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Tuned to the weather

An apparatus controls humidity and permits the correct use of fungicides

Two engineers, one an agronomist and the other electronic, came together in a project that protects growing areas and the environment: a piece of equipment that forecasts attacks of fungi and the consequent sickness of the leaves, that serves for any tropical crop and drastically reduces the use of fungicides. Fábio Valadão, through his small company in Campinas, named Microdesign Informática, developed the project Equipment of the Prevention of Fungus Illnesses in Vegetables, and Nilson Villa Nova, a professor at the Luís de Queiroz College of Agriculture (Esalq) in the town of Piracicaba, coordinated the work that was financed through the Program of Technological Innovation in Small Companies (PIPE) of FAPESP.

The device reduces the costs with fungicides by up to a third of the total – which, depending on what is being grown, is equivalent to as much as 25% of the production costs. It also indicates the correct moment to spray the crop and the number of applications necessary. Furthermore, the use of the fungicide in the correct dosage avoids excesses in the contamination of the plants, of the environment, as well as the people who do the spraying of the poison and, finally, those who consume the plants.

The researchers explain that the potential for infestation of fungal illnesses is directly proportional to the number of hours that the water remains on the leaves. And this is always associated with high temperatures, and high rates of relative humidity of the air and of rain, which contribute to keeping the plants wet.

In general, the farmer decides to spray his crops simply because he notes that they have been wet for some time. The equipment, which operates as a health alert station, avoids the making this decision without scientific criteria. For this reason, it is has a forecast system for fungi occurrence on crops, which works with of meteorological data.

Solar panel
Called the Equipment for the Forecasting of Fungal Illnesses (EPF System), it has a variable radius of action, depending on the topography of the land. In flat areas, the amplitude of the monitoring can reach as high as 10 hectares. In any situation, it doesn’t need electricity. The EPF is fed by way of 6 volt batteries, which are recharged by a solar panel.

All of the information is collected for the apparatus through a grouping of sensors linked to a microprocessor, which processes and indicates on a screen or on a type of collecting interface (radio or electronic collectors) the possibility of the illness infestation and the severity degree to be expected. The sensors measure the maximum and minimum temperatures and the average over a period, the relative air humidity, rainfall rate, as well as the intensity and the duration of the period the foliage wetting.

The way that the equipment is structured, through its interfaces, allows the information of the agrometeorological sensors to be collected in up to 30 different points. Besides the collection being available by an automatic radio system, there is a bracelet with a metallic button which needs only to be placed beside the EPF for the collection of data. Afterwards, all of the data is stored and processed in the farmer’s computer, from where it is possible to make out a report that easily analyzes and programs the best moments for spraying.

Other pieces of equipment for the forecasting of vegetal illnesses exist in the country, most of them imported. They are expensive – the basic set costs between US$ 3,000 and US$ 5,000 in the country of origin and arrive in Brazil at double that price –, and here they do not come with technical assistance and their maintenance is difficult.

“These pieces of equipment” emphasizes Valadão, “also do not provide to the common user simple and clear cut information that can help him to decide, because they are destined more for use in the scientific area. They cannot graphic display and, since the data is registered in an ‘accumulated’ form, they demand previous knowledge of the monitored magnitude and of their importance on the final result, which makes their use difficult for the farmer.”

National technology
Already the equipment of Microdesign, according to Valadão “is adapted to tropical conditions and to the reality of Brazilian agriculture”. He reveals that the three components of the equipment – a transducer of relative humidity (captures the information and transforms it into an electrical pulse), pluviometer (measures the quantity of rain) and the box that houses the thermo-hygrometer (measures the air’s relative humidity and temperature) – are imported, because they are produced on a world scale with compatible prices and of good quality. The remainder is the fruit of national technology.

The Microdesign team developed the electronic circuits used in the sensors of foliage wetness and those of the thermo-hygrometer, since the conventional ones that exist on the market did not meet the project’s specifications – high precision, repeated results, trustworthiness, low cost and the possibility of being connected into a network. The company also developed the software built into the microprocessor (firmware), into which all of the mathematical signals processing was incorporated.

