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Chinese Journal of Applied Ecology ›› 2021, Vol. 32 ›› Issue (6): 2209-2216.doi: 10.13287/j.1001-9332.202106.033

• Original Articles • Previous Articles     Next Articles

Long-term effects of imbalanced fertilization with lime and gypsum additions on denitrifying functional genes of an Ultisol at Yingtan, Jiangxi, China

DUAN Chun-jian1,2, WAN Song1,2, YE Gui-ping3, FAN Jian-bo4, WANG Quan-cheng1,2, HE Ji-zheng1,2, LIN Yong-xin1,2*   

  1. 1Cultivation Base of State Key Laboratory for Subtropical Mountain Ecology, Fuzhou 350007, China;
    2School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China;
    3Institute of Oceanography, Minjiang University, Fuzhou 350108, China;
    4Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
  • Received:2020-09-21 Accepted:2021-02-23 Published:2021-12-15
  • Contact: * E-mail: yxlin@fjnu.edu.cn.
  • Supported by:
    National Natural Science Foundation of China (41807048, 41930756) and the China Postdoctoral Science Foundation (2019T120474).

Abstract: The abundance of denitrifying functional genes plays a key role in driving the soil nitrous oxide (N2O) emission potential. Nitrite reductase genes (nirK and nirS) and nitrous oxide reductase genes (nosZ I and nosZ II) are the dominant denitrifying funtional genes. In this study, real-time quantitative PCR was conducted to evaluate the effects of 32-year imbalanced fertilization and lime and gypsum additions on the abundances of nirK, nirS, nosZ I and nosZ II genes in an Ultisol at Yingtan, Jiangxi Province. We further explored the underlying driving factors. The results showed that, compared with the balanced fertilization treatment, fertilization without phosphorus (P) signifi-cantly decreased the abundances of nirK, nirS, nosZ I and nosZ II genes. Fertilization without nitrogen (N) significantly reduced the abundances of nirK, nosZ I and nosZ II, but did not affect the abundance of nirS. Fertilization without potassium (K) did not affect the abundances of all denitri-fying functional genes. Results of stepwise regression analysis and random forest analysis showed that soil pH was a key environmental factor affecting the abundances of nosZ I and nosZ II. The application of lime or lime + gypsum significantly increased soil pH, which subsequently increased the abundances of nosZ II and nosZ II/nosZ I by 150%-231% and 127%-155%, respectively. Our results suggested that application of lime or lime + gypsum favored nosZ II more than nosZ I in upland Ultisols, which might enhance the relative importance of nosZ II in N2O reduction. Overall, fertilization without P would reduce denitrifying gene abundances, while the application of lime or lime + gypsum enriched nosZ II and increased ratio of nosZ II/nosZ I, which might be beneficial for reducing N2O emission potential in the Ultisols.

Key words: agricultural soil, long-term fertilization, liming, nosZ I, nosZ II