玉米绿豆间作模式下有机肥用量和灌水量对农田碳平衡的影响

Effects of Organic Fertilizer Amount and Irrigation Amount in Intercropping Mode on Carbon Balance in Maize Field

  • 摘要:
    目的 为揭示有机肥施用配合适宜灌水量协同作用对土壤碳排放、作物固碳及农田碳排放效率的影响。
    方法 在河北省邢台市开展大田试验,以鲜食玉米“金冠220”和绿豆“冀绿20”为试验材料,设置有机肥施用量0 kg hm−2(F0)、3750 kg hm−2(F1)、7500 kg hm−2(F2)和不同灌水量,按田间持水量(θFC)上下限控制在40%θFC < θ < 60%θFC(I0),60%θFC < θ < 80%θFC(I1),80%θFC < θ < 95%θFC(I2))。水肥用量组合为9个处理,研究有机肥量和灌水量对土壤碳排放和固碳特征的影响,分析土壤理化性质与CO2累计排放量的相关性。
    结果 ①土壤呼吸速率随有机肥施用量和灌水量增加,分别表现为先升高后降低和逐渐增加的趋势。②土壤温度与土壤呼吸速率之间存在二次回归关系(P < 0.05),不同处理下,土壤温度可以解释30.1% ~ 72.5%的土壤呼吸速率变化。③土壤CO2累计排放量与土壤电导率,田间持水量呈显著的正相关关系(P < 0.05),与有机质含量呈现极显著的正相关关系(P < 0.01),与pH、容重呈负相关关系(P < 0.05)。④不同处理下玉米在农田生态系统中表现为碳汇,其中,F1I1处理农田净初级生产力和碳排放效率均最高。
    结论 综合考虑作物产量、灌水量投入以及碳排放效率,该试验条件下F1I1处理(有机肥施用量为3750 kg hm−2,灌水量上下限为60%θFC < θ < 80%θFC)是适宜当地玉米/绿豆间作生产的管理模式。

     

    Abstract:
    Objective The aims were to explore the synergistic effects of organic fertilizer application and appropriate irrigation strategies on soil carbon (C) emissions, crop C sequestration, and the efficiency of C emissions in farmland.
    Method The field test was operated in Xingtai, Hebei, China. The test maize varieties were maize "Jinguan 220" and mung bean "Jilv 20" as experimental crops, with varying rates of organic fertilizer 0 kg ha−1 (F0), 3750 kg ha−1 (F1), 7500 kg ha−1 (F2) and irrigation quantities set according to field water capacity (θFC) 40%θFC < θ < 60%θFC (I0), 60%θFC < θ < 80%θFC (I1), 80%θFC < θ < 95%θFC (I2). The influence of organic fertilizer and irrigation levels on soil C emission and sequestration was analyzed, along with the correlation between soil physical and chemical properties and cumulative CO2 emissions.
    Result ① Soil respiration rate initially increased, then decreased, and gradually rose with the increase of organic fertilizer and irrigation levels. ② A significant quadratic regression relationship existed between soil temperature and respiration rate (P < 0.05), with soil temperature accounting for 30.1% to 72.5% of the variance in respiration rates under different treatments. ③ Soil CO2 emissions positively correlated with electrical conductivity, field water capacity (P < 0.05), showing a particularly strong positive correlation with organic matter (P < 0.01), while negatively correlating with pH and bulk density (P < 0.05). ④ Under various treatments, maize acted as C sink in the farmland ecosystem, with the F1I1 treatment yielding the highest net primary productivity and C emission efficiency.
    Conclusion Considering crop yield, irrigation input, and C emission efficiency, the F1I1 treatment (3750 kg ha−1 organic fertilizer application and 60%θFC < θ < 80%θFC irrigation level) emerged as the optimal management model for local maize/mung bean intercropping under experimental conditions.

     

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