Real-time in situ sensing of soil nitrogen status to promote enhanced nitrogen use efficiency in agricultural systems

Lead Research Organisation: University of Southampton
Department Name: Faculty of Engineering & the Environment

Abstract

Nitrogen (N) is vital for crop productivity, however, typically half of the N we add to agricultural land is usually lost to the environment. This wastes the resource and produces threats to air, water, soil, human health and biodiversity, and generates harmful greenhouse gas (GHG) emissions. These environmental problems largely result from our inability to accurately match fertiliser inputs to crop demand in both space and time in the field. If these problems are to be overcome, we need a radical step change in current N management techniques in both arable and grassland production systems. One potential solution to this is the use of technologies that can 'sense' the amount of plant-available N present in the soil combined with sensors that can report on the N status of the crop canopy. On their own, these sensors can provide useful information on soil/crop N status to the farmer. However, they need refining if they are then to be used to inform fertiliser management decisions. This is because climate variables (e.g., temperature, rainfall, sunlight hours) and soil factors (e.g., texture, organic matter content) can have a major influence on soil processes and plant growth, independent of soil N status. These sensors therefore need to be combined with other data and improved soil-crop growth models to provide a more accurate report of how soil N relates to crop N demand at any given point in time. In this project, we are demonstrating how adoption of precision agriculture techniques (in the form of soil nitrate sensors) can be used to improve N use efficiency in both arable (wheat, oilseed rape) and grassland systems. While we are focusing on soil nitrate, as it arguably represents the key form of soil N associated with productivity and the environment, the approaches we are taking are also readily applicable to other nutrients for which sensors are currently being developed (e.g., ammonium, phosphate, potassium).

We have designed our research programme in accordance with the strategic objectives of the BBSRC-SARIC programme and those recently produced by HM Government to facilitate delivery of sustainable intensification strategies. To maximise the potential for technology development, commercialisation and adoption we are working closely with a range of industry partners throughout the programme. Overall, we aim to (i) demonstrate the use of novel N sensors for the real-time measurement of soil N status; (ii) use geo-statistical methods to optimise the deployment of these in situ sensors; (iii) produce new mechanistic mathematical models which allow accurate prediction of crop N demand; (iv) validate the benefits of these sensors and models in representative grassland and arable systems from a N use and economic standpoint; and (v) explore how these new technologies can improve current fertiliser management and guidelines through enhanced industry-focused decision support tools.
Ultimately, this technology shift could result in substantial savings to the farmer by both reducing costs, maximising yields and minimising damage to the environment. For example, if our technology improves N use efficiency by 10% in agricultural land where fertiliser is applied in the UK (8.2 million hectares of grassland and tilled crops), we estimate it would save 100 thousand tons of N fertiliser (equivalent to a saving of £69 million per annum to farmers). When the direct and indirect costs of nitrate pollution are considered (e.g., removing nitrate from drinking water is estimated to cost UK water companies >£20 million annually), and the reduction in direct and indirect greenhouse gas emissions from manufacture and use of 100 thousand tons of N fertiliser are accounted for, the benefits of adopting a validated precision agriculture approach are clear.

Technical Summary

The inefficient use of nitrogen (N) within agricultural systems is almost ubiquitous with typically only 50% of the N applied to the land subsequently recovered in the crop. This gross inefficiency is largely caused by the poor spatial and temporal targeting of fertiliser N relative to crop N demand, leading to a major loss of N to freshwater, groundwater and the atmosphere (via leaching, surface runoff or gaseous emissions). This diffuse pollution has a major environmental impact as well as a producing significant social (including human health) and indirect economic cost. One of the biggest challenges facing the agricultural industry is therefore finding new ways to optimise the use of N fertiliser to both reduce costs and improve sustainability. In response to this challenge, and in direct alignment with both the strategic objectives of the SARIC programme and those of RCUK (2016), we describe a new integrated precision agriculture approach to achieve this goal. Our aim is to combine the power of new soil-based in situ N sensors with mathematical models, spatial statistics and existing canopy N sensors to develop new decision support tools to allow farmers and their advisors to decide when and where to apply N. A range of key industry partners have joined this project consortium to demonstrate how soil and canopy sensors can be deployed in arable and grassland systems for measurement of soil and crop N status. Geo-statistical methods will be used to show the optimal deployment of these sensors. This information will feed into new mechanistic models which will be used to predict crop N demand. Together with our industry partners, we will explore via workshops and outreach activities how these new technologies can improve current fertiliser management and guidelines through enhanced industry-focused decision support tools.

