Large Area Distributed Real Time Soil (DiRTS) Monitoring

提高我们对土壤生态系统，特别是氮素物种动态的认识，对于改善土壤肥力、提高作物生产力、管理温室气体通量和保护环境质量至关重要。本项目提出融合研究，开发下一代集成传感系统，用于大面积、原位、高分辨率的动态氮种，特别是铵和硝态氮，以及土壤水分、钾和盐的时空监测。无线分布式实时土壤（DiRTS）监测网络由以下组成：(1)采用先进的微流体模拟植物根系吸水的可穿透土壤的传感器；(2)采用超低功耗电路架构的用于读取和数字化的铵、硝、钾和盐的强大电化学传感器；(3)使用新兴标准的远程无线数据通信；盐度和湿度。该平台将解决我们对非管理（如森林）和管理（如农业）土壤中氮物种的理解和控制方面的根本弱点。除了技术影响之外，拟议的研究工作将通过创新课程为本科生和研究生提供教育和培训机会，并通过设计和部署无线分布式实时土壤（DiRTS）监测平台的公开培训模块为农民和其他土壤管理从业者提供教育和培训机会。DiRTS平台将在以下几个方面做出显著的科学贡献：(1)通过毛细管驱动对目标土壤养分进行连续采样，模拟根部和植物上部的蒸腾作用对自然水分的吸收；(2)离子敏感电极利用嵌入式海水淡化提高选择性，利用冗余度和贝叶斯校准提高灵敏度；(3)供电低于0.5V、功耗为纳瓦级的读出和数字化电路；(4)基于可用功率和数据重要性的概率传感器调度的事件驱动采样和无线通信；(5)基于统计机器学习的最新方法，用于从不规则采样数据中生成高分辨率时空化学图。所有技术都将在伯明翰森林研究所的实验森林bifor - face中使用传感模和DET/DGT传感器对目标变量进行实际的原位测量。在验证之后，感应mote将被安装在FACE设施的温室气体自动室中，用于同时感应动态氮种和N2O通量，使用PICARO温室气体分析仪进行监测，并使用DiRTS传感器网络进行测绘。该提案汇集了来自美国和英国的工程，生物地球科学和化学专家，他们在传感，电子，微流体，生物地球化学，土壤科学，信号处理和传感器网络等相关领域具有强大的背景和专业知识，以成功执行该项目。

Advancing our understanding of the soil ecosystem, especially the dynamics of nitrogen species, is critical for improving soil fertility, increasing crop productivity, managing greenhouse gas fluxes, and protecting environmental quality. This project presents convergent research to develop the next generation, integrated sensing system for large area, in situ, high resolution spatio-temporal monitoring of dynamic nitrogen species, specifically ammonium and nitrate, as well as soil moisture, potassium and salinity. The wireless Distributed Real Time Soil (DiRTS) monitoring network is comprised of (1) soil-penetrable sensor motes with advanced microfluidics mimicking plant root-like water intake, (2) robust electrochemical sensors for ammonium, nitrate, potassium and salinity utilizing ultra-low power circuit architectures for readout and digitization, (3) long range wireless data communication using emerging standards, and (4) advanced algorithms for geospatial mapping of soil mineral nitrogen, potassium, salinity and moisture. The platform will address fundamental weaknesses in our understanding and control of nitrogen species in both unmanaged (e.g. forest) and managed (e.g. agriculture) soils. Beyond the technical impact, the proposed research effort will offer educational and training opportunities for undergraduate and graduate students through innovative curriculum and for farmers and other soil management practitioners through publicly available training modules on design and deployment of the wireless Distributed Real Time Soil (DiRTS) monitoring platform.The DiRTS platform will make several notable scientific contributions: (1) Continuous capillary-driven sampling of the target soil nutrients mimicking the natural water intake by roots and transpiration through aboveground plant parts; (2) Ion sensitive electrodes utilizing embedded desalination to improve selectivity, and utilizing redundancy and Bayesian calibration to improve sensitivity; (3) Circuits for readout and digitization operating below 0.5V power supply and nanowatt level power dissipation; (4) Event-driven sampling and wireless communication using probabilistic sensor scheduling based on available power and data importance; and (5) State of the art statistical machine learning based approaches for generating high resolution spatio-temporal chemical maps from irregularly sampled data. All technology will be validated using actual, in-situ measurements of the target variable using the sensing mote and DET/DGT sensors in an experimental forest-BIFoR-FACE of the Birmingham Institute of Forest Research. Following validation, the sensing mote will then be fitted inside greenhouse gas auto-chambers in the FACE facility for concomittant sensing of dynamic nitrogen species and N2O fluxes to be monitored using a PICARO greenhouse gas analyzer and mapped using DiRTS sensor network. This proposal brings together experts in engineering, biogeosciences and chemistry from the US and UK, with strong backgrounds and expertise in relevant areas of sensing, electronics, microfluidics, biogeochemistry, soil science, signal processing and sensor networks, for successful execution of this project.