real-time nitrate sensing - infoag...–uses low cost sensors real-time nitrate sensing requires a...

18 July 2018 P2970-P-012 v2.0COMMERCIALLY CONFIDENTIAL

Mark Brannan, Mara Tavares, James Almond, Steve Thomas, Ed Bean, Roger Mainwaring-Burton

REAL-TIME NITRATE SENSINGENABLING PRECISION FERTILIZER APPLICATION

18 July 2018 P2970-P-012 v2.0COMMERCIALLY CONFIDENTIAL 2

▪ Appropriate fertilizer application is critical to maximising yield

– Reduce costs for farmers

– Reduces environmental impact

▪ Real-time sensing is the most effective way to determine appropriate levels

▪ This approach combines chemical detection with optical detection to propose system that is

– Fast response (


AN INTRODUCTION TO CAMBRIDGE CONSULTANTS


▪ 750+ staff in 7 offices

▪ 90% engineers, designers & scientists

▪ 6 decades of innovation

▪ 400+ projects every year

▪ 70% of work is repeat business

WORLD LEADERS IN

DISRUPTIVE INNOVATION

18 July 2018 P2970-P-012 v2.0

TOKYO

SINGAPORE

CAMBRIDGEBOSTON

ORLANDOSAN FRANCISCO

SEATTLE

OUR LOCATIONS

COMMERCIALLY CONFIDENTIAL 5


RF & ANALOGUE

ELECTRONICSDIGITAL ELECTRONICS

DIGITAL SIGNAL

PROCESSING

APPLICATION &

EMBEDDED SOFTWAREUSER INTERFACES

DATA SCIENCE

& BIG DATA

BIG SYSTEMS ALGORITHMS FLUIDICS ASICS SENSORS ULTRA LOW POWER

MECHANICAL INDUSTRIAL DESIGN HUMAN FACTORS REGULATORY SYNTHETIC BIOLOGYDESIGN FOR HIGH-VOLUME

MANUFACTURE

TECHNOLOGY EXPERTISE WE PROVIDE


UNDERSTANDING THE FIELD TO MAXIMISE YIELD


▪ In some locations up to 70% of applied nitrogen is wasted

– Leaching, denitirification and volatization

▪ Most applications in the US are now more efficient, having

been improved through multiple methods:

– Yield mapping

– Nitrogen stress detection

– Localized soil sampling

– Data management

▪ Nitrogen levels can vary significantly within a single field,

there are several steps to reach the maximum possible

efficiency:

– Knowledge of optimum levels for the crop

– Detection of nitrogen levels in the soil

– Understanding behavior of available nitrogen in the soil

– Targeted application of nitrogen

Although nitrogen is among the biggest expenses in farming, much is wasted


WHY IS A NEW NITRATE SENSING METHOD NECESSARY?


No current system can enable real-time sensing and application+ Positive

0 Neutral

- Negative

TIME RANGE ACCURACY CONSUMABLES SPECIFICITY SELF-CAL.MECHANICAL

COMPLEXITYROBUST SNR

CHEMICAL - + 0 - 0 0 - - +

SPECTROSCOPY + + + + + + + - -

ELECTRO-

CHEMICAL0 0 + - - - 0 - -

ELECTRICAL + 0 0 + - - 0 - 0

STAND-OFF

OPTICAL+ - - + - - + 0 -

CHEMICAL-

SPECTROSCOPY+ + + 0 + + - 0 +


SYSTEM REQUIREMENTS


To be a viable system for real-time nitrate sensing, several requirements are necessary

The system must be usable in a typical farm environment

An applicator will travel 36ft in 2s when travelling at 12mph.

Detected nitrates at the front of a tractor can then be adjusted

by an applicator at the back of the tractor.

This covers the range of interest for corn

Carrying large volumes of sensors, chemicals or filters is

unwieldy, increases operating costs and may pose handling and

disposal issues.

A measurement system should be self-calibrating with little to no

user intervention to minimise setup and downtime

The cost must be low enough for the average US farmer to use

on every applicator

DETECTION RANGE 20 – 250ppm

CONSUMABLES Minimal

DETECTION TIME


WHAT IS DIFFERENT ABOUT OUR APPROACH?


