Straw amendments did not induce high N₂O emissions in non‐frozen wintertime conditions: A study in northern Germany

Abstract

Oilseed rape (Brassica napus L.) is a major oil crop in Europe, and the harvested area doubled from 2001 to 2018 (FAOSTAT, 2020) following the rise in biodiesel production (Hamelinek, De Loveinfosse, & Koper, 2014). The cultivation of oilseed rape demands high amounts of nitrogen (N) fertilizer, to gain sufficient yield (Hegewald, Koblenz, Wensch-Dorendorf, & Christen, 2016). The harvest index of oilseed rape is low, which results in high N surpluses post-harvest (Sieling & Kage, 2010). The straw residues of wheat or oilseed rape crops are commonly left in fields after the autumn harvest

Biochar for sustainable soil management

“…Soil represents the largest terrestrial carbon pool (Le Quere et al., 2018). Soil carbon storage is affected by farm management strategies (Chowaniak et al., 2020; Govindasamy et al., 2020; Singh & Whelan, 2020) and soil microbial processes can also result in the emission of N 2 O (Davidson, 2009; Hu et al., 2020; Wang et al., 2020), a greenhouse gas with 298 times the atmospheric heat‐trapping ability of CO 2 (IPCC, 2014). Biochar application increases soil organic content in soil, resulting in carbon sequestration (Zhao, Lin, et al, 2020).…”

White Clover does not Increase Soil N2O Emissions Compared to Ryegrass in Non-Frozen Winter, but Increases CH4 Uptake

“…Similar to our findings, Röver et al (1998) reported that N 2 O emissions did not differ significantly between fertilized and unfertilized arable soils over the winter period, and the source of N 2 O may be independent from the N-fertilizer applied during growing seasons. Wang et al 2020 demonstrated that, beside soil mineral N, the availability of organic C was a more limiting factor for denitrification and N 2 O production in unfrozen winter. This was also in line with our results, that the lowest N 2 O emissions were recorded on bare soil, which had a much lower organic C and CH 4 fluxes.…”

Sustainable soil management and climate change mitigation

“…The N 2 O dynamic is affected by labile carbon content, as it can enhance anaerobic environment and thus increase N 2 O emissions. A study in northern Germany found that, when there was no extreme rainfall or freeze–thaw cycles, return of straw residue did not induce high N 2 O emissions; however, when glucose was added as a labile carbon source, N 2 O emissions increased by up to 32 times (Wang et al., 2020). N 2 O emissions are also affected by other site characteristics, such as soil mineralization–immobilization turnover and nitrification (Song et al., 2020), and clay content (Miller et al., 2020).…”