Temperature sensitivity of soil respiration to elevated temperature and nitrogen availability

• Published in: Soil & tillage research Vol. 244; p. 106267
• Main Authors: Li, Yufei, Zhang, Kaiping, Li, Yuling, Wan, Pingxing, Zhou, Zhongke, Zhao, Wucheng, Zhang, Ningning, Chai, Ning, Li, Zhixin, Huang, Yalan, Zhang, Feng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2024
• Subjects: Q10; Soil organic carbon; Soil respiration; Temperature sensitivity; Q10; Temperature sensitivity; Soil respiration; Soil organic carbon
• ISSN: 0167-1987
• DOI: 10.1016/j.still.2024.106267

Plastic film mulching (PFM) and nitrogen (N) fertilization are two important agricultural management methods that are used to enhance crop yields in semi-arid dryland agriculture. However, the impacts of PFM and N fertilization on the temperature sensitivity (Q10) of soil respiration (Rt), particularly its heterotrophic (Rh) and autotrophic (Ra) components, remain unclear. To investigate this, a trenching experiment was carried out between 2019 and 2021 in a rainfed maize-cultivated cropland that had been under cultivation for 7 years. There were four treatments: no PFM and N fertilization (control), full PFM without N fertilization (PFM), 150 kg N ha–1 fertilization without PFM (Nfer), and full PFM with 150 kg N ha–1 fertilization (PFM+Nfer). PFM and N fertilization not only enhanced crop yield and root biomass but also increased soil total respiration (Rt) and its components, due to improved soil hydrothermal conditions with PFM and increased N availability with N fertilization. Soil hydrothermal conditions and root biomass were identified as the most important factors influencing Rh and Ra, respectively. The greater increase in Ra (84 %–212 %) compared to Rh (9 %–29 %) resulted in a decrease in the proportion of Rh in Rt decreasing from 81.2 % in the control to 58 % under the PFM+Nfer treatment. The Rh/Rt ratio decreased in all three treatments compared to the control (p < 0.05). The increase in Rh under PFM led to a decrease in soil organic carbon (SOC) by 17 %. Specifically, the soil labile C content (i.e. LFOC 44 %) decreased more under PFM and PFM+Nfer (p < 0.05) compared to control, but not under the Nfer treatment (p > 0.05). Plastic film mulching increased the Q10 of Rh (p < 0.05) through decrease the content of soil labile C, whereas N fertilization had no effect (p > 0.05). Both PFM and N fertilization increased the Q10 of Ra (p < 0.05) by increasing root biomass. The impact of Ra’s Q10 (0.66) on Rt’s Q10 is greater compared to Rh’s Q10 (0.31). To our knowledge, this is the first long-term field study to examine the response of Rt components and their Q10 to PFM and N fertilization. Our results highlight that soil labile C and root biomass are the determining factors for the Q10 of Rh and Ra, respectively. We emphasize the importance of accurately modeling the temperature responses of Rh and Ra when predicting Rt under climate change scenarios.
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•Both plastic film mulching (PFM) and N increased the Q10 of total soil respiration.•PFM increased heterotrophic respiration's Q10 by reducing the soil labile C.•PFM increased autotrophic respiration's Q10 via soil hydrothermal improvement.•N increased autotrophic respiration's Q10 by increasing root biomass.•Total soil respiration's Q10 increase is primarily driven by autotrophic respiration.