摘要
【目的】研究施氮下多酚氧化酶、过氧化氢酶活性、微生物生物量碳氮、土壤养分和有机碳的动态变化特征,以期为深入探究施氮对森林生态系统土壤微生态环境的影响提供参考。【方法】以滇中高原高山栎(Quercus aquifolioides)林为研究对象,设置不同施氮梯度:对照(CK)[0 g N/(m^(2)·a)]、低氮(LN)[10 g/(m^(2)·a)]、中氮(MN)[20 g/(m^(2)·a)]、高氮(HN)[25 g/(m^(2)·a)],研究不同土层(0~10、10~20、20~30 cm)土壤养分、酶活性、微生物生物量碳(MBC)以及微生物生物量氮(MBN)动态变化特征。【结果】各测定指标随施氮时间延长未呈现显著变化规律;施氮浓度对多酚氧化酶、土壤pH、TN、铵态氮、硝态氮、土壤微生物生物量碳氮有极显著影响(P<0.001),对SOC有显著影响(P<0.05)。土层深度对多酚氧化酶、过氧化氢酶、土壤pH、TN、AN、铵态氮、土壤微生物生物量碳氮有极显著影响(P<0.001);①施氮处理2 a后,与CK相比,不同土层土壤有机碳(SOC)随施氮浓度升高而降低,降幅为10.93%~25.33%,土壤全磷(TP)则在HN下降低13.09%~15.74%;土壤全氮(TN)、土壤速效氮(AN)、土壤铵态氮(NH+4-N)、土壤硝态氮(NO3-N)随施氮浓度而升高,增幅分别为9.70%~27.72%、4.11%~14.72%、16.36%~51.50%、17.57%~59.52%和22.07%~93.55%;②随着施氮浓度升高,不同土层多酚氧化酶、过氧化氢酶活性分别下降3.76%~24.86%和6.14%~29.05%,2种酶活性的降幅随着施氮的增加而增加;③相较于CK,各土层中随施氮浓度升高,MBN和MBC则分别减少2.14%~94.99%和3.75%~40.53%;④相同施氮下,随着土层加深,土壤养分含量、MBC、MBN和2种酶活性均下降。施氮与SOC具有显著的负相关性,而相同条件下,TN、AN、NH_(4)^(+)-N、NO3-N受到显著促进作用,使森林土壤养分格局失衡,从而间接降低多酚氧化酶和过氧化氢酶的活性,进而改变高山栎林土壤微生物环境。【结论】施氮与SOC具有显著的负相关性,而相同条件下,TN、AN、NH_(4)^(+)-N、NO3-N受到显著促进作用,使森林土壤养分格局失衡,从而间接降低多酚氧化酶和过氧化氢酶的活性,进而改变高山栎林土壤微生物环境。
【Objective】This study investigated the dynamic changes in polyphenol oxidase and catalase activitives,microbial biomass carbon(MBC)and nitrogen(MBN),soil nutrients,and soil organic carbon(SOC)under nitrogen addition,with the aim of providing insights into the impact of nitrogen deposi‐tion on the soil microecological environment of forest ecosystems.【Method】A Quercus aquifolioides for est in the central Yunnan Plateau was selected as the study site.Four nitrogen addition treatments were established:control[CK,0 g/(m^(2)·a)],low nitrogen[LN,10 g/(m^(2)·a)],medium nitrogen[MN,20 g/(m^(2)·a)],and high nitrogen[HN,25 g/(m^(2)·a)].Soil samples were collected from three depths(0-10,10-20,20-30 cm)to assess changes in soil nutrients,enzyme activity,soil microbial quantity,MBC and MBN.【Result】Nitrogen addition duration did not result in significant temporal trends for most indicators.However,nitrogen concentration significantly affected polyphenol oxidase,soil pH,to‐tal nitrogen(TN),ammonium nitrogen(NH+4-N),nitrate nitrogen(NO−3-N),MBC and MBN(P<0.001),and had a significant impact on SOC(P<0.05).Soil depth very significantly influenced polyphe‐nol oxidase,catalase,soil pH,TN,available nitrogen(AN),NH+4-N,MBC,and MBN(P<0.001);①After 2 years of nitrogen addition,SOC decreased by 10.93%-25.33%with increasing nitrogen concentration,while soil total phosphorus(TP)decreased by 13.09%~15.74%under HN.In contrast,TN,AN,NH+4-N and NO−3-N increase by 9.70%-27.72%,4.11%-14.72%,16.36%-51.50%,17.57%-59.52%,and 22.07%-93.55%,respectively;②With larger decreases under higher nitrogen levels,Polyphenol oxidase and catalase activities declined by 3.76%-24.86%and 6.14%-29.05%,respectively;③Compared to CK,the dec rease in microbial numbers in each soil layer was 16.67%-64.75%as nitrogen ap‐plication concentration increased;MBC and MBN decreased by 3.75%-40.53%and 2.14%-94.99%,repsectively;④Across all treatments,soil nutrient content,enzyme activities,MBC,and MBN declined with soil depth.【Conclusion】Nitrogen addition was significantly negatively correlated with SOC,but markedly promoted TN,AN,NH_(4)^(+)-N,and NO−3-N,leading to an soil nutrient imbalances.These changes indirectly reduced the activities of polyphenol oxidase and catalase and altered the soil microbial environment in Quercus semacarpifolia forest.
作者
梁子琪
王克勤
宋娅丽
陈蕾西
梁阳森
周敬
LIANG Ziqi;WANG Keqin;SONG Yali;CHEN Leixi;LIANG Yangsen;ZHOU Jing(College of Ecology and Environment(College of Wetlands),Southwest Forestry University,Kunming 650224,China;Forest Fire Control and Forestry and Grass Information Center of Kunming,Kunming 650506,China)
出处
《四川农业大学学报》
北大核心
2025年第4期893-905,共13页
Journal of Sichuan Agricultural University
基金
云南省科技厅面上项目(202401AT070262)
云南省大学生创新创业训练计划项目(202210677011)。
关键词
施氮
多酚氧化酶活性
过氧化氢酶活性
微生物生物量碳氮
滇中地区
nitrogen deposition
polyphenoloxidase activity
catalase activity
microbial biomass carbon and nitrogen
central Yunnan
作者简介
梁子琪,硕士研究生,E-mail:liangziqi0621@163.com;宋娅丽,副教授,主要从事生态系统结构与功能研究,E-mail:songyali19851205@sina.com。
