| Summary: | 碩士 === 國立中興大學 === 園藝學系所 === 107 === The aim of this study was to promote the use of agricultural waste, maintain soil productivity, develop alternative technologies to pest-control chemicals,and advocate a sustainable agriculture modle that takes both the environment and industry into consideration.
In this study, biochar produced by Dazzeon Technology and biochar obtained by pyrolysis of stem and leaf residues of ground (Cucurbitaceae) or tomato plants at 350℃ and 550℃ were used. The physical and chemical properties of these biochar products were investigated, and the results indicated that their characteristics varied, and were mainly dependent on the production temperature. The pH values of the biochar were between 8 and 10. Biochar prepared at 350℃ had a low porosity, which was not conducive to water retention, and was hydrophobic; therefore, it was not suitable for addition to a growth medium. Dazzeon biochar (B), or biochar products made by pyrolysis of Cucurbitaceae (C550) or tomato plants (T550) at 550℃, were added to peat soil at 3, 6 or 9% (w/w), and the results showed that treatment with 6% C550 (C5506) significantly improved the germination rate of celery seeds, the leaf area of celery seedlings and the above-ground fresh dry weight. After planting for five weeks, only celery planted in growth medium with T550 showed a reduced above-ground dry weight, and there were no significant differences between the other treatments. When B and C550 biochar were added to the medium mixed with stem and leaf residue, the addition of 6% B biochar increased the plant height, petiole diameter and above-ground fresh weight by 1.3-, 1.2- and 1.4-fold, respectively, indicating that biochar application was of value for use in poorly-cultivated soil environment.
The application of B biochar in the soil of a continuously-monocropped celery system increased the plant height, petiole diameter, petiole number and above-ground fresh dry weight. Among the treatments, adding 6% B biochar (CB6) increased the crop yield by 1.4-fold that of the control, suggesting that biocharcan improved the inhibition effect of the soil due to continuous monocropping. The addition of biochar also promoted tha antioxidant capacity of continuously-moncropped celery. The catalase activity of celery grown in soil mixed with CB6 increased by 9-fold that of the control, and tha MDA content was reduced to 0.8-fold that of the control. The anti-oxidative effect of biochar was then studied using celery plants exposed to gallic acid to induce oxidative stress. GB3 treatment significantly reduced the inhibition effect on crop growth of the high concentration of gallic acid, even at 5000 ppm. GB6 treatment resulted in improved plant height, petiole diameter, above-ground and below-ground fresh dry weights as compared with the control. In the celery seedlings under gallic acid-induced stress, celery plants with biochar treatment had significantly higher activities of antioxidant enzymes, while no significant changes in the MDA content and EC value were observed. The results indicated that gallic acid induced oxidative stress in celery plants, and biochar reserved the inhibition effect on crop growth via increasing the anti-oxidative activity.
Compost materials made from leaf and stem residues of tomato or pumpkin plants by the rapid composting technology developed by Chiu-Chung Young, National Chung Hsing Universiy, were compared. The pH values of the tomato and pumpkin composts were 5.01 and 6.49, respectively. A covering of the compost to a height of 2 or 3 cm inhibited germination of celery seeds, while a compost covering of 1, 2, or 3 cm in height around celery seedlings was found to effectively inhibit weed growth, among which a 3-cm-high pumpkin compost covering had the highest weed inhibition rate of 95%. Covering by rapid compost promoted the growth of celery: a 3-cm-high pumpkin compost covering resulted in the best plant height and fresh weight of celery, at 45.5 cm and 51.5 g, respectivity. The effects of intercropping and the use of insect screens on pest and weed control in a field of rape (Brassica rapa L.) were investigated. The rape was either untreated, or treated with one of the four pest- and weed-control techiques: intercropping with celery, intercropping with shallots, covering with a 32-mesh common insect screen, or covering with a 32-mesh insectide-treated screen. The numbers of insects caught by yellow sticky papers and the total damaged leaf area were used as indices to estimate the effectiveness of pest control, and the fresh weight and dry weight of weeds were used to evaluate the effectivenedd of weed control. Both intercropping and use of an insect screen resulted in better pest and weed control as compared with control conditions. There was no significant difference in the effect on insect control between celery celery and shallot intercropping. The insect control effects of the 32-mesh common insect screen and the insecticide-treated screen were not significantly different, but both resulted in better control than intercropping. The fresh weight and dry weight of weeds under any one of the four control techniques were significantly lower than those of the control, indicating that intercropping and the use of an insect screen can reduce weed growth. In terms of the plant height, stem diameter, and above-ground fresh weight and dry weight of the rape plants, use of the insecticide-treated screen produced the best results, followed by the common insect screen. Furthermore, intercropping with celery or shallots had no significant effect in the growth of the rape plants.
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