RCUK (2016) A vision and high-level strategy for UK animal and plant health research to 2020 and beyond. BBSRC, ESRC, NERC, HM Government.

Planned Impact

UK agriculture uses over 0.85 million tonnes of nitrogen (N) fertiliser each year which is spread over 8.2 million hectares of tilled and grassland soil. A major proportion of this added fertiliser, however, is not taken up by the crop and is lost to the wider environment. This results in a major economic loss to farmers and can lead to pollution of water courses, groundwater and the atmosphere. As the use of synthetic fertilisers will continue to be pivotal in food production for the foreseeable future, new ways are needed to effectively target the efficient use of this resource. One of the major outputs from our research programme will be the creation of new decision support tools that are based on on-farm, real-time soil data which continually update during the growing season. This represents a major advancement in current fertiliser guidance systems (e.g. RB209, Planet, Farmscoper). The outputs of our research on society can be grouped as follows:

INDUSTRY: This research proposal is directly underpinned by key industry partners. These include (i) Yara UK who are one of the leading suppliers of N fertilisers, crop nutrient sensors (e.g. Yara-N-Sensor) and fertiliser guidance; (ii) Agricultural Industries Confederation (AIC) who are the agrisupply industry's leading trade association. AIC's Fertiliser Sector represents over 95% of the UK's agricultural fertiliser supply industry, worth about £2bn; (iii) British Grassland Society is a communication forum which through events and publications promotes the profitable and sustainable use of grass and forage; (iv) Agriculture and Horticulture Development Board (AHDB) is a Levy Board which represents the cattle, sheep, pigs, milk, potatoes, cereals, oilseeds and horticultural industries. AHDB are also responsible for reviewing current UK fertiliser recommendations associated with RB209. Our project directly aligns with the strategic priorities for all these industry organisations. All the main partners will be members of our management board, and will provide invaluable guidance throughout the project and will facilitate the dissemination of the project findings.

POLICY COMMUNITY: The results from this project will directly inform policymakers (e.g. Defra, DECC) by providing clear advice on future developments in precision agriculture including the environmental and economic costs and benefits and barriers to technology adoption. We will also provide guidance on the timelines and likely impact that adopting these technologies will have at the UK level and its potential impact on the UK N inventory. Policymakers are also central to our proposal (see WP5) ensuring dialogue throughout the programme. We will also build on our established links with Defra and Welsh Government to ensure effective dialogue.

WIDER COMMUNITY: A web page and Twitter feed from the Bangor website will provide ongoing information on the project and its results. Different aspects of the project will be used for teaching, generating student projects, and will be presented at open days at (1) the Bangor University Agricultural Extension Farm, which is one of Defra's Sustainable Intensification Platform flagship sites, and (2) by our industrial partners. We will also feature the project in School Science Week, using visualisation of nitrogen pollution to stimulate wider discussion about agriculture and the environment.

SCIENTIFIC COMMUNITY: Our research will inform scientists working in several areas of research (e.g. crop production, grazing management, water quality, greenhouse gas emissions and modelling). We will generate fundamental information on the use of in situ N sensors, plant-soil-microbial N cycling as well as providing new 3D mathematical modelling tools and information of the spatial heterogeneity of nutrients at a range of scales. These technologies will be promoted through the project-dedicated website, at national and international conferences and in journal publications.

Publications

10 25 50
 
Description Our specific key scientific finding is that as nitrogen fertiliser dissolves in soil depending on the level of soil saturation it can create a microbial death zone around the fertiliser pellet. More specifically, the drier the soil the more microbial death there is.
Exploitation Route Methodology of modelling is applicable in many fields ranging from agri and soil science to study of bxomineral composites and their function.
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Construction,Education,Energy,Environment

