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Real-time, in-situ, N, P, K, pH and electrical conductivity soil-analysis system to facilitate accurate nutrient management

Final Report Summary - NUTRI-STAT (Real-time, in-situ, N, P, K, pH and electrical conductivity soil-analysis system to facilitate accurate nutrient management)

Executive Summary:
Information on soil nutrient status is vital for optimal crop growth, consequently this information is the basis for appropriate fertilizer application and management. Soil testing by chemical analysis of N (Nitrogen), P (Phosphorus), K (Potassium), EC (electric conductivity) and pH levels help to determine the status of the nutrients in the soil. Producers use soil test results along with past soil management practices and cropping history to decide the amount of fertilisers that should be applied. Current practices in soil testing reveal that producers take soil samples to a laboratory to be analysed and results normally take up to 3 weeks to be issued. Farmers who implement this practice reap the benefits of having a comprehensive guide to better manage their production and economic expenditures. Farmers also ensure best practice in agriculture and guarantee that nutrient applications are solidly based on real information. This is especially important to reduce pollution and safeguarding both ground and surface water quality, as well as to ensure an even distribution of fertilizer applications on fields. Never the less, the process of soil testing is labour and time consuming. Farmers who do not practice regular soil tests are facing numerous difficulties such a lack of accurate statistical information for soil and crop management, increased costs for fertilizers, and challenges in meeting stringent EU guidelines.

NUTRI-STAT provides the producers with a tool that helps them optimise the usage of fertilizers. The project developed a real-time soil analysis system that takes measurements of the 3 macro nutrients, Nitrogen, Phosphorus and Potassium, as well as the EC and pH level in one combined test, and provides the results in less than 5 hours.

Project Context and Objectives:
The Nutri-Stat product is based on an innovative probe that is part porous ceramic and part PVC. The PVC encloses the electrochemical sensor, measuring approx. 4 x 3 cm, which contains four channels for each Ion-Selective Electrode (ISE).

Water/Liquid that flows from the soil into the porous ceramic cup via a micro pump creates a vacuum in the cup. Once in the cup, the water is in contact with the sensor, enabling an ISE to take a nutrient reading; measuring NO3- (Nitrate), K+ (Potassium), PO4 3- (Phosphorus) and pH respectively. The four ISEs are housed in a novel Lab-on-Chip platform, using Low Temperature Co-fired Ceramics (LTCC) technology and contain an electrode to measure the Electrical Conductivity of the soil. These processes, performed inside the porous ceramic enclosure, allow it to be buried in the soil for an indefinite time without enduring damages. It is managed through a small LCD controller that also displays results. The combined convergence of these technologies is an innovative basis for the Nutri-Stat project.

Obtaining these accurate real-time results in-situ allows growers to determine how much fertilizer their land actually needs, therefore having the forthcoming benefits:
- Saving of money through efficient application of fertilizer;
- Ensuring that crops are not malnourished (disease management) (IPM), which would result in wasted resources and capital;
- Preventing any fines due to breaching of EU agricultural laws and directives over excess amounts of applied fertilizer in soil;
- Safeguarding the surrounding environment from harmful pollution.

Nutri-Stat provides farmers with constant monitoring of fields, tailored crop analysis and disease management, making information on the nutrient status of arable land for the first time ever, easily accessible and available to the farmer anytime anywhere.

The Scientific Objectives of Nutri-Stat were:

1. To study how the management processes for fertilizer application in the field could be enhanced though the use of customized compiled nutrient data: The premise of Nutri-Stat was two-fold, first to create a technology which integrated various elements into a portable in-field permanent device and second, to provide the farming community the apparatus for the scientific process to take place in their application of fertiliser. The results from a Nutri-stat test provide important indicators into the levels of nutrients in the soil which can be interpreted to stem over-use or under-use. The grower can use the data compiled by Nutri-Stat to efficiently manage his fertiliser application.

