Benefits of smart sprayers

Smart sprayers are already a reality in some crops. In addition to generating savings of up to 50% in the volume applied, they also guarantee a lower environmental impact and greater control efficiency.

The life of Brazilian farmers had already been sweeter. Despite the trend of increasing global demand for food and energy, rural producers increasingly need to be competitive. In this scenario, phytosanitary treatment that refers to the control of insects, mites, diseases and weeds requires more efficiency in the field.

Reducing the number of liters applied per hectare, reducing losses due to drift during spraying and increasing the operational capacity of sprayers, that is, their yield in hectares treated per hour, are the goals desired by each and every farmer. However, this task has not been easy.

Despite constant and massive investments in new machines, achieving such goals with the current Brazilian portfolio of sprayers requires much more from the operator's qualification, training and basic theoretical and practical knowledge of application technology than from the technology itself embedded in the machines. sprayers.

The proposal for smart sprayers, a name that comes from the English term “smartsprayers”, consists of the use of sensitive technologies to detect invasive plants or plots with damage caused by pests and/or diseases and their localized spraying in real time, which does not happen with traditional spraying.

The traditional or total area spraying method is characterized by its considerable inefficiency due to the application of phytosanitary products in non-target areas, for example, between rows of cultivated plants in a plantation. According to research, such losses are approximately 60%. That said, the need to reduce waste and environmental pollution has driven the development of band and localized spraying methods.

In general, smart sprayers are characterized by the correct placement of the product on the target, in the required quantity, in an economical way and with minimum human and environmental contamination. Therefore, these sprayers represent a more sustainable type of phytosanitary intervention, being a solution to the excessive use of herbicides, fungicides, acaricides and insecticides in agriculture and, consequently, their environmental impacts.

Several sensitive technologies are being used in target detection, with artificial vision, spectral analysis and remote sensing being the main ones. Target detection by artificial vision uses morphological aspects to segment characteristics, such as: shape, structure, color and pattern of plants. In spectral analysis, multispectral images and reflectance features are employed. In remote sensing, vegetation indices and hyperspectral images sent by satellites or aircraft are adopted.

Using artificial vision and spectral analysis technologies, North American and European researchers developed a herbicide spraying system. With multiple cameras to collect images in the field, it was possible to detect, quantify and classify weed plants by size in the row and between rows of soybean and corn crops and, in this way, carry out localized spraying. In this study, there was a saving of 48% in herbicide.

In Australia, research also in this line is subsidized by the Sugarcane Research and Development Corporation (Sugar Research and Development Corporation – SRDC) demonstrated that it is possible to reduce the use of herbicides in sugarcane by 50%, using the Weedseeker technology, which adopts optoelectronic sensors to detect weeds and apply herbicides simultaneously.

Regarding remote sensing, this technology has been adopted to monitor the plant health of plantations and, consequently, make the decision to carry out chemical control. Remote sensors have the ability to acquire a large scale of information through aerial photography (for example, with drones), satellite images, among others. Exploring this information together with the spectral analysis of plant characteristics and vegetation indices, good results have been obtained. Researchers were able to detect the damage caused by aphid infestation in wheat crops. Different vegetation indices were found in localized areas of cultivation resulting from stress caused by two species of aphids.

It should be noted that there are several advantages provided by the mentioned technologies. However, the detection systems present in these equipment still have limitations and more research is needed. One of the main obstacles to these technologies still remains: most of the significant results so far have been achieved in specific conditions, making it difficult or economically unfeasible to reproduce them in practical conditions.

However, smart sprayers have high commercial potential. From the farmers' point of view, there is a reduction in the use of phytosanitary products and production costs; and from a scientific point of view, the perspective of making phytosanitary treatment more efficient, both in terms of economic, environmental and social sustainability.

Henrique BN Campos, Marcelo da Costa Ferreira Dieimisson P. Almeida, NEDTA/Unesp Jaboticabal)

Article published in issue 148 of Cultivar Máquinas.