Temperature decouples ammonia and nitrite oxidation in greenhouse vegetable soils

Pengpeng Duan; Qianqian Zhang; Zhengqin Xiong

doi:10.1016/j.scitotenv.2020.139391

Temperature decouples ammonia and nitrite oxidation in greenhouse vegetable soils

Sci Total Environ. 2020 Sep 1:733:139391. doi: 10.1016/j.scitotenv.2020.139391. Epub 2020 May 20.

Authors

Pengpeng Duan¹, Qianqian Zhang², Zhengqin Xiong³

Affiliations

¹ Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China.
² Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
³ Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: zqxiong@njau.edu.cn.

PMID: 32446093
DOI: 10.1016/j.scitotenv.2020.139391

Abstract

The influence of temperature on soil ammonia (NH₃) and nitrite (NO₂^-) oxidation and related NO₂^- accumulation in soils remain unclear. The soil potential NH₃ oxidation (PAO) and NO₂^- oxidation (PNO) rates were evaluated over a temperature gradient of 5-45 °C in six greenhouse vegetable soils using inhibitors. The values of temperature sensitivity traits such as temperature minimum (T_min), temperature optimum (T_opt), and maximum absolute temperature sensitivity (T_{m_sens}) were also fitted to the square root growth (SQRT) and macromolecular rate theory (MMRT) models. The ammonia-oxidizing archaea (AOA) and bacteria (AOB) were determined by quantifying amoA, and nitrite-oxidizing bacteria (NOB) were determined by quantifying the nxrA and nxrB. Both models identified that T_opt for PAO (34.0 °C) was significantly greater than that for PNO (26.0 °C). The T_{m_sens} (23.4 ± 2.1 °C) and T_min (1.0 ± 2.0 °C) for PAO were higher than those for PNO (16.8 ± 3.2 °C and - 11.7 ± 6.7 °C). PAO was positively correlated with AOB-amoA at 20-30 °C and with AOA-amoA at 30-35 °C, while PNO was positively correlated with nxrB at 5-30 °C. Additionally, NO₂^- and N₂O were positively correlated with the (AOA + AOB amoA) to (nxrA + nxrB) ratio, and the concentration of N₂O was positively correlated with NO₂^- accumulation. These results highlight that elevated temperatures resulted in the uncoupling of NH₃ oxidation and NO₂^- oxidation, leading to NO₂^- accumulation, which could stimulate N₂O emissions.

Keywords: Ammonia oxidation; Inhibitors; Nitrite; Nitrite oxidation; Nitrous oxide; Temperature.