 
Description The narrative impact summary is below: Knowledge: development of new knowledge and technology to deal with image based prediction of behaviour of partially saturated soil within the context of plant and N dynamics provides impetus and guidance to apply these methodologies to other porous media and granular flow systems such as powder storage and manipulation, mesoporous semiconductor device manufacture etc. Economy/industry: clear beneficiaries/impacts are geotechnical engineering consultancies (Arup, MottMacDonald, Atkins,Ramboll), agronomy consultancies (Adas, Agrii), and agencies involved in managing and maintaining large UK infrastructures (Highways Agency, Network Rail), Environment Agency, Defra. Society: 10% of world energy is spent on managing soil and other granular materials (UN, IPCC). Efficiencies in this will be crucial for mitigating climate change. UK infrastructure renewals, enhancements and maintenance is estimated to cost ~£13B pa. Our work contributes to management of green infrastructure in the changing climate. Education/academia: the new technology highlights to researchers in mathematical sciences where new fundamental research endeavours are needed and enables researches in civil engineering, biological/agri sciences, natural environment conservation sciences to apply these new tools developed to wide variety of problems they have not been able to address until now. Public: will clearly benefit and be impacted by better environment and infrastructure management. In addition, the grass roots outreach activities are hopefully on the longer term resulting in the larger numbers of school children being hopefully inspired to become engineers and increase the prosperity of the UK. I also want to highlight the issue of neurodiverse people being able to be top level engineers.
First Year Of Impact 2020
Sector Agriculture, Food and Drink,Education,Environment
Impact Types Societal,Economic,Policy & public services

 
Description Feb 14-17 2018 Phenome 2018 Tuscon Arizona US. Keynote speaker for the theme "Algorithms and Data Management for Phenotype Quantification and Analysis". 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Feb 14-17 2018 Phenome 2018 Tuscon Arizona US. Keynote speaker for the theme "Algorithms and Data Management for Phenotype Quantification and Analysis".
Year(s) Of Engagement Activity 2018
 
Description Imaging Solute Movement through Ridged and Flat Planting Systems 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk at the conference Rhizosphere in Saskatoon, Canada in July 2019 and at ToScA conference in the UK in Sept 2019.
Talk title: Imaging Solute Movement through Ridged and Flat Planting Systems
Authors: Callum Scotson, Simon Duncan, Tiina Roose
Year(s) Of Engagement Activity 2019
 
Description July 2018 Plenary speaker at Society of Mathematical Biology conference in Sydney. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact July 2018 Plenary speaker at Society of Mathematical Biology conference in Sydney.
Year(s) Of Engagement Activity 2018
 
Description Mechanical and biophysical constraints affecting soil bioturbation by earthworms and plant roots. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Ruiz, S., 2018., July. Mechanical and biophysical constraints affecting soil bioturbation by earthworms and plant roots. In 11th European Conference on Mathematical and Theoretical Biology (ECMTB).
Location: Lisbon, Portugal
Dates: 23/07/2018-27/07/2018
Number of people: 10-20
Demographic: Scientists, Professors
Year(s) Of Engagement Activity 2018
 
Description Minisymposia at BAMC titled "Multi scale analysis of porous media" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Porous materials are a fundamental building block of many terrestrialmaterials, eco-systems, biological tissues, and manmade engineering materials. There are numerous examples of porous materials for which enhanced modelling and optimisation techniques will offer significant gains in efficiency and productivity. In agriculture, 30% of UK wheat currently needs to be grown on drought-prone land, where yields are limited by the scarcity of water in the soil. In the construction industry, the reuse of pulverised fuel ash as a low porosity material for flood embankments is limited by the potential leaching of heavy metals into the surrounding environment. To overcome these, and many other problems there is a clear need to go beyond idealised models and develop a more detailed understanding of flow and transport phenomena in such systems.
The mathematics of multiscale modelling in porous media is a rapidly growing field with wide ranging applications and collaborative opportunities. In this mini symposium we will discuss the mathematics of porous media. We will focus on pore scale and continuous descriptions of transport, fluid dynamics and structural mechanics. In addition talks will focus on how asymptotic techniques can be used to exploit the large variations in scales within these materials to link properties on the pore scale to macro-scale observations.
Whilst the main focus of the session is on the mathematical developments occurring in different areas of porous media, we will also focus on application and how mathematical techniques can be integrated with Computed Tomography and continuum scale measurements to inform industry practise, answer fundamental questions, and optimise porous materials across a range of different applications
Speakers
The session will include talks from five speakers working in different areas of porous media at different scales.
Dr Keith Daly - University of Southampton
Combining homogenisation theory and image based modelling to predict the poro-elastic properties of multi-constituent soils
Dr Laura Cooper - University of Warwick
Macroscopic effects of microscale interfaces
Dr Rebecca Shipley - University College London
Porous medium models to predict spatial heterogeneity in anti-cancer therapy efficacy
Mr Simon Duncan - University of Southampton
Solute movement and uptake in dynamic poroelastic materials
Dr Matteo Icardi - University of Nottingham
Upscaling reactive and electrochemical transport in porous media
Year(s) Of Engagement Activity 2018
 
