GC099-0012
Influence of Cover Crops, Tillage, and Rotation Diversity on Field-Scale Cropland Soil N2O Flux
Influence of Cover Crops, Tillage, and Rotation Diversity on Field-Scale Cropland Soil N2O Flux
Tuesday, 15 December 2020
Poster
Abstract:
Greenhouse gas (GHG) emission reduction has gained increasing interest as concerns about climate change grew in recent years. Nitrous oxide (N2O), a potent GHG that is mainly released by cropland soils through microbial activities, contributes to atmospheric warming and ozone depletion. Agricultural management practices, such as cover cropping and tillage, are important for reducing N2O emissions by modifying soil conditions that drive microbial N-transforming processes such as nitrification and denitrification. In addition, seasonal freezing of cropland soils also induces elevated N2O emission during spring thaw in cold climates, which is also influenced by management practices. However, effects of these management practices are not well understood due to inconsistent practices and lack of year-round measurements presented in past studies.
Here we measure year-round N2O flux with half-hourly resolution over four 4-ha plots that are managed under four treatments in terms of cover cropping, crop rotation, and tillage at the Elora Research Station in Ontario, Canada from 2018 to 2020. This two-part study focuses on short-term and long-term influences of the three management practices. Between May 2018 and April 2019, we focus on short-term effect of inter-seeded cover crops and tillage on N2O emission from corn, especially following harvesting and tillage in Fall 2018, and during spring thaw in 2019. With two plots having a diverse crop rotation (corn-soybean-winter-wheat) and the cover cropping in 2018 also acting as a mean of crop diversification, we study the long-term effect of crop diversification on N2O emission between May 2018 to April 2020 by comparing emissions to a conventional (corn-soybean) rotation.
A flux-gradient system and a variety of instrument are employed and carefully maintained to obtain N2O flux time series with minimized gaps. Complemented with soil and plant data, flux data are statistically compared across treatments and interpreted to determine long- and short-term effects on N2O emissions.
Here we measure year-round N2O flux with half-hourly resolution over four 4-ha plots that are managed under four treatments in terms of cover cropping, crop rotation, and tillage at the Elora Research Station in Ontario, Canada from 2018 to 2020. This two-part study focuses on short-term and long-term influences of the three management practices. Between May 2018 and April 2019, we focus on short-term effect of inter-seeded cover crops and tillage on N2O emission from corn, especially following harvesting and tillage in Fall 2018, and during spring thaw in 2019. With two plots having a diverse crop rotation (corn-soybean-winter-wheat) and the cover cropping in 2018 also acting as a mean of crop diversification, we study the long-term effect of crop diversification on N2O emission between May 2018 to April 2020 by comparing emissions to a conventional (corn-soybean) rotation.
A flux-gradient system and a variety of instrument are employed and carefully maintained to obtain N2O flux time series with minimized gaps. Complemented with soil and plant data, flux data are statistically compared across treatments and interpreted to determine long- and short-term effects on N2O emissions.