Abstract:
Objectives The responses of maize yield and carbon footprint to different fertilization regimes were studied in reclaimed cropland, and the yield-increasing and emission-reducing effects of different fertilization methods were systematically evaluated, thereby to provide a scientific basis and technical support for sustainable agricultural development in reclamation areas.
Methods A 10-year reclamation experiment was conducted in Gujiao, Shanxi Province since 2012. four treatments were setup in the experiment, including: no fertilization (CK), chemical fertilization (NPK), organic manure alone (M) and chemical fertilizers combined with manure (MNPK). In 2021 after maize harvest, the yield and greenhouse gas emissions were analyzed. A life cycle assessment (LCA) approach was used to quantify the carbon footprint (CFy) of maize production under different fertilization treatments. Global warming potential (GWP) and greenhouse gas emission intensity (GHGI) were used to comprehensively evaluate the effects of fertilization on carbon sequestration and emission reduction in reclaimed soils.
Results Compared to the CK, long-term fertilization treatments significantly increased maize yield by 161.8%−258.1%, with organic manure treatments yielding the highest increase. Nitrogen fertilizer production and application constituted the primary source of greenhouse gas emissions. The CFy across treatments ranged from -0.80 to 1.06 kgCO2 eq/kg. Compared to the NPK treatment, the CFy of both M and MNPK treatments was significantly reduced. When accounting for the soil organic carbon (SOC) sequestration effect, the CFy of both M and MNPK treatments shifted from positive to negative, transforming them from ‘carbon sources’ to ‘carbon sinks’. Concurrently, the MNPK treatment exhibited net carbon sequestration while maintaining high yields, significantly reducing both GWP and GHG emissions.
Conclusions The combined application of organic manure with mineral fertilizers (MNPK) can simultaneously increase maize yield and reduce greenhouse gas emissions, thereby lowering yield-scaled carbon footprint and promoting cleaner and more sustainable maize production in reclaimed soils.
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