中文摘要：

本研究针对北京郊区汇源与正谷有机蔬菜基地,通过对不同蔬菜生产基地取样分析,研究有机和常规蔬菜生产条件下土壤养分平衡特征,分析有机生产蔬菜和土壤的15N特征。结果表明,（1）有机蔬菜生产与常规生产对比,由于施肥数量不同,汇源有机蔬菜基地土壤N、P及K盈余量（分别为356～472kg·hm-2、298kg·hm-2和200～226kg·hm-2）高于当地常规生产,而正谷有机蔬菜生产土壤N、P及K养分盈余量（分别为-164～190kg·hm-2、107.9～435.5kg·hm-2和-164.5～-136.8kg·hm-2）低于当地常规生产;（2）汇源有机蔬菜生产模式中,土壤N素养分有逐季累积的趋势,有机肥的N、P和K养分存在着不平衡性,这可能是造成0～20cm土层磷素大量累积的重要原因;（3）蔬菜类别不同,δ15N值不同,一般为叶菜类最高（10.49‰）,果菜类次之（10.07‰）,根菜类δ15N值最低（5.62‰）;（4）植物不同部位δ15N值也有差异。针对圆椒的分析表明,圆椒叶δ15N（12.44‰）〉圆椒果实δ15N（9.35‰）;（5）土壤δ15N与土壤全N之间有一定的相关性,回归方程为δ15N土壤=13.098N土壤＋3.7624,R2=0.938,而植物δ15N与土壤δ15N之间、植物δ15N与土壤全氮相关性较差。长期施用有机肥,使得土壤中15N更多来自有机肥,进而表现为蔬菜δ15N升高,高量有机肥可以短期内增加叶菜类植物δ15N值。

英文摘要：

This study reviewed organic and conventional vegetable bases in the Beijing suburbs, and took soil, vegetable and fertilizer samples for the analysis of soil nutrients balance and δ15N characteristics. The results indicated that：（1）when comparing types of farms, as organic fertilizer levels increased, the Huiyuan organic vegetable-soil system had more surplus of Nitrogen（N）, Phosphorous（P）and Potassium（K）nutrients（356～472 kg·hm-2, 298 kg·hm-2 and 200～226 kg·hm-2, respectively） than the Zhenggu farm（-164～190 kg·hm-2, 107.9～435.5 kg·hm-2 and -164.5～-136.8 kg·hm-2）; （2）the Huiyuan organic production system tended to accumulate an excess of P because of high fertilizer input; （3）leaf vegetables had the highest δ15N value（10.49‰）, fruit vegetables rank the second（10.07‰） and root vegetables had the lowest δ15N value（5.62‰）; （4）plant leaves are more sensitive than fruit to the application of nitrogen fertilizer, which is seen in the garden pepper, where its leaf had higher δ15N（2.44‰）value than its fruit（9.35‰）;（5）total N in soil was positively correlated with soil δ15N, with the following regression equation：δ15Nsoil=13.098Nsoil＋3.762 4, R2=0.938. However, there is low correlation between plant and soil δ15N, and between plant δ15N and soil total nitrogen. Long term application of organic fertilizers will increase the quantity of 15N and also δ15N of vegetables. Higher quantity of organic fertilizers will increase δ15N of leaf vegetables within short period.