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Report, 2022

Precision nitrogen application – potential to lower the climate impact of crop production

Karlsson Potter, Hanna; Delin, Sofia; Engström, Lena; Stenberg, Bo; Hansson, Per-Anders


The agriculture sector is a significant contributor to global greenhouse gas emissions, especially methane (CH4) and nitrous oxides (N2O). Nitrous oxide emissions originate primarily from nitrogen fertiliser production and use. A nitrogen fertilisation rate close to crop demand is desirable for several reasons, e.g. it limits fertiliser use per unit of crop produced and reduces the risk of N2O emissions and nitrogen leaching.

This study estimated the impact of two different measures for more accurate nitrogen fertilisation, field-specific nitrogen fertilisation (accounting for between-field variation) and variable-rate nitrogen application (accounting for within-field variation), compared with a uniform fertilisation application. Effects on nitrogen leaching, N2O emissions, grain yield and nitrogen balance were analysed. Calculations of leaching and N2O emissions were based on different examples of within- and between-field variation on two soil types, represented by two experimental fields in south-west Sweden from which measured data on grain yield and N2O emissions were obtained. Climate impact in a life cycle perspective, including fertiliser production and use, was calculated. The results for N2O emissions were compared with the results of simulations using the IPCC model for N2O emissions and a nitrogen balance-based model.

According to the results, the climate impact from field N2O emissions was reduced by around 5% when using field-specific nitrogen fertilisation. An additional reduction of 1-10% (depending on in-field variations in nitrogen demand) was achieved when using variable-rate nitrogen application. The amount of fertiliser used was very important for the overall climate impact of crop production, indicating that measures which increase nitrogen use efficiency and keep nitrogen fertiliser doses below the optimum rate are preferable in a climate impact perspective. The commonly used IPCC model for predicting field N2O emissions failed to predict reductions in N2O from better nitrogen use efficiency. The nitrogen balance-based model performed better in predicting field N2O emissions in relation to what could be expected based on measured N2O emissions, but the estimated reduction was not as high as that predicted from field measurements.


Precision fertilisation; nitrous oxide emissions; nitrogen fertilisation rate; nitrogen fertiliser recommendations

Published in

Mistra Food Futures Report
2022, number: 9
ISBN: 978-91-8046-766-7, eISBN: 978-91-8046-767-4
Publisher: Swedish University of Agricultural Sciences