RESUMO Dentre os métodos de controle de plantas daninhas, o químico, por meio de herbicidas, é um dos mais utilizados devido à sua praticidade e eficiência. No entanto, ainda faltam informações confiáveis sobre a eficácia de aplicações em baixo volume e o espectro de gotas a ser utilizado para herbicidas de contato, como o fomesafen. O objetivo deste trabalho foi determinar o volume de calda e espectro de gotas para aplicação do herbicida fomesafen, bem como a eficácia no controle de picão-preto (Bidens pilosa) e corda-de-viola (Ipomoea triloba). O herbicida foi aplicado utilizando pulverizador pressurizado por CO2, com pontas TT11002 espaçadas de 0,50 m, operando nas pressões de 100 kPa (gotas muito grossas) e 400 kPa (gotas médias) nos volumes de calda de 35, 70, 140 e 280 L ha-1, obtidos por meio da variação na velocidade de aplicação. No momento da aplicação foram avaliados a porcentagem de área coberta e a densidade de gotas (gotas cm-²) em etiquetas de papel hidrossensível, utilizando o programa DropScope®. Melhores índices de controle do picão-preto são obtidos quando a aplicação foi realizada com gotas muito grossas, na pressão de 100 kPa, com volume de calda entre 65 e 280 L ha-1, densidade de gotas superior a 60 gotas cm-2 e cobertura maior que 10%. O fomesafen não controla a corda-de-viola. daninhas químico eficiência entanto contato picãopreto picão preto Bidens pilosa cordadeviola corda viola Ipomoea triloba. triloba . triloba) CO2 CO TT TT1100 050 0 50 0,5 m 10 grossas 40 médias 35 70 14 28 ha1, ha1 ha 1, 1 ha-1 cm² cm ² cm-² hidrossensível DropScope DropScope® 6 cm2 2 cm- 10% cordadeviola. viola. TT110 05 5 0, 4 3 7 ha- TT11 TT1

ABSTRACT Among weed control methods, chemical control using herbicides is one of the most widely employed due to its practicality and efficiency. However, there is still a lack of reliable information regarding the effectiveness of low-volume spraying and the droplet spectrum for contact herbicides, such as fomesafen. The objective was to determine the spray volume and droplet spectrum for applying the fomesafen herbicide and its efficacy in controlling hairy beggarticks (Bidens pilosa) and littlebell (Ipomoea triloba). The herbicide was applied using a CO2-pressurized knapsack sprayer with TT11002 spray tip spaced at 0.50 m, operating at pressures of 100 kPa (very coarse droplets) and 400 kPa (medium-sized droplets) with spray volumes of 35, 70, 140, and 280 L ha-1, obtained by varying the application speed. At the time of application, the percentage of covered area and droplet density (droplets cm-²) were evaluated on water-sensitive paper labels using the DropScope® program. The best control results for hairy beggarticks were achieved when the application was performed with very coarse droplets at a pressure of 100 kPa, with a spray volume between 65 and 280 L ha-1, droplet density exceeding 60 droplets cm-2, and coverage greater than 10%. Fomesafen does not provide effective control of littlebell. methods efficiency However lowvolume low Bidens pilosa Ipomoea triloba. triloba . triloba) CO2pressurized COpressurized CO2 pressurized CO TT TT1100 050 0 50 0.5 m 10 40 mediumsized medium sized 35 70 140 28 ha1, ha1 ha 1, 1 ha-1 speed cm² cm ² cm-² watersensitive water sensitive DropScope program 6 cm2, cm2 2, 2 cm-2 10% TT110 05 5 0. 4 3 7 14 ha- cm- TT11 TT1

