ABSTRACT Renewable energies have been occupying more and more space in energy matrices worldwide, and lignocellulosic biomasses are promising for these energy sources. This study aimed to develop a fuzzy model to optimize the ferrous sulfate concentration and temperature in the pre-treatment of elephant grass. Five concentrations (10, 15, 20, 25 and 30 mM) and three temperatures (25, 40 and 55 ºC) were used as input. The application of the fuzzy model evidenced that the best results for cellulose exposure (53.1 %) were achieved by using a ferrous sulfate concentration between 20 and 22.5 mM and temperature between 39.5 and 42.5 ºC.

The global economy is directly dependent on fossil fuels, consuming a total of approximately 70% of these energy sources. However, renewable energies, especially biofuels produced by biomass, are gaining ground, with emphasis on elephant grass, which has been standing out in the production of bioethanol in Brazil. However, before fermentation takes place for the production of bioethanol, the biomass must undergo a process called pre-treatment. Therefore, when analyzing the chemical processes, the optimization of the variables for the pre-treatment is essential, thus the need to apply a mathematical modeling system such as fuzzy or fuzzy logic arises. Given this context, the objective of this article is to identify how the state of knowledge about the application of fuzzy logic in the alkaline pre-treatment of elephant grass is configured. By conducting the research using the Systemic Literature Review (RBS), it was possible to identify several opportunities for the application of fuzzy logic in alkaline pre-treatments in elephant grass. Of the 86 documents analyzed in this research, 100% were from research and bibliographic review articles, which demonstrates the relevance in academia of the use of elephant grass in the production of bioethanol and, in the same way, research on the application of pre- Biomass treatment has gained importance in recent years, being increasingly studied and developed by researchers in the area. Although it does not present any article with specific reference to the use of fuzzy logic in the alkaline pre-treatment of elephant grass, this opens up a wide range for further research using fuzzy logic.

Brazil stands out before other countries for having a gigantic area for food production. Paraná is the state that stands out among the nation's states with its gross production value (VBP), which in these values are the agricultural and livestock productions such as poultry farming. Moreover, Paraná stands out for having a high solar irradiation, which leads rural entrepreneurs to seek the use of renewable energies as electric energy, especially photovoltaic energy. With that, the present study refers to a qualitative systematic review, whose objective was to conduct an analysis of the scientific production on the panorama of solar photovoltaic energy in poultry farming in the state of Paraná, in the period from 2012 to 2021. The bibliographical search was carried out in the databases: Scopus and Scielo including others described on the theme, searching for information from government agencies responsible for production indicators, growth and development. This review showed that the State of Paraná has a great potential for photovoltaic solar energy generation, by the levels of solar radiation which is inserted and also for having the largest poultry herd in Brazil.

Brachiaria is considered essential for bovine feeding. Therefore, the producer seeks to find the best fertilizer dosages for high yields. The general objective of this work was to present a model, based on indicators and fuzzy logic, to optimize the dosages of two fertilizers in a Brachiaria cultivar. Variables related to fertilizers (mineral and organic) and to the height of the plant (in cm) were used to enter this system. The best results after optimizing the entry rules for the application of mineral and organic fertilizers were between 0 to 20 and 150 to 200 with 130 to 150 and 180 to 200, respectively in g/m(2), respectively. With the application of fuzzy rules using real data, it can present great benefits to those involved in the livestock production chain, thus being able to reduce the dosages in the applications and improving its final profitability.

The objective of this work was to test the Fenton reaction on pretreatment of elephant grass aiming the results of cellulose increase and the delignification process. A subsequent study of the enzymatic hydrolysis of the pretreated elephant grass and the mathematical modeling of hydrolysis was performed. A Doehlert-type experimental design was used into the pretreatment stage and the best results were obtained at the central point with an average of 53.80% of cellulose and 10.00% of lignin. The enzymatic hydrolysis of pretreated grass with Fenton reaction was performed, with a commercial enzyme, where the best yield (17.39%) of reducing sugars was obtained with 20 g L−1 of enzyme in 72 h and higher productivity (2.51 g L−1 h−1) observed in 2 h. It was possible to adjust the proposed mathematical model to the hydrolysis process. It was observed that, for higher concentrations of enzyme, the proposed mathematical model adjusts better the experimental results (R2 = 0.993). It can be observed with these results that there was an increment in the economic profitability of the enzymatic hydrolysis process due to the relation of the operational parameters, so that it can be used in new projects and industrial applications.

The objective of this article was through a systematic bibliographic review to verify the answer to the question How is the state of historical knowledge about the application of Fuzzy logic in agriculture registered?. The systematic bibliographic review is a scientific method for searching and analyzing articles from a specific area of science. It is widely used in research in medicine, psychology and agriculture and related areas, where there are large masses of data and sources of information. Due to relevance, the Scopus (R) ELSEVIER database was selected. It was observed that the words Agriculture and Logic fuzzy were used in the research as one-dimensional strings. After applying the filters, 42 articles were selected, which had a survey of the content to verify the results. After this survey, the articles were grouped by the themes bioenergy, soil, irrigation and drainage, digital humanities, sustainability, technology integrated to the internet and combinations between the themes. It was concluded that the Fuzzy Logic and its applicability in agriculture is widespread in the world and that it brought technological advances capable of collaborating to solve complex agricultural problems of great scope producer in some handling with animals and/or with the cultural treatments in the crops, thus consolidating the importance of interdisciplinary technique and capable of collaborating with the results of the producer rural.