Frost killed cover crops induced high emissions of nitrous oxide

Abstract

Establishing a cover crop after harvest of a main crop in late summer or early autumn can have several advantages, including weed control, decreased nitrate leaching and an increased potential for carbon sequestration. However, the addition of fresh plant material to the soil in late autumn or winter, either by active termination of the cover crop or by frost damage, could be a risk factor for nitrous oxide emissions, due to the simultaneous occurrence of wet soil conditions and freeze-thaw cycles. We measured field emissions of nitrous oxide from three cover crops – oilseed radish, (Raphanus sativus var. oleiformis), phacelia (Phacelia tanacetifolia) and oats (Avena sativa) – over a 43-day period in winter. All three cover crops were sensitive to frost and died, wilted and started to decompose during this period. The cover crops increased nitrous oxide emissions, relative to controls that were ploughed in autumn, by 1.8, 0.7 and 0.6 kg N2O-N ha−1 , for oilseed radish, phacelia and oats, respectively. We conclude that the choice of cover crop species and management options for cover crops need to be further researched to minimise their contribution to nitrous oxide emissions from agriculture.

Keywords

Phacelia; Oilseed radish; Oats; Greenhouse gases; Freeze-thaw; Winter emission

Published in

Science of the Total Environment
2022, volume: 837, article number: 155634

SLU Authors

• Ernfors, Maria

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network

UKÄ Subject classification

Agricultural Science

Publication identifier

• DOI: https://doi.org/10.1016/j.scitotenv.2022.155634

Permanent link to this page (URI)

https://res.slu.se/id/publ/117205