从湿地到农田:围垦对生态系统碳排放的影响

发布时间：2018-07-24 16:39

【摘要】：湿地围垦转化为农田直接影响碳循环过程,但之前的众多研究忽略了相关人为活动如农资生产、农用器械使用等所产生的碳排放.为了更全面认识湿地围垦为农田所导致的这种变化,以崇明岛为研究地区,基于通量观测和生命周期评价,本文分别探讨当考虑和不考虑人为活动伴随的碳排放时,生态系统总碳排放的变化.结果表明:如果只考虑生态系统与大气间的碳通量,农田仍表现为碳汇,但与自然湿地相比,其碳排放增加了10.47t(CO_2-eq)·hm~(-2);当将农业生产中人为活动碳排放纳入计算后,崇明岛自然湿地和围垦农田的碳排放总量分别为-15.38和6.54 t(CO_2-eq)·hm~(-2),碳排放增加了21.92 t(CO_2-eq)·hm~(-2),其中,人为活动碳排放为11.45 t(CO_2-eq)·hm~(-2);田间种植和农资生产的碳排放共占农田生命周期碳排放总量的84.6%,化肥的生产施用是农田生命周期碳排放的主要来源之一.围垦使生态系统乃至区域尺度的碳源汇属性发生变化,需重新评估其影响;同时,为了达到低碳农业的目的,需减少化肥施用、提高化肥使用效率.
[Abstract]:The transformation of wetland reclamation into farmland directly affects the carbon cycle process, but many previous studies neglect the carbon emissions produced by related human activities such as agricultural production and the use of agricultural instruments. In order to make a more comprehensive understanding of the changes caused by wetland reclamation as a farmland, Chongming Island is the research area based on flux observation and life cycle assessment. In this paper, we discuss the changes in the total carbon emissions of the ecosystem when considering and not considering the carbon emissions associated with human activities. The results show that, if only the carbon flux between the ecosystem and the atmosphere is considered, the farmland is still carbon sequestration, but its carbon emissions are increased by 10.47t (CO_2-eq) hm~ (-2) compared with the natural wetland; The carbon emissions of natural and reclaimed farmland in Chongming Island were -15.38 and 6.54 t (CO_2-eq) hm~ (-2) respectively, and carbon emissions increased by 21.92 t (CO_2-eq). Hm~ (-2), among which the anthropogenic carbon emissions were 11.45 t (CO_2-eq) and hm~. The carbon emissions from field planting and agricultural production accounted for the carbon emissions of farmland life cycle. 84.6% of the total amount, the application of chemical fertilizer is one of the main sources of carbon emission in the life cycle of farmland. Reclamation makes the carbon source and sink attribute of the ecosystem and the regional scale change, and it needs to be reassessed. At the same time, in order to achieve the purpose of low carbon agriculture, it is necessary to reduce the application of chemical fertilizer and improve the efficiency of the use of chemical fertilizer.
【作者单位】：复旦大学生物多样性与生态工程教育部重点实验室/上海崇明东滩湿地生态系统国家定位观测研究站;上海市环境科学研究院;
【基金】：国家重点基础研究发展计划项目(2013CB430404) 上海市科学技术委员会项目(13JC1400400) 上海市自然科学基金项目(14ZR1435100)资助~~
【分类号】：S181

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