Study by Rede AP points to cost reduction in cotton production in an on-farm system in MT

This is the conclusion of the first research carried out in the on farm system in cotton cultivation in the country. The study, conducted by Embrapa's Precision Agriculture Network, in partnership with the production sector on farms in the Brazilian Center-West, found that it is possible to reduce costs by up to 13% by applying varying input rates to plant production. Experiments in the on farm system take place in the production area, while the culture is developed, without changing the property's routine.

The researchers evaluated the spatial and temporal variability of the agricultural area in the 2019-2020 harvest using precision agriculture (PA) techniques to find the ideal dosage of inputs that would be applied to the crop. The agricultural management system, an AP concept, allows monitoring, collecting and analyzing information through technologies that facilitate decision-making by producers and workers.

With the use of AP, it is possible to use inputs more rationally, at the moment, locally, applying appropriate doses, with the potential to generate economic and environmental benefits for the producer. The generation of these benefits, with direct impacts on production costs, integrates research results proposed by the AP Network, created in 2009 with the participation of more than 200 researchers from Embrapa, universities, science and technology institutions and companies.

In its third and final phase, to be completed by the end of the year, the project proposes, among other solutions, the delivery of validated enabling technologies and generated experiences, as an application model for the rapid and effective implementation of precision agriculture in the cotton production system in Mato Grosso. Based on the results from the on-farm experiments, the researchers hope to consolidate AP practices with applicability in different production systems throughout Brazil.

Combined doses

Of great economic importance for Brazil, the fifth largest producer in the world, cotton cultivation is also considered very demanding, as it presents greater risks and investments. However, the increase in investments in culture is not proportional to the increase in expected productivity. Therefore, the Instituto Mato-Grossense do Algodão has been investing in the use of precision agriculture tools, more intensively, to reduce costs and increase productivity.

To try to balance the imbalance between expenses and income, a group of 16 professionals from Embrapa Instrumentação (São Carlos – SP), Embrapa Agricultura Digital (Campinas – SP), Embrapa Soja (Londrina – PR) and the Instituto Mato-Grossense do Algodão (IMAmt), joined forces and skills to make the research possible.

The results of the on-farm experiments, with the application of varying input rates, were presented by researcher Júlio Franchini, from Embrapa Soja, on the 23rd, at the Famato Embrapa Show, held from the 22nd to the 24th, in Cuiabá (MT). Franchini, one of the team members, participated in the entire process of study design, evaluation and interpretation, among other phases of the project.

According to the study coordinator, researcher Carlos Manoel Pedro Vaz, from Embrapa Instrumentação, the proposal for the on-farm experiment consisted of finding the ideal combination of dosages of the evaluated inputs, which would provide greater productivity. “In this model, it is possible to generate response curves for the application of inputs, which are important to support the definition of strategies when it comes to variable rates”, says Vaz.

Furthermore, the research also aimed to motivate producers to carry out on-farm experiments to evaluate crop productivity and costs, using the potential of the machines available on the property, which already come with onboard AP tools. The first step consisted of evaluating the spatial variability of three plots of two farms in Mato Grosso regarding crop vegetation indices, electrical conductivity, altimetry-slope and soil texture. All data layers obtained were then correlated with the productivity maps of the respective plots.

In the study, the researchers used already consolidated AP methods and tools, such as the granulometric analyzer, developed by Vaz, used to obtain data on the soil properties of the plots. The analysis of properties is essential for diagnosing your fertility. Unmanned aerial vehicles, known as vans or drones, were part of the set of tools used to capture images, in addition to satellites and resources already on board in the agricultural machines themselves.

The data was processed and evaluated to define georeferenced virtual plots, representing the three plots of around 200 hectares, and the installation of on farm experiments at the Três Lagoas farm, from the Scheffer group, and the Tucunaré farm, from the Amaggi group. The properties are located in the municipality of Sapezal, in Chapadão do Parecis, 480 kilometers from Cuiabá, capital of the state of Mato Grosso.

