Sulfur in soybeans - is direct application necessary?

By Scout Nelson

In the agricultural landscapes of Minnesota, the debate on the necessity of direct sulfur application for soybean crops has sparked interest among farmers.

Sulfur, an essential nutrient for all crops, has been shown to enhance soybean yields in the state. This response is more significant when sulfur is not already a routine part of row crop fertilization.

Recent studies, including one funded by AFREC, have investigated sulfur's carryover effects from corn to soybeans in a six-year rotation.

Initial findings showed minimal response to sulfur in soybeans when directly applied, but subsequent applications ahead of corn showed marked yield improvements in both corn and soybeans.

Further research by the Minnesota Soybean Research and Promotion Council delved into the effects of sulfur application methods on corn-soybean rotations.

Preliminary results indicated no yield difference in the first two years, although sulfur from prior corn crops was utilized by soybeans, enhancing certain sulfur-dependent nutritional components.

The interest in sulfur application for soybeans has grown nationally, with studies outside Minnesota showing varying results. Minnesota's early adoption of sulfur in crop rotations suggests a reduced necessity for its direct application on soybeans.

Sulfur applied ahead of corn not only benefits corn yields but also supports subsequent soybean crops without promoting excessive growth prone to disease.

For Minnesota soybean producers, direct sulfur application may not be the best investment. Research advises focusing sulfur applications on corn within the rotation for a more beneficial outcome.

For those considering sulfur for soybeans, conducting strip trials could offer insights, but the emphasis should remain on its application in preceding crops like corn for the overall health of the rotation.

Photo Credit -gettyimages-zoran-zeremski