Pedosphere 34(3): 540--552, 2024
ISSN 1002-0160/CN 32-1315/P
©2024 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Coupling changes of soil functional gene abundances and extracellular enzyme activities across the diagnostic horizons of agricultural Isohumosols |
Zhuxiu LIU1,2, Haidong GU1,2, Xiaojing HU1, Zhenhua YU1, Yansheng LI1, Junjie LIU1 , Jian JIN1, Xiaobing LIU1, Guanghua WANG1 |
1 State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081 (China);
2 University of Chinese Academy of Sciences, Beijing 100049 (China) |
| ABSTRACT |
| Soil functional microbial taxa and extracellular enzymes are involved in a variety of biogeochemical cycling processes. Although many studies have revealed the vertical change patterns of microbial communities along soil profile, the general understanding of the coupling changes in the functional gene abundances (FGAs) and extracellular enzyme activities (EEAs) in soil profiles is still limited, which hinders us from revealing soil ecosystem processes. Herein, we comparatively investigated the FGAs and EEAs in the diagnostic A, B, and C horizons of soil profiles obtained from two suborders of Isohumosols (Mollisols), Ustic and Udic Isohumosols, in Northeast China based on quantitative real-time polymerase chain reaction and standard fluorometric techniques, respectively. The distribution patterns of both FGAs and EEAs significantly distinguished by the two soil suborders and were also separated from A to C horizon. Additionally, the variations of EEAs and FGAs were greater in Udic Isohumosols compared to Ustic Isohumosols along soil profiles, and greater changes were observed in C horizon than in A horizon. Both FGAs and EEAs correspondently decreased along the soil profiles. However, when normalized by soil organic carbon, the specific EEAs significantly increased in deep soil horizons, suggesting that microorganisms will input more resources to the production of enzymes to ensure microbial nutrient requirements under resource scarcity. More importantly, we revealed that soil microbial nutrient demands were limited by carbon (C) and phosphorus (P), and the C and P limitations significantly increased along soil profiles with a greater C limitation observed in Ustic Isohumosols than in Udic Isohumosols. Overall, our findings provided solid evidence showing the links between FGAs, EEAs, and microbial nutrient limitations, which would be helpful for a better understanding of the ecosystem processes in soil profiles. |
| Key Words: ecoenzymatic stoichiometry,microbial nutrient limitation,microbial nutrient requirement,Mollisols,soil ecosystem process,soil profile |
| Citation: Liu Z X, Gu H D, Hu X J, Yu Z H, Li Y S, Liu J J, Jin J, Liu X B, Wang G H. 2024. Coupling changes of soil functional gene abundances and extracellular enzyme activities across the diagnostic horizons of agricultural Isohumosols. Pedosphere. 34(3): 540–552. |
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