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温室条件下,向盆栽山毛榉幼苗中施加1.92 g·m~(-2) ~(15)N示踪物,研究连续两个生长季沉积氮在森林土壤(含森林地被物)、沥出物、以及地上和地下部分生物量的分配.模拟了四种处理(栽培和非栽培)下的NH_4~+和NO_3~-沉积情况,每种处理各自标记为~(15)N-NH_4~+或者~(15)N-NO_3~-.在整个体系中施加~(15)N的总回收率分别是,盆栽处理的~(15)NH_4~+为67.3%～74.9%,非盆栽处理的~(15)N-NO_3~-为85.3%~88.1%.两种~(15)N示踪物主要沉积在森林土壤(包括森林地被物)中,其中盆栽处理的森里土壤中~(15)N-NH_4~+为34.6%～33.7%,~(15)N-NO_3~-为13.1%～9.0%,说明异养微生物有很强的固氮作用.森林土壤微生物对~(15)N-NH_4~+的固定能力比~(15)N-NO_3~-的固定能力强三倍.~(15)N-NH_4~+的优先异养利用造成土壤中~(15)N-NH_4~+的沉积量是植物体保存量的两倍:而土壤中~(15)N-NO_3~-的沉积量却低于植物体的.总之,植被-土壤系统中~(15)N-NH_4~+的沉积量比~(15)N-NO_3~-的沉积高了60%,说明了沉积氮的形式在森林生态系统中氮保存中的重要性.“,”The partitioning of nitrogen deposition among forest soil (including forest floor), leachate and above- and belowground biomass of pot cultured beech seedlings in comparison to non-cultured treatments were investigated by adding 1.92 g·m~(-2) ~(15)N tracer in throughfall for two successive growing seasons at a greenhouse experiment. Ammonium and nitrate depositions were simulated on four treatments (cultured and non-cultured) and each treatment was labeled with either ~(15)N-NH_4~+ or ~(15)N-NO_3~-. Total recovery rates of the applied ~(15)N in the whole system accounted for 74.9% to 67.3% after ~(15)N-NH_4~+ and 85.3% to 88.1% after ~(15)N-NO_3~- in cultured and non-cultured treatments, respec-tively. The main sink for both ~(15)N tracers was the forest soil (including forest floor), where 34.6% to 33.7% of ~(15)N-NH_4~+ and 13.1% to 9.0% of ~(15)N-NO_3~- were found in cultured and non-cultured treatments, respectively, suggesting strong immobilization of both N forms by hetero-trophic microorganisms. Nitrogen immobilization by microorganisms in the forest soil (including forest floor) was three times higher when ~(15)N-NH_4~+ was applied compared to ~(15)N-NO_3~-. The preferential heterotrophic use of ammonium resulted in a two times higher retention of deposited ~(15)N-NH_4~+ in the forest soil as compared to plants. In contrast, nitrate immobilization in the forest soil was lower compared to plants, although statistically it was not significantly different. In total the immobilization of ammonium in the plant-soil system was about 60% higher than nitrate, indicating the importance of the N-forms deposition for retention in forest ecosystems.