Sulfur Needs Increasing with Time
Published: Friday, December 27, 2024
The following is from Jeff Burbrink, LaGrange County Extension educator.
Back in the 1970s, we used to hear a lot about acid rain. We learned in school that smokestack pollution, in particular the emission of sulfur from power plants, was blamed for the creation of acid rain.
These days, you do not hear much about acid rain. Environmental rules require companies to reduce their smoke emissions and have drastically cut the sulfur smoke and acid rain. In fact, most of today's school kids have never even heard that phrase. That is good news, because people were able to work together to solve a problem that seemed large and economically threatening at the time.
Today, you can find evidence in your backyard of how acid rain and the additional sulfur affected us. If you look at the bark on most trees, you will find growths that are gray to green, sometimes tinted with yellow or orange. These growths are called lichens.
Lichens are a combination of a moss and algae living together symbiotically. Lichens and moss can be found on many outdoor surfaces, including tree limbs, rocks, soils, rooftops and swing sets. Lichens are often mistakenly blamed for the decline of trees or branches, but truth be told, their tiny roots do not extend into the inner workings of the tree, and they do not steal nutrients from trees. In short, they just use the tree as a place to grow.
When I first started working for Purdue Extension back in the 1980s, it was rare to get calls about lichens. The acid rain was killing the lichens. Today, however, it is a different story. Our office gets calls from concerned citizens about lichens, worried the lichens are killing their trees. The truth be told, lichens are a sign that the air is cleaner now than in the past, and they are not responsible for the death of the limbs.
Agriculture in our area has been decreasing sulfur as well. It was rare to see sulfur deficiencies in crops in our region in the 1970s and 1980s. In the late 1980s, the research suggests we were receiving 15-20 pounds of sulfate deposited per acre per year in local fields. Today, that figure is well below 4 pounds per acre per year.
As a result, we now are seeing sulfur deficiencies in some crops, particularly wheat, soybeans and corn. Sandy soils and soils with very little organic matter are most likely to need additional sulfur. You are more likely to see sulfur deficiencies in wet fields or where reduced tillage leaves much residue on the surface. The fact we are planting our crops earlier than we used to also contributes to early season sulfur deficiencies.
Shaun Casteel, Purdue's Extension soybean specialist, has seen better responses to sulfur applications when applied earlier in the season rather than later. Among the results are improved nitrogen fixation, longer leaf retention, increases in seed size and increased bean yields. It's certainly a subject you will want to discuss with your crop advisors this winter.
Return to Top of Page