Revista Brasileira de Engenharia Agrícola e Ambiental

(941 Artigos indexados)

Proposal of automated computational method to support Virginia tobacco classification - (2025)

Leonel P. C. Tedesco, Adriano da C. de Freitas, Rolf F. Molz, Jacques N. C. Schreiber

Volume: 23 - Issue: 10

Resumo. ABSTRACT This article proposes an automatic method for classification of cured tobacco leaves. Typically this process is performed manually, allowing the occurrence of human errors. In addition, the existence of an automated comparative procedure, helping to perform the classification, can make this process faster and more transparent. In order to implement the method, non-invasive to the agricultural product, 250 samples of Virginia tobacco digital images in the RGB and HSV color models were analyzed. The validation of the method was carried out using partial least squares (PLS) and artificial neural network (ANN), presenting a qualitative and quantitative analysis of both tools. It has been verified that the PLS can be applied to this method, as it has a shorter computational time, better suiting a real-time process. It can be verified that the ANN obtained better prediction results. Both methods employed had better results when adopting the RGB color model, reaching coefficient of determinations of 68 and 96% for the PLS and ANN methods, respectively.

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Application of artificial neural networks in the prediction of sugarcane juice Pol - (2025)

Anderson P. Coelho, João V. T. Bettiol, Alexandre B. Dalri, João A. Fischer Filho, Rogério T. de Faria, Luiz F. Palaretti

Volume: 23 - Issue: 1

Resumo. ABSTRACT Innovative techniques that seek to minimize the costs of production and the laboriousness of certain operations are one of the great challenges in the sugar-energy sector nowadays. Thus, the objective of the present study was to estimate the Pol values of sugarcane juice as a function of °Brix and wet cake weight (WCW) using artificial neural network (ANN) modeling. A database was organized consisting of 204 technological analyses from a field experiment with 15 treatments and 2 years of evaluation. 75% of the data were used for the calibration of the model and 25% for its validation. Multilayer Perceptron ANNs were used for calibration and validation of the data. Before calibration, the variables were normalized. The training algorithm used was backpropagation and the activation function was the sigmoid. The ANNs were established with two hidden layers and the number of neurons ranging from 4 to 20 in each. The 15 ANNs with the lowest root mean square errors were randomly presented by the software, among which 6 were chosen to verify the accuracy. The ANNs had a high accuracy in the estimation of sugarcane juice Pol, both in the calibration phase (R2 = 0.948, RMSE = 0.36%) and in the validation (R2 = 0.878, RMSE = 0.41%), and can replace the standard method of analysis. Simpler networks can be trained to have the same accuracy as more complex networks.

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Biomass of sugar-apple seedlings under saline water irrigation in substrate with polymer - (2025)

Aldeir R. Silva, Francisco T. C. Bezerra, Lourival F. Cavalcante, Walter E. Pereira, Leandro M. Araújo, Marlene A. F. Bezerra

Volume: 22 - Issue: 9

Resumo. ABSTRACT Application of saline water causes water and salt stress, changing the behavior of the plants. The aim of this work was to evaluate the accumulation and allocation of biomass in sugar-apple seedlings under frequencies of irrigation with saline water in a substrate with soil conditioner, as well as the effect of container volume. The treatments were obtained from the arrangement between polymer doses (0, 0.2, 0.6, 1.0 and 1.2 g dm-3) and electrical conductivity of irrigation water (0.3; 1.1; 2.7; 4.3 and 5.0 dS m-1), associated with irrigation frequencies (daily and alternated), plus two additional treatments to evaluate container volume (0.75 and 1.30 dm3), distributed in blocks. The evaluations were performed at 120 days after sowing. Irrigation frequency affected the variables, and the highest values were obtained with daily irrigation, except for root/shoot dry matter ratio. Increase in the electrical conductivity of the irrigation water inhibited biomass accumulation. The effect of the container was significant for daily irrigation; higher volume led to higher root, shoot and total biomass. Polymer doses did not affect the biomass of the seedlings. Daily irrigation with non-saline water favored biomass production in sugar-apple seedlings. In the production of sugar-apple seedlings, water with electrical conductivity below 1.0 dS m-1 should be used on a daily frequency of application in 1.30 dm3 containers.