The equipment is at the completion phase. After having tested the sensors and the data acquisition system, they have begun field testing. Valadão revealed: “We’re sending 20 prototypes to research centers such as the Agronomy Institute of Campinas (IAC), the Esalq and the São Paulo State University (Unesp) of Jaboticabal, for them to carry out phytopathological tests to assess the performance of the equipment and particularly the sensors, so we can know if there is the need or not of some modifications in the mode of operating them, in order to adapt them to more specific conditions, such as the manner of integrating the signals, or even for maximizing or turning more practical their application on the land, and in this way perfecting the use of the apparatus”.

Scientific participation
For Valadão, the agreements between his company and the scientific world are fundamental for the establishing of trustworthy parameters in the algorithms (a grouping of well defined rules for the solution of problems with a finite number of stages) of specific prevention for each type of crop. This is important because the algorithms vary depending of what is being grown. “In our project” emphasizes Villa Nova, “the alert algorithm has a specific formula for each type of crop, which relates to temperature, humidity and gives the degree of severity of the attack of the illness. If in a determined crop the plant remains wet, say, for 20 hours, at an average temperature of 18 degrees Celsius, it is being attacked by a serious fungal infection.”

The equipment in its current concept, with four types of sensors and destined to work in a planted area, has its cost estimated at between R$ 3,500 and R$ 4,000 (or from US$ 1,800 to US$ 2,000). It can monitor 10 hectares and can be used for any crop, assuming that it was calibrated with the corresponding software. The form of reading of the information is also going to influence the price of the equipment. Simply visualizing the information on the screen of the equipment or capturing by the bracelet with the button, are going to make the EPF System cheaper. However, with the adaptation for the radio transmitter system, which brings the information directly to the farmer’s computer, there will be an increase of R$ 2,500 on the cost.

The equipment processes and prepares the agrometeorological information; makes the calculation based on the algorithms installed and responds whether there will or won’t be the illness occurrence, as well as to the degree of severity of the infestation. From that point, the farmer calculates the dosage for spraying according to criteria defined by a phytopathologist.

Valadão intends to patent the antifungal equipment and calculates that it will be available in the market by the beginning of 2001. The farmer could buy it through a network of authorized retailers, who would have technical training for its installation and maintenance. It could also be purchased in a leasing operation via the Banco do Brasil or the Caixa Econômica Federal: the user would pay a monthly charge, receive technical assistance and at the end of 24 months keep the apparatus. As well as this, he would pay for the software for each crop, to the value of around R$ 500.

The financing by FAPESP has already been used in the development of the machine, in the purchase of the laboratory instruments and in the mounting of the prototypes that are going to the research centers where they should remain under test conditions for six months. These centers will receive royalties for their work which will lead to the perfecting of the solutions necessary for each culture grown.

The project has not finished with the equipment for the forecasting of fungal illnesses: it has as by-products a series of control apparatus to be used in hothouses, internal environments, washing filters (backwashing and washing in irrigation locations), balance tables in vivariums (which indicate the correct period for irrigation) and the pump/valve sets (allows for the synchronization of the motor pump and valves of the hydraulics system).

These pieces of apparatus were launched on the market and are already on sale. They are an important source of income at a monthly average of R$ 20,000 for the Microdesign company, an enterprise with only three employees who produce and sell twelve products.

Founded in 1984, the company concentrated on information technology and electronic apparatus for agricultural use. For example, Valadão developed an automatic system, via remote control, of the central pivots of an irrigation system and a sensor for monitoring the passage of grain in a planting machine, with which he won the State Governor’s Award at the 18th National Contest of Brazilian Inventions in 1990. In 1994, a tomato grower talked to him about the problems that he had with the plant sprayer and complained about the money spent on anti-fungal poisons often wasted when the application is done just before rain. As a consequence the engineer began to research his new invention.

Dr. Nilson Augusto Villa Nova, 67 years of age, is an agronomy engineer who graduated from the Esalq, in Piracicaba, where he also took his doctorate in agrometeorology. He is an associated professor at the University of São Paulo (USP) at the Esalq.
Fábio Taveira Valadão, 47 years of age, graduated in Electronic and telecommunications engineering at the School of Electrical Engineering of the State University of Campinas (Unicamp).

The project
Equipment of the Forecasting of Fungal Illnesses in Vegetables (nº 97/07351-9); Modality Innovative Research in Small Business (PIPE); Coordinator Nilson Augusto Villa Nova; Investment: R$ 98,277.20