河北省小麦玉米生产体系碳足迹分析

    Carbon Footprint Analysis of Wheat-maize Production System in Hebei Province

    • 摘要: 通过定量分析河北省小麦-玉米生产体系碳足迹及其影响因素, 为发展绿色低碳农业提供理论依据和科学支撑。基于2018年河北省小麦和玉米的化肥、农药、农膜和柴油用量, 以及灌溉耗电量、播种面积和产量等统计数据, 采用生命周期评价方法对小麦玉米生产体系碳足迹进行估算。结果表明, 河北省小麦种植季碳排放量、碳固定量和碳足迹量(以CO2计)分别为952万、463万和489万t, 玉米种植季分别为899万、588万和311万t。小麦种植季碳排放量高于玉米种植季, 碳固定量低于玉米种植季。灌溉、肥料和农田排放在碳排放源中排名居前3位, 其排放量分别占年碳排放总量的37.00%、31.17%和18.69%;秸秆还田的固碳量高于化肥施用, 占总固碳量的84.78%。化肥和农业机械对碳排放的贡献率分别为49.54%和43.97%, 对成本的贡献率均约为40%, 高于其他农资投入对碳排放和成本的贡献率。小麦玉米轮作体系碳足迹为正值, 即小麦-玉米生产过程为碳排放过程, 灌溉量大、单质氮肥用量高是造成小麦种植季碳排放量高于玉米种植季的主要原因。减量施肥和节水灌溉是减少河北省小麦玉米生产体系碳排放、降低生产成本和增加利润最直接有效的方法。

       

      Abstract: Analysis of carbon (C) footprint and related influence factors were beneficial for providing a theoretical support and scientific basis to low carbon agriculture development in Hebei province. Based on the statistical consumption of fertilizer, pesticide, agricultural film and diesel consumption, irrigation power consumption, sown area and yield of wheat and maize in Hebei Province in 2018, a life cycle assessment (LCA) method was used to calculate the C footprint during winter wheat and summer maize production process, which will provide a theoretical support and scientific basis for the development of low-carbon agriculture. The results show that the C emissions, C sequestration and C footprint of winter wheat were 952×104, 463×104 and 489×104 t CO2 eq in wheat season, and 899×104, 588×104 and 311×104 t CO2 eq in maize season, respectively. The annual total carbon emissions, carbon sequestration and carbon footprint of the province for the 2 crops were 1 851×104, 1 051×104 and 800×104 t CO2 eq, respectively. The C emissions and C footprint of winter wheat were 5.90% and 57.23% higher than that of summer maize, but the C sequestration was 21.26% lower than that of summer maize. The emissions related to irrigation, fertilizer and farmland dominated the CO2 emission, which accounted for 37.00%, 31.17% and 18.69% of the total annual C emissions, respectively. The C sequestration of straw incorporation accounted for 84.78% of the annual C sequestration, which was significantly higher than C sequestration caused by chemical fertilizer application. C emissions contributed by chemical fertilizer and machinery were 49.54% and 43.97%, respectively, and the contribution to cost were both with nearly 40% of the total cost inputs, which are significantly higher than the contribution of other agricultural inputs to carbon emissions and cost. The positive C footprint indicate that wheat-maize production system is the source of carbon emissions. The large amount of irrigation water input and the higher nitrogen fertilizer application are the main reasons for the higher carbon emissions of winter wheat. Therefore, reducing the amount of fertilizer application and reducing water irrigation are the most direct and effective ways to the reducing of C emissions and production costs of winter wheat-summer maize production system in Hebei Province.

       

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