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Gas exchanges and photochemical efficiency of West Indian cherry cultivated with saline water and potassium fertilization - (2025)

Adaan S. Dias, Geovani S. de Lima, Francisco V. da S. Sá, Hans R. Gheyi, Lauriane A. dos A. Soares, Pedro D. Fernandes

Volume: 22 - Issue: 9

Resumo. ABSTRACT The problem of the lack of adequate water resources for agriculture has intensified in recent years, making it necessary to use waters with relatively high concentration of salts for the irrigation of crops all over the world. The objective of this study was to evaluate the influence of potassium (K) fertilization as a salt stress attenuator on gas exchanges and photochemical efficiency of West Indian cherry. The crop was cultivated under greenhouse conditions in the municipality of Campina Grande, PB, in lysimeters filled with 250 kg of sandy loam soil. Treatments were distributed in randomized blocks, in a 2 x 4 factorial scheme, with two levels of electrical conductivity of irrigation water - ECw (0.8 and 3.8 dS m-1) and four K doses (50, 75, 100 and 125% of recommendation), in which the dose corresponding to 100% was equal to 19.8 g of K2O, with three replicates and one plant per repetition. Seedlings of the West Indian cherry cultivar BRS 366-Jaburu, grafted onto a locally developed rootstock from the clonal garden of the EMBRAPA Tropical Agroindustry, Pacajus, CE, were used. Irrigation with salinized water (electrical conductivity of 3.8 dS m-1) compromised the gas exchange and the photochemical efficiency of West Indian cherry plants. Potassium fertilization was not efficient at reducing the stress caused by water salinity on West Indian cherry plants.

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Weed interference in the initial growth of meristem-grown sugarcane plantlets - (2025)

Ricardo J. de Paula, Clara D. Esposti, Carlos R. de Toffoli, Phelippe S. H. Ferreira

Volume: 22 - Issue: 9

Resumo. ABSTRACT The use of new systems of sugarcane planting such as PleneTM, Plene EvolveTM, Plene PBTM and AgMusaTM requires specific studies on the initial interference of weed in the sugarcane crop. The objective of this study was to evaluate initial weed interference in meristem-grown sugarcane plantlets (Plene EvolveTM). The weed species used were Brachiaria decumbens and Panicum maximum, at four different densities (1, 2, 3 and 4 weed plants pot-1), plus a control treatment free from weed interference. The statistical design was completely randomized with four replicates per treatment, with an individual study for each weed species. The evaluations performed were: plant height at 45, 60 and 90 days after emergence (DAE), number of sugarcane tillers at 30, 60 and 90 DAE and dry matter of both sugarcane and weed plants at 90 DAE. B. decumbens and P. maximum caused reductions in the initial growth and development of sugarcane. P. maximum was more aggressive to meristem-grown sugarcane plants, during their early development, than B. decumbens.

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Effective diffusivity in yacon potato cylinders during drying - (2025)

Cícera G. C. de Lisboa, Josivanda P. Gomes, Rossana M. F. de Figueirêdo, Alexandre J. de M. Queiroz, Adelino de M. G. Diógenes, João C. S. de Melo

Volume: 22 - Issue: 8

Resumo. ABSTRACT The aim of this study was to obtain the effective diffusivity of yacon potato in fixed-bed dryer at different temperatures (50, 60 and 70 ºC) and drying air velocities (1.0, 1.5 and 2.0 m s-1). Non-linear regression analysis was performed by the Quasi-Newton method using the program Statistica 7.0, where the parameters of the models were estimated as a function of the drying air temperature. Approximation of Diffusion, Two Terms, Henderson & Pabis, and Page models fitted well the experimental data. Drying air temperature and speed influenced the drying time of the samples. The effective diffusivity increased with increasing temperature, ranging from 1.18 x 10-9 to 2.15 x 10-9 m2 s-1.

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Evidence of nitrogen and potassium losses in soil columns cultivated with maize under salt stress - (2025)

Claudivan F. de Lacerda, Jorge F. da S. Ferreira, Donald L. Suarez, Emanuel D. Freitas, Xuan Liu, Aureliano de A. Ribeiro