RESUMO O rompimento da Barragem do Fundão em Mariana, MG, ocorrida em 2015, trouxe o desafio de usar o Tecnossolo (tipo de solo) formado pela deposição do rejeito de mineração de ferro nas margens do Rio Doce para agricultura. O objetivo desta pesquisa foi obter a lâmina de água para otimizar a produção da forragem tropical Megathyrsus maximum cv. Mombaça, cultivada em rejeito de mineração de ferro e determinar seu coeficiente de cultura para as condições edafoclimáticas de Viçosa, MG. O experimento foi realizado durante as estações de verão, outono e inverno do ano de 2022, com a utilização de 21 lisímetros de drenagem. O experimento foi distribuído em delineamento inteiramente casualizado com 6 tratamentos (plantas em Tecnossolo com lâminas variando de 20 a 120% da evapotranspiração da cultura, obtida do tratamento-testemunha) e adição de uma testemunha (plantas em Latossolo com lâmina de 100%) com três repetições. Recomenda-se irrigação com reposição de 40% da evapotranspiração da cultura. O cultivo em Tecnossolo diminuiu a capacidade produtiva em 37,39% nos ciclos das estações do verão/outono e outono. Recomenda-se os coeficientes de cultura de 1,2 no verão e 1,5 no outono e no inverno, para o capim-Mombaça cultivado em um Latossolo. Mariana MG 2015 tipo solo agricultura cv Mombaça Viçosa 2022 2 drenagem plantas 120 tratamentotestemunha tratamento tratamento-testemunha 100% 100 repetições Recomendase Recomenda se 40 3739 37 39 37,39 verãooutono 12 1 1, 15 5 capimMombaça capim 201 202 10 4 373 3 37,3 37,

ABSTRACT The collapse of the Fundão Dam in Mariana, MG, in 2015 introduced the challenge of using Technosol, a soil type formed by deposition of iron mining waste along the Doce River banks, for agricultural purposes. This study aimed to determine the optimal water depth for enhancing production of tropical forage, Megathyrsus maximus cv. Mombasa, when grown on iron ore tailings. Additionally, it sought to establish a crop coefficient applicable to the edaphoclimatic conditions of Viçosa, MG, Brazil. The experiment was conducted throughout the summer, fall, and winter of 2022, employing 21 drainage lysimeters. A completely randomized experimental design was adopted, featuring six treatment groups (plants in Technosol receiving water depths ranging from 20 to 120% of the crop’s evapotranspiration, as derived from the control treatment), along with a control group (plants in Latosol with a depth of 100%), each with three repetitions. Our findings showed that irrigation must replace 40% of the crop evapotranspiration. Moreover, cultivating in Technosol resulted in a reduction of productive capacity by 37.39% during the summer/fall and fall seasons. For Mombasa grass grown in Oxisol, crop coefficients of 1.2 during the summer and 1.5 during the fall and winter are advised. Mariana MG 201 banks purposes forage cv tailings Additionally Viçosa Brazil 2022 2 lysimeters adopted plants 120 crops s evapotranspiration treatment, , treatment) 100%, 100 100% 100%) repetitions 40 Moreover 3739 37 39 37.39 summerfall seasons Oxisol 12 1 1. 15 5 advised 202 10 4 373 3 37.3 37.

RESUMO O Brasil atribui significativa importância econômica e social ao café, o qual é uma das principais commodities do agronegócio global. Os cafeicultores, especialmente aqueles que plantam café arábica, enfrentam desafios devido à falta de mão de obra e aos altos custos associados à colheita manual. Este estudo teve como objetivo avaliar o desempenho operacional e a eficiência de um protótipo de colhedora autopropelida de café de montanha com terraços. Com o propósito de avaliar as perdas durante o processo de colheita, bem como a eficiência e a capacidade operacional, o modelo experimental percorreu integralmente a área designada. Durante esse percurso, foi efetuado a derriça dos frutos sobre o sistema de recolhimento, considerando cinco diferentes ângulos de inclinação do terreno (8°, 17°, 25°, 30°, 38°). A perda foi determinada pela relação entre a massa de frutos retidas pelo sistema de recolhimento e a massa total de frutos colhidos. A fim de realizar uma comparação do método mecanizado em relação ao método tradicional, também se determinou a eficiência e a capacidade operacional de dois trabalhadores que realizam a colheita manual dos frutos. A declividade do terreno não impactou de forma significativa as perdas na colheita e a capacidade operacional. O valor mais alto da capacidade operacional foi de 0,11 ha h-1, alcançado em uma declividade de 17°. A eficiência operacional média foi de 66,2%. global cafeicultores arábica terraços designada percurso 8°, 8 (8° 17 17° 25 25° 30 30° 38°. 38 38° . 38°) colhidos tradicional 011 0 11 0,1 h1, h1 h 1, 1 h-1 662 66 2 66,2% 8° (8 3 01 0, h- 6 66,2 ( 66,

