Scielo RSS <![CDATA[Engenharia Agrícola]]> vol. 38 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[CHEMICAL AGENTS AND SHADING LEVELS FOR THE PRODUCTION OF PEPPER SEEDLINGS]]> ABSTRACT The aim of this study was to evaluate protected cultivation environments with different levels of shading and application of foliar chemical agents, on growth, photosynthetic pigments and seedling quality of Capsicum frutensens L. The experiment was developed at the State University of Mato Grosso do Sul, University Unit of Cassilândia, with chili pepper. Three cultivation environments (screen of 18, 35 and 50% of shading) and six leaf chemical agents were used [(1) control – without application; (2) Nitrogen (N) 1%; (3) Paclobutrazol 50 mg L-1 + N 1%; (4) Auxin 0.05 g L-1 + N 1%; (5) Gibberellin 0.05 g L-1 + N 1%; and (6) Auxin 0.05 g L-1 + Gibberellin 0.05 g L-1 + N 1%]. Each environment was considered an experiment in which the completely randomized design was adopted and, afterwards, a joint analysis of the same was carried out. The growth and the biometric relations were evaluated. The leaf nitrogen application positively influences the growth and chlorophyll content of pepper seedlings; the application of nitrogen + growth regulator via foliar produces seedlings with higher growth and biometric relations in environments with 50% shading. For the production of seedlings with desirable morphological and physiological aspects, it is recommended to use a foliar application of paclobutrazol + nitrogen in an environment with 50% shading. <![CDATA[ESTIMATION OF RESPIRATORY FREQUENCY AND RECTAL TEMPERATURE ON PIGS IN HEAT STRESS BY <em>FUZZY</em> LOGIC]]> ABSTRACT Physiological parameters such as respiratory frequency and rectal temperature stand out as indicators for heat stress in pigs, however, requiring time and labor for measurements. The possibility of using infrared thermography associated with prediction systems of these physiological variables can help in decision making, allowing greater welfare and productivity of the animals. With this objective, an experiment was carried out with growing pigs submitted to acute and chronic heat stress, working with a thermoneutrality temperature (22° C) and heat stress (34° C). The results were used for the development of a fuzzy model using as input variables: air dry bulb temperature (°C), average surface temperature (°C) and, as output variables: respiratory frequency (movements/minute) and rectal temperature (°C). The method of inference used was the one of Mamdani having been elaborated six rules and the defuzzification technique used was the one of the Center of Gravity. In the obtained results on simulation model when compared with experimental data was evidenced satisfactory efficiency in respiratory frequency determination and the rectal temperature, in which the R2 values calculated were respectively 0.997 and 0.951 for acute stress and 0.993 and 0.964 for chronic heat stress. <![CDATA[VALIDATION OF A HEATING SYSTEM IN THE FARROWING HOUSE USING A CFD APPROACH]]> ABSTRACT The current heating system for piglets in the farrowing usually uses incandescent lamps and, in some cases, heated floors with electric resistances, which in most cases generates a high energy cost. Thus, the implantation of systems that use renewable energies in the heating of piglets can allow the thermal comfort of the animals without reducing the productive development. The objective of this research was to evaluate a computer model in Computational Fluid Dynamics (CFD), which predicts surface temperature in the heating system of a farrowing house. The study was conducted during the summer season on the swine sector of Federal University of Lavras, Brazil. For this study, a prototype solar heater using alternative materials (ASWH) was developed and compared with a conventional solar water heater (CSWH). Two floors were built of cement to test both heating systems and four thermocouple sensors (K type) with digital display were used in each system to test and evaluate the heating efficiency. Based on the results, the average surface temperature in the ASWH and the CSWH treatments was 27.9 ± 2.6 °C and 27.1 ± 1.9 °C, respectively. Therefore, the experimental data showed no significant differences from the data obtained by the model, enabling the conclusion that it is suitable for predicting the thermal conditions of this type of heating system and could be used in swine factories to predict energy consumption. Thus, this computational model can be used as a useful tool for the design and selection of heating systems used in swine maternity systems. <![CDATA[MORTALITY, PRODUCTION AND QUALITY OF EGGS OF DIFFERENT REARING SYSTEMS]]> ABSTRACT The conventional production of eggs in