Abstract: The study with pot experiment showed that at the rapid-swelling stage of winter jujube fruit,the percent of nitrogen derived from fertilizer (Ndff%) was the highest (10.64%) in fine roots,followed by new-growth nutritive organs.The absorbed urea-¹⁵N decreased in leaves and deciduous supers,and accumulated preferentially in root systems after harvest.The Ndff% in coarse roots was the highest (3.69%) before budding stage,while that in new-growth organs (new branches,deciduous supers,leaves and flowers) was the highest at full-blooming stage.The urea-¹⁵N applied at core-hardening stage mainly allocated in nutritive organs (leaves,deciduous supers,roots) in the first year,with the distribution rate 54.01% in root systems in winter,which was higher than that in branches (45.99%).The ¹⁵N stored in main branches changed drastically from post-harvest to budding stage.Main branches could be regarded as the ‘target organs’ of N storage,while coarse roots were the ‘longterm sink’ of N storage.The N reserve distributed preferentially in contiguity organs,and the distribution center changed with the growth and development of winter jujube in next spring.

Key words: microbial biomass, soil carbon sequestration, extracellular enzyme, common garden., microbial metabolic quotient