ABSTRACT Coffee holds significant economic and social importance for Brazil, being one of the main commodities in global agribusiness. Coffee growers, particularly those cultivating arabica coffee, face challenges due to labor shortages and high associated costs during manual harvesting. This study aimed to evaluate the operational performance and efficiency of a self-propelled coffee harvester prototype in terraced mountain areas. To assess harvesting losses, efficiency, and operational capacity, the experimental model traversed the designated area entirely. Fruit stripping was performed over the collection system at five different terrain incline angles (8°, 17°, 25°, 30°, and 38°). Harvesting loss was determined by the ratio of the mass of fruits retained by the collection system to the total mass of harvested fruits. For comparison, the efficiency and operational capacity of two workers performing manual fruit harvesting were also measured. Terrain slope did not significantly impact harvesting losses or operational capacity. The highest operational capacity was 0.11 ha h⁻¹, achieved at a 17° slope. The average operational efficiency was 66.2%. Brazil agribusiness growers selfpropelled self propelled areas entirely 8°, 8 (8° 17 25 25° 30 30° 38°. 38 38° . 38°) comparison measured 011 0 11 0.1 h¹ h ¹ h⁻¹ 662 66 2 66.2% 8° (8 1 3 01 0. h⁻ 6 66.2 ( 66.

RESUMO A lichia é uma fruta perecível e a aplicação do ozônio destaca-se como uma tecnologia promissora na preservação da qualidade destes frutos. O objetivo deste estudo foi determinar os efeitos da aplicação do gás O3 e névoa ozonizada na qualidade físico-química de lichia. Foram realizados dois ensaios: gás ozônio e névoa ozonizada. Os experimentos foram conduzidos em esquema de parcelas subdivididas, tendo nas parcelas os tratamentos (concentrações de ozônio e tempos de exposição) e nas subparcelas os tempos de armazenamento, em delineamento inteiramente casualizado (DIC) com três repetições. No primeiro experimento foram testadas duas concentrações do gás ozônio (10 e 20 mg L-1) nos tempos de exposição de 15, 30 e 45 min. O tratamento controle correspondeu a frutas não expostas ao gás. No segundo experimento, foi definida uma concentração de 20 mg L-1 de ozônio nos tempos de exposição de 3, 5 e 7 min. Os frutos também foram expostos à névoa sem ozônio por 3, 5 e 7 min. Os parâmetros de qualidade das lichias foram avaliados após o tratamento (dia 0) e nos dias 2, 4, 6, 7 e 8. O gás ozônio foi mais eficiente na preservação da qualidade pós-colheita da lichia e na preservação da cor da casca dos frutos em relação à névoa ozonizada. Os efeitos do gás e névoa sobre as características da polpa (Dif*, h* e C*) foram semelhantes. O uso da névoa ozonizada é recomendado em vegetais com maior presença de cera cuticular ou maior tolerância a água. destacase destaca se físicoquímica físico química ensaios subdivididas armazenamento DIC (DIC repetições 10 (1 2 L1 L 1 15 3 4 min L- dia 0 6 8 póscolheita pós colheita Dif*, Dif (Dif* h C* C semelhantes água ( Dif* (Dif

