Plant nutrition has a long history of misconceptions. The Greek Aristotle thought that the bulk of a plant came from the ground. Experimentation in the 1600s showed little soil was consumed during plant growth, and the researcher concluded that growth must have come via the water added. In the 1700s, a scientist suggested that nourishment of plants was primarily by air.
Thus, we've understood only recently that plants make their own
food from carbon dioxide and water with the aid of energy from the sun. Nevertheless,
the soil does play a critical role. There are about 17 critical chemical elements
required by all plants, and almost all have to be absorbed from the soil by the roots.
Absorption, of course, has to occur through the interface between root and soil, and a
large surface area is critical in order to absorb enough water and minerals to support
life. It's to supply the huge surface area required, as well as to anchor a plant,
that the underground parts of a plant may approach or exceed what is above
ground.
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
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.