研究报告

  • 陈紫萱,周钟昱,蒋文婷,田琳琳,李彦,蔡延江.竹林河岸带土壤反硝化脱氮效果模拟及机理研究[J].环境科学学报,2022,42(6):426-436

  • 竹林河岸带土壤反硝化脱氮效果模拟及机理研究
  • Nitrogen removal by bamboo forest riparian soil denitrification and the associated mechanisms: A laboratory simulation
  • 基金项目:国家自然科学基金(No.41907268);长江水利委员会长江科学院开放基金(No.CKWV2019760/KY);浙江农林大学校科研发展基金(No.2018FR005,2018FR006,2018FR061)
  • 作者
  • 单位
  • 陈紫萱
  • 浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州 311300;浙江农林大学林业与生物技术学院,杭州 311300
  • 周钟昱
  • 浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州 311300;浙江农林大学林业与生物技术学院,杭州 311300
  • 蒋文婷
  • 浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州 311300;浙江农林大学环境与资源学院,杭州 311300
  • 田琳琳
  • 浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州 311300;浙江农林大学林业与生物技术学院,杭州 311300
  • 李彦
  • 浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州 311300;浙江农林大学林业与生物技术学院,杭州 311300
  • 蔡延江
  • 浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州 311300;浙江农林大学环境与资源学院,杭州 311300
  • 摘要:以太湖流域上游南苕溪流域农业区竹林河岸带土壤为研究对象,采用乙炔抑制法研究不同外源硝态氮(NO3--N)添加量(模拟添加NO3--N浓度分别为0、5和10 mg·L-1的污水,分别用N0、N5和N10处理表示)对不同离水距离(0~3、3~6、6~12 m)、不同深度(0~10、10~20、20~40 cm)土壤反硝化速率的影响.结果表明,N0、N5和N10处理的土壤72 h内的反硝化速率均值分别为59.65、163.56和295.81 μg·kg-1·h-1,不同处理间差异显著.N5和N10处理的土壤对外源NO3--N的脱氮率均值分别为0.45和0.51,且N5处理显著低于N10处理;土壤反硝化速率和对外源NO3--N脱氮率均随NO3--N添加量的增大而增加.土壤反硝化速率随离水距离的增加而降低,表层土壤的反硝化脱氮效果最好.高量外源NO3--N 添加能为土壤反硝化提供较为充足的底物,耦合较高的反硝化微生物功能基因(nirS、nosZ I和nosZ II)丰度,可显著提高表层土壤或离水距离越近土壤对外源NO3--N的脱氮率.本研究的竹林河岸带土壤反硝化可对过境与河流水体NO3--N的去除发挥重要的生态作用,也可为该区河流水体氮污染的控制提供一定的科学参考.
  • Abstract:Soil denitrification rates under the addition of different exogenous nitrate (NO3--N, simulating 0, 5 and 10 mg·L-1 polluted water, indicated as N0, N5 and N10 treatments, respectively) were determined by using acetylene inhibition technique in a bamboo forest riparian zone in agricultural area of the Nantiaoxi River watershed in the upper reaches of the Taihu Lake Basin during summer. Soil samples were collected at different distance from water (0~3, 3~6, 6~12 m) with three depths (0~10, 10~20, 20~40 cm) in the riparian zone. The results showed that the average soil denitrification rates within 72 h in the N0, N5, N10 treatments were 59.65, 163.56 and 295.81 μg·kg-1·h-1, respectively, with significant differences among these three treatments. The removal ratios of exogenous NO3--N were respectively 0.45 and 0.51 in N5 and N10 treated soils, with significant difference between them. Soil denitrification rates and removal ratios of exogenous NO3--N could be stimulated with the increase in exogenous NO3--N addition. Soil denitrification rate decreased with increasing the distance from water, and the highest removal ratio of exogenous NO3--N generally occurred in the top surface soil. It can be concluded that high exogenous NO3--N addition can provide sufficient substrate for soil denitrification, in combination with the high abundance of denitrification functional genes (nirS, nosZ I and nosZ II) in the top surface soil or the nearest soil from water, which subsequently result in high removal ratios of exogenous NO3--N in these two positions. This study further shows that soil denitrification in the bamboo forest riparian zone can play an important ecological role in the removal of exogenous NO3--N and also provides a certain scientific reference for mitigating nitrogen pollution in rivers in this area.

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