Straw addition and low soil moisture decreased temperature sensitivity and activation energy of soil organic matter
Peng He,
Lu-Jun Li,
Shan-Shan Dai,
Xiao-Li Guo,
Ming Nie,
Xuechen Yang,
Yakov Kuzyakov
Affiliations
Peng He
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, PR China; College of Forestry, Northeast Forestry University, Harbin 150040, PR China
Lu-Jun Li
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, PR China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, PR China; Corresponding authors at: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 138 Haping Rd., Harbin 150081, PR China.
Shan-Shan Dai
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, PR China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, PR China
Xiao-Li Guo
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, PR China
Ming Nie
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Coastal Ecosystems Research Station of the Yangtze River Estuary, and Shanghai Institute of Eco-Chongming, Fudan University, Shanghai 200438, PR China
Xuechen Yang
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, PR China; Corresponding authors at: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 138 Haping Rd., Harbin 150081, PR China.
Yakov Kuzyakov
Department of Agricultural Soil Science, Department of Soil Science of Temperate Ecosystems, Georg-August University of Göttingen, Göttingen, Germany; Agro-Technological Institute, RUDN University, Moscow 117198, Russia; Institute of Environmental Sciences, Kazan Federal University, Kazan 420049, Russia
Incorporating straw into soils is an effective and cost-efficient method for sequestering organic carbon (C) and enhancing soil quality. However, the interactive effects of soil moisture and temperature on soil organic matter (SOM) mineralization have remained unclear in the presence of plant residues. We assessed the impacts of 13C-labeled maize (Zea mays) straw on SOM mineralization in two soils with contrasting soil C content (3.0 % and 6.8 %) under two moisture levels (45 % or 65 % water holding capacity (WHC)) and two temperatures (12 °C or 22 °C) through an experimental incubation. In the absence of straw addition, CO2 production at 22 °C was 2–3 times more than at 12 °C, and was 31–40 % higher at 65 % WHC than at 45 % WHC in both soils. Soil temperature and moisture interactively affected straw decomposition. After a 66-day incubation, approximately 7–11 % of straw was decomposed to CO2, contributing 44–67 % to the total CO2 production. Straw addition increased SOM mineralization across all temperature and moisture levels, resulting in a positive priming effect (PE). The highest PE was observed at 45 % WHC and 22℃ in both soils. The temperature sensitivity (Q10 value) of native SOM mineralization decreased with straw addition due to higher quality SOM (i.e., higher the basal microbial respiration rate per unit organic C at 0 °C and DOC/SOC) compared with control (no straw addition). The Q10 values of SOM and straw decomposition was higher at 65 % WHC compared to 45 % WHC, indicating that drought conditions have potential to dampen effects of temperature on the decomposition. We also discovered a positive correlation between Q10 and activation energy and a negative correlation with soil C quality, providing support for the C quality temperature hypothesis. In summary, our findings contribute to advancing our understanding of how soil C dynamics respond to exogenous C inputs under environment change.
