Evapotranspiration in three plant communities of a Rhigozum trichotomum habitat at Upington.

Abstract

Evapotranspiration losses in three Rhigozum trichotomum plant communities namely, pure grass, pure R. trichotomum and a mixed stand of grass and R. trichotomum were determined during the 1985-86 growing season. Three hydrologically isolated plots in each community type were irrigated and changes in soil water content over time were subsequently measured by means of a neutron moisture meter. Evapotranspiration was calculated using the soil water balance equation. During the growing season the grass community consistently used more water than the R. trichotomum community. Nevertheless, water use by a dense stand of R. trichotomum was such that it was judged that the establishment of grasses in such stands would in practice be impossible under normal rainfall conditions. The suppressive effect of R. trichotomum on grass production as well as the effect of a dense stand of grass on the growth of R. trichotomum is discussed

Keywords: afrikaans; botany; condition; evapotranspiration; grass production; habitat; plant communities; plant competition; production; rainfall; rhigozum trichotomum; season; soil water competition; soil water content; south africa; upington; water use