Abstract
Daily variation in water potential was measured inCynodon dactylon in seasonally flooded areas of the Pongolo river floodplain. Soil moisture declined during the dry winter season when the plants were exposed, causing them to experience increasing water stress. Fog and mist appeared to relieve stress but it is concluded that water stress is sufficient to reduce production during exposure. The results are discussed in relation to the timing of flood releases from the upstream Pongolapoort dam and it is concluded that the period of exposure is of less significance than the duration and frequency of inundation in the formulation of guidelines for flood releases from the dam.
Similar content being viewed by others
References
Bornman, C. H., C. E. J. Botha & L. F. Nash, 1973.Welwitschia mirabilis:Observations on movement of water and assimilates under fohn and fog conditions.Madoqua, Ser. 2, 2: 25–31.
Cole, N. H. A., 1973. Soil conditions, zonation and species diversity in a seasonally flooded tropical grassherb swamp in Sierra Leone. J. Ecol. 61: 831–847.
Furness, H. D., 1981. The plant ecology of seasonally flooded areas of the Pongolo river floodplain with particular reference toCynodon dactylon (L.) Pers. Ph.D. Thesis. Univ. Natal, Pietermaritzburg, South Africa, 131 pp.
Furness, H. D. & C. M. Breen, 1980. The vegetation of seasonally flooded areas of the Pongolo river floodplain. Bothalia 13: 217–231.
Furness, H. D. & C. M. Breen, 1982. Decomposition ofCynodon dactylon (L.) Pers. in the seasonally flooded areas of the Pongolo river floodplain: pattern and significance of dry matter and nutrient loss. Hydrobiologia 97: 119–126.
Furness, H. D. & C. M. Breen, 1985. Interactions between period of exposure, grazing and crop growth rate ofCynodon dactylon (L.) Pers. in seasonally flooded areas of the Pongolo River floodplain. Hydrobiologia 126: 65–73.
Gardner, W. H., 1965. Water content. In: C. A. Black (ed.), Methods of Soil Analysis. Am. Soc. Agron. Madison, Wisconsin: 82–127.
Gindel, I., 1965. Irrigation of plants with atmospheric water within the desert. Nature 207: 1173–1175.
Haas, R. H. & J. D. Dodd, 1972. Water stress patterns in honey mesquite. Ecology 53: 674–680.
Heeg, J. & C. M. Breen, 1982. Man and the Pongolo floodplain. S. Afr. Natn. scient. Progm. Rep. 56, C.S.I.R. Pretoria, 117 pp.
Hillel, D., 1971. Soil and Water. Physical Principles and Processes. Academic Press, N.Y., 288 pp.
Hinckley, T. M. & D. N. Bruckerhoff, 1975. The effects of drought on water relations and stem shrinkage ofQuercus alba. Can. J. Botany 53: 62–72.
Junk, W. J., 1982. Amazonian floodplains: their ecology, present and potential use. Revue. Hydrobiol. trop. 15: 285–301.
Kerfoot, O., 1972. Mist precipitation on vegetation. For. Abstr. 29: 8–20.
Kramer, P. J., 1969. Plant and Soil Water Relationships: A Modern Synthesis. McGraw-Hill, Publishing Co. Ltd, N.Y., 482 pp.
Louw, G. N. & M. K. Seely, 1980. Exploitation of fog water by a perennial Namib dune grass,Stipagrostis subulicola. S. Afr. J. Sci. 76: 38–39.
Marshall, T. J., 1959. Relations between water and soil. Tech. Comm. 50, Commonwealth Bureau of Soils, Harpenden, England, 91 pp.
McNaughton, S. J., L. L. Wallace & M. B. Coughenour, 1983. Plant adaptation in an ecosystem context: effects of defoliation, nitrogen and water on growth of an African C4 sedge. Ecology 64: 307–318.
Millar, B. D. & G. K. Hansen, 1975. Exclusion errors in pressure chamber estimates of leaf water potential. Ann. Bot. 39: 915–920.
Moll, E. J. & N. Romoff, 1983. Evidence of mist trapping byThamnochortus punctatus Pillans at Pella in the southwestern Cape Province. S. Afr. J. Sci. 79: 432.
Oosting, H. J., 1956. The Study of Plant Communities. W. F. Freeman & Co., S. Francisco, 440 pp.
Rees, W. A., 1978. Ecology of the Kafue Lechwe: soils, water levels and vegetation. J. appl. Ecol. 15: 163–176.
Richards, L. A., 1949. Methods of measuring soil moisture tension. Soil Sci. 68: 95–112.
Richter, H., 1976. The Water Status in the Plant — Experimental Evidence. In O. L. Lange, L. Kappen & E. D. Schulze (eds), Water and Plant Life, Problems and Modern Approaches, Ecological Studies 19, Springer-Verlag, Berlin: 42–58.
Ritchie, G. A. & T. M. Hinckley, 1975. The pressure chamber as an instrument for ecological research. Adv. ecol. Res. 9: 165–254.
Schulze, R. E., 1974. Catchment Evapotranspiration in the Natal Drakensberg. Ph.D. Thesis. Univ. Natal, Pietermaritzburg, S. Africa, 244 pp.
Sheppe, W. & T. Osborne, 1971. Patterns of use of a floodplain by Zambian mammals. Ecol. Monogr. 41: 179–205.
Shure, D. J. & A. J. Lewis, 1973. Dew formation and stem flow on common ragweed (Ambrosia artemisiifolia). Ecology 54: 1152–1155.
Slatyer, R. O., 1967. Plant-Water Relationships. Academic Press, Lond. 366 pp.
Sojka, R. E. & L. H. Stolzy, 1980. Soil-oxygen effects on stomatal response. Soil Sci. 130: 350–358.
Stone, E. C., 1963. The ecological importance of dew. Q. Rev. Biol. 38: 328–341.
Vesey-Fitzgerald, D. F., 1963. Central African grasslands. J. Ecol. 51: 243–274.
Wareing, R. H. & B. D. Cleary, 1967. Plant moisture stress: evaluation by pressure bomb. Science 155: 1248–1254.
Welcomme, R. L., 1979. Fisheries Ecology of Floodplain Rivers. Longman, N.Y. 317 pp.
Went, F. W., 1955. Fog, mist, dew and the other sources of water. In: A. Stefferud (ed.) Yearbook of Agriculture. U.S. Dep. Agric., Washington: 103–109.
Westfall, R. H. & R. Drewes, 1984. Grass root pattern in an Orange Free State floodplain. Bothalia 15: 293–294.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Furness, H.D., Breen, C.M. An assessment of the importance of water stress in seasonally floodedC. dactylon on the Pongolo River floodplain in the formulation of guidelines for controlled flooding. Hydrobiologia 137, 175–184 (1986). https://doi.org/10.1007/BF00004213
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00004213