Ammonium

Ammonium (NH4+) is a positively charged ion comprised of four molecules of hydrogen and one molecule of nitrogen.

Manure consists of potassium nitrate, ammonium, and methane. 

In 2376, B'Elanna Torres detected elevated levels of carbon monoxide and ammonium on Kelemane's planet during a series of scans, indicating evolutionary progress by the planet's inhabitants.