Description Modeling the Comparative Impact of Root Hairs on Phosphorus Uptake Under Different Field Conditions 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Ruiz, S., Koebernick, N., Duncan, S., McKay Fletcher, D.M., Scotson, C., Boghi, A., Marin, M., Bengough, A.G., George, T.S., Brown, L.K., Hallett, P.D., and Roose, T., 2019. Modeling the Comparative Impact of Root Hairs on Phosphorus Uptake Under Different Field Conditions. In Rhizosphere 5.
Location: Saskatoon, Saskatchewan, Canada
Dates: 07/07/2019-11/07/2019
Format: talk
Year(s) Of Engagement Activity 2019
 
Description Monitoring phosphorus mobility in soil relevant for root uptake using microdialysis and X-ray computed tomography 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk at Rhizosphere conference
Title: Monitoring phosphorus mobility in soil relevant for root uptake using microdialysis and X-ray computed tomography
Co-authors: Chiara Petroselli, Katherine Williams, Callum Scotson, Daniel McKay Fletcher, Siul Ruiz, Tiina Roose
Audience: International scientific conference
Year(s) Of Engagement Activity 2019
 
Description Multimodal Imaging of Plant-Soil Interaction for Better and More Predictive Modelling of Rhizosphere Processes 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Roose, T., Petroselli, C., Williams, K., Dias, T., Scotson, C., McKay Fletcher, D.M., Ruiz, S. and Van Veelen, A., 2019, December. Invited Paper 487194: Multimodal Imaging of Plant-Soil Interaction for Better and More Predictive Modelling of Rhizosphere Processes. In AGU Fall Meeting 2019. AGU.
Location: San Francisco, CA, USA
Dates: 09/12/2019-13/12/2019
Demographic: Scientists, Professors, Students
Year(s) Of Engagement Activity 2019
 
Description Root induced compaction alleviation by root hairs -visualization with synchrotron imaging 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk at the European Geophysical Union conference in Vienna Spring 2018.
Year(s) Of Engagement Activity 2018
 
Description Scaling the impact of rhizosphere processes - from imaged pore scale nutrient uptake to full field continuum models. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Ruiz, S., et al., 2018., December. Scaling the impact of rhizosphere processes - from imaged pore scale nutrient uptake to full field continuum models. In AGU Fall Meeting Abstracts.
Location: Washington D.C., USA
Dates: 10/12/2018-14/12/2018
Number of people: 10-20
Demographic: Scientists, Professors, Students
Year(s) Of Engagement Activity 2018
 
Description Soil, Climatic and Biophysical Constraints Determine Global Distribution and Activity Windows of Earthworms 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Ruiz, S., Bickel, S., Lehmann, P. and Or, D., 2019, December. Soil, Climatic and Biophysical Constraints Determine Global Distribution and Activity Windows of Earthworms. In AGU Fall Meeting 2019. AGU.
Location: San Francisco, CA, USA
Dates: 09/12/2019-13/12/2019
Conference number: 5 BILLION
Number of people: 10-20
Demographic: Scientists, Professors, Students
Year(s) Of Engagement Activity 2019
 
Description Talk titled "High resolution synchrotron imaging of rhizosphere structure " at the EGU 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact High resolution synchrotron imaging of rhizosphere structure ; European Geophysical Union 2018 meeting

Nicolai Koebernick1, Keith R. Daly1, Samuel D. Keyes1, Timothy S. George2, Lawrie K. Brown2, Annette Raffan3, Laura J. Cooper1, Muhammad Naveed3, Anthony G. Bengough2,4, Ian Sinclair1, Paul D. Hallett3 and Tiina Roose1,$
1 Bioengineering Sciences Research Group, Engineering Sciences Academic Unit, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, United Kingdom
2 Ecological Sciences Group, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
3 Institute of Biological and Environmental Science, University of Aberdeen, Aberdeen AB24 3UU , United Kingdom
4 School of Science and Engineering, University of Dundee, Dundee DD1 4HN, United Kingdom
$ corresponding author
Email corresponding author: t.roose@soton.ac.uk
Keywords: non-invasive imaging, rhizosphere, root hairs, soil structure, root exudates

