典型区域水旱轮作系统气候变化智慧型农业计量与表征

The “Climate-smart agriculture” with the main objectives of adapting and mitigating climate change to ensure food security is an inevitable choice for agricultural development under future climate change. Therefore, balanced ecosystem services are undoubtedly requested for reaching “Climate-smart agriculture”. In this proposed project, an indicator system, linked with soil carbon, nitrogen, and water cycles, will be built for characterizing the ecosystem services and environmental impacts of crop production. A quantification and assessment methodology will then be developed to assess the sustainability of crop production through introducing life cycle assessment in ecosystem service quantification and combining multi-models simulation with big data integration approaches. Taking paddy rice-dry cropping rotation at the township scale as the research object, regional ecosystem services and environmental impacts will be quantified by the developed methodology in this project. Then the scenario analyses of climate change and farmland management will be employed to assess the impact of climate change on the sustainability of crop production. The synergy and trade-off relationships between various indicators will be distinguished using integrating method and trade-off analyses, then the key drivers of crop production sustainability will be explored to seek the pathways for maintaining and even improving ecosystem service under climate change. The innovation of this project is assessing the effects of future climate change on the sustainability of crop production and the trade-off relationship between various indicators in cropland under different management patterns from two aspects of ecosystem service and environmental impacts. This project will provide the methodological support and scientific basis for the technical pathways selections and policy formulation of “Climate-smart agriculture” development.

本项目拟从土壤碳、氮、水循环入手，建立用于评价农田生态系统服务和环境影响的指标体系；将生命周期评价与生态系统服务研究方法相结合，基于多模型模拟和大数据集成分析手段，发展用于评价农田生产可持续性的计量方法学。以乡镇尺度水旱轮作农田为研究对象，量化和对比区域农田稻作和旱作生产的生态系统服务和环境效应；通过气候变化和农田管理情景分析探讨气候变化对农田生产可持续性的影响风险，采用指标集成手段和指标权衡关系判别与定量方法，探讨不同可持续性指标之间的协同与抵消关系，并进一步挖掘影响农田生产可持续性的关键驱动力，以寻求气候变化下农田生态系统服务的维持或提升的技术途径。项目的创新之处在于从生态系统服务和环境影响两个方面定量评价了气候变化对不同管理模式农田生产可持续性及可持续性指标间权衡关系的影响。研究成果可为“气候变化智慧型农业”发展的技术路径选择和政策制定提供方法学支撑和和科学依据。

农田生产在提供粮食和生物质生产、土壤固碳、水源涵养等生态系统服务的同时，也通过温室气体排放、活性氮损失对生态环境带来影响，而未来气候变化将进一步威胁着农田生产系统的可持续性。本项目着眼于“气候变化智慧型农业”的表征与计量评价，提出了用于评价农田生态系统服务和环境影响指标体系，基于生命周期评价和模型模拟手段，发展了气候变化对农田生产可持续性影响的计量评价方法。以江苏省常熟市古里镇稻麦轮作农田为研究对象，模拟评价了气候变化对乡镇尺度稻麦轮作系统可持续性的影响程度，探索了气候变化下农田生态系统服务维持或提升的技术途径及其潜力。主要研究结果如下：（1）采用多元回归技术和机器学习算法，构建了模拟作物产量、农田土壤固碳、氧化亚氮排放、甲烷排放、氨挥发、氮氧化物排放和氮素径流与淋洗的经验数学模型，发现随机森林算法构建的经验模型模拟效果最优；（2）基于生命周期评价理论，优化了作物生产碳、氮、水足迹计量手段，并基于环境影响评价理论完善了作物生产综合环境足迹评价方法；采用统计年鉴数据评价了中国28种农作物生产的碳、氮、水足迹和综合环境足迹，识别了环境足迹的主要构成要素，发现氨挥发是作物生产生态环境影响的最大贡献者；（3）通过网格法采样以及以村为单位的实地调查，构建了古里镇稻麦轮作农田分布、土壤和管理数据空间数据集；采用构建的经验模型和优化的生态过程模型DayCent，对当前和未来气候条件下稻麦系统生态系统服务和环境影响风险进行了计量评估，发现未来气候变化对稻麦系统可持续性的影响以负面为主；通过情景分析构建了包括小麦秸秆炭化还田-氮肥减施-生物抑制剂使用的良好管理模式，发现良好管理模式可以显著降低同一气候条件下的环境足迹，但仍然无法完全抵消气候变化所带来的负面效应。研究成果可为“气候变化智慧型农业”的定量评价和技术选择提供方法学支撑和和科学依据。