Air high quality enhancements result in extra sulfur fertilizer use, exhibits examine

Sulfur, an important nutrient for vegetation, was as free as air again within the Eighties, drifting down onto farmers’ fields from the polluted sky. The nutrient additionally induced acid rain, nevertheless, and it triggered chemistry that meant extra mercury in fish. Regulations led to much less sulfur within the air, however within the Midwest, the place sulfur-hungry corn and soybean fields had been proliferating, crops nonetheless wanted the nutrient.

“We discover a clear enhance in sulfur fertilizer use commensurate with a decline in atmospheric deposition,” mentioned Eve-Lyn Hinckley, a Cooperative Institute for Research in Environmental Sciences (CIRES) fellow, University of Colorado Boulder ecologist and lead writer of a brand new evaluation of sulfur fertilizer use. “We have compiled the first time-series of sulfur fertilizer data spanning decades, from 1985-2015.”

As sulfur stopped dropping from the sky, farmers started making use of it instantly, Hinckley and her colleague, Charles Driscoll from Syracuse University, reported in late December within the journal Communications Earth & Environment. Moreover, sulfur fertilization accelerated shortly, they discovered, far outpacing the expansion in use of different vitamins equivalent to nitrogen and phosphorus.

That’s vital, as a result of sulfur’s impacts may be severe: the chemical can primarily make heavy metals, together with poisonous mercury, extra “mobile” and extra prone to make their method into fish, for instance.

Hinckley mentioned it isn’t but clear how extensively sulfur fertilization impacts the mercury cycle.

“It’s the identical type of sulfur as was occurring with acid rain. However, that was diffuse, widespread atmospheric deposition, and that is intense, focused functions in a lot bigger quantities.” She and her colleagues are already digging into the connection, “looking at the potential interaction between agricultural sulfur runoff and stimulation of methylmercury formation downstream.”

Even with the environmental risks, farmers do want sulfur fertilizers, Hinckley mentioned, and her work doesn’t counsel prohibiting them. In the case of different vitamins that may trigger environmental hurt when utilized in extra of crop necessities—equivalent to nitrogen and phosphorus—agricultural specialists have discovered find out how to decrease injury with selective timing and quantities of software. That’s the objective of her work with sulfur, she mentioned. “We want to help people use it smartly and understand what it does in the environment.”