摘要
氮是陆地生态系统生产力的主要限制性因素,土壤微生物是土壤氮转化的主要驱动因子,随着大气氮沉降的增加,盐渍化草地土壤微生物对不同水平氮输入的响应尚不清晰。在山西右玉黄土高原草地生态系统定位观测研究站不同水平氮添加平台(0、1、2、4、8、16、24和32 g·m^(–2)·a^(–1)),在实验处理的第4年(2020年)测定生长季(5–9月)氨氧化细菌(AOB)和氨氧化古菌(AOA)丰度,土壤真菌和细菌组成,以及土壤微生物生物量碳(MBC)、氮(MBN)含量,探讨土壤微生物特征对不同氮输入水平的响应机制。研究表明:(1)在2020年生长季的5–9月,由于土壤温度和水分的差异,取样日期显著影响氨氧化微生物、细菌和真菌的数量及MBC、MBN含量。(2)氮添加仅显著影响AOB丰度,对MBC、MBN含量及细菌和真菌丰度的影响均不显著。(3)氮添加对AOB丰度的影响与取样日期有关,在生长季早期和高峰期(5–8月), 24和32 g·m^(–2)·a^(–1)氮添加显著提高AOB丰度,在生长季后期(9月)氮添加对AOB丰度的影响不显著。(4)土壤阳离子浓度和土壤pH对AOB丰度的变异具有较高的解释度,分别解释了土壤微生物特征变异的21.8%和17.2%。由于不同水平氮添加并未显著改变土壤阳离子浓度和土壤pH,土壤MBC、MBN含量,细菌和真菌的丰度对氮输入的响应不敏感,仅在高氮处理显著提高了AOB的丰度,说明高氮添加可能会促进盐渍化草地土壤氮的转化速率。
Aims Nitrogen(N) availability is an important limiting factor for grassland ecosystem productivity, and soil microorganisms are the main driving factor on soil N transformation. With the increase of atmospheric N deposition,the response of soil microbial characteristics to different nitrogen input levels is still unclear especially in salinealkaline grassland.Methods The experiment was conducted in Youyu Loess Plateau Grassland Ecosystem Research Station, Shanxi Province. Eight different nitrogen addition levels were set, which were 0, 1, 2, 4, 8, 16, 24 and 32 g·m^(–2)·a^(–1), respectively. The Ammonia-oxidizing microorganisms(i.e. ammonia-oxidizing bacteria(AOB) and ammoniaoxidizing archaea(AOA)) abundance, soil bacterial and fungal abundance, as well as soil microbial biomass carbon(MBC) and nitrogen(MBN) content were measured in the growing season(May to September) in 2020 to explore the effects of different levels of N addition on soil microbial characteristics.Important findings Our results showed that:(1) Sampling month had a significant effect on soil AOB, bacteria,fungal abundance and MBC, MBN content due to the variation in soil temperature and soil water content in thegrowing season.(2) N addition had a significant effect on soil AOB abundance, while had no effects on soil MBC, MBN content, and bacterial and fungal composition.(3) Higher N addition(24 and 32 g·m^(-2)·a^(-1)) significantly increased the abundance of ammonia-oxidizing bacteria(AOB) on the early growth stage(May to August), while having no effect on late growth period(September).(4) Soil microorganisms were mainly regulated by soil cations concentrations and soil pH values, which explained the variation of soil microorganisms by 21.8% and 17.2%, respectively. We found that soil microorganisms were not sensitive to N addition in saline-alkaline grassland, while AOB showed a significant increase under higher N addition, indicating that higher N addition might promote soil N transformation.
作者
杨建强
刁华杰
胡姝娅
王常慧
YANG Jian-Qiang;DIAO Hua-Jie;HU Shu-Ya;WANG Chang-Hui(College of Life Science,Shanxi Agricultural University,Taigu,Shanxi 030801,China;College of Grassland Science,Shanxi Agricultural University,Taigu,Shanxi 030801,China;Youyu Loess Plateau Grassland Ecosystem Research Station,Youyu,Shanxi 037200,China;State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Bejing 100093,China)
出处
《植物生态学报》
CAS
CSCD
北大核心
2021年第7期780-789,共10页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(31770526)
国家重点研发计划(2017YFA0604802)
山西省博士毕业生、博士后研究人员来晋工作奖励资金科研项目(SXBYKY2021052)。
关键词
盐渍化草地
氮添加
氨氧化微生物
细菌
真菌
saline alkaline grassland
nitrogen addition
Ammonia-oxidizing microorganisms
bacteria
fungi