cage systems is intense and compromises the laying hens welfare. More demanding consumer markets have been pushing to abolish the use of cages and thus provide better welfare in poultry laying. This research evaluated the mortality, production, and egg quality of two alternative production systems (free-range and organic free range free-range) and compared them with the conventional system. The research was carried out in two commercial poultry farms and the variables egg weight, shell egg resistance, Haugh unit, mortality and production were recorded during eight months. The results showed that the conventional system presented better production, lower mortality and better shell egg quality. The alternative systems had better internal egg quality. Alternative systems had greater variability in outcomes and problems with disease control, which indicate greater difficulty for proper management. <![CDATA[THE USE OF VOCALIZATION SIGNALS TO ESTIMATE THE LEVEL OF PAIN IN PIGLETS]]> ABSTRACT Pain is considered a condition that most affect the welfare of animals and its measurement is seen as a difficult task. This research aimed to determine the level of pain in pigs by their vocalization. It was recorded the vocalizations of 20 male piglets under normal circumstances (I), marking by Australian method (II), tail trimming management (III), and castration (IV). A unidirectional microphone and a digital recorder were used to record the sound signals. The results suggested that Pitch frequency (Hz), the maximum amplitude (Pa), and intensity (dB) increased from pain-free pigs to the marking procedure; and from marking to both tail trimming and castration The tail trimming and castration vocal response did not differ. <![CDATA[DEVELOPMENT OF AN EQUIPMENT TO OBTAIN THE RELATION BETWEEN THE HORIZONTAL AND VERTICAL PRESSURE IN SILOS]]> ABSTRACT Silos are essential for sectors such as agriculture, industry, and mining in Brazil, but they are structures with a high degree of complexity in relation to pressure determination. Therefore, new researches on the influence of the product stored in their structure are stimulated. For granular materials, the K coefficient is the factor obtained between the horizontal and the vertical pressure. This study aimed to develop a test device capable of calculating this coefficient based on the recommendations of EN 1991-4 (2006) (Eurocode 1: Actions on structures – Part 4: Silos and tanks). For that, two cylinders of different heights were elaborated to study the influence of the device height in obtaining K coefficient. The results were measured by strain gauges and load cell connected to a data acquisition system. A vertical pressure was applied to the equipment, which responded with values of deformation correlated to the horizontal pressure. The values of K coefficient for corn were found and compared with those from the literature, concluding that the equipment could be used for the proposed purpose. <![CDATA[VERTICAL PRESSURES AND COMPRESSIVE FRICTION FORCE IN A LARGE SILO]]> ABSTRACT The grain flow is a dynamic phenomenon of high non-linearity, responsible for the occurrence of a high index of structural problems in silos, assuming particular interest in Brazil because the country does not have a standard of design of these structures. In order to determine the transfer of loads to the foundations, a silo in true magnitude was instrumented through pressure cells in the reinforced concrete slab of the bottom and through load cells under two of its column. The experiment was conducted during the period from December 2016 to February 2017 in Entre Rios do Oeste-PR. The profiles of vertical and the compression friction pressures were obtained during the loading, storage and unloading phases of corn grains. The vertical pressure distribution in the silo bottom was shown to be variable along its radius, in accordance with the formulation of the AS 3774 standard, an alternative to the simplified uniform distribution hypothesis prescribed by the EN 1991-4 and ANSI/ASAE EP433 standards. We also observed experimentally the non-occurrence of overpressure at the unloading of the silo under analysis. The load transfer coefficient to the column was 0.35, being that the ANSI/ASAE EP433, EN 1991-4 and AS 3774 standards increased this transfer by 6.57%, 35.91% and 75.03% respectively, reflecting the great divergence between these prescriptions. <![CDATA[PRODUCTION AND QUALITY OF JAPANESE QUAIL EGGS SUBMITTED TO ENVIRONMENTS WITH DIFFERENT LIGHT SPECTRUMS]]> ABSTRACT The aim of this research was to evaluate the performance of Japanese quail (Coturnix coturnix japonica), with 94 (+49) days of age, through the production and quality of the eggs, with the birds kept in environments