Justus von Liebig led 19th-century chemistry into the modern world. Among many contributions was one that, with some broadening of the concept, is known even today as Liebig's Law of the Minimum. In studying the chemical requirements of plants, Liebig realized that it wasn't the overall availability of minerals that held back plant production, but the necessary substance that was in shortest supply--that there could be an abundance of all nutrients except one, but that the one would prevent the plant from reaching its potential. The Law even today guides our concept of limiting factors.
Our Chihuahuan Desert soils, often loaded with
most minerals required by plants, nonetheless see pitiful
results. What's going on? Often, it's Liebig's Law
striking in the form of just one element--nitrogen--so lacking
that growth is curtailed. Most of the air is nitrogen, but not in
the form needed by plants. Much like the mariner's plaint of
"water, water everywhere, but nary a drop to drink",
our desert plants might cry, "nitrogen all around, but nary
a bit for us"!
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.