氮添加影响下新疆天山雪岭云杉林土壤酶活性及其与环境因子的相关性

Soil Enzyme Activity in Picea schrenkiana and Its Relationship with Environmental Factors in the Tianshan Mountains,Xinjiang

氮沉降可能影响森林土壤性状及代谢活性,为进一步了解氮沉降下森林土壤生化过程与生境相互作用机制,探究天山雪岭云杉林土壤酶活性及土壤环境因子对氮沉降的响应特征,本文以天山雪岭云杉森林土壤为研究对象,采用氮沉降梯度法开展施氮试验,分析不同施氮水平下土壤酶活性与土壤环境因子的特征,并结合冗余分析方法讨论了土壤酶活性与土壤环境因子的相关性.结果表明:①土壤酶活性均随施氮量增加表现出先上升后降低的趋势,除土壤酸性磷酸酶外,其余均在低氮处理下达到最大值.②外源氮添加导致土壤pH值降低,低氮或中氮处理后土壤电导率、土壤有机碳、土壤铵态氮、土壤铵态氮、土壤全磷和土壤C/N含量升高,土壤N/P呈现不规律下降.③土壤酶及其与土壤环境因子相关性分析结果显示,土壤含水量、土壤有机碳、土壤铵态氮、土壤全磷和土壤C/N均与土壤酶活性呈显著相关性,其中仅土壤C/N与土壤酶活性呈显著负相关,其余各项环境因子与土壤酶均呈极显著正相关;土壤pH值及土壤N/P与土壤酶活性无显著相关性.新疆天山雪岭云杉在施氮背景下,影响土壤酶活性的重要因子为土壤有机碳和土壤铵态氮.

Nitrogen deposition may affect forest soil traits and metabolic activity.We would like to further understand the mechanisms of soil biochemical processes and habitat interactions under conditions of nitrogen deposition in forests and to investigate the characteristics of soil enzyme activities and soil environmental factors in response to nitrogen deposition in Picea schrenkiana forests in the Tianshan Mountains.In this study,nitrogen application tests were carried out using the nitrogen sedimentation gradient method on Picea schrenkiana forest soils in the Tianshan Mountains.We analyzed the characteristics of soil enzyme activity and soil environmental factors at different nitrogen application levels and discussed the correlation between soil enzyme activity and soil environmental factors in conjunction with a redundancy analysis.The study showed that:①Soil enzyme activities showed a tendency to increase and then decrease with the increase in nitrogen application.With the exception of soil acid phosphatase,all enzyme levels reached maximums in the low nitrogen treatment.②Exogenous nitrogen addition led to low soil pH values,and in the low or medium nitrogen treatments,soil conductivity and the content of organic carbon,ammonium nitrogen,ammonium nitrogen,and total phosphorus increases,along with the C/N ratio,while the N/P ratio showed an irregular decline.③Soil enzymes and their correlation with soil environmental factors showed that soil water content,organic carbon content,ammonium nitrogen content,total phosphorus content,and the C/N ratio were all significantly correlated with soil enzymes activity.Only the C/N ratio was negatively correlated with soil enzyme activity,while all other environmental factors were positively correlated with soil enzyme activity.There was no significant correlation between pH and the N/P ratio and soil enzyme activity.The important factors influencing soil enzyme activity were soil organic carbon and ammonium nitrogen with nitrogen application in Picea schrenkiana,Xinjiang.