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A change in the European Union energy policy has markedly promoted the expansion of biogas production. Consequently, large amounts of nutrient-rich residues are being used as organic fertilizers. In this study, a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas(GHG) emissions following organic fertilizer application in energy maize cultivation.We hypothesized that cattle slurry application enhanced CO_2 and N_2O fluxes compared to biogas digestate because of the overall higher carbon(C) and nitrogen(N) input, and that higher levels of CO_2 and N_2O emissions could be expected by increasing soil organic C(SOC) and N contents. Biogas digestate and cattle slurry, at a rate of 150 kg NH_4~+-N ha~(-1), were incorporated into 3 soil types with low, medium, and high SOC contents(Cambisol, Mollic Gleysol, and Sapric Histosol, termed Clow, Cmedium, and Chigh, respectively). The GHG exchange(CO_2, CH_4, and N_2O) was measured on 5 replicates over a period of 22 d using the closed chamber technique. The application of cattle slurry resulted in significantly higher CO_2 and N_2O fluxes compared to the application of biogas digestate. No differences were observed in CH_4 exchange, which was close to zero for all treatments. Significantly higher CO_2 emissions were observed in Chigh compared to the other two soil types, whereas the highest N_2O emissions were observed in Cmedium. Thus, the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.
A change in the European Union energy policy has markedly promoted the expansion of biogas production. Therefore, large amounts of nutrient-rich residues are being used as organic fertilizers. In this study, a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas (GHG) emissions following organic fertilizer application in energy maize cultivation. We hypothesized that cattle slurry application enhanced CO_2 and N_2O fluxes compared to biogas digestate of the overall higher carbon (C) and nitrogen (N) input, and that higher Levels of CO 2 and N 2 O emissions could be expected by increasing soil organic C (SOC) and N contents. Biogas digestate and cattle slurry, at a rate of 150 kg NH_4 ~ + -N ha ~ (-1), were incorporated into 3 soil Types with low, medium, and high SOC contents (Cambisol, Mollic Gleysol, and Sapric Histosol, termed Clow, Cmedium, and Chigh, respectively). The GHG exchange (CO_2, CH_4, and N_2O) was measured on 5 replicates over a peri The application of cattle slurry resulted in significantly higher CO_2 and N_2O fluxes compared to the application of biogas digestate. No differences were observed in CH_4 exchange, which was close to zero for all treatments. CO 2 emissions were observed in Chigh compared to the other two soil types, whereas the highest N_2O emissions were observed in Cmedium. Thus, the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.