Janielle Souza Pereira

Soil compaction, often the result of intensive mechanization, is a major concern because it increases the bulk density of the soil, fundamentally altering its structure and reducing its capacity to support essential ecological and agricultural functions. Therefore, soil monitoring is essential, particularly through its main quality indicator, bulk density. However, the analysis of this attribute requires the collection of soil samples with subsequent laboratory analysis, which demands time and qualified labor. Thus, this study aimed to develop a neuro-fuzzy model to estimate the bulk density of sandy soils based on variations in the proportion of its particle size fractions. To achieve this, undisturbed samples were collected from soils in four municipalities in northern Bahia, located along the shores of Lake Sobradinho. The proportion of particle size fractions in the composition of each sample was used to develop models that integrate fuzzy logic and neural networks. They employed the Takagi-Sugeno inference method and hybrid learning algorithms for parameter adjustment and bulk density predictions. The performance of the models was evaluated using error statistics, with the model with the highest accuracy in density predictions being selected, achieving an R² of 71%. It is important to emphasize that the neuro-fuzzy model did not require data stratification and can be applied to estimate the sandy soil density of any soil type sampled.

The flavor, aroma, and color of coffee can be changed due to mechanical damage, reducing its quality. To measure the mechanical behavior of the fruit, compression tests can be performed at different stages of ripeness. In this study, we analyzed the deformation, strain energy, and von Mises stress of coffee fruits at mature, semi-mature, and immature stages under compression forces. Compression in three directions (x, y, and z) was simulated on coffee fruit models using the finite element method. A compression support was applied in the opposite direction to the force application axis. Numerical simulations of the compression process allowed us to verify that the more mature the fruit, greater the associated mean deformation (2.20 mm mm⁻¹, 0.78 mm mm⁻¹, and 0.88 mm mm⁻¹), the lower the mean strain energy (0.07 mJ, 0.21 mJ, and 0.34 mJ), and the lower the mean equivalent von Mises stress (0.25 MPa, 1.03 MPa, and 1.25 MPa), corresponding to ripe, semi-ripe, and immature fruits, respectively. These analyses not only save time and professional resources but also offer insights into how strain energy and von Mises stress affect fruits at different maturation stages. This information can guide machine adjustments to reduce coffee harvesting damages.

RESUMO: O uso agrícola do biossólido é considerado uma alternativa à problemática ambiental ocasionada pelo lodo gerado no tratamento biológico do esgoto doméstico ou sanitário. Esse resíduo pode promover economia na aquisição de fertilizantes por ser um condicionador do solo e possuir nutrientes essenciais ao desenvolvimento vegetal. Seguir a regulamentação vigente no país é condição determinante para viabilizar esse reaproveitamento. Assim, o trabalho teve como objetivo avaliar o potencial do biossólido proveniente de reator anaeróbio de fluxo ascendente para reúso na agricultura, após estabilização e higienização com óxido de cálcio, comparando os resultados de sua caracterização com o preconizado pelos critérios de qualidade estabelecidos por normas brasileiras vigentes. O biossólido atendeu às exigências da Resolução número 498/2020 do Conselho Nacional do Meio Ambiente para aplicação na agricultura. O resíduo não atendeu aos limites de tolerância para os elementos níquel, cobre, zinco, ferro e manganês estabelecidos pela Instrução Normativa nº 25 de 2009 do Ministério de Agricultura, Pecuária e Abastecimento. O biossólido pode ser utilizado para fins de condicionamento físico e fertilização do solo/substrato, contribuindo para minimização de impactos ambientais provenientes de um possível descarte inadequado.

The flavor, aroma and color of coffee may change due to mechanical damage, reducing its qual-ity. To measure the mechanical response of materials, compression tests can be performed, de-termining the effect of force application on the mechanical behavior of the fruit at different stages of ripeness. In this context, this study aimed to analyze the deformation, strain energy and equivalent von Mises stress of coffee fruits at mature, semi-mature and immature maturation stages and compressed by collapse forces. Compression in three directions (x, y and z) was sim-ulated on coffee fruit models using the finite element method, with a compression support in the direction opposite to the force application axis. The numerical simulation of the compression process allowed to verify that the more mature the fruit, the greater the associated mean defor-mation (2.20 mm mm-1, 0.78 mm mm-1 and 0.88 mm mm-1), the lower the mean strain energy (0.07 mJ, 0.21 mJ and 0. 34 mJ) and the lower the mean equivalent von Mises stress (0.25 MPa, 1.03 MPa and 1.25 MPa), corresponding to ripe, semi-ripe and immature fruits; and these proper-ties may be used to analyze how processes in the production chain affect the amount of mechan-ical damage.

Images obtained by Remotely Piloted Aircraft (RPA) used to monitor the crop can help evaluate leaf mass, plant formation, and plant population. In this context, the objectives of this study were to analyze plant growth in a grapevine crop trained in the trellis system, detect failures and determine the plant covered area using images obtained by RPA. The flight was parameterized with frontal overlap of 75%, lateral overlap of 70%, Ground Sample Distance (GSD) of 60 m, and flight speed of 5 m.s^-1, using a sensor in the visible range. Processed images showed a stand 3% smaller than projected, an area covered by vine branches occupying 60.8%, undergrowth and invasives represented 5.3%, and exposed soil 33.9%. Vines were identified in the vegetation indices as green points, invasive plants as yellow points, and exposed soil as red points. Image processing obtained with RPA allowed identification of plants in various stages of development, with predominance of vines in the formation process. It was possible to identify the plants and quantify the leaf mass using the MPRI vegetation index, as well as to differentiate exposed soil from plant material. It was also observed that the plot had an incomplete stand at the time the flight was performed.

