• ISSN 1008-505X
  • CN 11-3996/S

长期施用有机肥对瘠薄玉米农田土壤N2O排放的影响

The impact of long-term application of organic fertilizer on N2O emissions from depleted cornfields

    摘要
  • 摘要:
    目的 瘠薄型农田玉米生产严重依赖施肥。研究长期施用有机肥对土壤N2O排放和维持玉米产量的影响，为瘠薄型农田氮素高效管理提供理论依据。
    方法 长期定位试验始于2008年，试验设计包括4个处理：不施肥对照处理(CK)、当地常规施肥处理(NPK)、增施有机肥处理(MNPK)、50%有机肥替代化肥处理(RMN)。2023年5月至10月，采用静态箱―气相色谱法监测土壤N2O排放通量，计算施用有机肥对土壤N2O累积排放以及产量的影响，并探明影响土壤N2O排放的主要因素。
    结果 与CK相比，施用有机肥(MNPK、RMN)显著提高玉米产量，增幅在95%～103% (P<0.05)。在整个监测周期内，3个施肥处理促进土壤N2O排放，整体呈现出“脉冲式”排放规律。N2O 最大排放峰值由高到低依次为MNPK、NPK、RMN处理，分别达到4.71±0.68、3.29±0.62、1.71±0.15 µg/(m2·min)，MNPK处理土壤N2O最大排放峰值和累积排放量分别显著高于NPK处理43.00%、64.65%，而RMN处理比NPK处理分别降低了48%、26.22%。土壤N2O排放通量与土壤铵态氮(NH4＋-N)、全氮(TN)含量以及体积含水率(VWC)呈极显著正相关关系(P<0.01)，与有机碳(SOC)、地温(GT)呈显著正相关关系(P<0.05)。NPK处理平均温室气体净排放量为CO2-eq 361 kg/(hm2·a)，净温室效应为“源”，MNPK和RMN处理净温室气体排放强度(GHGI)较NPK处理分别降低了572%和655%，玉米种植所产生的净温室气体排放量分别减少了668%和737%，两个有机肥处理之间的温室气体排放强度和净排放量无显著差异。
    结论 施用有机肥可有效减少瘠薄农田土壤N2O排放，降低净温室效应并显著提高玉米产量。综合减排和产量因素，在本试验条件下，有机肥替代50%的常规化肥养分量可在有效降低温室气体排放的同时，降低氮肥损失，提高玉米生产效益。

     

    Abstract:
    Objectives Maize production heavily relies on fertilization in infertile farmland. We explored the effects of organic fertilization methods on reducing N2O emissions and maintaining crop yield, with a view to provide a theoretical basis for optimizing nitrogen management in infertile farmland.
    Methods The study was carried on the field of a 15-year-long localization experiment, which included a total of four treatments: no fertilization control (CK); conventional chemical fertilization (NPK); organic fertilizer plus NPK (MNPK), and 50% chemical fertilizer+ 50% organic fertilizer (RMN). The cumulative soil N2O emission fluxes were monitored from May to October 2023 using static chamber-gas chromatography, and the maize yields were recorded at harvest.
    Results The organic fertilizer treatments MNPK and RMN increased maize yield by 95% to 103%, compared to CK (P<0.05). Throughout the monitoring cycle, the soil N2O emissions in all the three fertilizer treatments turned in an overall “pulsed” patterns. The maximum emission peaks in treatment MNPK, NPK, and RMN were 4.71±0.68, 3.29±0.62, and 1.71±0.15 µg/(m2·min), respectively. The soil maximum emission peak and cumulative N2O emission in MNPK treatment were 43.00% and 64.65% higher than in NPK treatment, while those in RMN treatment were 48% and 26.22% lower (P<0.05). Soil N2O emission fluxes showed extremely significant and positive correlations with soil NH4+-N, total N, and volumetric water content (P<0.01), and significant and positive correlation with soil organic carbon and soil temperature (P<0.05). The average net greenhouse effect (GHG) emissions under the NPK treatment were CO2-eq 361 kg/(hm2·a), showing a net GHG “source”. Compared to NPK treatment, MNPK and RMN treatment decreased the greenhouse gas emission intensity (GHGI) by 572% and 655%, and reduced the net GHG emissions by 668% and 737%, showing a net GHG “sink”. And MNPK and RMN treatments were calculated similar GHGI and net GHG.
    Conclusions The use of organic fertilizer can effectively reduce soil N2O emissions in infertile farmland, lower the net GHG, and increase maize yield significantly. Under the experimental condition, replacing 50% chemical fertilizer with organic fertilizer is recommended as the more satisfactory reduction effect of N2O emission and increase maize yield.

     

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