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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。
In this study, the suburbs of Beijing Huiyuan and Zhenggu organic vegetable base, through the sampling analysis of different vegetable production base to study the characteristics of soil nutrient balance under organic and conventional vegetable production conditions, analysis of 15N characteristics of organic production of vegetables and soil. The results showed that: (1) Comparing the organic vegetable production with conventional production, the N, P and K surpluses of soil in Huiyuan organic vegetable base were 356 ~ 472kg · hm-2,298kg · hm-2 and 200 ~ 226kg · hm-2) were higher than those of conventional local production, while N, P and K nutrient surplus of organic vegetable production in Zhenggu (-164-190kg · hm-2, 107.9-445.5kg · hm-2 and -164.5 ~ -136.8kg · hm-2) were lower than the conventional production in the area. (2) N-nutrient in soil had a tendency of accumulative accumulation in the mode of production of organic vegetables in Huiyuan. The imbalance of N, P and K in organic manure , Which may be the main reason for the mass accumulation of phosphorus in 0-20cm soil layer. (3) The δ15N values of different vegetables are different, the highest is leafy vegetables (10.49 ‰), the second is fruit vegetables (10.07 ‰) The lowest value of δ15N was 5.62 ‰. (4) The δ15N values of different parts of plants were also different. The analysis of pepper showed that δ15N (12.44 ‰)> δ15N (9.35 ‰) of peppercorns, (5) δ15N of soil had some correlation with soil N, and the regression equation was δ15N soil = 13.098N Soil +3.7624 and R2 = 0.938, while the correlation between δ15N of plant and δ15N of soil and δ15N of plant was less than that of soil total nitrogen. Long-term application of organic fertilizer, making 15N more from the soil organic fertilizer, and then showed the δ15N increased vegetables, high-volume organic fertilizer can short-term increase δ15N value of leafy vegetables.