Scielo RSS <![CDATA[Engenharia Agrícola]]> vol. 37 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[FLOW PROPERTIES AND PATTERN FLOW PREDICTION OF FOOD INDUSTRIAL POWDERS]]> ABSTRACT: More and more industries are faced with new products that need to be stored in silos which, in general, require knowledge of their physical properties and, above all, flow. Food industries are among those using powders as raw materials likely to develop functional problems. Thus, the aim of the present study was to investigate the flow properties of six food powders using equipment called Powder Flow Tester, and the results were compared with those recommended by the Eurocode 1 Part 4 international standard. Wide range of variation in the flow properties responses was observed, suggesting that their expression through a single average value may not be suitable for vertical silos. It was concluded that only the bulk density of products is in accordance with the standard. In relation to flow, only flaked corn is able to flow without possibility of obstruction in the discharge with higher discharge outlet dimensions, being also recommended for flaked oat. <![CDATA[FULL CHARACTERIZATION OF <em>CALYCOPHYLLUM MULTIFLORUM</em> WOOD SPECIE]]> ABSTRACT: Wood is a material that for years has been used by man for a variety of purposes, particularly in rural and civil constructions and furniture industry. The possibility of shortages of some wood species, the characterization of other unfamiliar species is an alternative source for use in civil and rural construction. This study aimed to determine, with the aid of Brazilian standard NBR 7190, physical and mechanical properties of Castelo (Calycophyllum multiflorum) wood specie. Twelve determinations were obtained by property, totaling 204 experimental values. In the characterization of wood, regression models were used to estimate the values of timber strength and stiffness as a function of apparent density, being density the physical property more simple to be obtained. The results of mechanical properties showed consistent with the performance of other species used in construction, which highlights the potential use of the Castelo wood in structural design. Regression models, apparent density was considered significant in the estimation of only 4 among the 14 properties for wood strength and stiffness. <![CDATA[SUNFLOWER EMERGENCE AND INITIAL GROWTH IN SOIL WITH WATER EXCESS]]> ABSTRACT: Sunflower crops are grown in different regions worldwide. However, the stress caused by water excess in the soil impairs this crop growth and yield. The aim of the present study was to determine the response of sunflower plants to long periods of water excess during initial development stages. Water excess treatments were applied at the initial development of these plants at the sowing day, three days after sowing, at plant emergence, and at V2 and V4 stages. The treatments had different duration periods (0, 48, 96, 144, 192, and 240 hours) and were applied at three sowing dates. The current experiment is factorial and was carried out according to a completely random design. Two plant pots, treated under greenhouse conditions, made up the experimental units. Plant emergence, leaf area, plant height, shoot dry mass, maximum root length, main root length and root dry mass were herein assessed. Water excess is more harmful to sunflower plants during the sowing-emergence period. It substantially reduces emergence, plant density, shoot and root growth, even after 48-hour stress. Moreover, water excess leads to the formation of adventitious and secondary roots. <![CDATA[IN SITU MONITORING OF A CONTROLLED RELEASE OF FERTILIZERS IN LETTUCE CROP]]> ABSTRACT: Agriculture has sought ways to increase food production to meet global demands, intensifying dependence on natural resources. An alternative for intensive production has relied on the use of “smart” fertilizers that release nutrients in a controlled manner. Biodegradable polymers containing fertilizers has presented economic and environmental advantages when applied to the soil, as they release water and nutrients gradually to the environment without leaving residues. The objective of this study was to monitor the behavior of chitosan-clay hybrid microspheres, used as potassium nitrate soil ferti-releaser in lettuce cultivation. The experiment consisted of two treatments: (i) application of ferti-releasing chitosan-clay microspheres and (ii) use of conventional fertilization. Both treatments were monitored with TDR probes to