illuminated with LED lamps in the colors white, blue and red. The experimental design was a completely randomized design with three treatments (lamp colors) and seven replications. In the three environments, the relative air temperature averages can be considered above the thermal comfort zone for quails; however, the black globe temperature index, humidity and the thermal radiation load can be considered comfortable. The laying percentage of the birds kept under white LED was inferior to those maintained in the red LED. The feed intake, the feed conversion, the average weight and the egg quality were not affected by the different lamp colors (P &lt;0.05) or by the climatic indexes that were within the average for the species, and these lamps could be used in the production of quail eggs. <![CDATA[MODELING AND TESTING OF AN ICE BANK FOR MILK COOLING AFTER MILKING]]> ABSTRACT Based on mass and energy balance equations and data collected in specialized bibliographies, it was proposed a methodology for modeling of an ice bank for thermal storage of energy at low temperature to be used in milk cooling. The data obtained by the equations arrangement were used in the design and installation of a real system, which was tested to collect data and to compare it with the estimated. The data obtained in terms of prediction of ice formation, temperature of the ice bank, water and capacity of the selected refrigeration system prove the adequacy of the equations arrangement, showing that it can be used as a tool for sizing solid ice bank in smooth pipe coils, with good approximation. <![CDATA[ELECTRICITY GENERATION FROM BIOGAS ON SWINE FARM CONSIDERING THE REGULATION OF DISTRIBUTED ENERGY GENERATION IN BRAZIL: A CASE STUDY FOR MINAS GERAIS]]> ABSTRACT The objective of this study was to analyze the feasibility of using agricultural waste from a swine farm to produce biogas, which can be used to generate electricity. For this purpose, the waste production potential was evaluated to determine the biogas production capacity of the farm. This measurement allowed scaling the size of the generator used to the electricity production to meet the needs of the farm as well as surplus electricity. The surplus electricity may be used on the farm when the generator is under maintenance or the electricity consumption is larger than the energy generated. This process is regulated by Normative Resolutions 482 and 687 in Brazil. The results of the analysis of the net present value, internal return rate, payback period and benefit cost ratio indicated that the project was feasible. <![CDATA[DAIRY CATTLE BIOGAS USAGE IN MICROTURBINES FOR ENERGY GENERATION AND THERMAL EXPLOITATION]]> ABSTRACT The increase in confined cattle breeding reflects the modernization and automation of farming, which has significantly intensified in recent years and caused an increase in the energy demand of rural properties. This study investigated the use of biogas generated from dairy cattle manure confined in gas microturbines on a farm to generate electricity and the energy use of exhaust gases. At the end of the study, 6,195 to 16,077 kWh month-1 of electricity was obtained, which corresponds to 43.3% of the property's self-sufficiency energy demand. By performing an exhaust gas energy exploitation, between 6.8 and 13.6 m3 day-1 of water heated to 368 K can be produced, or between 11,880 and 23,661 kWh month-1 of cooling capacity can be obtained using a liquid cooler. <![CDATA[THE PHOTOVOLTAIC ELECTRIFICATION IN ISOLATED COMMUNITIES OF CARDOSO ISLAND STATE PARK - SP]]> ABSTRACT This study concerns a research conducted in 2014, in isolated communities of Cambriú and Foles belonging to the Cardoso Island State Park-SP, in order to establish a link between electrification through isolated photovoltaic systems type SIGIFI 30 (30 kWh/month) with the existing demands, interactions and changes in traditional communities studied. The energy in this case is presented as a structure component to these demands regarding to the labor, agriculture, fishing, health, education, comfort of buildings and income generation. The objective was to conduct an analysis of the implementation of photovoltaic electrification process, and to establish a relationship with the surveyed communities. The results demonstrated that electrification provided benefits to the residents of the communities, but it only achieves real success if linked to other public policy instruments such as health, education and transportation that considered the diversities and peculiarities of these populations with regard to the strong isolation to which they belong. It was also noted that the training or technical assistance provided was not characterized as causing problems for residents, that