Many fertilizer plants either produce or use anhydrous ammonia—a gas that is one part nitrogen and three parts hydrogen—as a base for creating different fertilizer types, said Kurt Steinke, a soil scientist at Michigan State University (MSU).

"Anhydrous ammonia can be combined with different compounds, such as nitric acid, sulfuric acid, or even carbon dioxide from the atmosphere to produce the different kinds of fertilizers that we use today," he said.

Anhydrous ammonia—often referred to as simply ammonia—can be cheaply manufactured and is an effective fertilizer in its own right. But producing it requires intense heat and it must be stored at high pressures.

"When used in agriculture anhydrous ammonia is compressed into a liquid and must be stored under high pressure