林冠氮沉降对毛竹林土壤磷组分的影响  

Effect of Canopy Nitrogen Deposition on Soil Phosphorus Fractions in a Moso Bamboo Forest

作　　者：魏经纬 肖向前 卓寿佳 蒋文婷 孙宏洋 陈有超 李永夫[1] 余兵 蔡延江 WEI Jingwei;XIAO Xiangqian;ZHUO Shoujia;JIANG Wenting;SUN Hongyang;CHEN Youchao;LI Yongfu;YU Bing;CAI Yanjiang(State Key Laboratory of Subtropical Silviculture,College of Environment and Resources,College of Carbon Neutrality,Zhejiang A&F University,Hangzhou 311300,China;Sichuan Zoige AlpineWetland Ecosystem National Observation and Research Station,Southwest Minzu University,Chengdu 610225,China)

机构地区：[1]浙江农林大学亚热带森林培育国家重点实验室/环境与资源学院,碳中和学院,杭州311300 [2]西南民族大学,四川若尔盖高寒湿地生态系统国家野外科学观测研究站,成都610225

出　　处：《土壤学报》2025年第1期233-245,共13页Acta Pedologica Sinica

基　　金：国家重点研发计划政府间国际科技创新合作重点专项项目(2022YFE0127800);国家自然科学基金项目(42277286);浙江省科学技术厅领雁计划项目(2023C02035)资助。

摘　　要：大气氮沉降是影响森林土壤磷循环的一个重要全球变化因素。以往在森林生态系统中的研究通常采用林下喷施无机氮的方式来模拟氮沉降,该研究方法忽略了林冠对氮的截留吸收,且未考虑大气中有机氮的影响,因而无法全面、准确地评估氮沉降的生态环境效应。因此,同步对比分析林冠、林下不同形态氮沉降对土壤磷的影响,可为更准确地评估氮沉降下森林土壤磷的动态变化提供重要科学依据。基于浙江农林大学毛竹林林冠氮沉降试验平台(包括林冠对照、林冠无机氮沉降、林冠有机氮沉降、林下对照、林下无机氮沉降和林下有机氮沉降处理),测定土壤理化性质、磷组分、微生物生物量磷、酸性磷酸酶活性和磷循环功能基因丰度等,探究不同模拟方式氮沉降和不同形态沉降氮对土壤磷组分的影响及其作用机制。结果显示,林下模拟氮沉降下土壤全磷、难利用磷和易利用磷含量分别显著高于林冠模拟氮沉降下相应的磷组分15.1%~26.5%、18.3%~21.5%和9.7%~38.3%。但是,土壤磷组分在林冠有机氮和无机氮沉降处理间无显著差异,而林下无机氮沉降较林下有机氮沉降显著降低了树脂磷和易利用磷含量。酸性磷酸酶、pH是影响毛竹林土壤磷组分的主要因素,磷循环功能基因丰度并未对氮沉降产生显著响应。综上可知,林冠方式模拟氮沉降显著降低了毛竹林土壤全磷和磷组分中难利用磷和易利用磷的含量,而用传统的林下方式模拟氮沉降则会低估该削减效应。【Objective】Nitrogen(N)deposition is an important global climate change factor affecting soil phosphorus(P)cycling in forest ecosystems.However,understory N application typically applied directly to the ground,has been widely used to simulate N deposition in forest ecosystems in the past.This simulation method may neglect the retention and adsorption effect of the forest canopy,which cannot truly assess the effect of N deposition on soil P cycling.Moreover,organic N is another important component of atmospheric N deposition,but the ecological effect of the organic N deposition has not been fully studied.【Method】To evaluate the effect of atmospheric N deposition on soil P cycling,a field experiment was conducted involving six treatments:canopy control(CNA-CK),canopy inorganic N addition(CNA-IN),canopy organic N addition(CNA-ON),understory control(UNA-CK),understory inorganic N addition(UNA-IN),and understory organic N addition(UNA-ON)based on the Anji Moso Bamboo Ecosystem Research Station of Zhejiang A&F University,in Anji County,Zhejiang Province.The N deposition rate was set at 50 kg·hm^(-2)·a^(-1)(based on the atomic mass of N,the same as below).IN uses ammonium nitrate while ON uses a mixture of 25 kg·hm^(-2)·a^(-1)urea and 25 kg·hm^(-2)·a^(-1)glycine as the N source.The CK treatment involves adding an equal amount of water.Soil P fractions,microbial biomass P,acid phosphatase activity,P cycling functional gene abundance,and some physicochemical properties were measured to investigate the effects of different N deposition simulation approaches and N components on soil P fractions and their driving factors.【Result】The results showed that canopy N addition(CNA)significantly reduced soil total P,occluded P,and labile P concentrations compared to understory N addition(UNA)with the percentage of 15.1%-26.5%,18.3%-21.5%and 9.7%-38.3%,respectively.However,soil P fractions did not differ significantly between CNA-ON and CNA-IN treatments,whereas UNA-IN treatment significantly reduced resin P and labi

关 键 词：土壤磷组分 林冠氮沉降 林下氮沉降 有机氮 酸性磷酸酶活性 

分 类 号：S714[农业科学—林学]