DOI: 10.1111/gcb.12519
论文题名: A long-term nitrogen fertilizer gradient has little effect on soil organic matter in a high-intensity maize production system
作者: Brown K.H. ; Bach E.M. ; Drijber R.A. ; Hofmockel K.S. ; Jeske E.S. ; Sawyer J.E. ; Castellano M.J.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2014
卷: 20, 期: 4 起始页码: 1339
结束页码: 1350
语种: 英语
Scopus关键词: agricultural ecosystem
; concentration (composition)
; crop production
; crop residue
; fertilizer
; fertilizer application
; greenhouse gas
; maize
; nitrogen
; soil carbon
; soil organic matter
; Zea mays
; carbon
; fertilizer
; nitrogen
; soil
; agriculture
; biomass
; chemistry
; crop
; maize
; microbiology
; procedures
; soil
; United States
; Agriculture
; Biomass
; Carbon
; Crops, Agricultural
; Fertilizers
; Iowa
; Nitrogen
; Soil
; Soil Microbiology
; Zea mays
英文摘要: Global maize production alters an enormous soil organic C (SOC) stock, ultimately affecting greenhouse gas concentrations and the capacity of agroecosystems to buffer climate variability. Inorganic N fertilizer is perhaps the most important factor affecting SOC within maize-based systems due to its effects on crop residue production and SOC mineralization. Using a continuous maize cropping system with a 13 year N fertilizer gradient (0-269 kg N ha-1 yr-1) that created a large range in crop residue inputs (3.60-9.94 Mg dry matter ha-1 yr-1), we provide the first agronomic assessment of long-term N fertilizer effects on SOC with direct reference to N rates that are empirically determined to be insufficient, optimum, and excessive. Across the N fertilizer gradient, SOC in physico-chemically protected pools was not affected by N fertilizer rate or residue inputs. However, unprotected particulate organic matter (POM) fractions increased with residue inputs. Although N fertilizer was negatively linearly correlated with POM C/N ratios, the slope of this relationship decreased from the least decomposed POM pools (coarse POM) to the most decomposed POM pools (fine intra-aggregate POM). Moreover, C/N ratios of protected pools did not vary across N rates, suggesting little effect of N fertilizer on soil organic matter (SOM) after decomposition of POM. Comparing a N rate within 4% of agronomic optimum (208 kg N ha-1 yr-1) and an excessive N rate (269 kg N ha-1 yr-1), there were no differences between SOC amount, SOM C/N ratios, or microbial biomass and composition. These data suggest that excessive N fertilizer had little effect on SOM and they complement agronomic assessments of environmental N losses, that demonstrate N2O and NO3 emissions exponentially increase when agronomic optimum N is surpassed. © 2014 John Wiley & Sons Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/61957
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Agronomy, Iowa State University, Ames, IA 50011, United States; Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, United States; Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
Recommended Citation:
Brown K.H.,Bach E.M.,Drijber R.A.,et al. A long-term nitrogen fertilizer gradient has little effect on soil organic matter in a high-intensity maize production system[J]. Global Change Biology,2014-01-01,20(4)