Acessibilidade / Reportar erro
Engenharia Agrícola, Volume: 41, Número: 4, Publicado: 2021
  • USE OF PUPILLOMETRY IN THE DIAGNOSIS OF STRESS IN PIGLETS TRANSPORTED IN A TROPICAL CLIMATE Scientific Papers

    Machado, Nítalo A. F.; Barbosa-Filho, José A. D.; Souza-Junior, João B. F.; Ramalho, Geraldo L. B.; Parente, Michelle de O. M.

    Resumo em Inglês:

    ABSTRACT The objective of this study was to evaluate the reactivity of the pupillary area (PA) as a non-invasive method for diagnosing stress in piglets submitted to transport. A total of 10 journeys were monitored and grouped according to the transport distance (15 and 75 km). Were sampled 360 piglets (25±3.8 kg) to measure the PA, body temperature (BT), and serum concentrations of cortisol and creatine kinase (CK). The micrometeorological characterization of the load was performed using enthalpy comfort index (ECI). It was possible to identify an increase of 19.32% (+18.91 mm2; P< 0.001) in PA of piglets transported in shorter journeys (15 km), as well as the highest mean values of BT (+ 1.24 °C; P< 0.001), cortisol (+ 2.37 ng/mL; P< 0.001) and CK (+ 379 U/L; P= 0.025). In this study, high correlations of PA were observed with r = 0.922, 0.900, 0.842 and 0.829 ( P< 0.05) for cortisol and CK, BT and ECI of trailer, respectively. In conclusion, we state that PA reactivity is a physiological response for the diagnosis of stress of piglets transported. Further research will refine this technique in order to make this non-invasive acquisition method more practical and adaptable to different transport conditions.
  • USE OF BENCHES WITH REFLECTIVE MATERIAL TO FAVOR PRODUCTION OF RUBBER TREE ROOTSTOCK SEEDLINGS Scientific Papers

    Costa, Edilson; Silva, Bruna L. B. da; Aguiar, Franciele K. O. M.; Pereira, Talita C. C.; Binotti, Flávio F. da S.

    Resumo em Inglês:

    ABSTRACT Success in production of any perennial tree depends on the use of high-quality seedlings. This study aimed to evaluate cultivation benches with reflective material and protected environments for production of rubber tree rootstock seedlings. The experiments were conducted in two types of protected environments: 35% shading aluminized screen and 30% shading black screen. Cultivation benches with and without reflective material were tested inside the protected environments. A completely randomized design with 7 replications and 5 seedlings per plot was adopted for each environment, and the environments were compared by joint analysis. Solar radiation (global and photosynthetically active) was the most influencing micrometeorological factor on plant environment and plant growth differentiation. Regardless of the environment, the use of reflective material in cultivation bench had a positive effect on production of rubber rootstock seedling (clone GT1), providing seedlings with a robust root system and better quality. The use of reflective material also improved rubber tree rootstock seedlings (clone GT1) grown in the black screen environment.
  • FUZZY LOGIC MODELING OF THE OCULAR TEMPERATURE OF CATTLE IN THERMAL STRESS CONDITIONS Scientific Papers

    Lins, Ana C. de S. S.; Souza, Ingrid J. S.; Lourençoni, Dian; Yanagi Júnior, Tadayuki; Santos, Italo E. dos A.

    Resumo em Inglês:

    ABSTRACT This study proposes a fuzzy logic model capable of predicting the ocular temperature (OT) of beef cattle by means of infrared thermography. The goal of this study is to establish a methodology for making decisions related to animal welfare. The experiment was carried out at a commercial beef production farm, located in the south of Minas Gerais state, where twenty-eight Brahman cattle (Bos Taurus Indicus) raised in extensive production systems were evaluated. Thermal images of the entire head of the animal were collected in order to measure the ocular temperature (OT). Concurrently, the variables air dry bulb temperature (DBT) and relative humidity (RH) were recorded. The fuzzy logic model was developed using the Mandani inference method, based on the input variables DBT and RH and the output variable OT, and using the experimental data as reference. The proposed fuzzy logic system allows the estimation of the ocular temperature of beef cattle with an error of 1.71% and a coefficient of determination R 2 of 0.8749. These values validate the proposed fuzzy logic system for helping to make decisions for better animal welfare.
  • TRAILER HEAT ZONES AND THEIR RELATION TO HEAT STRESS IN PIG TRANSPORT Scientific Papers

    Machado, Nítalo A. F.; Barbosa-Filho, José A. D.; Ramalho, Geraldo L. B.; Pandorfi, Héliton; Silva, Iran J. O. Da

    Resumo em Inglês:

