| Summary: | 碩士 === 國立中興大學 === 園藝學系 === 88 === The objective of this study is to investigate the 13 commercial media on plugs seedling growth of cabbage and tomato. The seeds of cabbage and tomato were sown in 128 cell-PE plugs at TSS greenhouse. The changes of physical and chemical properties of different media were investigated before and during seedling growth stages. Seedling growth parameter were assessed seedling growth and after transplanting in field.
The major components of tested media were white and black peat mosses. Total porosity was increased with increasing of white peat moss and the smaller of the particles had smaller in total porosity. Degree of the air-filled porosity and container capacity were varied with ratios of perlite, vermiculite, sand and wetting agent. Bluk density was decreased as white peat moss and perlite increased, but would increased with increasing of fine sand. The pH value of sphagnum peat moss was below 4 originally, however, after adding of lime into the media, the pH value would be above 5. The EC value was higher than 1.0mS/cm when media contained more black peat moss and fertilizer.
Total porosity had been declined rapidly at the early seedling stage, nevertheless, risen again to the prior value during the seedling growth in cabbage. On the contrary, total porosity had declined gradually and risen again to the original value in tomatoes. The rising range of total porosity was higher in media which contained more fine black peat moss. Air-filled porosity of the media had been increased significantly at the early stage and become mildly later. Container capacity had decreased substantially at the early stage and level off after middle stage. The change in bluk density of medium was not distinct. The pH values of media were changing toward 6.8-7.0 which conincide with the pH value of irrigation water for medium with pH values either below 6 or above 7 originally. EC value of medium had decreased dramatically at the early stage of seedling growth and then slowly decreased in late stages. Days after fertilization, the EC value would risen a little.
Moderate air-filled porosity (5 to 6%) and EC below 0.38 were the best medium for the early stage seedling growth in cabbage. A lower air-filled porosity (15.78 to 16.71%), container capacity around 74.5 to 75.6% and EC value about 0.16 to 0.22mS/cm were the best conditions for the middle-stage seedling growth. However, at the late stage, air-filled porosity 15 to 17% and EC value 0.26 to 0.29mS/cm would be recommended.
The optimal ranges of physical and chemical properties of medium for the tomato seedlings were wider than cabbage. At the early stage, air-filled porosity 8.36 to 9.10%, container capacity from middle to high (80 to 85%) and EC value 0.43 to 0.26mS/cm. For the middle stage of seedling growth, container capacity from middle to low (72 to 80%), pH value 5.7 to 6.6, EC value 0.25 to 0.5, were the best conditions. After all, the physical and chemical properties of medium did not significantly affect the growth. However, the pH value below 5.78, EC value 0.36 to 0.47 would be suggested.
The effects of physical and chemical properties of medium decreased as the days after transplanting increased. There were no significant differences in total yields of cabbage while using of different medium in nursery.
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