Excessive tillage operations under inadequate conditions can raise the cost of agricultural production and lead to soil degradation without adequate crop response. The objective of this study was to evaluate the onion crop response to soil water contents and tillage systems. Three tillage systems were evaluated: P1 (plowing + two harrowings + two seedbed raising operations), P2 (two harrowings + one seedbed raising operation), P3 (one harrowing + one seedbed raising operation); and four soil water contents: 12, 15, 23 and 26%. The experiment was conducted in the irrigated perimeter of Tourão, Juazeiro, BA, Brazil (9° 24’ 7.3” S; 40° 26’ 8.7” W and altitude of 368 m), in 2017, and was installed in split plots, in a randomized block design, with four repetitions. Water contents were arranged in the plots and tillage systems in the subplots. Crop response to the applied treatments was evaluated through the determination of the emergence speed index of the seedlings, regularity of the longitudinal distribution of seedlings, final stand, total and marketable yields of the crop and yield per bulb transverse diameter class. The variation of soil water content had a quadratic effect on the variables emergence speed index, final stand and total onion yield. The treatments did not significantly affect the longitudinal distribution of plants and marketable yield. The tillage system composed of one harrowing and one seedbed raising operation showed to be the most appropriate for onion cultivation by direct seeding.

Cowpea, a short-cycle legume with large production in the North and Northeast regions, has its productive potential limited by edaphic characteristics and degradation processes of soil physical quality, such as compaction. This process may interfere with plant development and productivity by restricting root system growth, aeration, water and nutrient availability. The objective of this work was to analyze the interference of different levels of compaction in the soil physical characteristics, root growth, development of the aerial part and productivity of cowpea. The experiment was conducted in a greenhouse following a completely randomized design with a control (control) and four levels of soil compaction, with four replications. Each experimental unit was composed of PVC tubes composed of a 0.05-m layer of gravel, cotton fabric and a 0.04-m layer of soil. The different levels of compaction were obtained using a proctor socket and a wooden base. Based on the value of penetration resistance (PR) of 1.00 MPa, soil reached the macroporosity considered as critical theresohold for soil aeration. Results indicate that the higher the PR of the soil, the lower the development of the root system and the aerial part. The productive aspects of cowpea presented better results in plants grown in soils with a level of resistance to penetration close to 0.8 MPa.

Anais do XVII Encontro Nacional de Estudantes de Engenharia Ambiental e V Fórum Latino-Americano de Engenharia e Sustentabilidade (978-85-5722-291-5) - Mudas De Moringa Oleífera Lam. Cultivadas Em Substratos À Base De Resíduo Agrícola E Sanitário

O feijão caupi ou feijão de corda é uma das principais culturas da atividade econômica no nordeste brasileiro e apresenta boa tolerância à seca e às altas temperaturas, tendo sua produtividade condicionada pelo estresse hídrico advindo dos longos períodos de seca na região. Assim, objetivo do trabalho foi a avaliação do potencial do polímero hidrorretentor na melhoria da retenção de água, das características biométricas e da produtividade da cultura do feijão caupi em solo de textura arenosa. O delineamento experimental foi em blocos inteiramente casualizados, com sete tratamentos e quatro repetições. Cada parcela foi composta por um vaso com capacidade de 7L, com solo e a devida quantidade de polímero hidrorretentor ou ausência do mesmo (testemunha). Foram semeadas quatro sementes por vaso e, após a germinação, realizou-se o desbaste, mantendo-se duas plântulas. Durante e ao final do ciclo da cultura, foram avaliados parâmetros biométricos e de produtividade, e determinadas a umidade e a curva de retenção de água no solo. A utilização do polímero hidrorretentor aumentou a retenção de água e melhorou grande parte das propriedades morfológicas e produtivas da cultura. Dentre as dosagens avaliadas, as proporções de 1,50; 2,00 e 4,00 g L-1 se apresentaram como as que mais favoreceram ao desenvolvimento vegetal.

O uso agrícola e a retirada da caatinga podem alterar a qualidade dos atributos físicos do solo do semiárido nordestino. Assim, objetivou-se avaliar as alterações de atributos físicos do solo sob diferentes usos na região do semiárido baiano. Foram selecionadas vinte e quatro propriedades rurais localizadas nos municípios de Sobradinho, Casa Nova, Sento Sé e Remanso. Em cada propriedade foram coletadas três amostras de solo, compostas a partir de dez amostras simples, nas camadas de 0,00-0,10; 0,10-0,20 e 0,20-0,40 m, tanto na área agrícola como na área de caatinga, perfazendo 18 amostras, a fim de avaliar os atributos físicos: diâmetro médio ponderado (DMP), diâmetro médio geométrico (DMG), densidade do solo (Ds), porosidade total do solo (Pt), argila (ARG), silte (SIL), areia (ARE), grau de floculação (GF) e argila dispersa em água (ADA). Os dados foram submetidos ao teste t de Student para comparação das médias de cada atributo entre as áreas e, em seguida à análise multivariada pela técnica de análise de componentes principais (ACP). A conversão da caatinga em sistemas agrícolas promove mudanças nos atributos físicos do solo, sugerindo efeito do manejo agrícola. A partir do uso da ACP, os atributos relacionados à estruturação (DMG, DMP, Ds, Pt) mostraram-se sensíveis às alterações nas áreas com uso agrícola dos municípios. A variabilidade de classes de solos estudados influencia as alterações na camada de 0,20-0,40 m, onde a textura condiciona à estruturação.