THE OXYGEN required by plants for respiration usually reaches the root system from the open atmosphere by diffusing through the air spaces in the soil, and by then dissolving in the water surrounding the root and diffusing into the root. However, rice and some other plants can grow very well under completely flooded conditions. When the soil is flooded, the air space is eliminated in the soil. Oxygen, therefore, cannot move through the soil system to the roots.

Has been associated with the Department of Soils and Plant Nutrition, University of California, Riverside during the 1968—69 year.