摘要
利用中国唯一的稻麦轮作臭氧FACE(free-air O3 concentration enrichment,开放式空气臭氧浓度增高)试验平台,研究近地层臭氧浓度升高对稻田不同生育时期植株氮吸收量、土壤氮含量与脲酶活性、土壤氨氧化细菌与反硝化细菌数量以及成熟期土壤硝化与反硝化作用强度的影响。结果发现,臭氧浓度升高条件下,单株水稻(Oryza sativaL.)的氮吸收量趋于升高,土壤全氮含量趋于下降、脲酶活性趋于增强,在成熟期土壤全氮与对照相比平均下降9%,土壤脲酶活性与对照相比平均升高13%。在水稻整个生长季节,土壤氨氧化细菌和反硝化细菌的数量均呈现出先增多后减少的趋势,且均在开花期达到峰值,但臭氧熏蒸土壤与对照相比趋于升高;在水稻成熟期,土壤中单个氨氧化细菌和反硝化细菌的活性均趋于下降,土壤硝化强度和反硝化强度与对照相比也平均下降17%和24%。结果表明,近地层臭氧浓度升高条件下,稻田土壤氮素转化因为水稻氮素吸收增强而加快,土壤氨氧化细菌和反硝化细菌的数量均趋于增多,但它们的生理代谢活性均趋于下降。
An O3-FACE（free-air O3 concentration enrichment） system in a rice/wheat rotation field was used to investigate the effects of elevated surface O3 concentration on rice N-uptake,soil N concentration,soil urease activity,and the numbers of ammonia-oxidizing bacteria（AOB） and denitrifying bacteria（DNB） as well as soil nitrification and denitrification potentials.With the elevated O3 concentration,individual rice N-uptake tended to increase,while soil total N concentration tended to decrease during the whole period of rice growth.Soil total N concentration decreased by 9% on average at rice maturing stage.Elevated O3 concentration tended to enhance soil urease activity with an increase of 13% on average at rice maturing stage.During the whole period of rice growth,the numbers of soil AOB and DNB increased first and then decreased,and both numbers of AOB and DNB reached the peak at rice flowering stage.Elevated O3.concentration tended to increase the number of AOB and DNB but tended to decrease soil nitrification and dnitrification potentials with an decrease of 17% and 24% on average,respectively,which may be due to low specific nitrification potential of AOB and specific dnitrification potential of DNB at rice maturing stage.These results suggested that under elevated O3 concentration,soil N transformation was accelerated because of increasing rice N-uptake,the population of soil AOB and DNB tended to increase but their metabolic activity tended to decrease.
出处
《生态环境学报》
CSCD
北大核心
2010年第8期1789-1793,共5页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(40771202)
科技部国际科技合作计划项目(2009DFA31110)
中国科学院科研装备研制项目(YZ0603)
国际合作重点项目(GJHZ0748)
日本环境厅全球环境研究基金项目(中日合作)(C-062)
关键词
臭氧浓度升高
氨氧化细菌
反硝化细菌
脲酶活性
水稻氮吸收量
elevated O3 concentration
ammonia-oxidizing bacteria
denitrifying bacteria
urease activity
rice N-uptake
