氮添加对色季拉山急尖长苞冷杉林土壤呼吸的影响  

The Effect of Nitrogen Addition on Soil Respiration in the Abies Georgei var.Smithii Forest of Sygera Mountains

作　　者：朱乐洋 张西哲 陶江 王秀 韩艳英 叶彦辉[1,2,3] ZHU Leyang;ZHANG Xizhe;TAO Jiang;WANG Xiu;HAN Yanying;YE Yanhui(Institute of Plateau Ecology,Tibet Agriculture and Animal Husbandry College,Linzhi 860000,P.R.China;Tibet Key Laboratory of Forest Ecology of Plateau,Ministry of Education,Linzhi 860000,P.R.China;Faculty of Forest Resources and Environmental Science,Tibet Agricultural and Animal Husbandry College,Linzhi 860000,P.R.China)

机构地区：[1]西藏农牧学院高原生态研究所,西藏林芝860000 [2]西藏高原森林生态教育部重点实验室,西藏林芝860000 [3]西藏农牧学院资源与环境学院,西藏林芝860000

出　　处：《生态环境学报》2024年第9期1384-1396,共13页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(31860141,31360119);西藏高原森林生态教育部重点实验室研究生创新计划项目(XZA-JYBSYS-2023-26)。

摘　　要：西藏氮沉降相对较低,但是近些年随着工业的建设和发展,西藏氮沉降也呈现出上升趋势。氮沉降对西藏森林土壤呼吸产生了较大影响,从而影响土壤生态环境和森林生态环境。对西藏色季拉山急尖长苞冷杉(Abiesgeorgeivar.smithii)林,通过设置对照(CK,0kg·hm^(-2)·a^(-1))、低氮(LN,10kg·hm^(-2)·a^(-1))、中氮(MN,15kg·hm^(-2)·a^(-1))和高氮(HN,20kg·hm^(-2)·a^(-1))4种氮添加梯度试验组,评估氮沉降对土壤呼吸和生态环境的影响。在2020-2023年期间,持续进行施氮肥试验,并定期检测土壤呼吸指标。结果表明:1年期各梯度的氮添加对土壤呼吸均有抑制作用,并且抑制作用:HN>MN>LN。1年期CK、LN、HN添加的土壤呼吸速率均在9月最大,MN添加的土壤呼吸速率则在6月最大。1年期各梯度的氮添加均降低了各月间土壤呼吸的变化幅度,且具有显著差异性。1年期氮添加的单日土壤呼吸速率总体上在12:00-16:00较大,在2:00-4:00较小,但是在不同时刻的变化幅度不大,不具有显著差异性。4年期HN添加对土壤呼吸的抑制作用明显减弱,MN添加甚至会在6月促进土壤呼吸,对土壤呼吸的总体抑制作用:HN>LN>MN。与1年期相比,4年期的各梯度氮添加处理的土壤呼吸速率在10月下降幅度显著增大,单日土壤呼吸速率变化的单峰分布趋势增强,并且个别时刻出现了土壤呼吸速率与平均值偏离较大的现象。此外,4年期的氮添加会提升土壤酶活性,并且显著增加土壤温度与土壤呼吸的指数相关性,4年期LN、HN添加还会显著增加土壤呼吸的Q10值。总体而言,长期氮添加减弱了对土壤呼吸的抑制作用。该研究为了解高海拔地区土壤呼吸和氮沉降之间的关系,以及保护高原山地生态系统提供了理论依据。Nitrogen deposition in Xizang is relatively low;however,recent industrial construction and development have led to an upward trend in nitrogen deposition.This increase in nitrogen deposition has notably affected soil respiration in the forests of Tibet,consequently affecting both the soil ecological environment and forest ecosystems.In Abies georgei var.smithii forest in Sygera Mountains,Xizang,by setting up control(CK,0 kg·hm^(-2)·a^(-1)),low nitrogen(LN,10 kg·hm^(-2)·a^(-1)),medium nitrogen(MN,15 kg·hm^(-2)·a^(-1))and high nitrogen(HN,20 kg·hm^(-2)·a^(-1))four nitrogen addition gradient experimental groups,the impact of nitrogen deposition on soil respiration and ecological environment was evaluated.From 2020 to 2023,nitrogen fertilizer experiments were conducted continuously,and soil respiration indicators were regularly monitored.The results indicated that nitrogen addition at various gradient levels over a one-year period had an inhibitory effect on soil respiration,with HN>MN>LN.Soil respiration rates were the highest in September for the CK,LN,and HN treatments throughout the year,whereas the MN treatment showed the highest rate in June.Nitrogen addition at various gradient levels over a one-year period reduced the variation in soil respiration between months,showing significant differences.In addition,the daily soil respiration rate generally increased between 12:00 and 16:00,and decreased between 2:00 and 4:00 during the one-year period of nitrogen addition.However,the variation in soil respiration at the different time points was not statistically significant.The inhibitory effect of HN addition on soil respiration significantly decreased over the four-year period,whereas MN addition promoted soil respiration in June,suggesting that the overall inhibitory effect on soil respiration was HN>LN>MN.Compared with the one-year period,the soil respiration rate of the nitrogen addition treatments at various gradient levels significantly decreased in October,and the daily soil respiration rate showed an

关 键 词：氮添加 温度 土壤性质 色季拉山 土壤呼吸 

分 类 号：S154.1[农业科学—土壤学] X171.1[农业科学—农业基础科学]