How Plants Use Water
How Plants Use Water
In the landscape, water is transpired by plants and evaporated from the soil. This process is defined as evapotranspiration or ET. ET is usually expressed as the quantity of water in inches, millimeters, or gallons that needs to be replaced in order for the plant materials to maintain optimal growth and aesthetic appearance.
The physiology and structure of a plant, its location in the landscape, and weather conditions are the primary factors affecting ET. For example, when growing under the same conditions, bluegrass uses more water than English ivy. Similarly, more water would have to be applied to both bluegrass and English ivy growing in the desert region of Palm Springs than to the same plants growing at the coast in Long Beach because of the hotter and drier conditions found in the desert.
The primary climatic factors that affect ET are:
· solar radiation.
· air temperature.
· relative humidity.
· wind speed.
Generally, as sunlight, temperature, and wind increase and as relative humidity decreases, ET increases. Studies of pasture water use and weather data have led to the development of relationships for predicting ET from climatic factors and weather data.