Are Sulfur Deficiencies Becoming More Common in Ohio?

Soybeans

Sulfur is an essential macronutrient for crop production, often ranked behind only nitrogen, phosphorus, and potassium in importance. Overall, for corn and soybean, deficiencies are fairly rare. However, deficiencies can occur and are most likely on sandy soils with low organic matter (<1.0%). Much like nitrogen, the primary form of sulfur in the soil is found in the organic fraction, and the form taken up by plants (sulfate) is highly mobile. For every 1 percent of organic matter, there is approximately 140 pounds of sulfur, most of which is unavailable. Like nitrogen, sulfur must be mineralized to become plant available. (Plants may exhibit sulfur deficiencies under cool, wet conditions when mineralization is slow.) Historically, sulfur was deposited in large quantities from rainfall primarily due to burning of fossil fuels. However, emission standards have resulted in a sharp decrease in sulfur deposition from the atmosphere. As this trend continues, coupled with higher yielding crops, sulfur fertilization may become more important in the future.

Three-Year Total Sulfur Deposition

Figure 1. Sulfur deposition maps from 2000-2002 and 2015-2017 (USEPA, 2019).

A common question these days, is ‘Do I need to fertilize with sulfur?’ Table 1 summarizes on-farm sulfur trials conducted in Ohio from 2016 through 2019. Overall, only one trial (out of eight) resulted in a yield increase due to sulfur application (3 bu/acre in soybean). In addition to these on-farm trials, sulfur (applied as gypsum) did not increase yield in sixteen different environments across Ohio in studies conducted in 2013 and 2014. Lack of yield response is likely due to soils with organic matter levels >1%. (In our sixteen-environment study, soil organic matter levels ranged from 2.0 to 5.1%).

Table 1. Summary on on-farm sulfur trials in corn and soybean from 2016-2019.

Year

County

Crop

Sulfur Source, Rate, and Timing

Yield Response?

Reference

2019

Madison

Soybean

Thio-sul at V3

None

Nate Douridas (eFields report)

2019

Crawford

Soybean

Thiosulfate, 20 lb S/acre, starter

+3 bu/acre

Jason Hartschuh (eFields report)

2019

Darke

Soybean

AMS, R1 and R3

None

Sam Custer

(eFields report)

2018

Darke

Corn

Starter

None

Sam Custer

(On-Farm Report)

2017

Darke

Corn

Starter

None

Sam Custer

(On-Farm Report)

2017

Darke

Corn

Ammonium thiosulfate, 20 and 40 lb S/acre, starter and sidedress)

None

Sam Custer

(On-Farm Report)

2016

Muskingum

Corn

Starter

None

Clifton Martin & Van Slack

(On-Farm Report)

2016

Darke

Corn

Starter

None

Sam Custer

(On-Farm Report)

Sulfur deficiency symptoms are similar to nitrogen, but unlike nitrogen, chlorosis (yellowing) is more visible on newer, upper leaves. If you think your crop is deficient in sulfur, plant tissue testing is the best way to assess. (Sulfur soil analysis is not recommended.) If possible, collect plants exhibiting deficiency symptoms and also plants not exhibiting deficiency symptoms for comparison.

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Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.