Over the last 20 to 30 years, legislation has implemented laws to improve air quality and combat pollution. Power plants have acted by switching to natural gas and low-sulfur coal as well as the use of scrubbers. This has led to a reduction in acid rain which contained sulfur from the use of fossil fuels. In fact, there was about 25 percent as much atmospheric sulfur available in 2016 compared to 40 years prior.1 For many years, agriculture benefited from the atmospheric sulfur and nitrogen through rainfall. There is still sulfur and nitrogen from rainfall, but it is considerably less than in the past.
Sulfur deficiency in corn can cause yellow whorls, stunted corn with delayed maturity, interveinal yellowing, and reduced yield potential (Figure 1). These symptoms have been historically rare because sulfur is a secondary nutrient and plant requirements were supplied by decomposing organic matter and prior to anti-pollution laws, through power plant emissions.
Sulfur is the fourth most important corn nutrient and is essential for protein synthesis, photosynthesis, chlorophyll formation, and other plant functions. Corn plants require sulfur the entire time the plant is growing but has a dramatic increase in uptake when plants are growing rapidly from V12 to VT growth stages (Figure 2).
Sulfur is mobile in the soil; therefore, soils that have water moving through them can leach sulfur out of the root zone. If fields have good organic matter levels (>3%), mineralization is likely occurring; however, organic matter decomposition alone may not supply season-long sulfur requirements.
If corn plants are exhibiting sulfur deficiencies, an investment in a tissue test should be considered to help determine if sulfur content is inadequate. Sulfur deficiencies are more likely on soils that are course in texture, low in organic matter, and do not have an history of manure applications. Manure normally can provide enough sulfur for a growing season.
If you determine you need additional sulfur, it can be applied in season. There are numerous sources of sulfur and some of your current fertilizers may contain sulfur.
1University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES). "Sulfur levels are in decline." ScienceDaily. ScienceDaily, 9 May 2016. https://www.sciencedaily.com/releases/2016/05/160509105735.htm .
2Bender, R.R., Haegele, J.W., Ruffo, M.L., and Below, F.W. 2013. Modern corn hybrids’ nutrient uptake patterns. Better Crops With Plant Food. A Publication of the International Plant Nutrition Institute (IPNI). 2013 Number 1.
Maximize yields and sulfur availability. Mosaic® AgriSight®. Issue 7:2014. The Mosaic Company. https://www.cropnutrition.com/resource-library/maximize-yields-and-sulfur-availability.
Web sources verified 7/25/22.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Performance may vary, from location to location and from year to year, as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts of these conditions on the grower’s fields.
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