太湖和滇池流域保护地蔬菜氮肥去向研究

Fate of Nitrogen Fertilizer Applied to Vegetables Cultivated in Plastic Greenhouses in Taihu and Dianchi Watersheds,China

为了研究化肥氮在保护地土壤-蔬菜系统中的当季利用与损失,在浙江嘉兴和云南昆明15个点位上进行15N田间微区试验。结果表明,保护地莴苣化肥氮当季利用率为8.32%~14.52%,保护地西芹化肥氮当季利用率为6.34%~13.85%,保护地结球生菜化肥氮当季利用率为11.34%。相同土壤、同一种类蔬菜保护地种植中,随着保护地种植年限的增加,蔬菜对化肥氮当季利用率显著降低。莴苣和西芹吸收化肥氮和土壤氮的比例在不同种植年限保护地土壤上差异不显著。当季蔬菜收获后,0～20 cm土层15N丰度和化肥氮残留量显著高于20 cm以下各土层。在保护地莴苣种植系统中,施入土壤中的化肥氮有18.98%～42.5%损失。在保护地西芹种植系统中,有11.7%~18.9%损失。在保护地生菜种植系统中,施入土壤中的化肥氮有16.0%损失。

The application of large amounts of fertilizers,a conventional practice for the production of vegetable,generally lead to substantial accumulation of soil nutrients within a relatively short period of time.Fifteen 15N-labeled micro-plot field experiments were carried out to in-vestigate the utilization and loss of chemical nitrogen fertilizer in soil-vegetable systems in Jiaxing,Zhejiang Province and Kunming,Yunnan Province.The results showed that nitrogen use efficiency of lettuce（Lactuca sativa）,celery（Apium graveolens L.）and leaf lettuce（Lactuca sativa）grown in the greenhouse in the same season were 8.32%~14.52%,6.34%~13.85% and 11.34%.For the same kind of vegetables grown in the same soil,the nitrogen fertilizer use efficiency decreased with increasing cultivation time.There was little difference in ratio of nitrogen uptake of fertilizer and soils.After the current vegetable harvest,15N abundance and nitrogen residue of 0~20 cm soil were signifi-cantly higher than that of deeper soil.18.98%~24.3% of nitrogen was lost from soil-lettuce system.11.7%~18.9% of nitrogen was lost from soil-celery system.16.0% of nitrogen was lost from soil-leaf lettuce system.