ABSTRACT Lychees are perishable fruits, and the application of ozone is a promising technology to preserve their quality. This study aimed to determine the effects of ozone gas and ozonated mist on the physicochemical properties of lychees. Two assays were performed using ozone gas and ozonated mist. The experiments were performed using a split-plot scheme, in which the plots corresponded to the treatments (ozone concentration or exposure time) and the subplots to the storage time, following a completely randomized design with three replicates. In the first experiment, ozone gas concentrations were tested (10 and 20 mg L-1) at exposure times of 15, 30, and 45 min. Corresponding control treatments included fruits that were non-exposed to ozone gas. In the second experiment, an ozone concentration was set (20 mg L-1) for exposure times of 3, 5, and 7 min. Exposure to ozone-free mist for 3, 5, and 7 min and control treatment were performed. The quality parameters of lychee fruits were assessed immediately after treatment (day 0) and on days 2, 4, 6, 7, and 8. Ozone gas was more effective for postharvest preservation of lychee than ozonated mist. Ozone gas was also proven to be more efficient than ozonated mist in maintaining the color of lychee peels. The effects of ozone gas and ozonated mist on pulp characteristics (Dif*, h*, and C*) were similar. Ozonated mist is recommended for vegetable species with an outer waxy cuticle or a high tolerance to water. lychees splitplot split plot scheme time replicates experiment 10 (1 2 L1 L 1 L-1 15 30 4 nonexposed non exposed (2 3 5 ozonefree free day 0 6 8 peels Dif*, Dif (Dif* h h* C* C similar water ( L- Dif* (Dif

ABSTRACT The collapse of the Fundão dam in Brazil caused one of the biggest environmental disasters. One of the challenges was how to manage the tailings so that affected areas could be reused. This study aimed to verify whether applying different irrigation depths to Xaraés grass grown with iron mining tailings would affect grass shoot and root dry masses. The experiment was set up in a randomized design with five irrigation depths (40%, 60%, 80%, 100%, and 120% of crop evapotranspiration) and two additional treatments (grass grown in tailings with soil conditioner, and grass grown in natural soil), each with three repetitions. The grass was cut four times, and the shoot dry mass was evaluated after each cut, while the root dry mass was evaluated at the end of the experiment. Our results showed that irrigation depths had a positive linear effect on shoot dry mass and an exponentially increasing effect on root dry mass, with the highest averages in the treatment applying 120% of crop evapotranspiration. This study showed that even in adverse conditions, Xaraés grass was able to grow and develop well. disasters reused masses 40%, 40 (40% 60 60% 80 80% 100 100% 120 evapotranspiration conditioner soil, , soil) repetitions times conditions well 40% 4 (40 6 8 10 12 (4 1 (

ABSTRACT Iron mining tailings have limitations for plant growth and development due to low fertility, coupled with great restriction of physical characteristics such as low water retention, high density, and lack of structure. This study aimed to evaluate whether different irrigation depths applied to Xaraés grass grown in mining tailings influence its yield and bromatological aspects. The experiment was carried out in a completely randomized design with five irrigation depths (40, 60, 80, 100, and 120% of the crop evapotranspiration), two additional treatments consisting of grass grown in tailings with soil conditioner and in natural soil, and three repetitions. Forage dry mass, plant height, leaf: stem ratio, as well as neutral detergent fibre, acid detergent fibre, crude protein, and mineral matter content, were evaluated during four cutting cycles. Xaraés grass could establish and produce forage despite cultivation limitations in iron mining tailings, which are due to their properties. Irrigation depths showed positive and linear effects on Xaraés grass dry matter yield and heights of plants grown in iron mining tailings. The soil conditioner has potential for use in pasture cultivation in iron mining tailing.

