研究报告
陈晨,许欣,毕智超,熊正琴.生物炭和有机肥对菜地土壤N2O排放及硝化、反硝化微生物功能基因丰度的影响[J].环境科学学报,2017,37(5):1912-1920
生物炭和有机肥对菜地土壤N2O排放及硝化、反硝化微生物功能基因丰度的影响
- Effects of biochar and organic manure on N2O emissions and the functional gene abundance of nitrification and denitrification microbes under intensive vegetable production
- 基金项目：国家自然科学基金（No.41471192）；公益性行业农业科研专项（No.201503106）；国家科技支撑计划（No.2013BAD11B01）
- 作者
- 单位
- 陈晨
- 南京农业大学, 江苏省低碳农业和温室气体减排重点实验室, 南京 210095
- 许欣
- 南京农业大学, 江苏省低碳农业和温室气体减排重点实验室, 南京 210095
- 毕智超
- 南京农业大学, 江苏省低碳农业和温室气体减排重点实验室, 南京 210095
- 熊正琴
- 南京农业大学, 江苏省低碳农业和温室气体减排重点实验室, 南京 210095
- 摘要：通过室内培养试验和实时荧光定量PCR技术，研究了田间施用生物炭和有机肥对菜地土壤氧化亚氮（N2O）排放、氨单加氧酶（amoA）和亚硝酸盐还原酶（nirS、nirK）、氧化亚氮还原酶（nosZ）基因丰度的影响，并探讨功能基因丰度对N2O排放的影响.试验设置5个处理：CK（对照）、N（尿素）、N+BC（尿素和生物炭）、N+M（尿素和有机肥）和N+BC+M（尿素、生物炭和有机肥）.结果表明，与CK处理相比，各施肥处理均降低了土壤氨氧化细菌（AOB）和氨氧化古菌（AOA）丰度，增加了nirK、nirS和nosZ基因丰度，并提高了培养期间N2O累积排放量.与N处理相比，N+BC处理的土壤pH值提高了11.1%，并增加了AOB、AOA、nirS、nirK和nosZ基因丰度，增幅分别为105.8%、57.3%、22.0%、176.2%和204.9%，同时显著降低了培养期间N2O累积排放量，降幅为58.1%；N+M处理增加了nirK和nirS基因丰度，增幅分别为58.8%和7.1%，对N2O排放的影响不显著；N+BC+M处理增加了AOB、nirK、nirS和nosZ基因丰度，增幅分别为30.7%、68.7%、6.5%和84.5%，降低了N2O累积排放量，降幅为14.4%.生物炭通过增加amoA、nirS和nirK基因丰度间接增加N2O排放，同时通过增加nosZ基因丰度促进N2O还原，综合效应表现为降低了菜地土壤N2O排放.因此，通过施用生物炭改善土壤性质，增加功能基因丰度，降低土壤N2O排放，是一种较好的N2O减排措施.施用有机肥可以增加反硝化作用功能基因丰度，但对N2O减排效果不显著.
- Abstract：A 6-week incubation experiment with vegetable soils was conducted using real-time quantitative polymerase chain reaction (PCR) method to investigate the effects of biochar and organic manure on N2O emissions and functional marker genes of ammonia monooxygenase gene (amoA), nirK, nirS and nosZ, which are responsible for nitrification and denitrification. The field experiment included five treatments as following, CK:control, N:urea nitrogen fertilizer, N+BC:urea nitrogen fertilizer+biochar, N+M:urea nitrogen fertilizer+organic manure fertilizer and N+BC+M:urea nitrogen fertilizer+biochar+organic manure fertilizer. Results showed that compared with the CK treatment, the treatments receiving urea (N, N+BC, N+M and N+BC+M) greatly inhibited the copies of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA), stimulated the copies of nirS, nirK and nosZ genes and increased N2O cumulative emissions throughout the incubation period. Compared with the N treatment, the N+BC treatment significantly increased soil pH by 11.1%, and simulated the copies of AOB, AOA, nirS, nirK and nosZ genes by 105.8%, 57.3%, 22.0%, 176.2% and 204.9%, respectively, thus decreased cumulative N2O emissions by 58.1%. Although it greatly increased nirK and nirS genes by 58.8% and 7.1%, respectively, the N+M treatment had no significant influence on N2O emissions as compared with the N treatment. The N+BC+M treatment greatly stimulated AOB, nirK, nirS and nosZ gene copies by 30.7%, 68.7%, 6.5% and 84.5%, respectively, and finally decreased cumulative N2O emissions by 14.4% as compared with the N treatment. Results suggested that biochar addition decreased overall N2O emissions by enhancing the expression of nosZ gene although it enhanced N2O production by stimulating the expression of amoA, nirK and nirS genes. In conclusion, the addition of biochar could serve as an appropriate practice for mitigating N2O emissions and increasing N-cycling microbial community under intensive vegetable fields. However, the addition of organic manure had little effects on N2O emission although it increased the gene abundance of denitrification microbes.
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