University of Illinois Urbana-Champaign

Understanding the impact of residue and nitrogen inputs on soil carbon and nitrogen dynamics

Jesmin, Tanjila

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JESMIN-DISSERTATION-2022.pdf

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https://hdl.handle.net/2142/115948

Description

Title
Understanding the impact of residue and nitrogen inputs on soil carbon and nitrogen dynamics
Author(s)
Jesmin, Tanjila
Issue Date
2022-07-15
Director of Research (if dissertation) or Advisor (if thesis)
Mulvaney, Richard L
Doctoral Committee Chair(s)
Arai, Yuji
Committee Member(s)
  • Margenot, Andrew J
  • Boutton, Thomas W
Department of Study
Natural Res & Env Sci
Discipline
Natural Res & Env Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Soil fertility, C mineralization, C sequestration, 13C, Incubation study, CO2 production, Gross N mineralization/immobilization, Active biomass, Microbial biomass, Cellulase, Protease, B-glucosidase, Deaminase, Residue decomposition, N fertilization
Abstract
The effect of N fertilization on residue decomposition has been studied extensively; however, contrasting results reflect differences in residue quality, the form of N applied, and the type of soil studied. Two 60-d laboratory incubation experiments were conducted to compare the effect of synthetic N addition (as NH4+ or NO3–) on the decomposition of corn (Zea mays L.) stover, in which (1) a Mollisol was treated with high and low C:N ratio residues; or (2) a single residue was incorporated in two Alfisols of contrasting N supply. In both projects, CO2 emissions were monitored continuously with or without atmospheric 13C analysis and periodic measurement of active biomass, microbial biomass C and N, enzyme activities involved in C (cellulase and β-glucosidase) and N (protease and deaminase) cycling, and gross N mineralization and immobilization by 15N pool dilution. Cumulative CO2 production was greater for the high than low N residue treatment, and was significantly increased by the addition of exogenous N. The stimulatory effect of mineral N was greater for the low- than high-N supplying soil and more prominent in the first than in the second month of incubation, as would be expected due to more rapid substrate depletion from microbial C utilization previously enhanced by greater N availability. The stimulatory effect of exogenous N was verified with respect to microbial indicators, all of which were significantly correlated with cumulative CO2 production. No consistent soil- or treatment-specific differences occurred in measuring gross N mineralization and immobilization; however, net immobilization was usually observed in both studies. Intensive N fertilization in modern corn production increases the input of residues but is not conducive to soil C sequestration.
Graduation Semester
2022-08
Type of Resource
Thesis
Handle URL
https://hdl.handle.net/2142/115948
Copyright and License Information
Copyright 2022 Tanjila Jesmin

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