    ABSTRACT This study evaluates the dynamics of heat zones in the load and its relationship with the stress of pigs during transport. Four journeys of 170 km were monitored, recording the physiological variables of 192 animals (48 per journey), namely rectal temperature (RT), body temperature (BT), respiratory rate (RR), blood lactate concentrations and salivary cortisol. Heat zones and ventilation patterns were characterized by the spatial variability of the enthalpy and the Computational Fluid Dynamics of the load. The formation of a thermal core was observed in the frontal region of the load, which extended through the lower (LD) and upper (UD) decks. Pigs transported in the LD had higher means of RR (UD = 89 and LD = 94 breaths/min), and salivary cortisol (UD = 33.84 and LD = 34.92 ng/mL). The pigs transported in the UD presented the highest mean BT (UD = 38.9 and LD = 38.1 °C) and lactate (UD = 61.63 and LD = 58.26 mg/dL). Pigs transported in the LD of the load were more susceptible to thermal stress, while pigs transported in the UD showed greater physical stress and muscle exhaustion.
  • MATHEMATICAL MODELS FOR ESTIMATING METHANE PRODUCTION IN COVERED LAGOON BIODIGESTERS TREATING PIG MANURE Scientific Papers

    Lopes, Juciara O.; Rosa, André P.; Sousa, Izabelle de P.; Oliveira, Nathalia S.; Borges, Alisson C.

    Resumo em Inglês:

    ABSTRACT Covered lagoon biodigesters (CLB) have been widespread in Brazil in the treatment of pig manure. However, the quantification of biogas production in CLB using mathematical models is still limited and scarce. This study aimed to evaluate and compare six mathematical models—Chen-Hashimoto (Chen, 1983), CETESB (2006), COD Conversion (Chernicharo, 2016), IPCC (2006), Deng (Deng et al., 2014), and modified Stover-Kincannon (Yu et al., 1998)—usually used to estimate methane (CH 4 ), and propose improvements to the models, if necessary. The results were compared with the monitored production (P actual ) in a farm with CLB using the t-test (α = 5%). The Chen-Hashimoto, IPCC, Deng, and modified Stover-Kincannon models showed no statistical difference compared to P actual (405.0 m 3 CH 4 d −1 ), whereas the CETESB and COD Conversion models presented no statistical difference after the proposed improvements. All models can be considered reliable for estimating volumetric methane production after the adaptations, being relevant tools for diagnosis and decision-making regarding the energy recovery of biogas with CLB operation in pig farms.
  • INFLUENCE OF DROPLET SIZE ON SPRAY DEPOSITION AND WEED CONTROL USING GLYPHOSATE Scientific Papers

    Oliveira, Osmar G. T. M.; Lopes, Paulo R. M.; Raetano, Carlos G.; Lima, Ronaldo C.; Prado, Evandro P.

    Resumo em Inglês:

    ABSTRACT Droplet size is one of the most important factors that affect spray deposition and weed control through the use of herbicides. The aim of this study was to evaluate the influence of the droplet size on the spray deposition and control of Euphorbia heterophylla and Urochloa ruziziensis by using glyphosate. The treatments included spraying glyphosate with fine, medium, coarse, very coarse, and ultra-coarse droplet sizes to determine the deposition, uniformity of distribution, visual control, and dry weight reduction (DWR). The treatments were compared with the values of the dose required to achieve 50% DWR or 50% visual control (C50) at 7, 14, 21, and 28 days after herbicide application. Fine and medium droplet sizes afforded high deposition values and low distribution uniformities in E. heterophylla . Fine and medium droplet sizes yielded the lowest C50 on visual control and DWR in E. heterophylla, respectively. The droplet size did not affect the spray deposition on U. ruziziensis plants; however, the larger droplets had less uniformity of distribution. In U. ruziziensis plants, spraying glyphosate with coarse and medium droplet sizes yielded the lowest values of C50 to visual control and DWR, respectively.
  • MULTIVARIATE ANALYSIS APPLIED TO SPRAY DEPOSITION IN GROUND APPLICATION OF PHYTOSANITARY PRODUCTS IN COFFEE PLANTS Scientific Papers

    Palma, Roxanna P.; Cunha, João P. A. R. da; Guimarães, Ednaldo C.; Santana, Denise G. de; Assunção, Heli H. T. de

    Resumo em Inglês:

    ABSTRACT An adequate combination of factors involved in the technology used for phytosanitary product application contributes to an efficient spray deposition on the target. The objective of this study was to use multivariate analysis to characterize the magnitude of effects and the order of influence of three factors that interfere with the quality of phytosanitary product application in coffee plants. An entirely randomized design was adopted, with four repetitions, using a 2 × 2 × 3 factorial scheme, with two classes of droplets quality (fine and coarse), two application rates (250 and 400 L ha-1), and the use of adjuvants (with no adjuvant or with Fighter®and Aureo® adjuvants). The quality of the application was determined by jointly analyzing the spray deposition on three thirds of leaves, in their internal and external layers, the runoff to soil, coverage, droplet density, relative amplitude, and the volumetric median diameter. The results underwent analysis of variance (ANOVA) to measure the effect sizes (η2). After testing the assumptions of multivariate analysis, clustering and principal component analyses were performed. The class of droplets was found to be the most influential factor in the quality of the phytosanitary product application (spray deposition and runoff to soil). When focusing on spray deposition on leaves, the second-most influential factor was the application rate and the relation between the application rate and the adjuvants. For the other variables, the second-most influential factor was the application rate.
  • PATH ANALYSIS OF PHYSICAL ATTRIBUTES OF CHAYOTE FRUIT Scientific Papers

