Nitrification inhibitors reduce N2O emissions induced by application of biogas digestate to oilseed rape

• Published in: Nutrient cycling in agroecosystems Vol. 120; no. 1; pp. 99 - 118
• Main Authors: Kesenheimer, Katharina, Augustin, Jürgen, Hegewald, Hannes, Köbke, Sarah, Dittert, Klaus, Räbiger, Thomas, Quiñones, Teresa Suárez, Prochnow, Annette, Hartung, Jens, Fuß, Roland, Stichnothe, Heinz, Flessa, Heinz, Ruser, Reiner
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-05-2021; Springer Nature B.V
• Subjects: Agriculture; Biodiesel fuels; Biofuels; Biogas; Biomedical and Life Sciences; Cultivation; Diesel; Emission measurements; Emissions control; Fertilization; Grain cultivation; Greenhouse gases; Inhibitors; Life Sciences; Nitrification; Nitrous oxide; Oilseed crops; Oilseeds; Original Article; Rape plants; Rapeseed; Soil conditions; Weather; GHG reduction; Winter oilseed rape; Nitrification inhibition; N-fertilization; Yield-related emission; Biodiesel
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-021-10127-8

Winter oilseed rape (WOSR) is the major oil crop cultivated in Europe and the most important feedstock for biodiesel. Up to 90% of the greenhouse gas (GHG) emissions from biodiesel production can occur during oilseed rape cultivation. Therefore, mitigation strategies are required and need to focus on direct nitrous oxide (N
2
O) emission as one of the largest GHG contributors in biodiesel production. Earlier studies show that nitrification inhibitors (NIs) can reduce N
2
O emissions derived from N-fertilization. Since information on the effect of biogas digestates with or without NIs on N
2
O emissions from WOSR fields is scarce, the aim of this study was to evaluate their effects on N
2
O emissions, mineral N dynamics, and oil yield in WOSR production fertilized with digestate. The study was conducted at five sites across Germany over three years resulting in 15 full site-years data sets. Across all sites and years, N
2
O emission from WOSR fertilized with biogas digestate (180 kg NH
4
+
-N ha
−1
yr
−1
) ranged between 0.2 and 3.5 kg N
2
O–N ha
−1
 yr
−1
. Due to the reduction of the nitrate concentrations following digestate application, application of NI significantly reduced annual N
2
O emission by 36%. Our results demonstrate that NI can be an effective measure for reducing N
2
O emissions from digestate application, but its effectiveness depends on soil and weather conditions, and ultimately on the site-specific potential for N
2
O production and release. There was no effect of NI application on grain and oil yield.