Integrated management practices significantly affect N2O emissions and wheat–maize production at field scale in the North China Plain
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Shi Y, Wu W, Meng F, Zhang Z, Zheng L, Wang D. 2013. Integrated management practices significantly affect N2O emissions and wheat–maize production at field scale in the North China Plain. Nutrient Cycling in Agroecosystems 95(2): 203-218.
Permanent link to this item: http://hdl.handle.net/10568/33749
In the North China Plain, a field experiment was conducted to measure nitrous oxide (N2O) and methane (CH4) fluxes from a typical winter wheat–summer maize rotation system under five integrated agricultural management practices: conventional regime [excessive nitrogen (N) fertilization, flood irrigation, and rotary tillage before wheat sowing; CON], recommended regime 1 (balanced N fertilization, decreased irrigation, and deep plowing before wheat sowing; REC-1), recommended regime 2 (balanced N fertilization, decreased irrigation, and no tillage; REC-2), recommended regime 3 (controlled release N fertilizer, decreased irrigation, and no tillage; REC-3), and no N fertilizer (CK). Field measurements indicated that pulse emissions after N fertilization and irrigation contributed 19–49 % of annual N2O emissions. In contrast to CON (2.21 kg N2O-N ha−1 year−1), the other treatments resulted in significant declines in cumulative N2O emissions, which ranged from 0.96 to 1.76 kg N2O-N ha−1 year−1, indicating that the recommended practices (e.g., balanced N fertilization, controlled release N fertilizer, and decreased irrigation) offered substantial benefits for both sustaining grain yield and reducing N2O emissions. Emission factors of N fertilizer were 0.21, 0.22, 0.23, and 0.37 % under CON, REC-1, REC-3, and REC-2, respectively. Emissions of N2O during the freeze–thaw cycle period and the winter freezing period accounted for 9.7 and 5.1 % of the annual N2O budget, respectively. Thus, we recommend that the monitoring frequency should be increased during the freeze–thaw cycle period to obtain a proper estimate of total emissions. Annual CH4 fluxes from the soil were low (−1.54 to −1.12 kg CH4-C ha−1 year−1), and N fertilizer application had no obvious effects on CH4 uptake. Values of global warming potential were predominantly determined by N2O emissions, which were 411 kg CO2-eq ha−1 year−1 in the CK and 694–982 kg CO2-eq ha−1 year−1 in the N fertilization regimes. When comprehensively considering grain yield, global warming potential intensity values in REC-1, REC-2, and REC-3 were significantly lower than in CON. Meanwhile, grain yield increased slightly under REC-1 and REC-3 compared to CON. Generally, REC-1 and REC-3 are recommended as promising management regimes to attain the dual objectives of sustaining grain yield and reducing greenhouse gas emissions in the North China Plain.