2. To decrease response time for the grower to implement alterations in the soil nutrient composition. The waiting period for results of current methods of soil analysis is too long and does not allow the grower to identify problems rising from actual depletion or saturation of nutrients within the soil in time. This can result in crop diseases, yield loss, soil erosion and the loss of beneficial organisms contained in the soil. Nutri-Stat reduces the current 2 week waiting period of high-end analysis results (namely those delivered by industry standard Lab tests) down to under a day, allowing growers ample time to track the rate of nutrient alterations and take corrective measures to counter problems.

3. To increase the awareness of precision agriculture, its benefits and usage amongst the average farmer. At present there is a science barrier in the agricultural community, where technological products in the market only cater for high-end users and are not feasible for the average farmer to purchase. However ongoing research on precision agriculture could have great benefits to offer average farmers too. Nutri-Stat - which is simple to use, accurate, reliable and cost-effective - has the potential to open up the precision agriculture market for the average grower, therefore allowing them to produce optimum crops to gain a stronger foothold in the market place.

The Technological Objectives of Nutri-Stat were:

1. To develop a set of ISFETs with the following range and accuracy

Nitrate Range 0 to 650mg/L ±5% F.S
Phosphate Range 0 to 200mg/L ±10% F.S
Potassium Range 0 to 800 mg/L ±5% F.S
pH Range 0.0 - 14.0 ±0.05% F.S

2. Integrate the ISEs and accompanying components into an LTCC Lab-on-Chip: The components required to take measurements were integrated in an LTCC lab-on-chip configuration. The electrical conductivity electrodes were also placed in the LTCC. This configuration allows a test to be carried out with a small volume of water extracted from the soil. Since it is based on the same LTCC board, all components operate simultaneously under the same conditions. This allows issues such as temperature changes, varying humidity levels and other conditions to be tackled within the LTCC structure.

3. Develop the probe controller to automate the testing process: Although the probe is submerged in the soil, a controller above the soil monitors the whole testing process. The controller contains a battery operated LCD. When enough water is acquired in the probe from the soil, the controller starts a sequence, pumping the sample into the LTCC Lab-on-Chip, takes the readings and discards the sample into a waste collection cup. If a wash is required after the measurement, the controller starts the washing procedure and resets the equipment for another test. The controller stores the results in its removable flash memory that can later be retrieved from a personal computer to be used by the nutrient management software. The grower or consultant using Nutri-Stat are able to see the results in real-time through the LCD or via the software on a PC.

4. Develop software for better nutrient management: With the results from the Nutri-Stat system in hand, the grower and/or crop consultant need to implement a number of decisions based on the final statistics. Nutri-Stat is accompanied by special software for nutrient and crop management. The software is based on the UK RB209 standard for nutrient management. The system allows the user to enter a profile of data about the field, crop, etc. Using on-line real-time weather data, along with the results from Nutri-Stat, the software provides the farmer and consultant with accurate information and suggestions relating to nutrient management in the field.

Other Objectives of Nutri-Stat were:

1. Maintaining an affordable unit price to be accessible to the agriculture community. The cost of the Nutri-Stat Basic device is €500, whereas the cost price of the Nutri-Stat Advanced system €2,400 which will include 4 probes. The Nutri-Stat system has a payback of <2 years for the farmer.

2. Safeguarding the European environment: Nutri-Stat helps preserve Europe’s collective agricultural land and waters. By using Nutri-Stat, growers are able to apply the precise amount of fertiliser to their soil, which will help prevent desertification and loss of fertilised land due to inadequate application of fertiliser on the land. Nutri-Stat also helps tackle pollution caused by harmful run-off in surface and sea water. Exact specifications of nutrients added to the soil are altogether absorbed by the plants/crops, leaving a minimal, almost negligible, amount of excess which could potentially leach into any surrounding water sources.

