Evaluating Gas Emissions from Different Feed Cropping Systems in the North China Plain: A Two-Year Field Measurement

Abstract

The cultivation of silage crops is encouraged to enhance the connection between crop and livestock production in the North China Plain (NCP). A field experiment was designed to evaluate the ammonia (NH3), nitrous oxide (N2O), and methane (CH4) emissions of five silage cropping systems, including triticale-summer maize (Tr-SuM), triticale-spring maize (Tr-SpM), triticale-double forage maize (Tr-DFM), double forage maize (DFM), and winter wheat-summer maize (WW-SuM), as well as their biomass- and crude protein-scaled emission intensities, with respect to NH3 and greenhouse gas (GHG). The annual nitrogen (N) emissions through NH3, N2O, and CH4 emissions of these systems were 13.43–23.77 kg ha−1 (4.2–5.6% of N fertilizer input), 3.43–4.56 kg ha−1 (0.75–1.08% of N fertilizer input) and 2.10–2.85 kg ha−1, respectively. The total GHG emissions of these systems was dominated by the contributions of N2O. Ranking these systems according to their biomass and crude protein production gave Tr-DFM > DFM > WW-SuM > Tr-SuM and Tr-SpM, their partial factor productivity was in the order of Tr-DFM > WW-SuM > Tr-SuM and Tr-SpM > DFM, and the order of their emission intensity was DFM > Tr-SuM > Tr-DFM > WW-SuM > Tr-SpM. In conclusion, the Tr-DFM needs to be further investigated for its suitability in the NCP, owing to its superior productivity and moderate emission intensities.

Keywords

• crop rotation
• ammonia
• greenhouse gases
• emission intensity
• crude protein