DOI: 10.1007/s10533-015-0157-5
Scopus记录号: 2-s2.0-84951569077
论文题名: Chronic nitrogen fertilization and carbon sequestration in grassland soils: evidence of a microbial enzyme link
作者: Cenini V.L. ; Fornara D.A. ; McMullan G. ; Ternan N. ; Lajtha K. ; Crawley M.J.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2015
卷: 126, 期: 3 起始页码: 301
结束页码: 313
语种: 英语
英文关键词: Extracellular enzyme activity
; Fertilization
; Liming
; Root C:N ratio
; Soil carbon sequestration
; β-1,4-Glucosidase
Scopus关键词: carbon sequestration
; enzyme activity
; fertilizer application
; grassland soil
; liming
; nitrogen
; soil carbon
英文摘要: Chronic nitrogen (N) fertilization can greatly affect soil carbon (C) sequestration by altering biochemical interactions between plant detritus and soil microbes. In lignin-rich forest soils, chronic N additions tend to increase soil C content partly by decreasing the activity of lignin-degrading enzymes. In cellulose-rich grassland soils it is not clear whether cellulose-degrading enzymes are also inhibited by N additions and what consequences this might have on changes in soil C content. Here we address whether chronic N fertilization has affected (1) the C content of light versus heavier soil fractions, and (2) the activity of four extracellular enzymes including the C-acquiring enzyme β-1,4-glucosidase (BG; necessary for cellulose hydrolysis). We found that 19 years of chronic N-only addition to permanent grassland have significantly increased soil C sequestration in heavy but not in light soil density fractions, and this C accrual was associated with a significant increase (and not decrease) of BG activity. Chronic N fertilization may increase BG activity because greater N availability reduces root C:N ratios thus increasing microbial demand for C, which is met by C inputs from enhanced root C pools in N-only fertilized soils. However, BG activity and total root mass strongly decreased in high pH soils under the application of lime (i.e. CaCO3), which reduced the ability of these organo-mineral soils to gain more C per units of N added. Our study is the first to show a potential ‘enzyme link’ between (1) long-term additions of inorganic N to grassland soils, and (2) the greater C content of organo-mineral soil fractions. Our new hypothesis is that the ‘enzyme link’ occurs because (a) BG activity is stimulated by increased microbial C demand relative to N under chronic fertilization, and (b) increased BG activity causes more C from roots and from microbial metabolites to accumulate and stabilize into organo-mineral C fractions. We suggest that any combination of management practices that can influence the BG ‘enzyme link’ will have far reaching implications for long-term C sequestration in grassland soils. © 2015, The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83444
Appears in Collections: 气候减缓与适应 气候变化事实与影响
There are no files associated with this item.
作者单位: Environmental Sciences Research Institute, University of Ulster, Coleraine, United Kingdom; Agri-Food & Biosciences Institute, Belfast, United Kingdom; School of Biomedical Sciences, University of Ulster, Coleraine, United Kingdom; Department of Crop and Soil Sciences, Oregon State University, Corvallis, OR, United States; Department of Life Sciences, Imperial College, Silwood Park, Ascot, Berkshire, United Kingdom
Recommended Citation:
Cenini V.L.,Fornara D.A.,McMullan G.,et al. Chronic nitrogen fertilization and carbon sequestration in grassland soils: evidence of a microbial enzyme link[J]. Biogeochemistry,2015-01-01,126(3)