Project Results:
The main scientific and technological results of the project are in line with the original objectives the project set out to achieve. The main results are outlined below:

Development of membranes for the ISFET sensors – ISFETs behave the same way as regular Field Effect Transistors with the exception that their gate is ‘excited’ by a flow of ions present in the sample instead of a voltage provided directly to the gate of the transistor. For the ISFET to work, it requires a special membrane which acts like a ‘filter’ that allows only a particular ion to flow. For example a Nitrate ISFET only allow Nitrate ions (NO3-) to pass. A major part of the research focused on creating the membranes for Nitrate, Potassium and Phosphate which is very hard to achieve. The team has managed to develop all the membranes and all the ISFETs have been tested to work at the specifications defined.

Development of ISFETs for the Lab-on-chip system - The ISE module is composed of four ISFET sensor elements and a miniature reference electrode, mounted onto a support consisting of a LTCC (low temperature co-fired ceramics) microfluidic element, a PCB for contacting of the sensor elements and a PMMA mounting frame. In the scope of D2.1 a miniature quasi-solid-state reference electrode has been adapted, tested for use in the ISE module.
The ISE module was evaluated with respect to the pH response and the long-term stability. It could be shown, that the pH response of the system using the novel miniature reference electrode is equivalent to the response of a system using a more traditional reference electrode. In both cases a pH sensitivity of about -55mV/pH is obtained.
Study various LTCC structures that can be used to provide better sample flow with less turbidity and air clogs.
Low Temperature Co-Fired Ceramics (LTCC) is a microelectronics packaging technology used for many applications today. These include pace makers, high speed RF system and sensors. The technology is based on thin ceramic films placed on top of each other and then sintered to produce one unit. Using this technique, it is possible to create 3D channels for liquid flow, along with pads for sensors and other technologies. Furthermore, electronics can be placed on the back side of the module, hence minimizing noise and costs for special connectors. The Nutristat project focused on the development of different structures to minimize turbidity and air clogs. 3D structures were developed to allow nutrient analysis along with the possibility to add extraction agents and other clients.

Development of fluidic system to automatically extract water from the soil.
The process to acquire water from the soil and pass it through the Lab-on-chip has to be automated for the system to be totally automated. This is achieved using a complex fluidic system that automatically extracts water from the soil and supplies it into the lab-on-chip system. A special water level sensor was developed to measure the liquid level using a technology used in touchscreen based on capacitive technology. This allows the system to measure water level without having any contact with the sample. Several micro pumps and micro vacuum pumps are integrated in the probe to provide fluid flow.


Development of circuitry to drive actuators and measure the output from the sensors
The Nutristat Lab-on-chip contains ISFETs that require special driving circuitry. The circuitry works at very low current and voltages and requires special ICs that have very low drifts. A circuit was designed to provide 4 channel input and provide output in a standard digital format – Modbus. This allows the lab-on-chip to be integrated into other systems easily using the Modbus protocol.

Development of a special EC meter with integrated EC pads in the Lab-on-chip.
The ISFETs in the system measure N, P, K and pH but Electrical Conductivity cannot be measured using ISFETs and has to be measured through conductance in the water. To integrate the sensor in the Lab-on-chip system, the LTCC structure was designed to have two EC pads for EC measurements. A special chip was used to make EC readings through impedance measurements. The circuit was incorporated in the ISFET driving circuit to have one system incorporated together.

Development of a controller that automates the testing process and provides an interface to the user on the system
To integrate all the systems together, the system contains a special controller that controls all the sub systems inside the system. The controller is based on an Embedded Linux system and provides a web interface to the system. This allows users of the system to connect the system with the network and access the system over the network or through the internet. This makes the system easier to access in remote areas through 3G connection.

Development of a hand-held device that can be used in specific situations where the extraction is not required.
During the course of the meeting it was identified that some specific scenarios (such as hydroponics) do not require an extraction procedure as it is easier for crop consultants to extract water from the hydroponic slab and insert into the lab-on-chip manually. A special device was created to host the lab-on-chip and the ISFET driving circuitry. The device hosts an LCD and 4 buttons that allow it to be portable and battery powered. The LCD provides an interface to settings and other configurations inside the system.

