等氮量条件下有机肥替代化肥对玉米农田温室气体排放的影响

[目的]明确大田等氮量条件下,有机肥替代化肥对玉米农田土壤温室气体(N20和Co2)排放及其增温潜势的影响,为稳定作物产量、减少化肥投入、减少氮肥流失、提高氮肥利用效率提供理论依据.[方法]2018和2019年大田采用静态箱-气相色谱法,以不施肥(CK)为对照,比较等氮量条件下常规单施化肥(NPK)、有机肥替代30％(...

Effect of Organic Fertilizer Replacing Chemical Fertilizers on Greenhouse Gas Emission Under the Conditions of Same Nitrogen Fertilizer Input in Maize Farmland

【Objective】 The aim of this study was to investigate the effects of organic fertilizer replacing chemical fertilizer on soil greenhouse gas emission and global warming potential (GWP), so as to provide the theoretical basis for keeping crop yield stable, reducing fertilizer input and nitrogen (N) loss, and improving N use efficiency.【Method】In 2018 and 2019, a field experiment was conducted to study the effects of different organic fertilizers replacing chemical fertilizers rate on soil N₂O flux, CO₂ flux and GWP and carbon footprint by using static chamber and gas chromatography in maize yield. Four treatments, including control (CK), single application of inorganic fertilizer (NPK), organic fertilizer replacing 30% inorganic fertilizers (inorganic fertilizers 180 kg N·hm^-2+ organic fertilizer 90 kg N·hm^-2, NPKM30), and organic fertilizer replacing 50% inorganic fertilizers (inorganic fertilizers 135 kg N·hm^-2+organic fertilizer 135 kg N·hm^-2, NPKM50), were established during maize growth periods.【Result】There was no significant difference of maize grain yield among NPK, NPKM30 and NPKM50 in 2018 and 2019. During the maize growth periods, the N₂O emission flux showed temporal variations, and the average fluxes under three fertilizer treatments were higher than that under CK. Compared with NPK, NPKM30 increased the N₂O cumulative emission by 5.22%, while reduced by 7.92% for NPKM50 treatment. The N₂O cumulative emission over the maize growth periods accounted for 12.91? -18.74? of soil total N. During the maize growth periods, soil CO₂ flux showed similar temporal patterns among the four treatments, and the average flux for the two years ranged from 74.53 to 367.04 mg·m^-2·h^-1. Fertilization input significantly increased the cumulative CO₂ emission, and the average CO₂ accumulation under NPKM30 and NPKM50 treatments increased by 0.91% and 5.79% than that under NPK treatment, respectively. The average GWP under NPKM30 and NPKM50 treatments was 2.07% and 2.10% higher than that under NPK treatment, respectively. Compared with the NPK treatment, the GHGI and carbon emissions from per unit yield under NPKM30 treatment decreased by 2.46% and 1.43%, respectively, and increased by 3.37% and 1.43% under NPKM50 treatment, respectively. 【Conclusion】 Suitable organic fertilizer rate replacing some chemical fertilizer could keep maize yield stable, increase greenhouse gas emission and global warming potential, while reduce greenhouse gas emission intensity and carbon emissions from per unit yield. Considering the ecological benefits of maize production and greenhouse gas emissions, the organic fertilizer replacing 30% inorganic fertilizers would be a more ideal proportion of organic fertilizer to replace chemical fertilizer.