Volume: 22 - Issue: 8

Resumo. ABSTRACT The aim of this study was to evaluate the accumulation of salts in the soil from irrigation water and of N and K from fertilization. The experiment was conducted in PVC columns (20 cm in diameter and 100 cm in height), filled with non-saline soil, and cultivated with maize. A completely randomized block design in a 4 x 4 factorial was used, with four levels of salinity (0.5, 2.5, 5.0 and 7.5 dS m-1), four N rates, and five replicates. Nitrogen was applied as urea and potassium nitrate at the following rates: N1: N recommendation for maize (2.6 g column-1); N2: 0.3 times (0.78 g column-1) the recommended N1 dose; N3 and N4 with N based on N1 and N2 doses, respectively, reduced proportionally based on the evapotranspiration reduction caused by salinity. After 74 days from sowing, root and soil samples were collected at different soil depths. The electrical conductivity of the saturated extract (ECe) and the concentration of ions (Ca2+, Na+, and Cl-) increased as a function of salinity and soil depth. The opposite was observed for the root system. The increase in salinity also resulted in K+ and NO3- accumulation in the soil column, mainly in treatments with higher N rates (N1 and N3). At the end of the experiment, 88% of the NO3- applied at the highest salinity treatment (7.5 dS m-1) and the highest N rate (N1) was below 20 cm soil depth, evidencing a N loss process caused by leaching.

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Yield of lettuce grown in hydroponic and aquaponic systems using different substrates - (2025)

Rodrigo A. Jordan, Evaldo F. Ribeiro, Fabricio C. de Oliveira, Luciano O. Geisenhoff, Elton A. S. Martins

Volume: 22 - Issue: 8

Resumo. ABSTRACT This study had as objective to evaluate the effect of the substrate on the yield of lettuce grown in aquaponic and hydroponic systems. The study was conducted at the Federal University of Grande Dourados, located in Dourados, MS. A randomized complete block design was used, with three treatments and 16 replicates. The cultivation systems were analyzed independently. The substrates analyzed were: coconut shell fiber, phenolic foam and expanded vermiculite. The plants were grown in two systems (aquaponic and hydroponic), using the NFT (Nutrient Film Technique) system. The crop used was lettuce cv. ‘Alcione’. The parameters analyzed were: crop yield and percentage of roots per plant. In addition, macronutrient contents were analyzed in the leaves. The substrate composed of coconut shell fiber was more suitable for lettuce production, since it led to higher yields for both aquaponic (2.88 kg m-2) and hydroponic (2.58 kg m-2) systems. The use of phenolic foam as growing substrate led to lower mean crop yields in both production systems analyzed, 1.94 and 2.15 kg m-2 for aquaponic and hydroponic systems, respectively.

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Economically optimal water depth and grain yield of common bean subjected to different irrigation depths - (2025)

Chaiane G. da Conceição, Adroaldo D. Robaina, Marcia X. Peiter, Ana R. C. Parizi, João A. da Conceição, Jhosefe Bruning

Volume: 22 - Issue: 7

Resumo. ABSTRACT Common bean crop plays an important role in the world, not only in economic aspects but also in social development. The objective of this study was to evaluate the grain yield and the economically optimal water depth which reflects the maximum technical efficiency of the common bean crop. The experiment was conducted in greenhouse, in Alegrete - RS, from February to May 2016. A completely randomized design was used, consisting of five water replacement treatments (25, 50, 75, 100 and 125% crop evapotranspiration - ETc) and four replicates. Based on the obtained results, both water deficit and water excess directly affected the final grain yield of the crop. Maximum grain yield was 3,554.1 kg ha-1, obtained by applying 492.72 mm (100% ETc). On the other hand, the economically optimal water depth was estimated at 91.2% ETc, indicating that water depths above this value are not suitable for maximum technical efficiency in the common bean crop under these conditions. It was concluded that the water depth equivalent to 100% ETc maximizes grain yield for the region of Alegrete-RS, and irrigation is considered a solution in the water supply to the common bean crop during critical periods.

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Salt balance in substrate cultivated with ‘Sunki’ mandarin x ‘Swingle’ citrumelo hybrids - (2025)

Juliana F. Almeida, Giuliana N. B. Sales, Marcos E. B. Brito, Pedro D. Fernandes, Walter S. Soares Filho, Isidro P. Almeida Neto