measure electrical conductivity and soil moisture. The results indicate that both moisture and electrical conductivity are higher in soils treated with the ferti-releasing material. In addition, there was a gradual and homogenous release if compared to the conventional fertilization. The statistical analysis showed that the microspheres were efficient mainly for the controlled nitrogen release. <![CDATA[SODIUM PHYTOREMEDIATION BY GREEN MANURE GROWING IN SOIL IRRIGATED WITH WASTEWATER OF DAIRY INDUSTRY]]> ABSTRACT: Phytoremediation is a technique that uses plants to decontaminate soils containing harmful organic and inorganic elements. The aim of this study was to evaluate the potential of three species of forage green manure in phytoremediation of saline soil irrigated with treated effluent from dairy processing plant. The design used was randomized blocks (3×3) with four replicates. The treatments were three different water sources (anaerobic treated effluent, aerobic treated effluent, and tap water) applied to growing table beets combined with the post-cultivation of three forage green manure: Calopogonium mucunoides Desv (Calopo), Cajanus cajan (L.) Millsp (Pigeon pea), and Pennisetum glaucum (L.) R. Brown (Millet). The treatment with Millet had higher dry mass production with all water sources, although showing growth reduction after irrigation with anaerobic treated effluent. Millet presented higher sodium extraction efficiency (22.4 kg ha−1); however, it was not effective in soil phytoremediation because the exchangeable sodium percentage was not reduced to levels that allowed for new effluent input. <![CDATA[MECHANIZED AND INDIVIDUALIZED APPLICATION OF N-P-K IN COMBINED OPERATIONS IN SUGARCANE]]> ABSTRACT: A new concept of fertilizer machine is under development and shows as differential individually fertilizer application, that is sources of N, P and K are applied separately for the purpose of improving the distribution efficiency of the quantities applied. The aim was to compare the quality of the individualized mechanized distribution of N, P and K in combined operations with and without herbicide application, as well as to evaluate the fertilizer application on each side of the fertilizer machine. The experiment was carried out on Cascavel farm, in the municipality of MatãoSP. The experimental design was established according to the criteria of quality control, and variables monitoring carried out in the place during fertilization operation, having the fertilizer distribution operation; simultaneous operation of fertilizer distribution and herbicide application treatments; and two simple operations, fertilizer distribution followed by herbicide application. We concluded that the better operational quality was in two distinct operations. The right side of the fertilizer had the best result because it applied the amount close to the regulated dosage. The distribution of potassium chloride expressed in the control charts greater operational quality compared to other fertilizers. <![CDATA[MONITORING OF SOYBEAN MECHANICAL HARVESTING AS A FUNCTION OF PLOT SHAPES]]> ABSTRACT: Information on harvester performance is important in the management and optimization of mechanized agricultural systems. In this sense, the aim of this study was to monitor the operation quality of soybean mechanical harvesting in different plot shapes by means of statistical process control. The harvest was carried out in an agricultural area of a farm located in Uberaba, MG, Brazil, with an experimental design based on the assumptions of statistical quality control and 18, 28, and 24 replications for irregular, rectangular, and trapezoidal plots, respectively. The variables and/or quality indicators of harvester performance were forward speed, engine speed, cylinder speed, and concave opening. The lowest variation occurred in the irregular plot for the quality indicators forward speed and engine speed of harvester. Engine speed and the concave opening of harvester were unstable for all plot shapes. Only the cylinder speed of the soybean harvester presented process stability during operation for the three plot shapes. <![CDATA[EFFECTIVE POWER AND HOURLY FUEL CONSUMPTION DEMANDED BY SET TRACTOR- COFFEE HARVESTER IN FUNCTION OF ADEQUACY TRACTOR BALLASTING]]> ABSTRACT: The mechanized gathering process of sweeping coffee is extremely important to reduce the losses of fruit not used in the harvesting operation. But this operation usually has a low operational performance and a high cost per unit collected