Large Area Distributed Real Time Soil (DiRTS) Monitoring

Lead Research Organisation: Keele University
Department Name: Faculty of Natural Sciences

Abstract

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.

Planned Impact

Overview:
Motivated by the National Academy of Engineering (NAE) grand challenge of "Managing the Nitrogen
cycle", and the National Academy of Sciences (NAS) call for "Breakthroughs in Field Deployable
Sensors for Advancing Food and Agricultural Research", this project presents a convergent research to
develop the next generation, integrated sensing system for large area in situ spatiotemporal monitoring of
both dynamic nitrogen species, specifically ammonium and nitrate, as well as soil moisture and salinity.
Towards this goal, we propose a distributed wireless network of soil-penetrable sensor motes with
advances in microfluidics that mimics plant-like water intake, robust electrochemical sensors for
ammonium, nitrates etc., ultra low power circuit architectures for readout and digitization, long range
wireless communication using emerging standards, and advanced algorithms for geospatial mapping. The
platform will address the fundamental weakness in our understanding and management of nitrogen
species in unmanaged (e.g. forest) and managed (e.g. agriculture) soils.

Intellectual Merit:

The proposed wireless Distributed Real Time Soil (DiRTS) monitoring platform makes several notable
intellectual contributions: (1) Continuous sampling of soil micronutrients mimicing the natural water
intake and transpiration in plants using the capillary (wicking) effect in multifilament threads and
evaporation (2) Ion sensitive electrodes utilizing redundancy and Bayesian calibration for enhanced
sensitivity; embedded desalination to improve selectivity to ammonium and nitrate (3) Sub-0.5V circuits
for readout and digitization consuming nanowatt level power (4) Event-driven sampling and wireless
communication using probabilistic sensor scheduling based on available power and data importance; (5)
Sparsity-based and stochastic gradient descent based approaches generating high resolution spatiotemporal
chemical maps from irregularly sampled data and (5) All technology validated using actual, insitu
measurements in an experimental forest, with soil science investigation quantifying N2O fluxes to be
monitored and mapped using DiRTS sensor network. This proposal brings together experts in
engineering, geosciences and chemistry with a strong background and expertise in relevant areas of
sensing, electronics, microfluidics, biogeochemistry, signal processing and sensor networks, needed for
successful completion of this project.

Broader Impacts:

Empowered by the proposed DiRTS monitoring platform, the new and improved understanding of the
complex dynamic nitrogen transformational processes in soil will have broad applicability for agricultural
and environmental monitoring and management. The system will help optimize fertilizer treatment
thereby saving costs while improving food security and reducing contamination of soil and water sources
from fertilizer run-off. Sensors for ammonium, nitrates, salinity and moisture, with ultra low power
circuits will have broad applicability for wearable health monitoring, point of care diagnostics, and food
water and air quality monitoring. Advanced geospatial mapping algorithms will be useful in processing
data from a wealth of sources such as satellite data for weather and agriculture. There are opportunities
for licensing and commercialization through the Tech Transfer offices at the participating universities.

Beyond technical impact, proposed research will offer educational and outreach opportunities
through (1) interdisciplinary two-term course development for undergraduate and graduate students on internet of things (2) Training modules on the design and deployment of the DiRTS monitoring platform available to practitioners and (3) diversity outreach through mentoring enable via successful established programs such as Leadership Alliance, Bridging Engineers for Success at Tufts, and Access to Birmingham Uni outreach activity at BiFOR-FACE.

Publications

10 25 50
 
Description IES\R3\203138 - International Exchanges 2020 Round 3
Amount £12,000 (GBP)
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2021 
End 03/2023
 
Description Multi-sensor array for mapping plant nutrients in soils and natural fertilizers
Amount £12,000 (GBP)
Funding ID IES\R1\221138 
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 07/2022 
End 08/2024
 
