Introducing Evja - "Rugged" Intelligent Support System for precision farming ACTA IMEKO ISSN: 2221-870X June 2020, Volume 9, Number 2, 83 - 88 ACTA IMEKO | www.imeko.org June 2020 | Volume 9 | Number 2 | 83 Introducing EVJA: a ‘rugged’ intelligent support system for precision farming Niccolò Loret1, Antonio Affinito2, Giuliano Bonanomi3 1 EVJA R&D, EVJA Neaples, Italy 2 EVJA CTO, EVJA Neaples, Italy 3 Department of Agricultural Sciences, Federico II University, Neaples, Italy Section: TECHNICAL NOTE Keywords: precision farming; internet of things; predictive models; bremia lactucae; hyaloperonospora parasitica; fusarium head blight. Citation: Niccolò Loret, Antonio Affinito, Giuliano Bonanomi, Introducing EVJA: a ‘rugged’ intelligent support system for precision farming, Acta IMEKO, vol. 9, no. 2, article 13, June 2020, identifier: IMEKO-ACTA-09 (2020)-02-13 Editor: Mauro D'Arco, University of Naples Federico II, Italy Received February 28, 2020; In final form May 14, 2020; Published June 2020 Copyright: This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: Some of the research projects described in this article are funded by the iGUESS-MED PRIMA programme, funded under Horizon 2020, the European Union’s Framework Programme for Research and Innovation. Corresponding author: Niccolò Loret, email: niccolo@evja.eu 1. INTRODUCTION Smart farming is revolutionising agriculture, helping farmers to increase the quantity and the quality of their products. When we refer to smart farming, we are talking about a vast array of systems, differing in terms of their technology and scope. However, at its core, smart farming consists of sensors managed by software that is aimed at making the farmers’ job more efficient and effective. Some smart farming products focus on robotics, machine automation, location technology, or data analysis. When smart farming is based on IoT systems, it is called precision farming [1][2][3][4]. Precision farming follows a four- step cycle that starts with the monitoring of the plants via sensors, followed by the diagnostics of the collected data and ending either with the decision-making of the farmer or with the activation of another system; for example, in automatic irrigation systems connected to the precision farming platform. The result is a more controlled crop cycle, with plant and weather conditions monitored metre by metre, and a more accurate intervention by the farmers, with action undertaken only when it is really needed. The advantages are significant: less pesticides and fertilisers are used; irrigation is more efficient; and the final product is healthier and more abundant. Said results are achieved with minimum impact on the environment, leading to a win-win situation for the farmers, consumers, and the environment. We now introduce ‘EVJA: Observe, Prevent, Improve’ (or just ‘EVJA’), a precision farming system of our design. EVJA is an intelligent support system that helps farmers optimise the usage of chemical products and water. By using IoT and artificial intelligence, EVJA allows farmers to monitor their fields in real time, wherever they are. EVJA gathers data from a network of customisable sensor nodes (see Figure 1) connected to servers ABSTRACT Precision agriculture is a farming system based on the combination of detailed observations, measurement, and rapid response used to optimise energetic input to maximise crop production. Precision agriculture uses a Decision Support System (DSS) for optimising farm management. In this context, ‘EVJA: Observe, Prevent, Improve’ (or just ‘EVJA’) is an intelligent support system used for precision agriculture. A vast set of data (temperature, relative humidity, deficit of vapour pressure, leaf wetness, solar radiation, carbon dioxide concentration, and soil moisture) is continuously collected, submitted to a local control unit, and processed through algorithms specifically developed for different crops. On the other hand, farmers can access EVJA from their PC and mobile devices, and they may monitor complex agronomic data analysis presented in a user-friendly interface. In this article, we show how EVJA works and how its output can be used to assess the health status of plants through a specific set of functions. Moreover, we show the methodology utilised to develop useful predictive models based on this information. Specifically, we describe a predictive algorithm that is capable of predicting the infection risks of downy mildew for baby leaves plantations and for Fusarium ear blight of wheat. mailto:niccolo@evja.eu ACTA IMEKO | www.imeko.org June 2020 | Volume 9 | Number 2 | 84 where those data are processed. Thanks to its self-calibrating agronomic models, EVJA helps farmers prevent plant diseases. EVJA is equipped with a simple and intuitive interface (see Figure 2), which makes it very easy to use. It is available for every kind of crop and offers specific advanced features for greenhouse farms. We extensively describe the entire system in the following paragraphs, for the data collection process and data analysis. 