in this way any measures that can effectively reduce costs increase the viability of the operation. In this sense, studies on adequacy tractor mass for each operation show improvement in energy use, reducing fuel consumption. So, this study aimed to quantify the fuel consumption and effective power along the process of a tractor 4x2 FWD pulling the coffee harvester. I was used as treatments three ballasting settings, these being equivalent the relations power to weight of 36, 39 and 42 kg hp-1 working with and without activated FWD, randomized statistically, with 10 repetitions each configuration. It was conclude that, at low power-weight ratio, the front wheel drive assist had no significant influence on the hour fuel consumption. Already in the configuration with higher ratio, the use of front wheel drive favored in reducing fuel consumption and better energy use. <![CDATA[SPRAY NOZZLES PERFORMANCE IN FUNGICIDES APPLICATIONS FOR ASIAN SOYBEAN RUST CONTROL]]> ABSTRACT: The performance of fungicides in controlling Asian soybean rust depends, in part, the spray quality of these products. The market of components to spray offers new types of nozzles which generate droplets with different characteristics. This study aimed to verify whether applications of fungicides with different spray nozzles interfere in soybean rust control. The experiment was conducted in the 2013/2014 harvest. The experimental design was a randomized block with three replications, and compared ten spray nozzles and a control without fungicide application. The applications were made with a backpack sprayer pressurized with CO2, set to apply a spray volume of 150 L ha-1. For the determination of severity four plants per plot were sampled, quantifying in each leaflet the number of uredinia cm-2, which permitted to integrate the area under the disease progress curve (AUDPC). We concluded that HYPRO GUARDIAN® 120015 Single pre orifice flat spray nozzle, that generates medium size of droplets, provided the lowest AUDPC of soybean rust, as well as the use of fungicide reflected in grain yield, which was on average 288% higher than that obtained by the control without fungicide application. <![CDATA[MODELING OF BASIL ESSENTIAL OIL EXTRACTION WITH VARIABLE DIFFUSION COEFFICIENT]]> ABSTRACT: Essential oils are complex mixtures of volatile compounds found at low levels in aromatic plant specific parts. Soluble in organic solvents, these oils are characterized by their fragrance and antimicrobial activity, being widely used in industries. The mathematical modeling of essential oil extraction is a relevant step in the project of industrial plants because it is about achieving optimized operational conditions. A model is available in the literature describing the extraction process of basil essential oil, based on diffusion within the leaf. Parametric equations were tested for the variable diffusion coefficient with the concentration, resulting in a significant improvement in the description process, when compared to papers presented in the literature. <![CDATA[DRYING KINETICS OF NIGER SEEDS]]> ABSTRACT: The objectives of this study were to describe the process of drying niger seeds through the fitting of different mathematical models to the experimental drying data, to select the best model that represents the phenomenon, and to determine the diffusion coefficients and thermodynamic properties of the product. Seeds with an initial moisture content of 0.42 (d.b) were collected and dried at 40°, 50°, 60°, 70°, and 80°C in a fixed bed experimental dryer. After drying, different mathematical models were fitted to determine the diffusion coefficient by applying liquid diffusion theory, which allowed for calculation of the energy activation, enthalpy, entropy, and Gibbs free energy values. The Page model was selected to represent the drying process of niger seed drying, as it is a traditional and simple model. The effective diffusion coefficient increased as the temperature increased. The activation energy for liquid diffusion at the temperature range of 40°C to 80°C was 46.83 kJ mol−1. The enthalpy and entropy specific values decreased as the drying air temperature increased. The Gibbs free energy values also increased as the drying air temperature increased. <![CDATA[THERMODYNAMIC PROPERTIES OF BARU FRUITS (<em>Dipteryx alata Vogel</em>)]]> ABSTRACT: The objective of this study was to determine and evaluate the thermodynamic properties for different equilibrium moisture contents in baru fruits (Dipteryx alata Vogel), using