Title Supplementary information files for Concurrent measurement of nitrate and ammonium in water and soil samples using ion-selective electrodes: tackling sensitivity and precision issues 
Description Supplementary files for article Concurrent measurement of nitrate and ammonium in water and soil samples using ion-selective electrodes: tackling sensitivity and precision issues. In this paper, we demonstrate the suitability, sensitivity, and precision of low-cost and easy-to-use ion-selective electrodes (ISEs) for concurrent detection of NH4+ and NO3- in soil and water by technical and non-technical end-users to enable efficient soil and water management exposed to chronic reactive nitrogen loading. We developed a simplified methodology for sample preparation followed by the demonstration of an analytical methodology resulting in improvements of sensitivity and precision of ISEs. Herein, we compared and contrasted ISEs with traditional laboratory-based technique such as Flow Injection Analysis (FIA) and portable colorimetric assay followed by comparisons of linear regression and Bayesian nonlinear calibration approaches applied on both direct potentiometry and standard addition modes of analysis in terms of in-field applications and improvement of sensitivity and precision. The ISEs were validated for sensing on a range of ambient soil and water samples representing a range of NH4+ and NO3- concentrations from pristine to excessive saturation conditions. Herein developed methodology showed excellent agreement with lab-based and portable analytical techniques while demonstrating improvements in precision and sensitivity analysis illustrated by a decrease in confidence intervals by 50-60%. We also demonstrated the utilization of the entire ISE response curve thus removing the biases originating from linear approximation which is often currently employed. Therefore, we show that ISEs are robust yet low cost and an easy to use technology that can enable high-frequency measurement of mineral N and help to improve our understanding of N transformation processes as influenced by soil management, fertilization, land use, and climate change. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL https://repository.lboro.ac.uk/articles/dataset/Supplementary_information_files_for_Concurrent_measu...
 
Description Collaboration with Prof Kirsanov from St Petersburg State University 
Organisation Saint Petersburg State University
Country Russian Federation 
Sector Academic/University 
PI Contribution We published a collaborative paper where my research group contributed with a set of experimental data and discussion and analysis of the outcome of the combination of experimental data and chemometric approach for data processing provided by Prof Kirsanov.
Collaborator Contribution We published a collaborative paper where Prof Kirsanov's group contributed by chemometric approach for analysis of a set of experimental data provided by my group. Prof Kirsanov's group also had a significant role in the discussion and analysis of the outcome of the results.
Impact The paper has just been accepted for publication in Sensors and Actuators B: Chemical. The paper still has no DOI number but is expected soon after the deadline for submission of this report passes. The manuscript number is SNB-D-21-00056R1 This collaboration is multi-disciplinary. We combine experimental analytical chemistry (utilizing ionophore-based sensors) by the group of Dr Radu and chemometric by the group of Prof Kirsanov.
Start Year 2020
 
Description Collaboration with Prof Kirsanov from St Petersburg State University 
Organisation Saint Petersburg State University
Country Russian Federation 
Sector Academic/University 
PI Contribution We published a collaborative paper where my research group contributed with a set of experimental data and discussion and analysis of the outcome of the combination of experimental data and chemometric approach for data processing provided by Prof Kirsanov.
Collaborator Contribution We published a collaborative paper where Prof Kirsanov's group contributed by chemometric approach for analysis of a set of experimental data provided by my group. Prof Kirsanov's group also had a significant role in the discussion and analysis of the outcome of the results.
Impact The paper has just been accepted for publication in Sensors and Actuators B: Chemical. The paper still has no DOI number but is expected soon after the deadline for submission of this report passes. The manuscript number is SNB-D-21-00056R1 This collaboration is multi-disciplinary. We combine experimental analytical chemistry (utilizing ionophore-based sensors) by the group of Dr Radu and chemometric by the group of Prof Kirsanov.
Start Year 2020
 
Description EGU conference Vienna, Austria 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The General Assembly 2023 of the European Geosciences Union (EGU) is an international forum for practitioners and researchers in Geosciences and related sciences. The EGU23 General Assembly welcomed 18,831 registered attendees, of which 15,453 made their way to Vienna from 107 countries and 3,378 joined online from 105 countries. It was a great success with 16,357 presentations given in 938 sessions. Thereby, 57% of the abstracts were identified as contributions from Early Career Scientists (ECS).
Year(s) Of Engagement Activity 2022,2023
URL https://www.egu23.eu/
 
Description EGU conference Vienna, Austria 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The EGU General Assembly 2022, the first-ever fully hybrid EGU meeting, was a great success with 12,332 presentations in 791 sessions. 7,315 colleagues from 89 countries participated on site in Vienna, accompanied by 7,002 virtual attendees from 116 countries.
Year(s) Of Engagement Activity 2022
URL https://www.egu22.eu/
 
Description Matrafured 2022 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact We met engineers working on the development of marine environmental sensors and we were able to discuss the manufacturing process. We were struggling with drop-casting our membranes and not getting optimal results, so we had different meetings after the conference to share our methodologies and challenges, and we were able to improve our drop-casting technique by modifying some parameters such as viscosity, surface tension, etc. The PI of this research group is Amy V. Mueller (a.mueller@northeastern.edu) from Northeastern University, Boston, USA.
Year(s) Of Engagement Activity 2022
URL https://matrafured.ch/