RESUMO A produção de cebola é uma atividade agrícola cujo rendimento está associado a fatores ambientais, de mercado e ao manejo cultural. Objetivou-se com este estudo avaliar o custo de produção de cebola em função do sistema de preparo adotado e do teor de água do solo no momento de realização das operações. Foram avaliados três sistemas de preparo: P1 - uma aração + duas gradagens + duas operações de encanteiramento; P2 - duas gradagens + uma operação de encanteiramento; P3 - uma gradagem + uma operação de encanteiramento; e quatro teores iniciais de água do solo: 12, 15, 23 e 26%, em experimento conduzido no perímetro irrigado Tourão, Juazeiro, BA (9° 24’ 07.3” S; 40° 26’ 08.7” W, e altitude de 376 m), em 2017, em parcelas subdivididas, no delineamento em blocos casualizados, com quatro repetições. Foram determinados os custos referentes às operações mecanizadas, operações manuais, insumos e a irrigação da cultura. A eficiência econômica foi avaliada por meio das variáveis custo total e custo unitário de produção da cebola, receita bruta, receita líquida e taxa interna de retorno. A utilização do sistema de preparo com uma gradagem, um encanteiramento e semeadura, na condição de teor de água do solo a 23%, resultou em maior eficiência econômica.

ABSTRACT Onion production is an agricultural activity whose yield is associated with environmental, market and cultural management factors. The objective of this study was to evaluate the cost of onion production as a function of the tillage system adopted and the soil water content at the moment of the operations. Three tillage systems were evaluated: P1 - one 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%, in experiment conducted at the Tourão irrigated perimeter, Juazeiro, BA, Brazil (9° 24’ 07.3” S; 40° 26’ 08.7” W, and altitude of 376 m), in 2017, in split plots, in a randomized block design, with four repetitions. The costs related to mechanized operations, manual operations, inputs and crop irrigation were determined. The economic efficiency was evaluated through the variables total cost and unit cost of onion production, gross revenue, net revenue and internal rate of return. The use of the tillage system with one harrowing, one seedbed raising operation and seeding, under the condition of 23% soil water content, resulted in higher economic efficiency.

RESUMO O excesso de operações mecanizadas de preparo do solo em condições inadequadas pode elevar o custo da produção agrícola e ocasionar a degradação do solo, sem que sejam obtidas respostas adequadas da cultura. Objetivou-se com este trabalho avaliar a resposta da cultura da cebola em função de teores de água e sistemas de preparo do solo. Foram avaliados três sistemas de preparo: P1 (aração, duas gradagens e duas operações de encanteiramento); P2 (duas gradagens e uma operação de encanteiramento); P3 (uma gradagem e uma operação de encanteiramento); e quatro teores de água do solo, 12, 15, 23 e 26%. O experimento foi conduzido no perímetro irrigado Tourão, Juazeiro, BA (9° 24’ 7.3” S; 40° 26’ 8.7” W e altitude de 368 m), em 2017, sendo instalado em parcelas subdivididas, no delineamento em blocos casualizados, com quatro repetições. Nas parcelas foram dispostos os teores de água e nas subparcelas, os sistemas de preparo. A resposta da cultura aos tratamentos foi avaliada por meio da determinação do índice de velocidade de emergência das plântulas, regularidade da distribuição longitudinal das plântulas, estande final, produtividade total, comercial da cultura e produtividade por classe de diâmetro transversal dos bulbos. A variação do teor de água no solo apresentou efeito quadrático sobre as variáveis velocidade de emergência, estande final e produtividade total de cebola. Os tratamentos não afetaram significativamente a distribuição longitudinal das plântulas e a produtividade comercial. O sistema de preparo composto por uma gradagem e uma operação de encanteiramento se mostrou o mais adequado ao cultivo da cebola por semeadura direta.

ABSTRACT 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.

Com o objetivo de avaliar o efeito de diferentes ambientes sobre a qualidade fisiológica e atividade enzimática de sementes de milho, dois lotes de sementes da cv. ‘BR 106’ foram armazenados em embalagem de papel em três ambientes: câmara fria (12±2°C/60±5%UR), ambiente não controlado (média de 21,6°C/71%UR) e câmara controlada (30±2°C/70±5%UR). A qualidade fisiológica (germinação e vigor) e as atividades da peroxidase, catalase e α-amilase foram avaliadas no inicio e a cada 90 dias de armazenamento. A qualidade fisiológica das sementes foi reduzida ao longo do período de armazenamento, independente dos lotes, com menores reduções nas armazenadas em temperaturas mais baixas. A atividade enzimática da peroxidase, catalase e α-amilase decrescem com o aumento do período e da temperatura de armazenamento das sementes, sendo eficiente na avaliação da qualidade fisiológica de sementes armazenadas.