the direct static method to obtain the experimental data. The Modified Halsey model was used to determine the thermodynamic properties of baru fruits. Results concluded that thermodynamic properties are influenced by moisture content. The water vaporization latent heat increases with the decrease in equilibrium moisture content. The baru fruit desorption process is controlled by enthalpy. Gibbs free energy is positive for the temperatures studied with the increase over desorption, which describes a non-spontaneous process. <![CDATA[DATA MINING TECHNIQUES FOR SEPARATION OF SUMMER CROP BASED ON SATELLITE IMAGES]]> ABSTRACT: Due to the difficulty in discriminating soybean and corn in mappings obtained by the time series of satellite images, this study aimed to apply the data mining techniques to separate soybean and corn. Pure pixels selection from Landsat-8 were extracted and used to build a standard spectro-temporal EVI profile for both crops. These profiles were obtained with the Timesat software and, further incorporated in the Weka software. Five out of eleven variables of the standard spectro-temporal EVI profile for each crop were found through the decision tree, a data mining technique. These five variables were sufficient to achieve the separation of soybean and corn crops with an accuracy of 96.3% and a kappa index of 0.92. <![CDATA[SPATIAL VARIABILITY OF SOYBEAN YIELD THROUGH A REPARAMETERIZED T-STUDENT MODEL]]> ABSTRACT: The t-Student distribution has been used to the spatial dependence modelling of soybean yield as an alternative to the normal distribution, being used for data with heavier tails or discrepant values. However, a usual Student t-distribution does not allow direct comparisons of geostatistical methods with a normal distribution. The aim of this study was to assess the soybean yield spatial variability through a reparameterized t-Student linear model, comparing the results with those of a Gaussian linear model. For parameter estimation, a complete maximum likelihood (CML) method was used through an expectation-maximization (EM) algorithm. The maps constructed with both reparameterized t-Student and normal distributions are dissimilar and present a kappa index (K) equivalent to 0.64. The reparameterized t-Student distribution is an alternative in studying data with discrepant values, showing the ability to decrease the influence of these points. <![CDATA[TEMPORAL VARIABILITY IN ACTIVE REFLECTANCE SENSOR-MEASURED NDVI IN SOYBEAN AND WHEAT CROPS]]> ABSTRACT: Optimization of N management is one of the great challenges to be overcome in grain production, as it is directly related to productivity and can also cause environmental damage. Precision agriculture aims to solve this problem by applying nitrogen fertilizer at varying rates. Reflectance sensors are instruments capable of estimating N needs in various crops, including grain crops. However, it is not clear how these sensors perform under varying solar radiation and cloud cover, due to a lack of research on their temporal variability. Thus, this study examined the temporal variability of the NDVI (normalized difference vegetation index), as measured by an active reflectance sensor, in both soybean and wheat crops. The NDVI data were collected using a GreenSeeker sensor every 15 minutes over 12 or 14 consecutive hours. Incident solar radiation was recorded using an Instrutherm MES-100 pyranometer. In all experiments in soybean and wheat, NDVI was negatively influenced by irradiation, showing higher values at the beginning and end of the day. Changes in cloud cover also affected NDVI values during the experiments. <![CDATA[USING PASSIVE AND ACTIVE MULTISPECTRAL SENSORS ON THE CORRELATION WITH THE PHENOLOGICAL INDICES OF COTTON]]> ABSTRACT: The investment in precision agriculture technologies has been growing as well the investment in vegetation index sensors with different types of data collection. This study aimed to evaluate the NDVI potential use obtained from passive and active multispectral sensors as phenological parameters indicator of cotton growth. The experiment was conducted in cultivated cotton fields during the harvest seasons of 2013/14 and 2014/15. The phenological variables analyzed in the field, were cotton plant height and number of branches per sampled cotton plant. The active sensors Crop Circle and Green Seeker were mounted on a manual support. The passive sensor Tetracam was installed on a support positioning the sensor at 4 m height from the ground. NDVI readings are positively correlated