    Oliveira, Job T. de; Oliveira, Rubens A. de

    Resumo em Inglês:

    ABSTRACT Chayote is originally from southern Mexico and Guatemala and has been a staple food highly appreciated in Brazil and worldwide. This study was carried out on a Red Yellow Latosol in 2020 to investigate the relationship between the physical properties of chayote fruit of the variety Cambray and their mass, aiming to indicate criteria for direct selection of more attractive fruits. The fruit parameters evaluated were mass (MAS), largest transverse diameter (LTD), smallest transverse diameter (STD), length (FTL), volume (FTV), area (FTA), and perimeter (FTP), as well as seed area (SDA) and seed perimeter (SDP). Initially, correlations among these morphological variables were assessed by Pearson's correlation coefficient, and a correlation network was used to express the results graphically. A diagnosis of multicollinearity was performed, and a condition number of 6639 (multicollinearity severe) was found. Path analysis considered the fruit mass as the main dependent variable. Our analyses showed that MAS, FTV, FTA, FTP, and STD are physical attributes with the greatest potential for selection and identification of more attractive chayote fruits of the variety Cambray for commercial purposes.
  • PREDICTIVE MODELS OF CHLOROPHYLL CONTENT IN SUGARCANE SEEDLINGS USING SPECTRAL IMAGES Scientific Papers

    Oliveros, Nelson; Tinini, Rodolpho; Costa, Daniel dos S.; Ramos, Rodrigo; Wetterich, Caio; Teruel, Bárbara

    Resumo em Inglês:

    ABSTRACT Chlorophyll content is a widely used parameter for nutritional status diagnosis in sugarcane. This study aimed to develop a predictive model of chlorophyll content in sugarcane seedlings using spectral imagery analysis within the electromagnetic spectrum visible range. The experiment was carried out in a split-plot design, with two fertilization rates and three sugarcane cultivars. For chlorophyll analysis, 144 leaves were collected from seedlings. Chlorophyll contents were extracted and measured by SPAD-502 meter. Spectral images within the range of 480 to 710 nm were analyzed using reflectance, absorbance (white source), and fluorescence (source at 405 and 470 nm) responses. Predictive models were developed using multivariate regression methods such as Principal Component Regression and Partial Least Squares Regression. We chose the best model through absorbance response using variable selection and the PLSR method (R2P = 0.718 and RMSEP = 7.665). The wavelengths of 480, 490, 500, 600, 630, and 640 nm were identified as the best for total chlorophyll content determination. The spectral image processing-based method can provide a chlorophyll measurement equivalent to SPAD, with the advantage of having a higher spatial coverage over the entire leaf area. Besides, it can also support automation of the chlorophyll measurement in greenhouses.
  • ASSESSMENT OF SOIL LOSS SUSCEPTIBILITY IN SANTA RITA WATERSHED IN SOUTHERN BRAZIL Scientific Papers

    Zanchin, Mayara; Moura, Maíra M. de; Nunes, Maria C. M.; Tuchtenhagen, Ivana K.; Lima, Cláudia L. R. de

    Resumo em Inglês:

    ABSTRACT Estimation of soil loss susceptibility is of great importance for the management of watersheds. Thus, several models for soil loss prediction have been proposed. This study estimated the total annual soil loss for the Santa Rita watershed, located in southern Brazil, using the Revised Universal Soil Loss Equation. In addition, a classification to soil loss index (ISL) was proposed to identify regions with critical soil loss values. Altitude, slope, land use, and soil class data were applied to the model, in addition to spatial information for 78 soil samples collected within the study area. It was found that there is an average annual loss of 35.94 Mg ha-1 year-1, with the most substantial loss occurring in areas with predominantly exposed soil and annual cropping. Furthermore, the ISL values indicated that approximately 50% of the study area is experiencing erosion estimates above the tolerable limit. Results emphasize the need for changes in conservation and application practices present in the watershed, considering land use and soil bearing capacity.
Associação Brasileira de Engenharia Agrícola SBEA - Associação Brasileira de Engenharia Agrícola, Departamento de Engenharia e Ciências Exatas FCAV/UNESP, Prof. Paulo Donato Castellane, km 5, 14884.900 | Jaboticabal - SP, Tel./Fax: +55 16 3209 7619 - Jaboticabal - SP - Brazil
E-mail: revistasbea@sbea.org.br