摘要： 利用好气淋洗培养法研究了京郊蔬菜保护地耕层土壤氮素矿化状况。结果表明：110个土壤样品2周培养期间氮矿化量分布在2.0～112.00.mg/kg，均值为17.0.mg/kg，81%的样品集中在2.0～23.99 mg/kg，变化范围较大，土壤氮素矿化量与有机质、全氮含量显著正相关，与碱解氮不相关；筛选其中4个土壤样品进行21周的长期好气培养，土壤累计氮矿化量变化范围是19.00～337.00.mg/kg，均值为102.00.mg/kg。表层土壤氮矿化速率的变化可分为3个阶段，第一阶段(0～21 d)，矿化速率较快；第二阶段(21～91 d)，矿化速率趋缓；第三阶段(91 d以后)，矿化速率保持稳定。21周内京郊保护地土壤平均可供氮量为214.00.mg/kg(相当于86.00.kg/hm²)，超过了保护地蔬菜正常生长当季所需氮量。

关键词: 保护地, 氮矿化量, 氮矿化速率

Abstract: To characterize soil nitrogen mineralization in protected vegetable fields of Beijing suburbs,110 soil samples were studied by both shortterm and longterm aerobic incubation with intermittent leaching.Results showed that the average quantity of mineralized nitrogen of all the samples was 17.50 mg/kg,ranging from 2.50 to 112.00 mg/kg,but 81 percent of the samples were between 2.50 and 23.99 mg/kg in two weeks,indicating a relatively consistent mineralization capacity of the soils in protected vegetable fields in Beijing suburbs.The soil mineralized nitrogen has significantly positive correlation with organic matter and total nitrogen,but no correlation with alkali nitrogen.In addition,45 soil samples were chosen for longterm incubation in 21 weeks.The cumulative quantity of the mineralized nitrogen ranged from 19.00 to 337.00 mg/kg(avg.102.00 mg/kg).There were three phases for the change of mineralized nitrogen rate:a fast phase in the first three weeks;a slower one between the third and the seventeenth week;and a steady mineralization phase later.Nitrogen supplied by soil of protected vegetable fields in Beijing suburbs was 214.00 mg/kg in 21 weeks at average,which was higher than the nitrogen requirements of crops for normal growth in one growth season.

Key words: Protected vegetable fields, Quantity of the mineralized nitrogen, Nitrogen mineralization rate

中图分类号: 

• S18.2