This paper originally appeared in the journal Proceedings of the National Academy of Sciences of the United States of America in February 1999. It is available from the web site of the PNAS for members of the PNAS and member institutions.

Citation: Proc. Natl. Acad. Sci. USA Vol. 96, Issue 4, pp. 1175-1180, February 16, 1999

Nitrogen fertilizer: Retrospect and prospect

Charles R. Frink*, Paul E. Waggoner*, and Jesse H. Ausubel**

* The Connecticut Agricultural Experiment Station, New Haven, CT, 06504-1106
** Program for the Human Environment, The Rockefeller University, New York, NY 10021-6399

Contributed by Paul E. Waggoner, November 6, 1998


The rising fertilizer use accompanying more people eating more has been called exponential and prompted fears of polluted water and consequent methemoglobinemia and hypoxia. It also has raised alarm about greenhouse warming and an altered global N cycle and thus primary production and diversity of vegetation. In this plethora of issues we concentrate on a few, beginning with the fundamental one of how fast N fertilizer use has risen in the world and in an industrial nation, the United States, where early, rapid adoption may foretell the course in the world. We also shall explore how much deposition of N from the atmosphere has increased. After examining the changing ratio of fertilizer N application to its intended incorporation in crop yield, we shall discuss prospects for more or less N fertilizer by 2070 when the earth's farmers may be feeding 10 billion people and sparing more or less habitat for nature.

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