Validation of the system in different soil conditions.
Several systems were installed in different locations and the extracted sample was then fed into the lab-on-chip system to validate the technology. During the validation, several considerations were taken such as daily drift from the ISFETs and other considerations. All the sites were carefully selected so as to include different soil types and different conditions. Of the sites selected, two were greenhouses under intensive farming and the others were in field conditions were fertigation is not as frequent. For all sites, a sample of the soil was taken and sent to a professional laboratory. The values were compared and were all in the tolerance band as specified in the project specifications.

Mapping of results on a GIS for better representation of the nutrient content in the soil
The Nutristat Advanced system contains a GPS module to allow it to map data obtained from different nodes on a map and interpolate the data between the nodes. This allows farmers and crop consultants to provide accurate fertilizers in the field based on the status in different locations. Results are shown on the web interface, augmented on a map of the site where the system is installed.

Enhanced management process for fertilizer application in the field making it easier for Farmers to adhere to the Nitrate directive.
With this project, Farmers now have a tool that makes it easier for them to provide fertilizer in the field whilst adhering to the nitrate directive. This tool also provides the farmer information about the uptake of nutrients by the crop itself hence giving the farmer information about the status of the plant. The results from a Nutri-stat test provide important indicators into the levels of nutrients in the soil which can be interpreted to stem overuse or under-use. The grower can use the data compiled by Nutri-Stat to efficiently manage their fertiliser application.

Decreased response time for the grower to implement alterations in the soil nutrient composition.
The waiting period for results of current methods of soil analysis is too long and does not allow the grower to identify problems rising from actual depletion or saturation of nutrients within the soil in time. This can result in crop diseases, yield loss, soil erosion and the loss of beneficial organisms contained in the soil. Nutri-Stat reduces the current 2 week waiting period of high-end analysis results (namely those delivered by industry standard Lab tests) down to under a day, allowing growers ample time to track the rate of nutrient alterations and take corrective measures to counter problems.

Increased the awareness of precision agriculture, its benefits and usage amongst the average farmer.
At present there is a science barrier in the agricultural community, where technological products in the market only cater for high-end users and are not feasible for the average farmer to purchase. However ongoing research on precision agriculture could have great benefits to offer average farmers too. Nutri-Stat - which is simple to use, accurate, reliable and cost-effective - can open up the precision agriculture market for the average grower, therefore allowing them to produce optimum crops to gain a stronger foothold in the market place.

Potential Impact:
Agriculture is an extensive and significantly valuable sector of the European Union. Between 2007 and 2013, the common agricultural policy took up 34% of the EU budget. 51.2% of the EU’s territory is made up agricultural land, where 135.3 million ha of land are fertilised with more than 16 million tonnes of artificial fertiliser. Fertilised land in Europe is split into 68% arable crops (cereals, oilseeds, fodders, etc), 9% of permanent crops and 23% of grassland.

The SMEs in the consortium will profit from this project through sales of the Nutri-Stat system.
The principle projected target clients for the Nutri-Stat product are growers who possess medium to larger scaled agriculture lands (>1 ha) and crop consultants. Other targeted clients are greenhouse growers and hydroponic growers. The Nutri-Stat system is available in Basic and Advanced versions, in order to better accommodate different land sizes.

Nutri-Stat Basic contains the system with 1 probe; this caters for farmers with small areas of cultivated land and individual crop consultants. Nutri-Stat Advanced contains the system with up to 4 probes that connect via wireless networking; this caters for the needs of growers will larger areas of land.

Impact from using Nutri-Stat in the field:

The main benefits Nutri-Stat offer to growers come from an increase in yield and from savings on reduced fertilizer costs.

