N2O and CO2 emissions following repeated application of organic and mineral N fertiliser from a vegetable crop rotation

Daniele De Rosa; David W Rowlings; Johannes Biala; Clemens Scheer; Bruno Basso; Peter R Grace

doi:10.1016/j.scitotenv.2018.05.046

N₂O and CO₂ emissions following repeated application of organic and mineral N fertiliser from a vegetable crop rotation

Sci Total Environ. 2018 Oct 1:637-638:813-824. doi: 10.1016/j.scitotenv.2018.05.046. Epub 2018 May 12.

Authors

Daniele De Rosa¹, David W Rowlings², Johannes Biala², Clemens Scheer², Bruno Basso³, Peter R Grace²

Affiliations

¹ Institute for Future Environments, Queensland University of Technology, 2 George St, Brisbane, QLD 4000, Australia. Electronic address: d.derosa@qut.edu.au.
² Institute for Future Environments, Queensland University of Technology, 2 George St, Brisbane, QLD 4000, Australia.
³ Institute for Future Environments, Queensland University of Technology, 2 George St, Brisbane, QLD 4000, Australia; Department of Earth and Environmental Sciences, and W.K. Kellogg Biological Station, Michigan State University, 288 Farm Lane, East Lansing, MI 48823, USA.

PMID: 29758436
DOI: 10.1016/j.scitotenv.2018.05.046

Abstract

Accounting for nitrogen (N) release from organic amendments (OA) can reduce the use of synthetic N-fertiliser, sustain crop production, and potentially reduce soil borne greenhouse gases (GHG) emissions. However, it is difficult to assess the GHG mitigation potential for OA as a substitute of N-fertiliser over the long term due to only part of the organic N added to soil is being released in the first year after application. High-resolution nitrous oxide (N₂O) and carbon dioxide (CO₂) emissions monitored from a horticultural crop rotation over 2.5 years from conventional urea application rates were compared to treatments receiving an annual application of raw and composted chicken manure combined with conventional and reduced N-fertiliser rates. The repeated application of composted manure did not increase annual N₂O emissions while the application of raw manure resulted in N₂O emissions up to 35.2 times higher than the zero N fertiliser treatment and up to 4.7 times higher than conventional N-fertiliser rate due to an increase in C and N availability following the repeated application of raw OA. The main factor driving N₂O emissions was the incorporation of organic material accompanied by high soil moisture while the application of synthetic N-fertiliser induced only short-term N₂O emission pulse. The average annual N₂O emission factor calculated accounting for the total N applied including OA was equal to 0.27 ± 0.17%, 3.7 times lower than the IPCC default value. Accounting for the estimated N release from OA only enabled a more realistic N₂O emission factor to be defined for organically amended field that was equal to 0.48 ± 0.3%. This study demonstrated that accounting for the N released from repeated application of composted rather than raw manure can be a viable pathway to reduce N₂O emissions and maintain soil fertility.

Keywords: Compost; Crop residues; Emission factor; Manure; Nitrous oxide; Organic amendments.