Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Department name when degree awarded

Soil Physics


Sterling A. Taylor


Transpiration is the loss of water in vapor form from a plant. This is essentially the same process as evaporation except that it is modified by plant structure. Large quantities of water are removed from the soil, transferred through the conducting tissues of the plant, and dissipated into the air each day. As soon as the water is lost to the atmosphere, it becomes unavailable for human use.

Few people are aware of the actual magnitude of this process. Over 95 percent of the water absorbed by the plant is lost through transpiration, the other 5 percent being used in photosynthesis and as a plant constituent. Herbaceous plants may transpire several times their own volume of water in a single day. Many forests lose over 20 inches of water in a year. Such large quantities, when dissipated in vapor form, are sufficient to modify the climate in the surrounding area.