in the majority did not present significant complaints to the management and the operation of the installed systems. <![CDATA[RETENTION CURVES AND AVAILABLE WATER CAPACITY IN LATOSOLS]]> ABSTRACT Water stored in the soil between field capacity and the permanent wilting point, is known as the available water capacity. Its availability to be effectively used by plants depends on the type of soil and its water retention characteristics. The aim of this work was to compile information about water retention curves in Latosols, and to provide a first approximation of values and most likely amplitudes for water storage and available water capacity of these soils. The database was constituted from information collected from articles, theses, dissertations and other publications. Soil water retention curves, as well as available water, were estimated for the order Latosols, and for the suborders Red Latosol (RL), Red-Yellow Latosol (RYL) and Yellow Latosol (YL). RL presented the lowest amplitude of water storage between field capacity and permanent wilting point, resulting in lower available water capacity compared to Yellow and Red-Yellow Latosols. YL presented the highest available water capacity among analyzed soils. <![CDATA[APPLICABILITY OF FINGERPRINTING FOR IDENTIFICATION OF SEDIMENT SOURCES IN A MESOSCALE SEMIARID CATCHMENT]]> ABSTRACT The study aimed at identifying sediment sources in a mesoscale catchment (933 km2) located in the Brazilian semiarid region. The research explored the potential of using a fingerprinting technique to verify the origin of eroded sediments in a catchment by comparing physical and mineralogical properties of potential sediment sources and sediments deposited in a pond (6 × 103 m3 storage capacity) and a reservoir (20 × 106 m3 storage capacity). The goal was to assess the feasibility of using such material to identify sediment sources in a semiarid environment with a high density of surface reservoirs. Chemical variables were studied by mineralogical analysis using scanning electron microscopy (SEM) and multivariate statistics. The results showed that the fingerprinting technique is a potential tool to identify sediment sources comparing the properties of soils with silted material in reservoirs, allowing its use even in regions with low frequency of runoff. <![CDATA[IDENTIFICATION AND QUANTIFICATION OF FACTORS AFFECTING THE OPERATIONAL CAPACITY OF SUGAR CANE HARVESTERS]]> ABSTRACT Several studies determined the theoretical and effective capacity of sugarcane harvesters. However, in field conditions, some variables affect sugarcane production and their effect on machine productivity is difficult to measure. The objective of this study is to analyze the correlation of the operational capacity of sugarcane harvesters with property size, sugarcane yield, total operation time of harvesters, and lost productive time. This correlation will be used to construct models that estimate machine capacity under different working conditions. Harvest data were collected from 41 farms with different sizes and rates of productivity, with the harvesting of 412,207 tons of sugarcane by eight harvesters. Property size was the variable that, in isolation, better represented the operational capacity of harvesters in both mg day−1 and mg h−1, with a positive and strong correlation between these two variables. <![CDATA[POSITION ERRORS IN SOWING IN CURVED AND RECTILINEAR ROUTES USING AUTOPILOT]]> ABSTRACT The use of automatic routing significantly increases the yield and quality of agricultural operations and reduces the overlap rates between the mechanized set passes during the operation. The objective of this study was to analyse the quality of peanut sowing using automatic routing in two paths, curved and rectilinear, based on the error of parallelism and execution error, through statistical process control. The maps used came from an area of peanut seed production, in the city of Luzitânia, São Paulo, Brazil. The sowing was carried out by the execution of a project elaborated in CAD software that, for its elaboration, was taken into consideration the working width of the seeder-fertilizer, as well as the spacing of the crop. The CenterPoint RTX signal was used on both routes. The errors were measured in the Agrocad® program, by means of the orthogonal difference between the lines, and the execution errors were calculated based on the difference between the previously projected lines and the lines executed by the tractor. In general, the sowing operation presented better quality in the rectilinear path, providing smaller parallelism and execution errors. The maximum errors of parallelism were 8.75 and 5.22 cm in the curved and rectilinear path, respectively. The RTX signal ensured good