Novel tools for quantifying and managing sediment and nutrient loss from agricultural land

由于全球土壤侵蚀和养分流失问题通过污染和富营养化威胁着水质，因此欧盟制定了《水框架指令》立法，这一研究项目应运而生。WFD涉及到到2027年实现所有水体具有“良好生态状况”的目标，同时确定哪些变量限制或维持这一目标。这些变量通常是特定地点的，与地貌、气候和土地利用有关。在北爱尔兰，超过一半的水体没有达到“良好”的生态状态。研究表明，漫漫性农业污染源是水体养分富集和富营养化的主要来源，特别是通过化肥和浆料施用的磷和硝酸盐。北爱尔兰在战后过度施用化肥方面存在问题，与农业集约化相吻合，导致土壤中遗留的氮和磷水平过高。最近关于集水区管理的研究表明，观测技术要么过于具体，要么粗糙，无法理解导致水道退化的变量。有必要开展以流域为基础的研究，以了解沉积物养分流失的规模、频率和程度。该项目旨在开发一种多方法的方法来评估和监测农业用地的养分和沉积物损失。本研究的目的包括：1。开展实地调查，调查沉积物和营养物质的来源和损失，同时收集水样，通过分析底栖植物、大型无脊椎动物和植物群落来调查水质。利用卫星和无人机设备的遥感数据构建用于建模模拟的数字高程模型，以了解沉积物和养分损失的机制。这些数据还将用于模拟保护方法，以得出一套改善水质的建议。3. 应用多光谱图像和基于实地工作的证据来量化、绘制和评估所研究流域的营养和沉积物损失区域。4. 运行流域尺度土壤侵蚀模型，模拟当前气候、未来气候变化、土地利用和管理情景下的径流和土壤流失变化，以便设计适当的缓解战略。北爱尔兰实地考察的重点是黑水、上班恩和科尔布鲁克三个集水区。第一年：调查集水区沉积物和营养物质的来源和损失。量化路径和运动，评估对土地和水体的破坏程度。利用实地调查（以及遥感，如无人机和激光雷达数据）和实验室分析技术，建立损失和水质状况的参数。第二年：在场地推行管理策略，以处理沉积物/养分流失及水污染问题。就已采用管理技术的集水区对苏格兰进行实地访问，并显示北爱尔兰以外的水污染和沉积物/营养物损失的更广泛背景。第三年：在实施管理战略后监测集水区的改善情况，重复原来的实地调查/实验室分析，以确定其对水质的好处和减少沉积物/养分损失。本项目开发的技术和观察技能/方法将适用于许多集水区，在其理论框架中并非纯粹针对北爱尔兰，因此该项目可能推动新的研究领域。改善水质和减少沉积物损失方面的项目建议可应用于研究集水区，以推动目前的指示，并指出到2027年实现世界粮食计划署目标的新的优先管理技术。

This research project has arisen in relation to the EU's legislation of the Water Framework Directive established due to the global issue of soil erosion and nutrient loss threatening the water quality through pollution and eutrophication. The WFD involves achieving targets of all waterbodies possessing 'good ecological status' by 2027, alongside determining which variables constrain or maintain this. These variables are often site-specific, relating to geomorphology, climate and land-use. In Northern Ireland over half of all waterbodies fail to achieve the 'good' ecological status. Research has indicated that sources of diffuse agricultural pollution, typically from phosphorus and nitrates applied through chemical fertilisers and slurry, are the main source of waterbody nutrient enrichment and eutrophication. Northern Ireland has issues regarding excessive post-war application of fertilisers, coinciding with agricultural intensification, leading to excessive legacy levels of nitrogen and phosphorus present in soils. Recent research on catchment management has shown that observational techniques are either too site-specific or coarse to appreciate the variables contributing to waterway degradation. There is a requirement to develop catchment-based studies to understand the scale, frequency and magnitude of sedimentutrient loss. This project aims to develop a multi-method approach to evaluate and monitor nutrient and sediment loss from agricultural land. The objectives of this study include;1. Undertaking fieldwork to investigate the sources and losses of sediments and nutrients, alongside collecting water samples to investigate water quality with analysis on phytobenthic, macroinvertebrate and plant communities.2. Using remote-sensed data from satellites and drone equipment in the construction of digital elevation models for usage in modelling simulations to understand mechanisms of sediment and nutrient losses. This data will also be used to model conservation methods to derive a set of recommendations to improve water quality. 3. Apply multispectral imagery and fieldwork-based evidence to quantify, map and assess nutrient and sediment loss zones across the studied catchments. 4. Run catchment-scale soil erosion models to simulate runoff and soil loss changes under present-day climate, future climate change, land use and management scenarios in order to design appropriate mitigation strategies. Northern Ireland fieldwork focuses upon three catchment sites of the Blackwater, Upper Bann and Colebrooke.Year One: Investigating the sources and losses of sediment and nutrients in catchments. Quantifying pathways and movement, assessing levels of damage to both land and water bodies. Usage of fieldwork (alongside remote sensing e.g. drones and LiDAR data) and laboratory analysis techniques to establish parameters of losses and water quality status.Year Two: Management strategies instigated at sites to deal with issues of sediment/nutrient loss and water pollution. Field visits to Scotland concerning catchments where management techniques have been introduced and a showing wider context of water pollution and sediment/nutrient loss beyond Northern Ireland.Year Three: Monitoring improvements on catchments following the implementation of management strategies, repetition of original fieldwork/laboratory analysis to establish if benefits to water quality and a reduction in sediment/nutrient losses. The techniques and observational skills/approach developed in this project will be applicable across many catchment areas and is not purely specific to Northern Ireland in its theoretical framework and as such the project may drive new areas of research. The project recommendations in terms of water quality improvement and sediment loss mitigation could be applied to the study catchments to drive current directives and indicate new preferential management techniques to achieve the WFD target by 2027.