This combination is known to chemists as N2. But natural processes like this have been supplemented by human activities since the beginning of agriculture. Since ancient times, people have used manure, guano and other substances to replenish the nitrogen in soil. About a century ago, humans began to make fertilizer in factories. What's more, terrestrial systems continually lose nitrogen back to rivers, oceans and the atmosphere.
Most scientists think so.
The question is important enough that a world nitrogen conference is planned for next October. Our thanks today to the Camille and Henry Dreyfus Foundation . We're Block and Byrd for Earth and Sky.