| Summary: | 碩士 === 國立中興大學 === 水土保持學系所 === 103 === Bahiasgrass (Paspalum notatum Flügge) has been be promoted as the major cover plant for slopeland fruit tree planting areas in Taiwan, and it is used with hillside ditches to reduce labors. A slopeland citrus orchard in the Dahu Township, Miaoli County, is selected as the research area in this study. The environment factors (luminosity, soil water content) and ground cover plants in orchards which have been completely covered with Bahiasgrass for 27 years were investigated. The relationships between the spatial distribution of vegetation and environment factors show that luminosity is the key factor for vegetation composition, and the adaptability of ground cover plants to luminosity is discussed. Furthermore, soil under five types of dominant ground cover plants is sampled and analyed to discuss their soil conservation function. Bahiasgrass can effectively enhance soil porosity, water content, organic matter, and aggregate stability; Knotweed (Polygonum chinense L.) and Chinese Dicliptera (Dicliptera chinensis (L.) Juss.) enhances soil porosity and water content, appears to largely increase organic matter and nutrient availability, and outperforms Bahiasgrass for aggregate stability; Sour Grass (Paspalum conjugatum Berg.) effectively enhances soil porosity, water content, and organic matter; Hairy Beggar Ticks (Bidens pilosa L. var. radiata Sch. Bip.) presents low soil conservation effect.
Finally, the adaptability to luminosity, the soil conservation function, and the management convenience are integrated to evaluate the applicable cover plants for orchards. Bahiasgrass is a favorable slopeland cover plants, but is not suitable for orchards with the relative luminosity below 40% because of low tolerance to shade; however, it could be applied to cover working roads and young orchards. Naturally regenerated grasses, Knotweed, Chinese Dicliptera, and Spreading Dayflower (Commelina diffusa Burm f.), with good shade tolerance can be kept as cover plants in the understory of orchards because they are good for soil conservation effect and management convenience. Sour Grass with broader adaptability to luminosity can grow well under fruit trees and on working roads; because it presents the advantages of soil conservation and management convenience that it can be used in orchards and on working roads.
|
|---|
