The impact of nitrogen application on the stoichiometry of soil and microorganisms in secondary forests of Changbai Mountain
To elucidate the mechanisms by which nitrogen deposition modifies soil and microbial stoichiometric ratios,and consequently impacts soil nutrient cycling dynamics,an experiment was conducted in a secondary forest dominated by Populus davidiana-Betula platyphylla in the Changbai Mountain.Utilizing a simulated nitrogen deposition methodology,three nitrogen application rates were established:0 kg·hm-2·a-1(N0),25 kg·hm-2·a-1(N25),and 50 kg·hm-2·a-1(N50).This study aimed to investigate the influence of nitrogen addition on soil and microbial stoichiometry,thereby providing insights into microbial nutrient limitation patterns.The results indicated that nitrogen application led to significant reduction in soil available phosphorus(AP)content(P＜0.05).Concurrently,it significantly elevated levels of soil dissolved organic carbon(DOC,P＜0.05)and nitrate nitrogen(NO3-N,P＜0.05),thereby increasing the ratios of soil active carbon to phosphorus(DOC/AP)and nitrogen to phosphorus(AN/AP).Notably,nitrogen application did not alter the stoichiometric ratios of total soil carbon,nitrogen,and phosphorus(C/N/P).In contrast,nitrogen addition significantly increased microbial biomass phosphorus(MBP)content(P＜0.05),and simultaneously decreased the ratios of microbial biomass carbon to phosphorus(MBC/MBP)and microbial biomass nitrogen to phosphorus(MBN/MBP).This shift resulted in a pronounced imbalance in C/P and N/P ratios between soil and microorganisms(P＜0.05).Correlation analysis,coupled with random forest modeling,revealed that the observed imbalance in C/P and N/P ratios between soil and microorganisms was primarily attributed to MBP content.These findings suggest that under nitrogen deposition conditions,soil microorganisms in the secondary Populus davidiana-Betula platyphylla forest are significantly constrained by phosphorus availability,prompting them to enhance their phosphorus utilization efficiency.
nitrogen depositionChangbai Mountainsecondary forestsstoichiometric imbalancemicrobial biomassstoichiometric ratio
万方数据
维普
