施肥对露地菜地氨挥发和氧化亚氮排放的影响

为探究施氮量和不同肥料调控措施对露地菜地土壤氨(NH₃)挥发和氧化亚氮(N₂O)排放的影响,在华北地区典型露地菜地设置了不同施氮水平和肥料调控措施的田间试验.结果表明: 春播黄瓜生育期内减氮20%和50%分别比常规施氮量降低氨挥发25.7%和48.0%;添加抑制剂(脲酶抑制剂+硝化抑制剂)和生物炭分别比等氮量氮肥处理氨挥发降低10.0%和6.1%;春播黄瓜生育期内减氮20%和50%分别使N₂O排放量比常规施肥处理降低28.8%和61.0%;等氮量条件下添加联合抑制剂使N₂O排放降低58.9%,而添加生物炭处理的N₂O排放增加14.1%;在同样的条施覆土施肥方法下,与纯化学氮肥处理相比,有机肥替代30%氮肥对氨挥发和N₂O减排的作用效果都不显著.对于集约化菜地,合理控制氮肥用量是降低土壤氨挥发及N₂O排放的最有效措施.

Impact of fertilization on ammonia volatilization and N2O emissions in an open vegetable field

A field experiment with different nitrogen fertilization rates and mitigation measures was conducted in an open-ground vegetable field on the North China Plain to investigate the effects of nitrogen application level and management practices on ammonia volatilization and N₂O emission. Reducing the nitrogen fertilization rate by 20% and by 50% decreased ammonia volatilization by 25.7% and 48.0%, respectively, during the spring-sowed cucumber growth period. Amendment with combined inhibitors and biochar decreased ammonia volatilization loss by 10.0% and 6.1%, respectively. Reducing nitrogen fertilization rate by 20% and 50% decreased N₂O emission by 28.8% and 61.0% during the spring-sowed cucumber growth period. Addition of combined inhibitors decreased N₂O emission by 58.9%, while it was increased by 14.1% with biochar addition. Under the same application method of banding application, replacing 30% nitrogen fertili-zer with organic manure did not show any significant mitigation for ammonia volatilization and N₂O emission. For the intensively managed vegetable fields, reducing the nitrogen application rate appropriately was the most effective measure to reduce ammonia volatilization and N₂O emission.