▪ Standard field test kit chemical reactions take a long time to complete

– Require lengthy, manual sample preparation

– Large volumes of reagents are required per sample (10+ ml)

▪ Spectroscopic methods require highly controlled conditions or very sensitive detectors

– Lab-grade equipment uses liquid nitrogen cooled detectors

– Significant processing may be required to interpret the data

– Samples often require careful preparation

▪ Combining chemical reactions with spectroscopy exploits the best of both

– Chemical reactions are inherently highly specific

– Spectroscopy has a high resolving power and can rapidly detect the reaction

– A smaller volume of reagents is required due to the high resolving power from spectroscopy

– Ratiometric measurement can be used to make the system robust and calibration-free

Integration of many disciplines early in the design offers numerous benefits


▪ Optimum levels of nitrogen are known for specific crops

▪ Our system focuses on detection, which could enable:

– increased understanding of nitrogen movement

– targeted application

▪ Within detection itself there are several challenges

Nitrogen detection is not just about detecting nitrogen


▪ The final absorption level is dependent on ion concentration, and spectrum is dependent on ion type

– Other ions can be compensated for using additional wavelengths

▪ A ratiometric measurement between reacted and unreacted paths will make this measurement robust to other factors e.g. laser

intensity fluctuations, reagent discoloration, imperfect particulate filtering, etc.

Detection occurs through spectroscopic interrogation of nitrogen ion reactions


WHAT WE HAVE ACHIEVED


The foundations for a field-applicable system are in place

System uses standard components with no

special controls

Scaling of the system should achieve detection in


APPARATUS DESCRIPTION


▪ A reaction with nitrate ions in solution produces a color change

▪ Tests began on the principles using a large cuvette (50 ml)

▪ Two laser modules (0.9 mW @ 532 nm, 3.5 mW @ 850 nm)

▪ 3,5-dihydroxybenzoic acid (3,5-DHBA) is reacted within the cuvette/chip under low pH

▪ Reagents are injected by hand

A macro fluidic setup using large liquid volumes was used to assess the reaction


▪ Large volumes mean timescales are longer, making reaction progress easier to monitor

Initial tests clearly show predictability and repeatability

BASELINE

READING

INJECTION

POINT INITIAL MIXING

WITH MANUAL

INJECTION

REACTION

COMPLETE


▪ The reaction occurs with both nitrates

and nitrites

▪ Distinct absorption spectra

differentiate the two

Absorption spectra for the reagents of nitrates and nitrites are distinct


FUTURE OF THE APPARATUS

REQUIRED REAGENTS


▪ Custom fluidic chip design for improved mixing speed and interrogation length

– Volumetric reduction from 50 ml to


SYSTEM CONCLUSIONS AND REMAINING WORK


▪ Detection: opto-fluidic chip design, consumable integration and flow control

– Demonstrate increased detection speed

– Minimize reagent volumes

– Minimize operator complexity

▪ Sample extraction at speed and while moving

– Extraction of a repeatable sample

– Movement of the sample from in the ground to the detection apparatus

▪ Sample preparation

– Consistent nitrate extraction

– Separation of light-obscuring solids

▪ Overall system integration

– Robust architecture for minimal maintenance

– System design and component selection for minimal cost

– Data and control interface for integration with existing mapping and application systems

The technology shows significant promise, though there are many challenges remaining


WHAT DOES THIS MEAN FOR THE

FUTURE OF NITROGEN APPLICATION?


▪ Direct measurement of nitrate concentration decouples it from other factors

▪ Minimise nitrogen usage in applications through several enhancements

– Limiting excess application at the point of application

– Direct nitrate sensing across the field for data gathering across the season

– Understanding localised denitrification for application forecasting

Development of this technology could enable real time nitrate sensing

Detected levels:80-100

ppm

Application rate: 100

lbs/acre

Detected levels: 40-60 ppm

Application rate: 140 lbs/acre





18 July 2018 P2970-P-012 v2.0COMMERCIALLY CONFIDENTIAL

Mark Brannan, Mara Tavares, James Almond, Steve Thomas, Ed Bean, Roger Mainwaring-Burton

REAL-TIME NITRATE SENSINGENABLING PRECISION FERTILIZER APPLICATION

18 July 2018 P2970-P-012 v2.0

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real-time nitrate sensing - infoag...–uses low cost sensors real-time nitrate sensing requires a...

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