Water Relations in Soils as Related to Plant Communities in Ruby Valley, Nevada

Abstract

Distinct patterns of vegetation on ancient lake sediments in Ruby Valley, Nev., define differences in soil-water-plant relations resulting either from differences in depth to ground water or from differences in water-retention capacities of soils deriving water only from precipitation. In order of increasing depth to ground water, dominant plant species are Juncus balticus, Distichlis stricta, Potentilla fruticosa, Elymus cinereus, Sarcobatus vermiculatus, and Chrysothamnus nauseosus. Dominant species on soils in order of increasing water-retention capacity are Artemesia tridentada nova, Chrysothamnus viscidiflorous pumilus, Ceratoides lanata, Artemesia tridentada tridentada, Atriplex nuttallii gardneri, and Atriplex confertifolia. Minimum and maximum levels of soil-water stress measured were systematically related to water-retention capacities of soils. A relationship was defined that permits approximation of amounts of water evapotranspired by different plant communities from percent of area under live plant cover. There are separate relationships, relating plant cover to amounts of plant stress or to amount of water evapotranspired, for habitats that receive water from the water table and those that do not. Levels of osmotic stress encountered in surface soils appear to influence plant-community distribution.