| Summary: | 碩士 === 國立中興大學 === 水土保持學系 === 87 === Mudstone is one of the problem soils regarding soil and water conservation in Taiwan. High salinity in surface soils hinders vegetation growth in the drought season. The purposes of this study are to introduce salt tolerance herbs and screen the suitable plants for the use of vegetated buffer strips at the mudstone bare areas. Three salt tolerance herbs Sporobolus virginicus, Suaeda nudiflora, Sea-purslane and two major conservation grasses Paspalum notatum and Cynodon dactylon were used to rate the salt tolerance. Two plots were selected at mudstone distributed areas in Wu-Shan-Tou reservoir watershed for the observation of drought and/or salt tolerance of the herbs. The results were summarized as follows:
In a sequence of 0, 50, 100, 150 mmhos/cm of NaCl gradient treatment, Suaeda nudiflora shows the best tolerance in salinity. Sporobolus virginicus has slight declines in coverage at the initial treatment of 150 mmhos/cm NaCl, while soon recovers a week later. The higher soil salinity, the lower coverage Sea-purslane and/or Cynodon dactylon has. Paspalum notatum was discarded because of susceptible to salt damage in the pilot experiment. Photosynthesis efficiency of Suaeda nudiflora and Sporobolus virginicus were not obviously affected by the salt treatment, while that of Sea-purslane and Cynodon dactylon show a decline against the salinity treatment.
After a week of leaching process to remove the salts, coverage increases of each tested plant and there is a 5% level of significant difference comparing with that at the stage of 150 mmhos/cm salinity treatment. The increment of coverage in order for the tested plants is Sea-purslane, Cynodon dactylon, Sporobolus virginicus and Suaeda nudiflora. Photosynthesis efficiency of tested plants were all increasing and showing a 5% level of significant difference with that of 150 mmhos/cm salinity treatment respectively. Photosynthesis efficiency of Sea-purslane even recovered to the level of pre-salinity treatment.
Leaves of Sporobolus virginicus show obviously salt excretion. Water soluable salts in plant tissue of the tested plants is Sporobolus virginicus, Cynodon dactylon, Sea-purslane and Suaeda nudiflora in order at the stage of 150 mmhos/cm salinity treatment.
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