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

Table 4 N₂O emissions on an annual base, during the fertilization period, and outside the fertilization period as affected by site, year and nitrification inhibitor (+ NI; –NI). Means not sharing any letter are significantly different within one site, year, and period by Fishers LSD-test at the 5% level of significance (bold marked)

Study site	Year	N₂O emission
Study site	Year	Annual [kg N₂O-N ha⁻¹]		Fertilization period^† [kg N₂O-N ha⁻¹]		Outside fertilization period [kg N₂O-N ha⁻¹]
		–NI	+ NI	–NI	+ NI	–NI	+ NI
Berge	2013	1.08^a	0.40^a	0.42	0.08^a	0.66^a	0.33^a
	2014	0.27^a	0.22^a	0.07^a	0.05^a	0.20^a	0.16^a
	2015	0.19^a	0.24^a	0.01^a	0.01^a	0.18^a	0.23^a
	2013–2015	0.51	0.29	0.17	0.05	0.35	0.24
Dedelow	2013	1.13^a	0.47^a	0.22^a	0.09^a	0.91^a	0.38^a
	2014	1.20^a	0.64^b	0.15^a	0.03^b	1.05^a	0.60^b
	2015	1.10^a	0.25^b	0.44^a	0.01^b	0.68^a	0.24^a
	2013–2015	1.14	0.45	0.27	0.04	0.87	0.41
Ihinger Hof	2013	1.40^a	1.72^a	0.06^a	0.10^a	1.34^a	1.63^a
	2014	0.94^a	1.15^a	0.06^a	0.07^a	0.88^a	1.09^a
	2015	0.54^a	0.35^a	0.19^a	0.04^b	0.35^a	0.32^a
	2013–2015	0.96	1.08	0.11	0.07	0.86	1.01
Hohenschulen	2013	0.98^a	0.96^a	0.12^a	0.08^a	0.86^a	0.87^a
	2014	1.54^a	1.21^a	0.47^a	0.20^b	1.07^a	1.01^a
	2015	1.88^a	1.28^a	0.49^a	0.15^b	1.39^a	1.13^a
	2013–2015	1.47	1.15	0.36	0.14	1.10	1.00
Merbitz	2013	3.53^a	1.78^b	1.82^a	0.51^b	1.71^a	1.27^a
	2014	2.64^a	1.90^a	0.05^a	0.04^a	2.60^a	1.87^a
	2015	2.23^a	2.23^a	0.17^a	0.03^a	2.06^a	2.20^a
	2013–2015	2.80	1.97	0.68	0.19	2.12	1.78

^† Fertilization period started with the day of the first digestate application and ended 4 weeks after the second digestate application (Table S2)