quality of operation in rectilinear path, with low probability of errors occurrence above 3.8 cm. <![CDATA[USE OF SURFACTANT WITH DIFFERENT VOLUMES OF FUNGICIDE APPLICATION IN SOYBEAN CULTURE]]> ABSTRACT Application volume, adjuvants that act on the drop surface tension and droplet spectrum are the main factors affecting leaf surface coverage and the spray penetration droplets inside the canopy of the soybean crop, which may have an impact on fungicide efficiency, since those used in the handling of Asian-rust, including those that are absorbed by the plant, present a small displacement from the point of deposition. Thus, it was sought to determine the impacts on the use of the organosilicone surfactant compared to the changes in the spray volumes. For that, five spray volumes and the combination of two adjuvants were compared in randomized blocks with a factorial arrangement 5×2. Reductions in volume negatively impacted the number of drops cm−2 affecting the leaf surface cover which did not exceed 13% in the lower third, in the absence of the surfactant. Also, the reduction in the volume provided decreases in the control of Asian-rust, and the use of surfactant minimized the negative impacts of the disease, reflecting on the index of the leaf area which varied up to 6.5 times on changes in the spray volume, and up to 2.8 times against the use of the surfactant in relation to the mineral oil isolated. Grain yield was negatively affected as reductions in the spray volumes, occurred with less impact when the surfactant was used. Thus, coverage of the leaf surface and the number of drops cm−2 along the plant profile respond to the addition of the surfactant and to the increase of the spray volume, having relation with the control of soybean Asian-rust, and affecting the leaf area index and productivity. <![CDATA[PHYSICAL PROPERTIES OF DIFFERENT SOYBEAN CULTIVARS DURING DRYING]]> ABSTRACT The knowledge of physical properties of grains is important for the optimization of postharvest operations. Thus, this study aimed to evaluate the effect of moisture content over physical properties of different cultivars of soybean. Soybean of cultivars NS7901RR, TMG1180RR, P98Y70 and TMG132RR were used, with initial moisture content of 0.32, 0.27, 0.25 and 0.21 dry basis (d.b.), respectively. In order to dry the samples, an oven of forced air circulation was used. Samples were dried at temperature of 50 °C, being the drying procedure stopped when the moisture content of soybean was equal or inferior than 0.15 (d.b.). During drying, for interested moisture contents, physical properties were determined: bulk density, equivalent diameter, sphericity, circularity and surface/volume ratio. It was noticed that all physical properties analyzed presented a direct relationship with moisture content. With exception of the equivalent diameter, all the remaining physical properties increased linearly with moisture content reduction. Physical differences were observed among soybean cultivars during drying. However, variation of analyzed properties occurred in different proportions during drying for each cultivar. <![CDATA[CLASSIFICATION OF RICE GRAINS OF LOWLAND CULTIVARS GROWN UNDER FLOOD IRRIGATION AND SPRINKLER IRRIGATION]]> ABSTRACT The objective of this study is to analyze the classification of rice grains of lowland cultivars grown under flood and sprinkler irrigation. The study was carried out in the agricultural years 2011/2012 and 2014/2015 using a completely randomized block design with split plots. In 2011/2012, the treatments were three lowland rice cultivars grown under flood irrigation system and five sprinkler irrigation depths with four replications. In 2014/2015, the experimental design was maintained but flood irrigation was not performed. After harvest, the samples were processed in a rice testing machine, including peeling, polishing and classification. Whole and broken grains were weighed to calculate hulling and milling yield. The classifications followed the guidelines described in Normative Instruction No. 6 of the Ministry of Agriculture, Livestock, and Supply of Brazil. In 2011/2012, there was interaction between sprinkler irrigation depths and the cultivars on hulling and milling yield, and in 2014/2015, there was significant difference in hulling yield between the cultivars. Genetic characteristics and water availability affected the classification of rice grains grown under sprinkler irrigation. In two sprinkler irrigation depths, the quality of the grains was similar to flood irrigation system. The highest milling yield was obtained in cultivar IRGA 417. <![CDATA[APPLICATION EFFECT OF DIFFERENT RATES OF WASTEWATER FROM GELATIN PRODUCTION IN THE CHEMICAL ATTRIBUTES OF THE SOIL]]> ABSTRACT