The University of Southampton
University of Southampton Institutional Repository

Image-based quantification of soil microbial dead zones induced by nitrogen fertilization

Image-based quantification of soil microbial dead zones induced by nitrogen fertilization
Image-based quantification of soil microbial dead zones induced by nitrogen fertilization
Microbial communities in agricultural soils underpin many ecosystem services including the maintenance of soil structure, food production, water purification and carbon storage. However, the impact of fertilization on the health of microbial communities is not well understood. This study investigates the spatial and temporal dynamics of nitrogen (N) transport away from a fertilizer granule with pore scale resolution. Specifically, we examined how soil structure and moisture content influence fertilizer derived N movement through the soil pore network and the subsequent impact of on soil microbial communities. We develop a mathematical model to describe N transport and reactions in soil at the pore-scale. Using X-ray Computed Tomography scans, we reconstructed a microscale description of a soil-pore geometry as a computational mesh. Solving two-phase water/air model produced pore-scale water distributions at 15, 30 and 70% water-filled pore volume. The N-speciation model considered ammonium (NH4+), nitrate (NO3-) and dissolved organic N (DON), and included N immobilization, ammonification and nitrification processes, as well as diffusion in soil solution. We simulated the dissolution of a fertilizer pellet and a pore scale N cycle at three different water saturations. To aid interpretation of the model results, microbial activity at a range of N concentrations was measured. The model showed that the diffusion and concentration of N in water films is critically dependent upon soil moisture and N species. We predict that the maximum NH4+ and NO3- concentrations in soil solution around the pellet under dry conditions are in the order of 1×103 and 1×104 mol m-3 respectively, and under wet conditions 2×102 and 1×103 mol m-3, respectively. Supporting experimental evidence suggests that these concentrations would be sufficient to reduce microbial activity in the short-term in the zone immediately around the fertilizer pellet (ranging from 0.9 to 3.8 mm), causing a major loss of soil biological functioning. This model demonstrates the importance of pore-scale processes in regulating N movement and their interactions with the soil microbiome.
Nitrogen cycling, Fertilizer dynamics, Pore-scale modeling, Soil health, Diffusion, Microbial activity
0048-9697
Ruiz, Siul Aljadi
d79b3b82-7c0d-47cc-9616-11d29e6a41bd
Mckay Fletcher, Daniel
db06e7e0-69af-4fa2-89b3-26f6599e43d4
Boghi, Andrea
54a72da6-c8a2-468c-9773-897efac0638f
Williams, Katherine
a13f30b4-2f53-4a14-ad38-c733923a6450
Duncan, Simon
fa8481c1-3788-41a0-a304-02515b93ef7d
Scotson, Callum, Paul
47901c28-548c-41cc-9cbd-f0429a24c7cb
Petroselli, Chiara
19266726-2dc0-4790-af77-7ccdc45865eb
Gerheim souza dias, Tiago
cbb905da-3e22-4933-8b7b-663c52345e3a
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
Chadwick, D.R
fd9ad7e0-a8e3-4c2b-bdc6-537e24334497
Jones, D.L.
4c7d0ebb-b7e3-4afc-adbc-ece2ba1fc54f
Ruiz, Siul Aljadi
d79b3b82-7c0d-47cc-9616-11d29e6a41bd
Mckay Fletcher, Daniel
db06e7e0-69af-4fa2-89b3-26f6599e43d4
Boghi, Andrea
54a72da6-c8a2-468c-9773-897efac0638f
Williams, Katherine
a13f30b4-2f53-4a14-ad38-c733923a6450
Duncan, Simon
fa8481c1-3788-41a0-a304-02515b93ef7d
Scotson, Callum, Paul
47901c28-548c-41cc-9cbd-f0429a24c7cb
Petroselli, Chiara
19266726-2dc0-4790-af77-7ccdc45865eb
Gerheim souza dias, Tiago
cbb905da-3e22-4933-8b7b-663c52345e3a
Roose, Tiina
3581ab5b-71e1-4897-8d88-59f13f3bccfe
Chadwick, D.R
fd9ad7e0-a8e3-4c2b-bdc6-537e24334497
Jones, D.L.
4c7d0ebb-b7e3-4afc-adbc-ece2ba1fc54f

Ruiz, Siul Aljadi, Mckay Fletcher, Daniel, Boghi, Andrea, Williams, Katherine, Duncan, Simon, Scotson, Callum, Paul, Petroselli, Chiara, Gerheim souza dias, Tiago, Roose, Tiina, Chadwick, D.R and Jones, D.L. (2020) Image-based quantification of soil microbial dead zones induced by nitrogen fertilization. Science of the Total Environment. (In Press)

Record type: Article

Abstract

Microbial communities in agricultural soils underpin many ecosystem services including the maintenance of soil structure, food production, water purification and carbon storage. However, the impact of fertilization on the health of microbial communities is not well understood. This study investigates the spatial and temporal dynamics of nitrogen (N) transport away from a fertilizer granule with pore scale resolution. Specifically, we examined how soil structure and moisture content influence fertilizer derived N movement through the soil pore network and the subsequent impact of on soil microbial communities. We develop a mathematical model to describe N transport and reactions in soil at the pore-scale. Using X-ray Computed Tomography scans, we reconstructed a microscale description of a soil-pore geometry as a computational mesh. Solving two-phase water/air model produced pore-scale water distributions at 15, 30 and 70% water-filled pore volume. The N-speciation model considered ammonium (NH4+), nitrate (NO3-) and dissolved organic N (DON), and included N immobilization, ammonification and nitrification processes, as well as diffusion in soil solution. We simulated the dissolution of a fertilizer pellet and a pore scale N cycle at three different water saturations. To aid interpretation of the model results, microbial activity at a range of N concentrations was measured. The model showed that the diffusion and concentration of N in water films is critically dependent upon soil moisture and N species. We predict that the maximum NH4+ and NO3- concentrations in soil solution around the pellet under dry conditions are in the order of 1×103 and 1×104 mol m-3 respectively, and under wet conditions 2×102 and 1×103 mol m-3, respectively. Supporting experimental evidence suggests that these concentrations would be sufficient to reduce microbial activity in the short-term in the zone immediately around the fertilizer pellet (ranging from 0.9 to 3.8 mm), causing a major loss of soil biological functioning. This model demonstrates the importance of pore-scale processes in regulating N movement and their interactions with the soil microbiome.

Text
N_Paper-v11_revised_v4 - Accepted Manuscript
Restricted to Repository staff only until 23 March 2022.
Request a copy
Slideshow
figures_FORESNT_Revised - Accepted Manuscript
Restricted to Repository staff only until 23 March 2022.
Request a copy

More information

Accepted/In Press date: 23 March 2020
Keywords: Nitrogen cycling, Fertilizer dynamics, Pore-scale modeling, Soil health, Diffusion, Microbial activity

Identifiers

Local EPrints ID: 438956
URI: http://eprints.soton.ac.uk/id/eprint/438956
ISSN: 0048-9697
PURE UUID: db3c0299-520e-4a17-aa30-a6108a598908
ORCID for Daniel Mckay Fletcher: ORCID iD orcid.org/0000-0001-6569-2931
ORCID for Andrea Boghi: ORCID iD orcid.org/0000-0002-9387-326X
ORCID for Katherine Williams: ORCID iD orcid.org/0000-0001-6827-9261
ORCID for Tiina Roose: ORCID iD orcid.org/0000-0001-8710-1063

Catalogue record

Date deposited: 30 Mar 2020 16:30
Last modified: 18 Feb 2021 17:41

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×