- Increased profit from better quality of the produce: Better nutrient management results in better quality produce. Typical ‘G’ grade (top quality) Roma Tomatoes cost €4.58/6kg while ‘MM’ grade (low quality) Roma Tomatoes cost €2.5/6kg. This near doubled difference in price could potentially see a radical impact in end-users’ profits through Nutri-Stat.
Reduced costs from Reverse Osmosis (RO) treatment: Excess fertiliser seeps through the soils and infiltrates into the same water systems that growers use to irrigate their crops. In areas where the electrical conductivity of the water is higher than 2.5mS RO treatments have to be used to filter out the excess salts at great expense to the grower. Growers using Nutri-Stat will hence save on water treatment costs simply because no excess fertiliser will be applied to the soil in the first place. This will therefore effectively reduce the amount of fertiliser seeping into the water system.

- Better prices in organic products: Organic produce yields better prices than normal produce. Farmers who opt to grow plants organically require precise data about their soil in order to apply natural fertilizers (manure) accurately and in time. Nutri-Stat will facilitate the production of organic produce by providing farmers a rapid and real-time means of accessing data on soil chemical content.

- The Nutri-Stat system is also faster, more accurate and cheaper than any other current method of soil sampling and testing. Once installed on site, the system can be programmed to automatically run tests periodically. The results of the soil tests can be plotted electronically on a map representing the field, which can then be sent directly to the grower/crop consultant via email or SMS. Should laboratory practices be employed to carry out the analysis proposed by the Nutri-Stat system; costs and time waiting for results make the exercise impracticable.

Nutri-Stat directly benefits the end-user SMEs, helping them get the most out of their fields whilst also streamlining their fertiliser costs, thus making them more competitive in the market.

Social Impact

With a growing population of about 78 million per year, there is an urgent need for sustainable agriculture to be reinforced to meet the inadvertently increasing demands for produce. The EU has taken action in this regard, issuing a number of policies, directives and legislations related to sustainable agriculture. These include:

- The common agricultural policy (CAP) – enforcing the competitiveness of European farmers and promoting development in rural areas. The policy also focuses on environmental protection and on the quality, rather than quantity, of production.

- The water framework directive - Council Directive 91/676/EEC - concerning the protection of waters against pollution caused by nitrates from agricultural source.

Nutri-Stat facilitates accurate and frequent soil testing, fertilisation and irrigation management. Such nutrient concentration homogeneity across the field optimises the yield and the quality of the produce for the benefit of consumers, creating a positive impact on healthy foods and healthy eating in society.

Environmental Impact

With farmers managing almost half of the EU’s land area, the agricultural sector is a major source of pressure on Europe’s environment. Over the past fifty years, the EU’s CAP has encouraged the sector to become more and more intensive, as has the growing globalisation of the world’s economy. In consequence, the agricultural sector is responsible for a significant share of the pollution of surface waters and seas through nutrients, for the loss of biodiversity, and for pesticide residues in groundwater.
According to the European Environment Agency, the agriculture sector is the main source of methane 48% (CH4), and nitrous oxide 52% (N2O) emissions in the EU. Agriculture wastes such as fertilisers, and other pesticides dumped or used disproportionately gives rise to excessive chemical content in soil and decrease soil fertility. Agricultural run-off is the single most extensive source of surface water pollution, where 53% of lakes in Europe are eutrophic, i.e. water loses oxygen due to pollution, resulting in significant biodiversity losses.

Nutri-Stat not only benefits the growers’ profits, but also the collective European environment by helping tackle the issue of pollution in surface and sea water. By using Nutri-Stat, exact specifications of nutrients added to the soil are absorbed by the plants/crops, leaving a minimal - almost negligible - amount of excess that could potentially leach into any surrounding water sources.

List of Websites:
www.nutristat-project.com

NUTRI-STAT supplier:

MMM tech support GmbH & Co. KG
Weigandufer 18
12059 Berlin
Germany

+49 - (0)30 - 62 73 68 66
info@mmm-tech.de
www.mmm-tech.de