delware environmental institute

NSF: How much fertilizer is too much for Earth's climate?

Helping farmers around the globe apply more precise amounts of fertilizer nitrogen can combat climate change. That's the conclusion of a study published this week in the journal Proceedings of the National Academy of Sciences. In the paper, researchers at Michigan State University (MSU) provide an improved prediction of nitrogen fertilizer's contribution to greenhouse gas emissions from agricultural fields.

The study uses data from around the world to show that emissions of nitrous oxide (N2O), a greenhouse gas produced in soil following nitrogen addition, rise faster than previously expected when fertilizer rates exceed crop needs.

Nitrogen-based fertilizers spur greenhouse gas emissions by stimulating microbes in the soil to produce more nitrous oxide. Nitrous oxide is the third most important greenhouse gas, behind carbon dioxide and methane.

Agriculture accounts for about 80 percent of human-caused nitrous oxide emissions worldwide, which have increased substantially in recent years due to increased nitrogen fertilizer use.