With the objective of evaluating the effect of different environments on the physiological quality and enzyme activity of maize seed, two seed lots of cv. ‘BR 106’ were stored in paper packing in three environments: cold chamber (12±2°C/60±5%UR), uncontrolled (mean 21.6°C/71%UR) and controlled chamber (30±2°C/70±5%UR). The physiological quality (germination and vigor) and the activities of peroxidase, catalase, and α-amylase were evaluated at the beginning and every 90 days of storage. The seed quality was reduced throughout the storage period, regardless of the lots, with smaller reductions when stored in low temperature. The enzymatic activity of peroxidase, catalase and α-amylase decreases with increasing time and temperature of storage of seeds, being efficient in assessing the physiological quality of stored seeds.

RESUMO A couve-flor é uma brássica bastante produzida e consumida no Brasil, cujo cultivo é dependente do suprimento adequado de água e nutrientes. Portanto, objetivou-se com este estudo, avaliar o efeito da aplicação de lâminas de irrigação e doses de nitrogênio nos componentes de produção e na produtividade da água da cultura da couve-flor híbrida ‘Barcelona CMS’. Foram avaliadas as lâminas de 0, 75, 100, 125 e 150% da evapotranspiração da cultura combinadas com cinco doses de nitrogênio (0, 75, 150, 300 e 450 kg ha-1). O experimento foi conduzido em delineamento inteiramente casualizado com arranjo em parcelas subdivididas. Os efeitos da desses fatores foram avaliados pela metodologia de superfície de resposta. Observou-se que a produtividade da água pela cultura apresenta relação decrescente com a lâmina de água aplicada; portanto, a produtividade é maior quando a reposição de água é menor que o recomendado. A maior produtividade total da couve-flor estimada é de 24.547,80 kg ha-1, com diâmetro médio de 19,60 cm, altura média de 12,25 cm e massa fresca da inflorescência de 858,90 g por planta, obtida com irrigação equivalente a 132,09% da evapotranspiração da cultura e 450 kg ha-1 de nitrogênio. Para obtenção do maior diâmetro e altura de inflorescência é necessária lâminas de irrigação equivalentes a 128,70 e 108,20% da evapotranspiração da cultura, respectivamente, na dose de 450 kg ha-1 de nitrogênio. Portanto, a melhor resposta da produtividade da couve-flor híbrida ‘Barcelona CMS’ pode ser obtida com lâmina de irrigação superior à evapotranspiração da cultura, independentemente da dose de nitrogênio aplicada.

ABSTRACT Cauliflower is a brassica produced and consumed in Brazil, whose cultivation depends on the adequate supply of water and nutrients. The objective of this study was to evaluate the effect of irrigation depths and nitrogen doses on the production components and water yield of cauliflower hybrid Barcelona CMS. The treatments consisted of five irrigation water depths (0, 75, 100, 125 and 150% of the crop evapotranspiration) combined with five nitrogen doses (0, 75, 150, 300 and 450 kg ha-1). The experiment was conducted in a completely randomized design with a split-plot arrangement. The effects of these factors were evaluated using the response surface methodology. The water yield of the crop decreases with increasing irrigation water depth; therefore, the yield is higher when water replenishment is lower than the recommended. The highest estimated total inflorescence yield is 24,547.80 kg ha-1, with a inflorescence mean diameter of 19.60 cm, a inflorescence mean height of 12.25 cm, and an inflorescence fresh weight of 858.90 g plant-1, obtained with an irrigation water depth equivalent to 132.09% of the crop evapotranspiration (ETc) and a nitrogen dose of 450 kg ha-1. The highest inflorescence diameter and height are obtained with an irrigation depth equivalent to 128.70 and 108.20% of ETc, respectively, and a nitrogen dose of 450 kg ha-1. Therefore, the best productivity response of the Barcelona CMS cauliflower hybrid can be obtained using an irrigation depth greater than the crop evapotranspiration, regardless of the nitrogen doses.