Volume: 22 - Issue: 7

Resumo. ABSTRACT During initial plant development stage, an experiment was conducted to evaluate the balance of salts in the substrate used for the production of 10 hybrids from the cross between ‘Sunki’ mandarin (TSKC) and ‘Swingle’ citrumelo (CTSW), all with potential to be used as rootstock. ‘Rangpur Santa Cruz’ lime, ‘Sunki Tropical’ mandarin and the hybrid LVK (‘Volkamer’ lemon) x LCR (‘Rangpur’ lime) - 038 were included as controls, totaling 13 genotypes. Substrate samples were collected in the experiment conducted in a greenhouse at the Federal University of Campina Grande, Campus of Pombal, from December 2015 to June 2016. Two levels of irrigation water salinity were tested, using a 2 x 13 factorial scheme, with 4 replicates. The substrate was a mixture of vermiculite, pine bark and humus (1:1:1). For the salinity level of 3 dS m-1, the substrate is less salinized when cultivated with the hybrids TSKC x CTSW - 044, TSKC x CTSW - 045, TSKC x CTSW - 048, TSKC x CTSW - 049 and ‘Rangpur Santa Cruz’ lime. On the other hand, highest salt concentration was obtained in the substrate cultivated with TSKC x CTSW - 042, TSKC x CTSW - 047, TSKC x CTSW - 048, TSKC x CTSW - 053, TSKC x CTSW - 055 and TSKC x CTSW - 057.

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Structural static and modal frequency simulations in a coffee harvester’s chassis - (2025)

Evandro P. da Silva, Fábio M. da Silva, Ednilton T. de Andrade, Ricardo R. Magalhães

Volume: 22 - Issue: 7

Resumo. ABSTRACT Coffee harvesters are subject to stresses and vibrations in their structure, originating from engines and harvesting system. These structures must be designed to avoid rupturing of the components due to fragility of the materials, inadequate geometries, or the phenomenon of resonance, which increases the displacements/deformations of the components. In this scenario, the main objective of this study is to analyse the results of stresses and displacements from two static simulations and to present results of natural vibration frequencies from two modal simulations in a self-propelled coffee harvester. For this purpose, 20 modal shapes were generated, considering coffee harvester reservoir as empty and full. The simulations were carried out using the finite element method in which actual boundary conditions were applied to the motor chassis of the harvester. As results, stresses above the material’s yield strength were observed in some regions of the components. Greater displacements were observed at the rear of the chassis, suggesting a new positioning of the rear wheel to obtain a uniform load distribution. Some natural frequencies, which presented greater displacements/deformations, can be affected by the operation of the main motor, also associated with the vibrating system in the coffee harvest, which may cause rupture of components.

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Genetic fuzzy system for prediction of respiratory rate of chicks subject to thermal challenges - (2025)

Patrícia F. P. Ferraz, Tadayuki Yanagi Junior, Yamid F. Hernandez-Julio, Gabriel A. e S. Ferraz, Maria A. J. G. Silva, Flavio A. Damasceno

Volume: 22 - Issue: 6

Resumo. ABSTRACT The aim of this study was to estimate and compare the respiratory rate (breath min-1) of broiler chicks subjected to different heat intensities and exposure durations for the first week of life using a Fuzzy Inference System and a Genetic Fuzzy Rule Based System. The experiment was conducted in four environmentally controlled wind tunnels and using 210 chicks. The Fuzzy Inference System was structured based on two input variables: duration of thermal exposure (in days) and dry bulb temperature (°C), and the output variable was respiratory rate. The Genetic Fuzzy Rule Based System set the parameters of input and output variables of the Fuzzy Inference System model in order to increase the prediction accuracy of the respiratory rate values. The two systems (Fuzzy Inference System and Genetic Fuzzy Rule Based System) proved to be able to predict the respiratory rate of chicks. The Genetic Fuzzy Rule Based System interacted well with the Fuzzy Inference System model previously developed showing an improvement in the respiratory rate prediction accuracy. The Fuzzy Inference System had mean percentage error of 2.77, and for Fuzzy Inference System and Genetic Fuzzy Rule Based System it was 0.87, thus indicating an improvement in the accuracy of prediction of respiratory rate when using the tool of genetic algorithms.

