不同干扰强度对闽楠林土壤酶化学计量特征的影响OA

To assess the impacts of human disturbance on soil extracellular enzyme activities and their stoichiometry and to further elucidate the ecological processes and mechanisms of nutrient cycling in forest ecosystems,this study selected Phoebe bournei forests under mild and severe human disturbance intensities in Jianyang,Fujian,China as the research objects.Soil samples(0-10 cm depth)were collected to determine the activities of four enzymes:β-glucosidase(BG),β-1,4-N-acetylglucosaminidase(NAG),leucine aminopeptidase(LAP),and acid phosphatase(AP),along with soil physicochemical properties and microbial biomass.Enzyme stoichiometry and vector analysis were employed to characterize the enzyme activity patterns and nutrient limitations under different disturbance intensities.The results showed that BG activity was significantly higher under mild disturbance than under severe disturbance,whereas LAP activity showed the opposite trend.Severe disturbance resulted in significantly higher N-acquiring enzyme(LAP)activity than mild disturbance.In contrast,the enzymatic C∶N and C∶P ratios were higher under mild disturbance.Vector angles were below 45° under both disturbance intensities,indicating a consistent nitrogen(N)limitation on microorganisms.Moreover,the vector length decreased significantly as the disturbance intensity enhanced.Redundancy analysis identified soil microbial biomass carbon,soil nutrients,pH,and water content as key factors influencing BG,NAG,LAP,and AP activities.Increased disturbance intensity led to reduced C-acquiring enzyme activity,increased N-acquiring enzyme activity,and decreased enzymatic C∶N and C∶P ratios.