New research: synthetic nitrogen destroys soil carbon, undermines soil health
Last modified: 2010-03-08 20:35:39
"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.
The use of artificial manure, particularly [synthetic nitrogen] ... does untold harm. The presence of additional combined nitrogen in an easily assimilable form stimulates the growth of fungi and other organisms which, in the search for organic matter needed for energy and for building up microbial tissue, use up first the reserve of soil humus and then the more resistant organic matter which cements soil particles.
In other words, synthetic nitrogen degrades soil.
Read the complete article by Tom Philpott 23 Feb 2010
Keywords: Nitrogen, soil, fertilizer, GRIST, Philpott, artificial manure