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Germination and tolerance of cowpea (Vigna unguiculata) cultivars to water stress - (2025)

Emanoela P. de Paiva, Francisco V. da S. Sá, Salvador B. Torres, Marcos E. B. Brito, Romulo C. L. Moreira, Luderlândio de A. Silva

Volume: 22 - Issue: 6

Resumo. ABSTRACT The objective of this study was to evaluate the tolerance of cowpea cultivars to water stress, during seed germination and seedling establishment. For this, a completely randomized experimental design was used in a factorial scheme consisting of nine cultivars of cowpea (BRS Guariba, BRS Potengi, BRS Itaim, BRS 17 Gurguéia, BRS Aracê, Paulistinha, Maratanã, Costela-de-Vaca and Canapu-Branco) and two levels of osmotic potential induced by PEG 6000 (0.0 MPa (control) and -0.4 MPa) in four replicates of 50 seeds. The variables analysed were germination, germination first count, root and shoot lengths, and dry matter accumulation of shoots and roots. The dissimilarity between the genotypes was also determined by Euclidean distance. Germination and initial development of cowpea cultivars are impaired by the reduction in the potential to -0.4 MPa. The cultivars BRS Guariba, BRS Aracê, Paulistinha and Canapu-Branco are the most tolerant to water stress, while BRS Potengi, BRS Itaim, BRS 17 Gurguéia, BRS Maratanã and Costela-de-Vaca are the most sensitive in the early development stage.

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Contamination of soil and pineapple fruits under fertilization with sewage sludge - (2025)

Mauro F. C. Mota, Rodinei F. Pegoraro, Silvânio R. dos Santos, Victor M. Maia, Regynaldo A. Sampaio, Marcos K. Kondo

Volume: 22 - Issue: 5

Resumo. ABSTRACT Sewage sludge is rich in organic matter and nutrients for the plants, and can be used in pineapple production, but there are few studies with scientific evaluation of possible inorganic and biological contaminants in pineapple plantations. In view of the above, this study aimed to evaluate the contamination of the soil and in fruits of pineapple fertilized with sewage sludge. The study was conducted in the municipality of Janaúba-MG. Treatments were arranged in a randomized block design, with four replicates, in a 2 x 5 factorial scheme, consisting of two different fertilizers: sewage sludge (SS) and mineral fertilizers (MF), and five pineapple varieties (Pérola, Vitória, Smooth Cayenne, MD-2, Fantastic IAC). Nitrogen was adopted as the base element to calculate the sewage sludge dose in the pineapple crop. Fertilization with sewage sludge increased the Zn and Cu contents in the soil and the Zn content in the leaves of the pineapple plants. Sewage sludge did not change the contents of As, Pb, Ba, Cu and Zn in the fruit, and Cr, Ni and Cd contents were not detected by the method used. Pineapple fruits did not show microbiological contamination above the limits established by the Brazilian legislation.

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Prediction of ‘Gigante’ cactus pear yield by morphological characters and artificial neural networks - (2025)

Bruno V. C. Guimarães, Sérgio L. R. Donato, Alcinei M. Azevedo, Ignacio Aspiazú, Ancilon A. e Silva Junior

Volume: 22 - Issue: 5

Resumo. ABSTRACT Estimating cactus pear yield is important for the planning of small and medium rural producers, especially in environments with adverse climatic conditions, such as the Brazilian semi-arid region. The objective of this study was to evaluate the potential of artificial neural networks (ANN) for predicting yield of ‘Gigante’ cactus pear, and determine the most important morphological characters for this prediction. The experiment was conducted in the Instituto Federal Baiano, Guanambi campus, Bahia, Brazil, in 2009 to 2011. The area used is located at 14° 13’ 30” S and 42° 46’ 53” W, and its altitude is 525 m. Six vegetative agronomic characters were evaluated in 500 plants in the third production cycle. The data were subjected to ANN analysis using the R software. Ten network architectures were trained 100 times to select the one with the lowest mean square error for the validation data. The networks with five neurons in the middle layer presented the best results. Neural networks with coefficient of determination (R2) of 0.87 were adjusted for sample validation, assuring the generalization potential of the model. The morphological characters with the highest relative contribution to yield estimate were total cladode area, plant height, cladode thickness and cladode length, but all characters were important for predicting the cactus pear yield. Therefore, predicting the production of cactus pear with high precision using ANN and morphological characters is possible.

