無機態氮（硝酸態氮和銨態氮）是植物重要的養分之一，尤其對於不施肥的森林土壤更具重要性，而氮礦化及硝化現象則是重要氮肥力指標，但目前多用少量變數或單一時間(當月或當季)去研究礦化和硝化作用，忽略氣候因子的綜合影響。本研究目的為綜合多量、不同時間點的氣象因子，嘗試以不同的研究角度進一步研究森林土壤的礦化和硝化作用。研究以台大實驗林-塔塔加之三主要植被區雲杉、鐵杉和草原為試驗區，草原和阿里山氣象站的氣象資料為材料，並透過逐步迴歸法篩選出最主要的影響氮礦化和硝化作用的氣候因子。利用氣候因子推估無機態氮含量之試驗結果顯示，鐵杉和雲杉的銨態氮濃度有適合的氣候因子可以建立相關高的迴歸式，而在氮轉化過程中，草原與鐵杉礦化速率主要與採樣當月降水比率有關(R2=0.870及0.747)，雲杉礦化速率主要與採樣當月的降水日數有關(R2=0.801)。草原硝化速率主要與採樣前1個月降水量有關(R2=0.849)，鐵杉硝化速率主要與採樣當月降水比率有關(R2=0.852)，而雲杉硝化速率主要與採樣當月最低氣溫相關(R2=0.841)。

Ammonium and nitrate are important nutrients for plants, especially in forest soil without fertilization. Nitrogen mineralization and nitrification are important index of fertility. However by far, limited numbers of variables and single period were used to study mineralization and nitrification, ignoring the synthetically infections of climate. The aim of this study is using multiple kinds and variable climate factors to discuss the mineralization and nitrification of forest soil. The sampling sites were divided into three vegetation areas in Ta-Ta-Chia forest. Using climatic factors to estimate the inorganic nitrogen content, the ammonium concentrations of hemlock and spruce soils had the suitable climatic factors to establish a high correlation regression equation. In the nitrogen transformation processes, the mineralization rate of grassland and hemlock soils are mainly related with the ratio of precipitation in the sampling month (R2=0.870 and 0.747). The mineralization rate of spruce soil is mainly related with the days of precipitation in the same month (R2=0.801). The nitrification rate of grassland is mainly related with precipitation from previous to sampling month (R2=0.849). The nitrification rate of hemlock is mainly related with the ratio of precipitation in the sampling month (R2=0.852). The nitrification rate of spruce is mainly related with the minimum temperature in the same month (R2=0.841).