouri Extension Agronomy Update
Determining the Likelihood of a Yield Response to Sulfur Fertilization
Wayne Crook, MU Extension Regional Agronomist: 660/288-3239
With today’s high fertility costs, producers are asking themselves if it pays to apply sulfur. Several factors have
contributed to the decline of sulfur in the soil. America is cleaning up its industrial smokestacks and the
amount of sulfur reaching the soil in rain has dropped 30 – 60% since the 1980’s, according to the National
Atmospheric Deposition program. Progressively higher corn yields have increased sulfur removal. The shift to
conservation tillage has slowed the decomposition of organic matter, which is the main source of soil sulfate.
Also, livestock production has consolidated so many farmers no longer apply manure - another prime source
of sulfur for the plant. These factors suggest that there might be a response to application of sulfur.
Various studies have been conducted across the Midwest with a majority of the information from Northern
states (Iowa, Minnesota, Ohio and Nebraska). In these studies, a response to sulfur does occur in limited
situations. In Iowa on a loess soil with low organic matter, yields were boosted by 18 bu/ac across a variety of
soil textures. The most dramatic response was on coarse-textured soils, where yields were increased by 25
bu/ac. Results from South Dakota indicated that sulfur fertilizer produced an economic return in reduced
tillage corn grown on soils with less than 2.5% organic matter and on eroded knolls and slopes.
The latest research on heavy-textured soils confirms that in most instances, adding sulfur will not return the
investment. Field trials across Iowa in 2000 and 2001 or in southwest Iowa from 2000 to 2005 did not show an
increase in corn yields with sulfur application. Research from current trials in Ohio indicates that the
probability of sulfur response by corn and soybeans is still quite low with a few exceptions. A corn trial in
Northeast Missouri also produced no response to sulfur fertilization. Sulfur management in corn is tricky.
There is no soil test that accurately predicts need and not every field responds according to Brian Lang, Iowa
State University Extension Agronomist.
Results from the various trials indicate that the greatest likelihood of a response from sulfur fertilization is on
coarse-textured soils, soils with low organic matter, on no-till or conservation till soils, or some combination of
these factors. The higher organic matter, fine-textured soils have produced little to no response to sulfur
fertilization. With today’s production costs, this may be one input that can be managed differently this year.
It would also provide an opportunity to conduct some comparisons on your own operation. Conducting strip
tests on various soil types can help determine if sulfur fertilization produces a yield response and more
important if it produces an economic return on your fertility investment.