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Hydropriming as inducer of salinity tolerance in sunflower seeds - (2025)

Janete R. Matias, Salvador B. Torres, Caio C. P. Leal, Moadir de S. Leite, Sara M. C. Carvalho

Volume: 22 - Issue: 4

Resumo. ABSTRACT Sunflower is a species with multiple potentialities and its yield can be affected by the presence of soluble salts in the soil, which is common in arid, semi-arid and irrigated regions. The objective of this study was to evaluate the effect of hydropriming as inducer of salinity tolerance in seeds and seedlings of sunflower, hybrid MG305CP. The germination tests were set with four replicates of 50 seeds per treatment, maintained in germinator at 30 ºC for ten days. To simulate salinity, sodium chloride diluted in distilled water was used at electrical conductivities of 0 (control), 4, 8, 12 and 16 dS m-1. On the tenth day, the number of normal seedlings was counted and the length and dry matter of shoots and roots were determined. Seedling fresh matter was used to determine the contents of total chlorophyll, total soluble sugars and proline. The experimental design was completely randomized, in a 2 x 5 factorial scheme (with and without hydropriming and five levels of salinity). Hydroprimed sunflower seeds showed greater vigor expression, with higher number of normal seedlings and faster germination.

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Ozone saturation and decomposition kinetics in porous medium containing different hybrids of maize - (2025)

Jefferson V. da S. Souza, Ernandes R. de Alencar, Ana M. R. Junqueira, Gustavo P. de Oliveira

Volume: 22 - Issue: 4

Resumo. ABSTRACT The objective of this study was to evaluate ozone saturation and decomposition kinetics in porous medium containing grains of different hybrids of maize. The following hybrids were used: common maize hybrid AG 1051, super sweet maize hybrids Tropical Plus, GSS 42072, GSS 41499 and GSS 41243. 1 kg grain samples with water contents of 13.0% (w.b.) were placed in glass containers with 3.25 L capacity. The grains were ozonized at the concentration of 1.28 mg L-1, at 25 ºC, with gas flow rate of 5.0 L min-1. Saturation time and concentration, half-life time and physical properties such as apparent specific weight, actual specific weight, porosity, sphericity and circularity of each maize hybrid were determined. The experiments were conducted in a completely randomized design with three replicates, using regression analysis of the data. Ozone saturation times remained between 6.6 and 163.9 min, with saturation concentration varying from 0.34 to 1.12 mg L-1. As for the ozone half-life time, the highest value was 10.5 min for the common maize hybrid AG 1051 and the lowest value was 0.14 min for the super sweet maize hybrid GSS 41499. It was concluded that ozone saturation and decomposition kinetics in maize depends on the hybrid contained in the porous medium. Ozone decomposition is faster in porous medium containing super sweet maize hybrids compared with the common maize hybrid.

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Strategies for fertilization with pig and cattle slurry in wheat crop - (2025)

Júnior M. Damian, Dionei S. Muraro, Claudir J. Basso, Alieze N. da Silva, Marlo A. B. Pinto, Antônio L. Santi

Volume: 22 - Issue: 4

Resumo. ABSTRACT This study aimed to evaluate the effect of different managements with pig slurry (PS) and cattle slurry (CS) on wheat dry matter and grain yields, and the potential to estimate this variation with the NDVI (normalized difference vegetation index) and NDRE (normalized difference red edge index) vegetation indices. The experiment was conducted in Frederico Westphalen-RS, Brazil, in a randomized block experimental design, in a 2 x 7 factorial scheme with four replicates and seven forms of surface and subsurface application, with and without the use of the dicyandiamide (DCD) nitrification inhibitor, distributed as follows: control without application of slurry and DCD; control without application of slurry and DCD, but scarified only with the injection machine; surface application; surface application with DCD; subsurface injection; subsurface injection with DCD; and application of NPK in mineral form. At flowering of the wheat crop, dry matter was collected and readings of NDVI and NDRE were taken, and finally grain yield was quantified. For PS and CS, best results of dry matter and grain yields were found in managements with subsurface injection and subsurface injection with DCD, respectively. Among the vegetation indices, only NDVI was efficient to estimate variations in the management using CS for wheat dry matter and grain yields.

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Agronomic characteristics of common bean and castor bean hybrids in intercropping and monocropping - (2025)

Cristiane F. Lisboa, Deyner D. A. Silva, Itamar R. Teixeira, Alessandro G. da Silva, José H. Mota

