Objective In order to elucidate the influence of mycorrhizal types on forest soil enzyme activity, this study investigated the differences in soil enzyme activities and the environmental regulatory mechanisms between the arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) types of forests in China.
Methods The data before 2017 were from the Database of Soil Enzyme Activity and Related Factors in Chinese Forest Plots, and the data from 2017 to 2025 was obtained through Google Scholar searches using the keywords “soil enzymes, enzyme activity, and forests”, the data covered a total of 701 forest samples. Based on the mycorrhizal type of the dominant species, 290 forests exclusively featured AM-type and 296 forests exclusively featured ECM-type mycorrhizae. Differences in soil enzyme activity between the two mycorrhizal forest types were calculated using software such as SPSS 26.0. Regression analysis was performed to study the relationship of enzyme activities with environmental factors, and a partial least squares path model was constructed.
Results In AM-type forest soils, invertase (INV) and acid (or alkaline) phosphatase (AP) activities were 10753 μg/(g·2 h) and 591 μg/(g·2 h), respectively, significantly higher than the 5444 μg/(g·2 h) and 280 μg/(g·2 h) observed in ECM-type forests. While urease (URE) activity in AM-type forest soil was 426 μg/(g·d), significantly lower than the 745 μg/(g·d) in ECM-type forest soil. The soil factors influencing forest soil enzyme activity include soil depth, pH, and soil organic matter (SOM), and the climatic factors were mean annual temperature, mean annual precipitation, and altitude. The activities of INV, AP, and protease (PRO) in AM-type forest soil as well as the activity of PRO in ECM-type forest soil were primarily regulated by soil factors. The INV enzyme activity decreased with the increasing of soil depth in AM forests, whereas it increased with increasing soil depth in ECM forests.
Conclusion Mycorrhizal type can influence soil enzyme activities. AM-type forest soils exhibit high INV and AP activities, whereas ECM-type forest soils dominated show high URE activity. The regulatory effects of environmental factors on enzyme activities are mycorrhizal-dependent. The activities of INV, AP, and protease (PRO) in AM-type forest soils, as well as PRO activity in ECM-type forest soils, are primarily regulated by soil factors. In contrast, CAT activity in AM-type forests is mainly influenced by climatic factors. The responses of soil enzyme activities to environmental gradients also vary with mycorrhizal type. INV activity decreases with increasing soil depth in AM forests, while showing an opposite trend in ECM forests. AP activity decreases with rising pH in AM forests, whereas it increases with the augmentation of SOM in ECM forests. The regulatory pathways of environmental factors on soil enzyme activities in ECM forests are more complex than those in AM forests.
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