Synthetic nitrogen destroys soil carbon, undermines soil health

New research: synthetic nitrogen destroys soil carbon, undermines soil health
By Tom Philpott

[This is an excerpt from a story originally published at Grist.com]

“Fertilizer is good for the father and bad for the sons.”
~Dutch saying

For all of its ecological baggage, synthetic nitrogen does one good deed for the environment: it helps build carbon in soil. At least, that’s what scientists have assumed for decades.

If that were true, it would count as a major environmental benefit of synthetic N use. At a time of climate chaos and ever-growing global greenhouse gas emissions, anything that helps vast swaths of farmland sponge up carbon would be a stabilizing force. Moreover, carbon-rich soils store nutrients and have the potential to remain fertile over time—a boon for future generations.

The case for synthetic N as a climate stabilizer goes like this. Dousing farm fields with synthetic nitrogen makes plants grow bigger and faster. As plants grow, they pull carbon dioxide from the air. Some of the plant is harvested as crop, but the rest—the residue—stays in the field and ultimately becomes soil. In this way, some of the carbon gobbled up by those N-enhanced plants stays in the ground and out of the atmosphere.

Well, that logic has come under fierce challenge from a team of University of Illinois researchers led by professors Richard Mulvaney, Saeed Khan, and Tim Ellsworth. In two recent papers (see here and here) the trio argues that the net effect of synthetic nitrogen use is to reduce soil’s organic matter content.

Why?

Continue reading this and other stories in Philipott's series "The Nitrogen Dilemma" at Grist.com


It well worth reading, please educate yourself, it's one of the best tools you can have.
Blessings,
Kelle