ABSTRACT This study was conducted with the aim of assessing the effects of different ambient temperature values on the performance of laying birds from one to 42 days of age in order to obtain optimal comfort temperatures. A total of 864 laying hens were distributed in four climatic chambers with different temperature ranges. One of the chambers was maintained within the thermal range recommended by the literature and the others were maintained under temperatures that consisted of mild and moderate cold stress and moderate heat stress. The experiment was conducted according to a completely randomized design in a split-plot arrangement and six replications. The data were analyzed by means of the analysis of variance and regression. The final performance of birds with temperatures of 33, 28, 26, 23, 19, and 19 °C (for the first, second, third, fourth, fifth, and sixth week of age, respectively) presented better productive results, confirming the assertiveness regarding the best thermal comfort and welfare of laying birds during the rearing stage. The results showed that under conditions of cold thermal stress, birds presented a worse performance, thus affecting their development and productive efficiency.

RESUMO O objetivo do trabalho foi avaliar o crescimento do tomateiro cultivar Upiã nos sistemas de cultivo Vertical, Cerca Cruzada e Viçosa, visando obter esclarecimento para os ganhos produtivos alcançados no sistema Viçosa. O experimento foi conduzido em Viçosa-MG, no período de 21 de agosto a 05 de dezembro de 2012, no esquema de parcelas subdivididas, sendo as parcelas representadas pelos sistemas de cultivo: Vertical, tutorado com fitilho em espaçamento 1,0 x 0,5 m; Cerca Cruzada, tutorado com bambu em espaçamento de 1,0 x 0,5 m; e Viçosa, tutorado com fitilho em espaçamento 2,0 x 0,2 m. As subparcelas foram compostas pelas épocas de amostragem das plantas: 15, 30, 45, 60 e 75 dias após o transplantio. O delineamento experimental foi em blocos casualizados, com quatro repetições. Cada parcela foi constituída por três linhas de 10 plantas, perfazendo um total de 30 plantas por parcela, sendo avaliadas as quatro plantas centrais de cada parcela. Avaliou-se matéria seca de folhas (MSF), caule (MSC), inflorescências (MSI), frutos (MSFr) e total (MST). Utilizando-se a área foliar, medida em escâner digital, e as massas secas previamente obtidas, foram determinados os seguintes índices fisiológicos de crescimento: índice de área foliar (IAF), área foliar específica (AFE), taxa de crescimento relativo (TCR) e taxa assimilatória líquida (TAL). O sistema Viçosa alterou o padrão de crescimento do tomateiro, quantificado pela análise de crescimento, em relação ao Cerca Cruzada e Vertical. O prolongamento da segunda fase de crescimento para a matéria seca de frutos, possivelmente, explicaria os ganhos produtivos obtidos no Sistema Viçosa. Estudos adicionais são necessários para esclarecer a relação entre a duração da 2a fase de crescimento da matéria seca de frutos, os índices fisiológicos AFE, IAF e TAL com o tamanho e produção de frutos do tomateiro.

ABSTRACT The objective of this work was to analyze the growth of the Upiã tomato cultivar in the Vertical, Crossed Fence and Viçosa cultivation systems, in order to obtain explanations for the productive gains achieved in the Viçosa system. The experiment was conducted in Viçosa, Minas Gerais State, Brazil, from August 21st to December 5th, 2012, in the scheme of subdivided plots, being the plots represented by the cultivation systems: Vertical, using tape, 1.0×0.5 m spacing; Crossed Fence, staked with bamboo, 1.0x0.5 m spacing; and Viçosa, using tape, 2.0x0.2 m spacing. The subplots were composed by the sampling times of the plants: 15, 30, 45, 60 and 75 days after transplanting. The experimental design was in randomized blocks, with four replications. Each plot was composed by three lines of 10 plants, making a total of 30 plants per plot, being evaluated the four central plants of each plot. We evaluated the dry matter of leaves (MSF), stem (MSC), inflorescences (MSI), fruits (MSFr) and total (MST). Using the foliar area index, measured by digital scanners and the previously obtained dry masses, we determined the physiological growth indices: foliar area index (IAF), specific foliar area (AFE), relative growth rate (TCR), and net assimilation rate (TAL). The Viçosa system altered the growth pattern of the tomato, quantified by the growth analysis, in comparison to Crossed and Vertical Fences. The prolongation of the second growth phase for the dry matter of fruits could possibly explain the productive gains obtained in the Viçosa system. Additional studies are required in order to clarify the relationship between the duration of the second phase of fruit dry matter growth, the physiological indexes AFE, IAF and TAL with the size and fruit yield of the tomato.