2. STATE OF THE ART IoT has the potential to monitor irrigation and productivity, and the data gathered by IoT sensors have the ability to provide information about the overall performance of the crops. Existing monitoring systems use drones and weather stations, which are inappropriate for greenhouse crops. Indeed, EVJA includes the first predictive algorithm for horticultural products in the European Union, while the main direct competitors commercialise solutions that address generally all type of crops, without focus and verticalisation on specific crops and weak results. On the other hand, greenhouse monitoring systems are often designed for fully climate-controlled environments, closer in concept to a scientific laboratory than a farmhouse, while EVJA’s ‘rugged’ sensor nodes are designed to be handled roughly, in any kind of working conditions. The main features characterising the EVJA system are: • technological: the integration with advanced predictive models; • product: the bundling of hardware and software in a single solution, which allows for a seamless user experience; and • business: the high scalability of EVJA, which allows for targeting agricultural businesses anywhere in the world. Indeed, compared to many other systems that are available, the EVJA hardware works not only with WiFi or mobile coverage but also everywhere else due to the use of an innovative communication technology called a Long-Range (LoRa) network [5], which can fully operate with radio frequencies. Furthermore, EVJA is a software, which is more flexible, more extendable, and more user-friendly than that of the majority of its peers. The EVJA system is based on a Software as a Service (SaaS) model, which offers an array of features, including real-time monitoring, forecasting, management, business intelligence, and social features like chat and media sharing. Farmers can monitor and manage everything, in each field, directly from their desktop, tablet, or smartphones. They can mark every event, like an above-average harvest, and go through the history to see trends and correlations between such events and the key factors registered by the sensors. If a worker in the field spots a plant affected by a parasite, they can take a picture and share it with the agronomist in order to check the type of disease and take immediate action. The hardware consists of a device with sensors to be installed in fields in an intuitive ‘plug and play’ manner and does not require maintenance. The sensors collect all the relevant data, such as humidity, temperature, light, and soil status. The EVJA system is totally wireless. It does not need cables for its power supply nor for communication with other devices. It includes an electronic package containing a customisable processing unit and a wireless communication unit to communicate wirelessly with external systems. More specifically, EVJA’s hardware includes: • the base station (12 × 12 × 8 cm³), which has a robust waterproof enclosure and covers a homogeneous area of about 3 hectares; • the battery, which is recharged using the internal or external solar panel (23 × 16 × 2 cm³) – the rechargeable battery has a load of 6600 mA h, which ensures non-stop working time for a month; • sensors, which are used to measure temperature, leaf wetness, humidity, and solar radiation; and • mobile radio options – WiFi and the LoRa network. 3. THE EVJA SYSTEM IN DETAIL The node’s core is a microcontroller powered by a battery charged by a solar panel. Sensor probes can be easily attached to the device by simply screwing them into the bottom sockets. In the same way, sensor probes may be easily replaced. The basic EVJA functions need just temperature, humidity, leaf wetness, and solar radiation sensors. However, the entire system is easily customisable, and new sensors can be added depending on the user’s requests. As we will explain in detail later, the next EVJA release will be integrated with soil moisture sensors. In addition Figure 1. The appearance of an EVJA sensor node. Figure 2. EVJA’s simple and intuitive interface ACTA IMEKO | www.imeko.org June 2020 | Volume 9 | Number 2 | 85 to the agronomic observables, the system gathers data about the state of the system, such as GPS, accelerometer data, the status of the battery, and GSM signal power. The data is collected by the sensors at every time interval (fixed by the system manager). At the end of the process, an antenna sends both agronomic and diagnostic data to the servers. The chosen data transmission protocol is very flexible, making use of 4G and WiFi protocols. In the case of poor coverage, a customised radiofrequency network is deployed ad hoc using Gateway to deploy a ‘star’ network or a mesh network of sensor nodes. In the case of a temporary lack of signal, the measurements are stored in a memory inside the control unit and are then communicated to the server when the signal is restored. The data stored in the servers are available to the users, who will always be able to access the required information through a simple and responsive interface (in Figure 2) on their smartphone or laptop. Logging into the interface, the user can see historical data in the form of simple graphics (as shown in Figure 2), select the required time intervals, and check the reports about thresholds exceeded, parasites, and other useful information on plant health. 