Volume: 22 - Issue: 3

Resumo. ABSTRACT Common bean has great importance in the Brazilian economy and castor bean is still emerging in Midwestern Brazil, but with great potential of exploitation by farmers due to the prevailing climatic conditions and flat topography. Hence, this study aimed to evaluate the agronomic characteristics of common bean cultivars and castor bean hybrids in intercropping and monocropping under the edaphoclimatic conditions of the Cerrado region. The randomized block design was used in 4 x 2 + 6 factorial scheme, with three replicates. Treatments were composed of four cultivars of common beans (BRS Pérola, BRS Esteio, BRSMG Realce and BRS Pitanga) intercropped with two castor bean hybrids (Tamar and Ag Ima), plus the respective crops in monocropping. In common bean cultivars, plant height was influenced in the intercropping with castor bean hybrids; however, agronomic characteristics of the castor bean hybrids were not influenced by common bean cultivars. The intercropping between common bean cultivars (BRS Esteio, BRSMG Realce and BRS Pitanga) and castor bean hybrids (Tamar and Ag Ima) was classified as viable by the area equivalence index, since this index presented values greater than 1.0 for the intercropping between these cultivars. This fact indicates that it would take more than one hectare in monocropping to produce the same amount than one hectare in intercropping.

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Growth and yield of sugarcane irrigated with brackish water and leaching fractions - (2025)

Raquele M. de Lira, Ênio F. de F. e Silva, Djalma E. Simões Neto, José A. Santos Júnior, Breno L. de C. Lima, Jucicléia S. da Silva

Volume: 22 - Issue: 3

Resumo. ABSTRACT The objective was to evaluate the growth and yield of sugarcane irrigated with brackish water and leaching fractions. A completely randomized experimental design was used, in a 5 x 2 factorial scheme, with four replicates. The treatments consisted of five irrigation water salinity levels (0.5, 2.0, 3.5, 5.0 and 6.5 dS m-1) and two leaching fractions (0 and 0.17), corresponding to 100 and 120% of the crop evapotranspiration. The irrigation management was performed daily. Irrigation water salinity levels were obtained by adding NaCl and CaCl2 to the public-supply water, in order to obtain a molar ratio between Na:Ca of 1:1. The following measurements were taken: height and stem diameter; number of tillers; number of leaves and leaf area with monthly frequency between 60 and 300 days after planting (DAP). It was concluded that irrigation water salinity negatively influenced the variables of growth and yield in the sugarcane, and the leaching fraction of 0.17 was capable of reducing the deleterious effects of the salts on the plants.

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Soybean agronomic performance in response to seeding rate and phosphate and potassium fertilization - (2025)

André S. Ferreira, Alvadi A. Balbinot Junior, Flávia Werner, Júlio C. Franchini, Claudemir Zucareli

Volume: 22 - Issue: 3

Resumo. ABSTRACT Most studies that found soybean high phenotypic plasticity under different seeding rates adopted the same fertilization levels used for the recommended seeding rates. Therefore, the interaction between these factors is little known. This study aims to assess the interaction between seeding rate and levels of phosphorus and potassium fertilization on soybean growth, grain yield and contents of protein and oil in the grains. The experiment was carried out under a randomized complete block design, in a split-plot scheme, with six replicates. Four seeding rates (150, 300, 440 and 560 thousand viable seeds ha-1) were used in the plots, and two levels of phosphorus and potassium fertilizer were applied in the subplots to meet the export of 3 and 6 t ha-1 of grains (level 1 = 30 kg ha-1 of P2O5 + 60 kg ha-1 of K2O; and level 2 = 60 kg ha-1 of P2O5 + 120 kg ha-1 of K2O). There was no interaction between the experimental factors. Increase in fertilizer doses did not alter the evaluated characteristics, regardless of the seeding rate. Seeding rate did not change grain yield or protein and oil contents, but at low densities there was an increase in the number of pods per plant, apparent harvest index and SPAD index.

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Spatial-temporal variability of leaf chlorophyll and its relationship with cocoa yield - (2025)

Caique C. Medauar, Ícaro M. Galvão, Luis C. C. Carvalho, Samuel de A. Silva

Volume: 22 - Issue: 3

Resumo. ABSTRACT The objective of this study was to evaluate the spatial-temporal variability of leaf chlorophyll index and its relationship with cocoa yield. The experiment was carried out in an experimental area of cocoa production located in Ilhéus, Bahia State, Brazil. Leaf chlorophyll content was measured in September, October, January, February, March and April in the 2014/2015 season, at each sampling point of a regular grid by using a portable chlorophyll meter. Under the same conditions, yield was evaluated and the data were submitted to descriptive statistics and a linear correlation study. Geostatistical analysis was used to determine and quantify the spatial and temporal variability of leaf chlorophyll index and yield. Leaf chlorophyll index varied over the period evaluated, but the months of February, March and April showed no spatial dependence in the study area, indicating absence of temporal stability. Cocoa monthly yield, except in January, presented high spatial variability. Under the conditions of this study, it was not possible to establish a relationship between leaf chlorophyll index and cocoa yield.

