【摘要】 应用分室模型，研究了高寒草甸（矮嵩草草甸）生态系统中氮素的分布与循环。结果表明：系统中，土壤库氮素总储量为 １０６３ｔ／ｈｍ ２，主要以有机态存在，土壤氮素全量养分丰富，而有效养分贫乏，仅能满足较低水平生产的供求关系；植物氮素主要储存于植物活根中，根系氮素储量为 １９０１１±４９６２ｋｇ／ｈｍ ２·ａ，活根内氮素占 ７９２６％ 。通过对该系统氮素收支平衡计算结果表明，氮素输出为 １５９３５ｋｇ／ｈｍ ２·ａ，大于系统的输入 ８４７３ｋｇ／ｈｍ ２·ａ，系统中氮素亏缺，成为限制草场生产力提高的限制因子。更多还原

【Abstract】 The N distribution and cycle in on Alpine Meadow Ecosystem by a compartment model was studied.The results showed that the N storage was 10 63t/hm 2,mainly existing as org. N in the soil pool.Although the total N was abundant,the available N was in deficiency.The N storage was 190 1±49 62kg/hm 2 in the plant sub system,and 79 26% of it stored in living roots.By estimating the N input and output amount in the Alpine Meadow Ecosystem,it appeared that the amount of N output(159 35kg/hm 2·a) was much more than input (84 73kg/hm 2·a).The lack of available N,limited the productivity of the grassland in the Alpine Meadow Ecosystem.The N amount existed in the living roots was 3 39times of the plant above ground and this could buffer the need of plants growth.更多还原