摘要
为了明确曝气灌溉下土壤N_2O排放特征及主要影响因子,实验设置了2个灌水量(70%和90%田间持水量)和2个增氧水平(5,40mg/L),采用静态箱法和q PCR技术对土壤N_2O通量及土壤关键功能基因进行测定,研究不同灌水量和增氧水平对土壤充水孔隙度、溶解氧、氧化还原电位(Eh)、矿质氮及氨氧化古菌(AOA)、氨氧化细菌(AOB)和反硝化基因(narG和nosZ)的影响.结果表明:培养过程中,各处理N_2O排放通量均呈现先增加后降低的趋势,于灌溉后1d达到峰值;曝气量和灌水量的增加可显著增加土壤N_2O的排放通量和排放峰值.灌溉造成土壤含水量增加的同时,降低了土壤溶解氧和Eh;曝气可提高土壤溶解氧和Eh,改善土壤通气性(P<0.05),而对土壤充水孔隙度无显著影响.土壤充水孔隙度、Eh、NO_3^--N含量是曝气灌溉下驱动土壤N_2O排放的主要理化因子.曝气显著增加了AOA的基因拷贝数,且N_2O排放与AOA的基因拷贝数呈显著正相关关系(P<0.05).研究结果为进一步明确曝气灌溉对土壤N_2O排放的影响机制和曝气灌溉模式下农田N_2O排放管理提供支撑.
To clarify the characteristics of soil N2O emission and identify the main factors under aerated irrigation(AI), the soil culture experiments were conducted at 2 irrigation levels with upper soil moisture limit as 70% and 90% of field capacity and 2 dissolved oxygen(DO) levels at 5 and 40 mg/L. Soil N2 O emission fluxes were monitored using static chamber-gas chromatography method and the copy number of nitrification and denitrification gene were determined using the real-time quantitative polymerase chain reaction(qPCR) technique. In addition, the main factors on soil N2 O fluxes were analyzed, including soil water filling porosity(WFPS), DO, redox potential(Eh), mineral nitrogen content(NO3--N and NH4+-N), as well as the abundance of soil ammonia-oxidizing bacterial(AOB) and ammonia-oxidizing archaea(AOA) and denitrifier genes(narG and nosZ). Results showed that soil N2 O flux increased from the beginning, peaked at 1 d after irrigation, dropped in the following 3 days, and then stabilized. An increase of aeration and irrigation amount resulted in the increase of average values and peak values of soil N2O fluxes. Irrigation caused an increase of WFPS, while a decrease of soil DO and Eh. Aeration treatments increased soil DO concentration and Eh(P<0.05), improved soil aeration. However, aeration treatments showed no significant impact on WFPS. The WFPS, Eh and NO3^--N content were the main physical, chemical influencing factors driving soil N2O emission under AI. The AI significantly affected AOA copy numbers. In addition, soil N2 O fluxes were significantly correlated with AOA copy number(P<0.05). The results could provide scientific support for the influential mechanism of AI on soil N2O and the farmland N2 O emission management.
作者
雷宏军
刘欢
臧明
潘红卫
陈德立
LEI Hong-jun;LIU Huan;ZANG Ming;PAN Hong-wei;CHEN De-li(School of Water Conservancy,North China University of Water Conservancy and Electric Power,Zhengzhou 450046,China;Faculty of Land and Food Resources,University of Melbourne,Victoria 3010,Australia)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2019年第5期2115-2122,共8页
China Environmental Science
基金
国家自然科学基金资助项目(U1504512
51779093)
河南省科技创新人才项目(174100510021)
华北水利水电大学研究生创新课题(YK2017-02)
中原科技创新领军人才项目(194200510008)
关键词
曝气灌溉
N2O排放
溶解氧
氧化还原电位
基因
拷贝数
影响因子
aerated irrigation
N2O emission
dissolved oxygen
redox potential
gene
copy numbers
influencing factor
