Riparian zones are the interface between rivers and terrestrial systems. Vegetation in riparian zones plays a key role in inhibiting soil erosion and facilitating nutrient cycling processes. However, few studies have quantified the relationship between spatial patterns of riparian zone vegetation and soil enzyme activities. In this study, we report the spatial variation of soil enzyme activities under four vegetation cover zones. We linked vegetation cover, soil physicochemical properties and soil enzymes, and used partial least squares structural equation modeling (PLS-SEM) to quantify the driving forces of soil physicochemical properties on changes in enzyme activity under vegetation cover. The activities of phosphorus (P)- and nitrogen (N)-acquisition enzymes in the riparian zone are higher than those of carbon (C)-acquisition enzymes, with alkaline phosphatase (AP) (ave = 69.39µmol·g− 1·h− 1) and leucine aminopeptidase (LAP) (ave = 135.39µmol·g− 1·h− 1) having higher activities, and cellulase (EG) (ave = 2.22µmol·g− 1·h− 1) having lower activities. There was significant spatial difference in soil enzyme activity, manifested as higher enzyme activity in the 0–20 cm (ave = 43.33µmol·g− 1·h− 1) soil layer than in the 20–50 cm (ave = 35.81µmol·g− 1·h− 1). Meanwhile, the average activity of soil enzymes under vegetation cover is 2.16 times that of bare land, indicating that vegetation cover significantly increases soil enzyme activity. Meanwhile, the average activity of soil enzymes under vegetation cover is 2.16 times that of bare land, indicating that vegetation cover significantly increases soil enzyme activity. The PLS-SEM results showed that the influence of soil physicochemical properties on soil enzyme activity was stronger in the 0–20 cm soil layer than in the 20–50 cm. The average weight coefficients of total nitrogen (TN), nitrate nitrogen (NO3-N), and soil organic carbon (SOC) in the two soil layers were 0.844, 0.809, and 0.905, respectively, which were the main factors affecting changes in soil enzyme activity. Research has shown that differences in vegetation cover greatly alter soil environmental factors in riparian zones, affecting the spatial distribution pattern of soil enzyme activity. Increasing the vegetation coverage area of the riparian zone and controlling its soil nitrogen pollution load can promote nutrient cycling in the soil vegetation system, thereby effectively improving the ecological environment of the watershed.

Dynamic Response of Soil Enzyme Activities in Riparian Zones: Insights From Vegetation Cover

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发表日期：

2025年1月16日

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Zixuan Yan,
Peng Li,
Zhanbin Li,
Naichang Zhang,
Chenxu Zhao,
Yongxiang Cao,
Minghui Zhang,
Yuchen Wang,
Xiaofeng Zhao

摘要

Riparian zones are the interface between rivers and terrestrial systems. Vegetation in riparian zones plays a key role in inhibiting soil erosion and facilitating nutrient cycling processes. However, few studies have quantified the relationship between spatial patterns of riparian zone vegetation and soil enzyme activities. In this study, we report the spatial variation of soil enzyme activities under four vegetation cover zones. We linked vegetation cover, soil physicochemical properties and soil enzymes, and used partial least squares structural equation modeling (PLS-SEM) to quantify the driving forces of soil physicochemical properties on changes in enzyme activity under vegetation cover. The activities of phosphorus (P)- and nitrogen (N)-acquisition enzymes in the riparian zone are higher than those of carbon (C)-acquisition enzymes, with alkaline phosphatase (AP) (ave = 69.39µmol·g^− 1·h^− 1) and leucine aminopeptidase (LAP) (ave = 135.39µmol·g^− 1·h^− 1) having higher activities, and cellulase (EG) (ave = 2.22µmol·g^− 1·h^− 1) having lower activities. There was significant spatial difference in soil enzyme activity, manifested as higher enzyme activity in the 0–20 cm (ave = 43.33µmol·g^− 1·h^− 1) soil layer than in the 20–50 cm (ave = 35.81µmol·g^− 1·h^− 1). Meanwhile, the average activity of soil enzymes under vegetation cover is 2.16 times that of bare land, indicating that vegetation cover significantly increases soil enzyme activity. Meanwhile, the average activity of soil enzymes under vegetation cover is 2.16 times that of bare land, indicating that vegetation cover significantly increases soil enzyme activity. The PLS-SEM results showed that the influence of soil physicochemical properties on soil enzyme activity was stronger in the 0–20 cm soil layer than in the 20–50 cm. The average weight coefficients of total nitrogen (TN), nitrate nitrogen (NO₃-N), and soil organic carbon (SOC) in the two soil layers were 0.844, 0.809, and 0.905, respectively, which were the main factors affecting changes in soil enzyme activity. Research has shown that differences in vegetation cover greatly alter soil environmental factors in riparian zones, affecting the spatial distribution pattern of soil enzyme activity. Increasing the vegetation coverage area of the riparian zone and controlling its soil nitrogen pollution load can promote nutrient cycling in the soil vegetation system, thereby effectively improving the ecological environment of the watershed.