21EJP SOIL: CropGas: The effect of conservation agriculture interventions on greenhouse gas emissions

21EJP 土壤：农作物气体：保护性农业干预措施对温室气体排放的影响

• 批准号: BB/X002993/1
• 负责人: Laura Cardenas
• 金额: $ 68.5万
• 依托单位: Rothamsted Research
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX002993%2F1
• 关键词: 21EJP; SOIL; CropGas; effect; conservation

Agriculture must ensure food security for all, sustainably and in the face of climate change. There is concern about the impact of farming on soil quality (losses of structural stability, soil organic carbon, biological functions), and greenhouse gas (GHG) emissions. The most recent IPCC report (Working Group 3) identified agriculture and land use change as a comparable source of anthropogenic GHG to the energy sector, with considerable scope for mitigation.There is widespread interest in how conservation agriculture (CA) might increase the sustainability of cropping, ranging from intensive temperate systems in the global north to smallholder and subsistence production in the global south. In all, zero or minimum tillage (ZMT) is implemented to reduce the disruption of soil structure. The retention of organic residues, or other means to build soil organic carbon (SOC), and the diversification of cropping systems through rotations or intercropping are all components of CA. While there is evidence that CA can increase the resilience of crop yields to climate variations and improve the structure of soils, the question of its impact on GHG budgets remains open. In particular, it is likely that different GHGs respond differently to changes in tillage practice and increase in SOC status, so a strong evidence base is needed to assess the trade-offs between components of the GHG budget under CA, and the net effect on global warming potential (GWP), given differences in the climate impact of different gases.This project brings together researchers from Europe and sub-Saharan Africa (SSA) who have been active in CA and GHG research to make a substantive contribution to the evidence base for the impact of CA practices on GHG budgets for agricultural soils. The evidence will span both temperate European systems, and systems in SSA, including smallholder production.We will use established experiments in the UK, Ireland, and Poland that include locally relevant ZMT and crop rotation interventions with conventional cultivation comparisons. Similarly, existing experiments in South Africa, Zambia, Zimbabwe and Malawi will be used. The last three sites are part of an existing network (CEPHaS, also including RR, BGS and UoN) designed to compare conventional management with ZMT and residue retention combined with other CA interventions.We shall install state-of-the art field instrumentation to measure soil GHG emissions and soil variables for plots across the experimental sites. This will provide measurements at fine-scale temporal resolution. We shall develop robust methods for statistical analysis and train each of the experimental groups in their use. The results will allow us to evaluate how local environment and crop management affect the relative importance of CO2, CH4 and N2O in GHG emissions from soil, and whether adoption of CA mitigates the GWP of these emissions.Measurements of emissions will be appraised alongside crop yield and other sustainability metrics allowing the wider assessment of tradeoffs in the systems. Where possible, data will be used to derive country specific emissions factors.We shall evaluate the prediction of observed differences in our experimental treatments by process models, and in particular whether it is necessary to account explicitly for how the physical and biogeochemical processes controlling emissions are affected by soil structure, which we will quantify by x-ray computerized tomography. Practically this will show the level of detail required in predictive models. It will also help to identify the key processes in the management-soil interaction which determine GHG production.To contextualise our analyses, we shall review the literature relating to GHG fluxes under CA and undertake a meta-analysis of reviewed studies. This will allow us to evaluate further the potential role of CA in mitigation strategies and assess various trade-offs in the system.

面对气候变化，农业必须可持续地确保所有人的粮食安全。人们担心农业对土壤质量（结构稳定性、土壤有机碳、生物功能的丧失）和温室气体（GHG）排放的影响。最近的 IPCC 报告（第三工作组）将农业和土地利用变化视为与能源部门类似的人为温室气体来源，具有相当大的缓解空间。人们广泛关注保护性农业 (CA) 如何提高种植业的可持续性，从全球北部的集约型温带系统到全球南部的小农和自给生产。总之，实施零耕或少耕（ZMT）是为了减少对土壤结构的破坏。有机残留物的保留或建立土壤有机碳 (SOC) 的其他方式，以及通过轮作或间作实现种植系统的多样化都是 CA 的组成部分。虽然有证据表明 CA 可以提高作物产量对气候变化的适应能力并改善土壤结构，但其对温室气体预算的影响问题仍然悬而未决。特别是，不同的温室气体对耕作方式的变化和 SOC 状态的增加可能有不同的反应，因此考虑到不同气体对气候影响的差异，需要强有力的证据基础来评估 CA 下的温室气体预算组成部分之间的权衡，以及对全球变暖潜势 (GWP) 的净影响。该项目汇集了来自欧洲和撒哈拉以南非洲 (SSA) 的研究人员，他们一直活跃于 CA 和温室气体研究，以做出实质性的研究 为 CA 实践对农业土壤温室气体预算影响的证据库做出贡献。证据将涵盖欧洲温带系统和SSA系统，包括小农生产。我们将使用在英国、爱尔兰和波兰进行的既定实验，其中包括当地相关的ZMT和作物轮作干预措施与传统种植的比较。同样，将使用南非、赞比亚、津巴布韦和马拉维的现有实验。最后三个站点是现有网络（CEPHaS，还包括 RR、BGS 和 UoN）的一部分，旨在将传统管理与 ZMT 和残留物保留与其他 CA 干预措施相结合进行比较。我们将安装最先进的现场仪器来测量整个实验站点地块的土壤温室气体排放和土壤变量。这将提供精细时间分辨率的测量。我们将开发稳健的统计分析方法，并对每个实验组进行使用培训。结果将使我们能够评估当地环境和作物管理如何影响土壤温室气体排放中二氧化碳、甲烷和氧化亚氮的相对重要性，以及采用 CA 是否会减轻这些排放的全球升温潜能值。排放量的测量将与作物产量和其他可持续性指标一起进行评估，以便对系统中的权衡进行更广泛的评估。在可能的情况下，数据将用于推导国家特定的排放因子。我们将通过过程模型评估对实验处理中观察到的差异的预测，特别是是否有必要明确考虑控制排放的物理和生物地球化学过程如何受到土壤结构的影响，我们将通过 X 射线计算机断层扫描对其进行量化。实际上，这将显示预测模型所需的详细程度。它还将有助于确定管理-土壤相互作用中决定温室气体产生的关键过程。为了使我们的分析符合背景，我们将回顾与 CA 下的温室气体通量相关的文献，并对审查的研究进行荟萃分析。这将使我们能够进一步评估 CA 在缓解策略中的潜在作用，并评估系统中的各种权衡。