Quantification and comparison of subnational and national agricultural nitrogen flows in Denmark and Sweden

TY - JOUR

T1 - Quantification and comparison of subnational and national agricultural nitrogen flows in Denmark and Sweden

AU - Grados, Diego

AU - Einarsson, Rasmus

AU - Sanz-Cobeña, Alberto

AU - Olesen, Jørgen Eivind

AU - Børsting, Christian Friis

AU - Abalos, Diego

PY - 2025/4

Y1 - 2025/4

N2 - Ensuring food production with low nitrogen (N) environmental emissions requires good quantitative knowledge of N flows in agricultural systems to monitor emissions and N use efficiency (NUE, the ratio of N outputs to inputs). Our study quantifies the main N agricultural flows at subnational and national scales in Denmark and Sweden from 2011 to 2020, calculating the NUE for crop and livestock production and associated nitrous oxide (N2O) and ammonia (NH3) emissions. In Denmark, our results indicate a similar use of organic (manure) and synthetic N fertilizers (230 and 213 kt N y−1, 83 and 77 kg N ha−1 y−1); in contrast, Sweden used more synthetic (162 kt N y−1, 54 kg N ha−1 y−1) than organic N (108 kt N y−1, 36 kg N ha−1 y−1), with subnational variation in manure use as determined by livestock population. Livestock feed N intake was twice as large in Denmark (384 kt N y−1) as in Sweden (176 kt N y−1), reflecting Denmark’s larger livestock population. Denmark’s national crop NUE was lower (0.51) than Sweden’s (0.72), likely due to a lower proportion of grass-clover leys, higher N input rates, and more intensive production systems. However, considerable subnational variation existed in both countries. The livestock NUE was 0.29 in Denmark and 0.25 in Sweden; these differences are mainly due to a higher proportion of ruminants in Sweden with lower N feed use efficiency than pigs. Sweden emitted less N2O and NH3 per unit area (∼56% for both gases) and in total (∼52% for both gases) than Denmark due to lower use of N inputs and less intensive farming systems. West Denmark and South Sweden were identified as emission hotspots. Our research provides essential information at subnational and national scales to improve N management and reduce gaseous N pollution, supporting the transition towards more sustainable agroecosystems in Denmark and Sweden.

AB - Ensuring food production with low nitrogen (N) environmental emissions requires good quantitative knowledge of N flows in agricultural systems to monitor emissions and N use efficiency (NUE, the ratio of N outputs to inputs). Our study quantifies the main N agricultural flows at subnational and national scales in Denmark and Sweden from 2011 to 2020, calculating the NUE for crop and livestock production and associated nitrous oxide (N2O) and ammonia (NH3) emissions. In Denmark, our results indicate a similar use of organic (manure) and synthetic N fertilizers (230 and 213 kt N y−1, 83 and 77 kg N ha−1 y−1); in contrast, Sweden used more synthetic (162 kt N y−1, 54 kg N ha−1 y−1) than organic N (108 kt N y−1, 36 kg N ha−1 y−1), with subnational variation in manure use as determined by livestock population. Livestock feed N intake was twice as large in Denmark (384 kt N y−1) as in Sweden (176 kt N y−1), reflecting Denmark’s larger livestock population. Denmark’s national crop NUE was lower (0.51) than Sweden’s (0.72), likely due to a lower proportion of grass-clover leys, higher N input rates, and more intensive production systems. However, considerable subnational variation existed in both countries. The livestock NUE was 0.29 in Denmark and 0.25 in Sweden; these differences are mainly due to a higher proportion of ruminants in Sweden with lower N feed use efficiency than pigs. Sweden emitted less N2O and NH3 per unit area (∼56% for both gases) and in total (∼52% for both gases) than Denmark due to lower use of N inputs and less intensive farming systems. West Denmark and South Sweden were identified as emission hotspots. Our research provides essential information at subnational and national scales to improve N management and reduce gaseous N pollution, supporting the transition towards more sustainable agroecosystems in Denmark and Sweden.

KW - ammonia

KW - croplands

KW - grasslands

KW - livestock

KW - nitrogen use efficiency

KW - nitrous oxide

UR - https://www.scopus.com/pages/publications/105003322168

U2 - 10.1088/1748-9326/adca4a

DO - 10.1088/1748-9326/adca4a

M3 - Journal article

AN - SCOPUS:105003322168

SN - 1748-9326

VL - 20

JO - Environmental Research Letters

JF - Environmental Research Letters

IS - 5

M1 - 054041

ER -