According to Vaz, random combinations of seed populations, doses of growth regulator and nitrogen were then created, to be applied at varying rates, depending on the dimensions of the virtual plots generated and loaded into the agricultural machines, so that they could perform the task. The researcher explained that the plots on the Três Lagoas farm were divided into 144 virtual plots, of 0,8 hectares each, while on the Tucunaré farm the division was by management zone, with 192 virtual plots, of 0,2 hectares. Virtual divisions exist only in the programming of the machines that apply the inputs and in the productivity maps generated by the harvesters.

The application of inputs was carried out according to the information obtained from the analyzes of electrical conductivity, vegetation index, soil texture, among others, and according to the architecture of the virtual plots, the quantity of which was relative to the number of proposed combinations. In other words, 4 nitrogen dosages, 3 seed populations and 3 growth regulator dosages were applied to the two plots of Fazenda Três Lagoas, with 4 replications, resulting in 144 virtual plots.

In the Tucunaré farm plot, there were 4 nitrogen dosages, 4 seed populations and a specific growth regulator dosage for each of the 3 management zones defined for the study.

Expressive results

According to the study, the composite combinations for the two plots of the Três Lagoas farm resulted in gains of 13% and 11% in relation to the average productivity of the cultivation units. “In the case of the plot, with a 13% gain in productivity, the combination of inputs that will provide greater profitability will result from the application of 13 seeds per meter, 564 milliliters (mL) of growth regulator per and application of 200 kg of nitrogen per hectare , resulting in productivity of 343,4 arrobas per hectare”, explained Vaz. One arroba is equivalent to 15 kg.

The analysis of the Tucunaré farm plot, carried out by management zone, showed that productivity reached 320 arrobas per hectare, considering that the average was 285,3 arrobas/ha. Vaz calculated that the gain was 12% with the application of 8 seeds per meter, 200 kg of nitrogen and 220 mL of growth regulator per hectare.

In a comparative analysis of input costs, the researcher said that, in the two plots of the Três Lagoas farm, the cost of applying the growth regulator, for example, an average of 600 milliliters per hectare, represented R$13.560. “If we consider that a liter of regulator in the Mato Grosso region is around R$ 113, saving this input with increased productivity becomes very interesting for the producer. For example, in one of the plots the best performance was obtained with 80% of the dose of growth regulator recommended by the farm, therefore resulting in savings of 20% of this agrochemical”, calculated physicist Carlos Vaz.

The researcher recalls that 2021 data from the National Supply Company (Conab) highlighted the high cost of cotton production. Agrochemicals, a category that includes growth regulators, together with fertilizers and seeds represented 87,1% of costs. The growth regulator is important for monitoring the height of the plant which, without the use of the input, can reach up to two meters, when the ideal is 0,5 meters.

For Ricardo Inamasu, leader of Embrapa's Precision Agriculture Network, the research showed the importance of the collaborative process with producers in the construction of methods, knowledge and procedures. “The AP brought challenges to refining recommendations suitable for local use. On-farm experimentation enables a quick response and an appropriate recommendation for the production process, using machines and equipment available on the properties”, says the researcher from Embrapa Instrumentação.

The president of the Mato-Grossense Cotton Institute (IMAmt), Álvaro Salles, says that carrying out validation of precision agriculture techniques, such as applying a variable rate depending on the plant's needs, in addition to demonstrating the direct benefit of saving resources For the producer, it brings another essential benefit to sustainability, since only the necessary dosages are applied to each part of the crop.

“Embrapa, in partnership with other institutions, should bring AP tools to the field more intensively, so that producers can evaluate and adopt these technologies, which should be increasingly present in everyday agricultural life”, says Salles. The president of IMAmt believes that the solutions currently adopted by large producers will soon be adapted and will allow small and medium-sized producers, from different crops, to also use them. “This will certainly bring much more efficiency and productivity for everyone”, he assesses.