Evapotranspiration is the evaporation of water from plant leaves into the atmosphere. The United States Geological Service defines it as "water lost to the atmosphere from the ground surface, evaporation from the capillary fringe of the groundwater table, and the transpiration of groundwater by plants whose roots tap the capillary fringe of the groundwater table." Grass varieties differ in their rates of evopotranspiration, which are calculated as inches of water loss per day.
Bermuda grass has smooth leaves and a flowering stem with three to seven terminal spiked branches. It has a lower rate of evaporation from its leaves than other turf grasses such as fescue. It is somewhat drought-resistant because of this feature. Bermuda grass is a low-growing wiry perennial with underground rhizomes and above-ground stolons that reproduce by rooting. Hybrid forms of Bermuda grass are used as turf grass.
Evaporation through Leaves
Transpiration of water through plant leaves such as Bermuda grass accounts for 10 percent of the environmental total. Oceans, lakes and rivers provide 90 percent of water transpiration into the atmosphere. Heat produces increased evopotranspiration by opening the stomata in leaves. Stomata are tiny cell openings through which plants give and receive water, nutrients and oxygen.
Evapotranspiration rates differ for different plant species, according to leaf size. Bermuda grass leaves emerge from the stem at 1/8 to ¼ inch, tapering to a pointed end. Other conditions affecting evaporation rates are temperature, humidity, sunlight availability and intensity, precipitation, soil type and saturation, wind, and land slope. Bermuda grass thrives in areas with long periods of sunlight.
Only 1 to 2 percent of water taken up by lawn grass is used for growth and development, according to Purdue University Extension website. "Most of the water taken up by turf grass plants is used for evapotranspiration to regulate plant temperature." Energy from the sun accumulates in grass leaves and is converted to water vapor through transpiration. Grass such as Bermuda grass use less water and are therefore a good choice for areas where there is water shortage.
Bermuda grass is considered a weed or an acceptable lawn grass. It grows as a perennial and can be managed as a turf grass. When used as a turf grass, elimination of other weed grass such as crabgrass is necessary. Organic methods such as hand picking, mulch and corn gluten meal pre-emergent herbicide are effect methods of control. Do not cultivate Bermuda grass when soil is moist because each chopped stem roots as a new plant.