Pedosphere 36(5): 1003--1012, 2026
ISSN 1002-0160/CN 32-1315/P
©2026 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effects of microtopographic modification on soil labile organic carbon fractions and enzyme activities in restored urban wetlands |
Kangting OUYANG1, Zhongyu SUN1, Long YANG1 , Guangqing HUANG1, Cunxiang FAN2, Zhibin LIN2 |
1 Guangzhou Institute of Geography, Guangdong Academy of Sciences, Guangzhou 510070 (China);
2 Haizhu Wetland Public Education and Research Center in Guangzhou, Guangzhou 510235 (China) |
| ABSTRACT |
| Soil labile organic carbon (LOC) and enzyme activities are highly sensitive to environmental changes. However, the impacts of microtopographic variations in restored urban wetlands on soil LOC fractions, enzyme activities and their mechanisms remain unclear. This study compared changes in soil organic carbon (SOC), LOC fractions, and enzyme activities across different microtopographic zones, including hummocks, flats, and hollows, in the Haizhu National Wetland Park in Guangzhou City, Guangdong Province, South China and explored interrelationships among these soil factors. The results indicated that microtopography identified significant levels of SOC and LOC fractions, with notable variations in soil enzyme activities and environmental variables (including soil chemical properties and water table) among the various microtopographic zones. Notably, although dissolved organic carbon showed relatively stable levels across the gradient from hummocks to hollows, the levels of SOC, microbial biomass carbon, and easily oxidizable carbon were the highest in hollows. Hydrolases were the most expressed in hummocks, whereas oxidases exhibited peak activity in hollows. Correlation analysis indicated that the hydrolase activities exhibited significant negative correlations (P < 0.01) with the contents of SOC and LOC fractions, as well as other soil chemical properties, while oxidase activities showed positive correlations. The partial least squares path model revealed that microtopography mediated changes in water levels, which in turn regulated soil pH and nutrient availability, thus affecting the activities of hydrolases and oxidases. In summary, microtopography influenced soil enzyme activities through altering the spatial distributions of SOC and LOC fractions at the site scale. This study highlights the important roles of microtopographic modification in wetland carbon storage and cycling processes, providing valuable insights for urban wetland restoration and management. |
| Key Words: environmental variable,microtopographic zone,soil organic carbon,urban wetland restoration,water table |
| Citation: Ouyang K T, Sun Z Y, Yang L, Huang G Q, Fan C X, Lin Z B. 2026. Effects of microtopographic modification on soil labile organic carbon fractions and enzyme activities in restored urban wetlands. Pedosphere. 36(5): 1003-1012. |
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