Work

Fertiliser nitrogen source and the use of nitrification inhibitors are tools to reduce nitrous oxide emissions and improve agronomic performance in temperate grassland

Year: 2025

Type: article

Abstract: The application of nitrogen (N) fertilisers to agricultural soils is a common practice that can result in significant nitrous oxide (N 2 O) emissions. Nitrogen source and the use of nitrification inhibitors (NIs) have shown potential to reduce N 2 O emissions from agricultural soils. However, to date most studies conducted in temperate grassland have tested one or two NIs in isolation, often with one N source such as urea. Hence, the present study tests the effect of four NIs: 3, 4-dimethylpyrazole phosphate (DMPP), dicyandiamide (DCD), nitrapyrin (NP) and a novel new NI 5-methoxy-3-methyl-1H-pyrazole (MMP) with both urea and urea ammonium nitrate (UAN) applied in autumn and spring seasons. Calcium ammonium nitrate (CAN) was included as a common N fertiliser used in Europe and also an acidified liquid amide-N (Flex-N) that is also in use but limited trial work has been published. This is the first study to report on N 2 O emissions and agronomic performance of the NI MMP, doing so with both solid and liquid fertiliser, and the acidified liquid amide N product (Flex-N). The urea, Flex-N and UAN fertilisers lowered the N 2 O-N emission factor (EF) by 84, 78 and 68 %, respectively compared to CAN across seasons. In autumn, urea and UAN treated with NIs reduced the N 2 O-N EF by up to 64 % and by up to 60 % compared to untreated urea and UAN, respectively. In spring, urea and UAN treated with NIs reduced N 2 O-N EF by up to 88 % and by up to 37 % compared to untreated urea and UAN, respectively. Inclusion of NIs increased pasture yield and N uptake in both seasons. These study results suggest that fertiliser N source and the use of NIs are effective tools for reducing N 2 O emissions while improving yields and N utilisation. • On average, the use of urea, Flex-N and UAN lowered the N 2 O-N emission factor by 84, 78 and 68 %, respectively compared to CAN fertiliser. • Urea and UAN treated with nitrification inhibitors (NIs) mitigated the N 2 O-N emission factor by up to 88 % and 60 % compared to untreated urea and UAN, respectively. • Urea or UAN treated with NIs showed a trend of improved pasture yield, N uptake and apparent fertiliser N recovery compared to untreated urea or UAN. • The use of NIs with urea had a stronger effect in spring than in autumn, whereas NIs with UAN had a stronger effect in autumn than in spring in the current study.

Source: Environmental Technology & Innovation

DOI: 10.1016/j.eti.2025.104232