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Nitrogen and phosphorus fertilization of sunflower crop in alkaline Cambisol - (2025)

Daniely F. Braga, Fabio H. T. de Oliveira, Hemmannuella C. Santos, Adelson P. Araújo, Everaldo Zonta

Volume: 22 - Issue: 2

Resumo. ABSTRACT Sunflower is a crop that has aroused the interest of farmers because of its adaptability to wide climatic conditions and for its use in biodiesel production. However, there are only a few studies on sunflower fertilization in alkaline soils. This study aimed to evaluate nitrogen (N) and phosphorus (P) fertilization in sunflower (Helianthus annuus L.) cultivated in alkaline soil. A field experiment was carried out in Baraúnas-RN, Brazil, in a Haplic Cambisol derived from calcareous rock, where the sunflower H-251 hybrid was cultivated. The treatments were a combination of four doses of N (30, 60, 90 and 120 kg ha-1) and four doses of P2O5 (30, 60, 90 and 120 kg ha-1). Sunflower growth and yield increased with the doses of N and P2O5. Doses of 30 kg ha-1 of N and 30 kg ha-1 of P2O5 were more economical, corresponding to grain yield of 2378 kg ha-1. Critical levels associated with these doses of N and P2O5 were 28.2 g kg-1 for N leaf content, 2.84 for P leaf content, and 6.75 mg dm-3 for soil available P extracted by Mehlich-1.

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Systems and rates of aerial application of fungicides in irrigated rice - (2025)

Tânia Bayer, Milton F. Cabezas-Guerrero, Casimiro D. Gadanha Junior, Alci E. Loeck

Volume: 22 - Issue: 2

Resumo. ABSTRACT The present research studied the performance of flat-fan and hollow-cone nozzles, with application rates of 20 and 30 L ha-1, and rotary disc atomizer with application rates of 10 and 15 L ha-1. The test was conducted with a fungicide spray tank composed of Azoxystrobin + Difenoconazole, in which the density and penetration of droplets into the canopy were evaluated using a water-sensitive paper and the distribution of the active ingredients in the plant was evaluated through the chromatographic analysis. Higher application rates resulted in higher droplet density in the upper stratum of plants. In all treatments, the penetration of the droplets was 26% into the middle stratum and 23% into the lower stratum, in relation to the top of the crop, resulting in an average 25% penetration of droplets into the leaf canopy. The active ingredients were distributed in greater quantity in the upper stratum of the plant. For the same weight, the upper part of the ‘Puitá Inta CL’ rice cultivar has a leaf area 6.4 times larger than the lower part. It was concluded that higher application rate leads to higher droplet density in the upper stratum of the leaf canopy and that all systems and application rates promoted similar penetration of droplets into the canopy.

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Hydraulic performance of drippers with different waters and lateral line slopes - (2025)

Flavio D. Szekut, Carlos A. V. de Azevedo, Marcio A. V. Boas, Thiago Zuculotto

Volume: 22 - Issue: 12

Resumo. ABSTRACT The operation of drip lateral lines is affected by the topography of the irrigated area and represent, depending on the type of water applied, changes in the discharge characteristics of the emitters. The research had as objective to evaluate the hydraulic performance of built-in labyrinth drippers, non-pressure compensating, with different waters and slopes of the lateral lines. The experiment was carried out on a test bench and consisted of a randomized block design with split-plots: first factor with four types of water, representing the plots: clean water, water with fertilizers, cassava starch wastewater and poultry slaughterhouse wastewater; second factor with slopes of the lateral line, constituting the sub-plots: upslope, level and downslope. The experimental statistics consisted of analysis of variance with subsequent simple-effect analysis and Tukey test at 0.05 probability level to compare the means of dripper flow rates. Quality control statistics was performed using Shewhart’s control charts with interpretations based on upper and lower control limits, as well as non-random pattern recognition. Waters of inferior quality modified the flow rates of the tested drippers regardless of the variation of internal pressure caused by the slope of the lateral line. Water with fertilizer (300 mg L-1) obtained the best conditions of temporal irrigation quality verified by the control charts. Irrigation with poultry slaughterhouse wastewater obtained the same flow rates in all slopes. Cassava starch wastewater caused the lowest flow rates among all the waters.

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