ABSTRACT The implementation of the ozonation process in the milling industry to control insect pests and improve wheat flour qualities requires understanding the behavior of ozone during ozonation. Therefore, this study aimed to investigate the reaction kinetics of ozone gas in wheat flour. Wheat flour ozonation at concentrations of 0.54, 1.07, 1.61 and 2.14 mg L−1 was used in a prototype consisting of a cylinder and a mixing system with a helical thread. The iodometric titration method was used to quantify the ozone concentration in the air stream. The reaction kinetics were characterized by determining the saturation time and the decomposition kinetics (decay rate and half-life time). With increasing ozone concentration, less time was required to saturate the wheat flour. The saturation times were 812, 434, 370 and 342 min for ozone concentrations of 0.54, 1.07, 1.61 and 2.14 mg L−1, respectively. Increasing the ozone concentration did not influence the constant decay rate and half-life time. The ozone decomposition kinetics could be represented by a first-order model, with a decay rate constant of 0.23±0.008 min−1 and a half-life time of 3.02±0.081 min.

ABSTRACT The objective of this study was to evaluate and model the traction performance parameters of a tractor 4x2 FWD, according to the tractor speed, the internal pressure and the type of tires construction. For each type of tire construction was assembled an experiment in which we evaluated the influence of internal pressures of the front and rear tires and the speed of the mechanical assembly. It was found that the sliding of the diagonal run, presented significant effect in all variables analyzed, since the radial showed no influence of the factors evaluated. The power available in the drawbar was higher when the tractor was equipped for radial tires. The response variables, fuel consumption schedule and specific fuel consumption were more sensitive to the speed of the internal tire pressure. The fuel consumption per area worked, did not affect the analyzed variables. As for the effort prediction models in the tractor drawbar, it was only possible for diagonal run, which are influenced by speed and internal pressure levels of the front and rear tires.

ABSTRACT In the correct pasture management, nutritional factors such as nitrogen and potassium fertilization play an important role in the forage production and quality. The aim was to evaluate the effects of the application of water levels, nitrogen and potassium doses in the Xaraés grass in the south of the State of Tocantins. For this, Xaraés grass was cultivated in the experimental field of the Federal University of Tocantins, municipality of Gurupi, TO. We used a mixture of fertilizer, combinations of N and K2O following the 1 N: 0.8 K2O ratio. To evaluate the effect of irrigation water levels and combinations of N and K2O doses in Xaraés grass, the plant height, the crude protein content and neutral detergent fiber were determined. The greatest height observed in the grass was 61.6 cm, with the dose application of 700 kg ha-1 yr-1 of N: 0.8 K2O and a water level of 120% of the ETc. The highest protein content was 11.7%, with the highest dose application of fertilizer and absence of irrigation. The highest fiber content in neutral detergent was 64%, with the estimated amount of 385.5 kg ha-1 yr-1 of N: 0.8 K2O and a water level of 120% of ETc. The conclusion was that the plant height, fiber detergent and crude protein content were influenced by the change in water level of irrigation and fertilizer doses. The values of plant height and crude protein increased with the increase of water levels and manure dose, while the fiber content of neutral detergent decreased with the increase of irrigation and varied little with the increase of fertilizer dose.