4. EVJA ALGORITHMS EVJA is equipped with several generic functions that are useful for defining plant status and needs, and it also has custom- designed predictive algorithms specifically designed to keep parasites under control. We give below some examples to better explain how the system works and how farmers can use it to rationalise their activities and spearhead resources. 4.1. Functions Using the EVJA interface, a farmer can check the conditions of a crop in real time. The system allows to fix thresholds for temperature, humidity, leaf wetness, solar radiation and other customisable observables (depending on the kind of sensors mounted on the device). In case those thresholds are exceeded, the system sends a warning email to the farmer. EVJA, however, does not just visualise those data. It also processes it in order to calculate the functions that are fundamental for depicting a clear picture of the plants’ health status, such as dew point, Vapour Pressure Deficit (VPD), Growing Degree Days (GDDs), and evapotranspiration. The dew point is the temperature T DP, to which air must be cooled to become saturated with water vapour. Dew point can be calculated through the formula: (1) where b = 18.678 and c = 257.14 °C. When the air temperature is close to the dew point, the air is saturated with moisture, plant perspiration will not evaporate, and droplets will form on leaves. Dew point can also be called frost point if TDP < 0 °; in this case, the system warns the user about the possible damage to the crops. GDDs is a parameter with the dimensions of a temperature, expressing the heat accumulation by plants and insects during their development. Ambient temperature influences plants and pests’ rate of growth; therefore, when specific predictive models 1 One should bear in mind that GDDs are defined by taking into account average daily temperatures, while the EVJA system can perform and store hundreds of measures each day. calculating some harmful insect outbreak probability or plant productivity are lacking, calculating the GDDs can be a simple preliminary step in setting an indicator [6] [7]. A simple estimation of the GDDs can be obtained by the formula . (2) where t is the time, N is the number of measures performed in one day,1 n is the total number of measures, and Tm and TM are respectively the minimum and maximum temperatures defining the survival range of a living being. Many calculation tricks, from trapezoid to Monte Carlo formulae for the numerical calculation of integrals, could make the approximation in Equation (2) more reliable. However, since phenomenological tables are compiled by taking into account the rough approximation of the rectangles, it is always better to stick with the simpler GDDs definition. For many species of insects, the time interval in which T < Tm is called diapause; in that period, their development process basically stops, only to resume when weather conditions are more favourable. Climate changes have recently affected the reliability of this indicator for pest control, because given the rising average temperatures in winter, many insects do not go through a diapause as they used to a few decades ago. Moreover, a crop can be infested by many different pests, like aphids or non-diapausing insects. That is why EVJA’s GDDs numbers should be used for pest control purposes only, with the careful assistance of an entomological specialist. Much simpler is the use of the GDDs indicator to predict the time left for a plant to develop and flourish: using weather forecast data, the system can estimate future heat accumulation and predict the period in which it is more likely that the plant will reach the GDDs value related to their full development (by confronting the system with well-known phenomenological tables). In this way, farmers are assisted in planning their future activities, such as harvesting or determining the right amount of irrigation needed by their crops in the near future. The system will then help farmers to save water through other parameters. VPD is the difference between the vapour pressure within the leaves and that of the atmosphere: (3) where Tl is the leaves’ temperature, and (Ta, Ua) are the temperature and humidity measured by the sensors. VPD is an indicator of the water flow within the plants, providing information on the efficiency of the inner steam pump in the plant’s stem. 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