Revista Engenharia na Agricultura - REVENG 2023-03-21T15:33:35-03:00 RENATA CÁSSIA CAMPOS Open Journal Systems <p>Engenharia na Agricultura é uma revista de fluxo contínuo que tem como objetivo divulgar e difundir a produção científica das diversas áreas da Engenharia Agrícola. É necessário que os diversos leitores interessados no assunto tenham acesso aos novos conhecimentos científicos e às inovações tecnológicas, e a publicação numa revista constitui uma forma prática, usual e eficiente para se divulgar trabalhos dessa natureza. O objetivo desta Revista é divulgar conhecimento científico atualizado, com a presteza e agilidade que não é possível ao livro e com a abrangência que é própria da revista.</p> Interannual rainfall variability and soybean yields in Mata Roma municipality, Maranhão 2022-12-30T09:52:03-03:00 Eduardo Silva dos Santos Plinio Antonio Guerra Filho Sheyla Sales de Oliveira Breno dos Santos Silva Antonio Emanuel Souta Veras Daniela Abreu de Souza <p>Among the activities affected by rainfall variability, agriculture is one of the most vulnerable. In this sense, this work aimed to relate the interannual rainfall variability with the soybean yields variability in Mata Roma municipality, Maranhão, considering dry and rainy events. For this, for the period from 2003 to 2019, data on average soybean yield and rainfall in this producing region, which is one of the main ones in the State, were analyzed. Monthly rainfall data for the period 1985-2019 were also analyzed and the dry and rainy events were identified in these two meteorological data series. The results showed that rainfall from January to May explains about 99%, on average, of the interannual variation of yields and that occurrence of dry and very humid periods disfavor the soybean crop, causing, in most cases, yields and productions far below the average for the study region. Based on the regression analysis, it was found that maximum average yield of 2942.52 kg×ha<sup>?1</sup> was reached with an average rainfall of 1709 mm.</p> 2023-03-21T00:00:00-03:00 Copyright (c) 2023 Revista Engenharia na Agricultura - REVENG Kinetics of drying in a Mentha crispa foam layer and adjustment of mathematical models 2023-01-05T10:35:12-03:00 Ana Carolina Nóbrega Leite Josilene de Assis Cavalcante Nagel Alves Costa Williane Silva Pinheiro <p><em>Mentha crispa</em> is a plant commonly used in folk medicine to treat illnesses and has wide industrial application. Dehydration has been used for several types of plants in order to reduce the levels of water content and water activity, so that it would allow na adequate storage due to the conservation of the active principles. The objective of this work is to investigate the process of drying mint in a foam layer. The foam was physically characterized in terms of density, expansion percentage, air incorporation capacity and stability. Drying was carried out according to a factorial experimental design, in which the input variables were: temperature (50, 60 and 70 °C), concentration of foaming agent (3, 5 and 7 %) and stirring time (3, 5 and 7 min); and the output variables were: drying time and water content (Xbs) of the product. The physical properties of the foam depended only on the foaming concentration. The rise in the temperature significantly reduced the drying time and the water content of the foam. The Page, Henderson &amp; Pabis, Newton and Modified Page mathematical models were adjusted to the experimental data and Page’s model was the one that showed to be the most adequate to represent the drying phenomenon.</p> 2023-03-21T00:00:00-03:00 Copyright (c) 2023 Engenharia na Agricultura