Greenhouse gas emissions from tillage practices and crop phases in a sugarbeet-based crop rotation

Abstract

Information is needed on greenhouse gas (GHG) emissions due to tillage and crop type on sugarbeet (Beta vulgaris L.)-based crop rotations. We measured CO₂, N₂O, and CH₄ emissions as affected by tillage (conventional till [CT], no-till [NT], and strip till [ST]) under sugarbeet and spring wheat (Triticum aestivum L.) phases of an irrigated sugarbeet–pea (Pisum sativum L.)–spring wheat rotation from 2018 to 2021 in the US northern Great Plains. Greenhouse gases were measured using a static chamber at 3- to 28-day intervals, depending on plant growth and environmental conditions, throughout the year. The CO₂ and N₂O fluxes peaked for 2–8 months immediately after tillage, planting, fertilization, intense precipitation, and irrigation. The CH₄ flux varied little, except for some peaks in the first year. Cumulative annual CO₂ flux was 19%–30% greater for CT than NT in 2019–2020 and 2020–2021, and 13% greater for CT than ST in 2020–2021. Cumulative N₂O flux was 31%–36% greater for CT than ST in 2018–2019 and 2020–2021, but 33%–83% lower for sugarbeet than spring wheat in all years. Cumulative CH₄ flux was 83% lower for CT than NT and 68% lower for sugarbeet than spring wheat in 2018–2019. The GHG balance was 15%–23% greater for CT than NT and ST in 2019–2020 and 2020–2021 and 31% greater under sugarbeet than spring wheat in 2018–2019. No-tillage can reduce GHG emissions compared to conventional tillage, and sugarbeet can reduce N₂O emissions compared to spring wheat in sugarbeet-based crop rotations.