| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 90 === In order to investigate the soil physical and chemical characters and the plant nutritional characteristics of May-foung area, the soil and plant samples were collected in some area of May-foung of montane experimental farm, National Taiwan University from August 2000 to July 2001. There were five different areas with different historic practices. The five areas were: area of just stopping agricultural cultivation and reforest about one year (Rf1), area of stopping agricultural cultivation and reforest about five years (Rf5), a burned area with reforest about 20 years (Frf20), area of virgin forest (Vf), and area of artificial pine forest about 20 years (Pn20). The leaves and stems of plants of higher population in each area were sampled randomly. And the total nitrogen, total phosphorus, total potassium, nitrate nitrogen, calcium, magnesium, iron, manganese, copper, zinc, and aluminum concentrations were analyzed. At the same time, the soil samples of each area were sampled and analyzed their basic physical and chemical properties.
The result showed that almost all soil textures of five areas were clay loam. However, the pH, organic matter content, cation exchange capacity, total nitrogen, total phosphorus, available phosphorus, exchangeable potassium, calcium, and magnesium of the soils differed with different areas and showed that they were easily affected by the agricultural practices. In general, the soil characteristics of cultivated area tended to change in the direction of disadvantage to the ecosystem. There were great differences in plant species in different areas and there were also differences in nutritional characteristics in different plant species. Owing to the heterogeneity in soil fertility in forest soils, the nutritional composition of plants of the same species grown in different areas were also different. The nitrate nitrogen concentration in the plants was low, therefore, the nitrogen may be the main growth limiting factor of the forest plants. In general, there was no significant accumulation of micronutrients in the plants grown in strongly acidic soil condition. However, in Rf1, Rf5, and Pn20 area, there were plants that accumulated some of micronutrients to high concentration.
|
|---|