Plant roots induce hydromechanical stresses and release organic compounds into soil, which are major drivers of soil structure formation. Whilst it is well known that roots impact the structure and physico-chemical properties of the rhizosphere, the underlying processes and their impact on resource flows to plants require greater investigation. We are exploring how different root traits physically manipulate soils, drawing on near isogenic barley lines that differ in root hairs, architecture and exudation, as well as new imaging approaches to quantify rhizosphere impacts.
A barley wildtype and its mutant with greatly reduced root hair growth were grown in specially designed assays that enabled high-resolution synchrotron imaging of rhizosphere structure with resolutions sufficient to detect root hairs. A sandy loam textured soil (Dystric Cambisol, sieved to < 1 mm) was used as a growth medium. The results showed that root hairs may play an important role in rhizosphere structure formation by alleviating the compression that is induced by growing roots. Root induced compression was evidenced by decreased air-filled pore space between 0.1 and 0.8 mm from the root surface. However, at the root-soil interface, the pore space increased for the root hair bearing barley genotype, but not for the barley mutants with no root hairs.
In a similar experiment, conducted with a remoulded soil (Dystric Cambisol, sieved to <250 um), both genotypes showed increased porosity at the root soil interface with no significant differences between the genotypes. Pore size distribution was narrower at the root-soil interface and became wider with distance from the root due to the decreased volume of large pores near the root surface.
Increased porosity near the root is discussed as an effect of the geometry of soil particles at the root surface. A model is proposed that describes the variation in porosity around roots, taking into account both root induced compression and the simplified geometry of solid mineral particles at the root surface.
Year(s) Of Engagement Activity 2018
 
Description Talk titled "Imaging and modelling of rhizosphere processes" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Geophysical Research Abstracts
Vol. 20, EGU2018-18157, 2018
EGU General Assembly 2018
© Author(s) 2018. CC Attribution 4.0 license.
Imaging and modelling of rhizosphere processes
Arjen van Veelen, Nico Koebernick, Dan McKay Fletcher, Callum Scotson, Keith Daly, Robbie Mayone, Simon Duncan, and Tiina Roose
University of Southampton, Faculty of Engineering and the Environment, United Kingdom (a.van-veelen@soton.ac.uk)
Most human food relies on the production of crops. Crops get their nutrients and water from the soil. In addition, soil has many other important functions, including the buffering of hydrological systems to prevent flooding and the provision of a carbon sink, lowering atmospheric carbon. Although bulk soil chemical processes are relatively well understood, there is a critical lack of studies characterising the dynamics of physico-chemical properties in the rhi- zosphere, such as nutrient cycles and release of plant exudates. These changes to the soil can drastically change the soil's hydraulic, nutrient and carbon functionality. This emphasises the importance to visualise physico-chemical information, in order to understand key processes of plant-soil interactions. In our interdisciplinary project, Data Intensive Modelling of the Rhizosphere Processes (DIMR), we aim to characterise and visualise these dynamics. The aim of the programme is to visualise pore geometry in soils using X-ray Computed Tomography (CT), com- bined with Nuclear Magnetic Resonance Imaging (NMRI) to visualize plant exudates and water distribution. In addition, we use synchrotron X-ray Fluorescence (XRF) and X-ray Absorption Spectroscopy (XAS) to understand both soil chemistry and speciation at the root-soil interface, all leading to a better understanding of rhizosphere processes. These methods can be combined with predictive models of soil-root processes to understand rhizosphere functionality. We will discuss how chemical data obtained from both NMR and XRF and XAS spectroscopy can enable a step change in multiscale modelling of rhizosphere processes.
Year(s) Of Engagement Activity 2018
 
Description Understanding the Fundamental Properties of Root Exudates Under Drying 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster presentation at Rhizosphere 2019 in Saskatoon Canada
Title: Understanding the Fundamental Properties of Root Exudates Under Drying
Authors: K. A. Williams, S. A . Ruiz, T. Roose
Poster, Rhizosphere 5, Saskatoon, Canada. (International conference on soil science)
Year(s) Of Engagement Activity 2019