The gelatin industry wastewater has nutrients in its composition, allowing its use in agriculture as an alternative to disposal and recycling of this residue. However, high application rates can cause the accumulation of elements such as sodium in the soil, and generate negative impacts on the environment. This study aimed to evaluate the effects of the application of rates up to 600 m3ha-1 of gelatin industry wastewater in soil columns, on soil chemical attributes in five depths. The experiment was conducted in a greenhouse, in PVC tube columns (0.20 m diameter) filled with distroferric Red Nitosol soil, of very clayey texture. The treatments consisted of increasing rates of wastewater equivalent to 0, 150, 300, 450 and 600 m3 ha-1, with a single application, at the soil surface and without incorporation. The application of the gelatin industry wastewater resulted no negative effects on soil chemical properties to a depth of 60 cm. The application of the levels of wastewater increased the concentration of sodium in the soil, but without causing problems with sodicity. <![CDATA[VIABILITY OF THE USE OF MINIMUM WATER QUALITY INDICES: A COMPARISON OF METHODS]]> ABSTRACT The achievement of all the water quality parameters that constitute the water quality indices can be a hamper to their use. The objective of this study was to analyze the viability of using minimum indices to monitor water quality, comparing different methods. For this purpose, the Environmental Company of the State of São Paulo database for the year 2016 of the Tietê/Jacaré and the Tietê/Batalha units was used. Four indices present in the literature were compared with the indices currently practiced in the states of São Paulo and Minas Gerais (“standard indices”). For feasibility analysis, the indices were classified by the “standard indices” methods and compared to them. The minimum indices were significantly correlated with the “standard indices”, from moderate to strong degree. The minimum indices, as a rule, overestimated water quality when compared to the index of the state of Minas Gerais; and underestimated when compared to the index of the state of São Paulo. It is concluded that the minimum indices are useful and practicable tools, with respect to the use of the WQI for management purposes. However, such indices should be evaluated periodically to avoid making mistaken decisions. <![CDATA[SOIL ATTRIBUTES AND WHEAT PERFORMANCE IN A GEOREFERENCED SEED PRODUCTION FIELD]]> ABSTRACT The aim of this research was to study the linear correlations and spatial distribution between soil attributes and productivity and physiological quality of wheat seeds. Soil samples were collected at georeferenced points in an area of 41 ha with a rectangular grid of 100 × 100 m to determine soil fertility. Grain productivity, number of ears m-2, protein content, and physiological seed quality were assessed. The results were submitted to Pearson's correlation analysis, descriptive statistics, and geostatistics. Phosphorus content presented a high spatial variability, with a coefficient of variation of 97.79%. Protein content, number of ears, and SMP index presented low values of coefficient of variation, indicating their low spatial variability. Physiological seed quality was not correlated with soil attributes. Wheat productivity showed a strong correlation between calcium and soil organic matter contents, as verified by analyzing the spatial distribution maps. The analysis of the spatial distribution maps of soil nutrients is a tool that can contribute to farmers’ decision making in the management of crop fertilization aiming at increasing productivity. <![CDATA[CLASSIFICATION OF MACAW PALM FRUITS FROM COLORIMETRIC PROPERTIES FOR DETERMINING THE HARVEST MOMENT]]> ABSTRACT Macaw palm (Acrocomia aculeata) is a promising crop for biofuel production due to the high concentration of its fruit oil, but the harvest date is an issue to be better understood so it could be cultivated on an industrial scale. The aim of this study was to use the colorimetric properties of the macaw palm fruits to develop a neural network classifier to determine the ideal moment for harvesting, based on the oil content of the fruit mesocarp. During nine weeks of maturation were sampled 900 fruits of macaw palm fruits and the colorimetric properties of the RGB, HSI and CIELab color models were used to classify the fruits into immature and mature fruits. Kappa index and the overall accuracy values were used to access the classifier performance. The classifiers based on RGB parameters and on hue were considered equivalents having a Kappa index of 0.901 and 0.942, respectively, indicating the 59th week of maturation as the ideal time to harvest with the highest oil content.