with plant height and number of branches per cotton plant. Active sensors present exponential correlations between NDVI and phenological readings. Passive sensor, when installed in a support above the cotton canopy level, presents linear correlation between NDVI and phenological readings. NDVI values obtained by the passive sensor are higher than the active sensors. Filtering the raw NDVI values obtained by passive sensor decreases the adjustment of the regression analyses with cotton height and number of branches per plant. <![CDATA[PERFORMANCE OF TIFTON 85 GRASS UNDER FERTIRRIGATION WITH SLAUGHTERHOUSE WASTEWATER]]> ABSTRACT: The aim of this study was to evaluate the performance of Tifton 85 grass cultivated in soil columns and fertilized with different wastewater doses of swine slaughterhouse. The experiment was conducted in the Environmental Engineering Center and Sanitary of UFLA/MG in PVC columns filled with Dark Red Latosol (Oxisol) and randomly distributed. The treatments applied with nitrogen based load (300 kg ha de N years−1) consisted of four doses of SW and AQT0 control at random. Three cuts were performed, at 60, 90 and 120 days after planting. The highest yields were 10.06, 16.82 and 20.39 t ha−1 in AQT0, AAT4 and AAT3 treatments, respectively. With the increase of nutrients by N rates and root development of Tifton 85 grass, we observed higher extractions of N, P and K in the second and third cut, with maximum extraction of 384 and 10.3 kg ha−1 of N and P in the higher dose treatments (AAT4), while the maximum extraction of the potassium was 117.7 kg ha−1 in the AAT3 treatment. There was productivity restriction in the third cut due to the reduction of availability of essential nutrients and losses by leaching. <![CDATA[CORN FERTILIZATION USING SWINE WASTEWATER AND SOIL-WATER ENVIRONMENTAL QUALITY]]> ABSTRACT: Soil application of swine wastewater for nutrient cycling may represent a correct destination of these residues and reduction in production costs. However, when applied to soil, such residue may cause environmental impacts. This study aimed to analyze the chemical characteristics of the soil, corn, and leachate after successive swine wastewater applications associated with mineral fertilization. The experiment was developed in drainage lysimeters under field conditions. Wastewater doses applied were 0, 100, 200, and 300 m3 ha−1 with and without mineral fertilization. The results were submitted to analysis of variance and Tukey's test. After nine years of application, a special attention should be taken regarding water quality from a dose of 200 m3 ha−1 since some elements may leach into the soil. In addition, a synchronism between residue application and crop requirements needs to be taken into account. Doses of 200 and 300 m3 ha−1 are considered as satisfactory to meet corn nutritional requirements. Moreover, an increase in fertility characteristics was observed, but a caution regarding Cu and Zn contents should be taken since these elements produce a cumulative effect in the soil. <![CDATA[TREATMENT OF SEPTIC TANK SLUDGE IN A VERTICAL FLOW CONSTRUCTED WETLAND SYSTEM]]> ABSTRACT: The study consisted of the evaluation of the treatment of septic tank sludge in a vertical constructed wetland system (CW), built according to the first stage of the French system. The system operated also for sewage treatment and one of the beds (area of 29.1 m2, height of the support medium of 0.7 m and planted with Tifton 85 grass, Cynodon dactylon Pers), began to receive the application of sludge from clean-pit trucks once a week. The percolated liquid was directed to post-treatment in the other two beds of the French system. The application of the raw sludge had average hydraulic loading rate of 13.1 m3/m2.year and solids loading rate of 81 kgTS/m2.year. The system improved the quality of percolated liquid in terms of carbonaceous and nitrogenous matter (average COD removal efficiencies of 82% and TKN of 63%), but the percolate post-treatment strategy did not result in substantial improvements. The dewatering of the accumulated sludge on top of the bed occurred satisfactorily (55% of dry solids), the Tifton 85 grass was resistant to the operational conditions and the system proved to be a compact technology (sludge treatment capacity of an equivalent population between 1140 and 3799 inhabitants in the unit of 29.1 m2, corresponding to 39 to 131 inhabitants per m2 of surface area). <![CDATA[EFFECT OF ORGANIC LOAD AND ALKALINITY ON DAIRY WASTEWATER BIOMETHANATION]]> ABSTRACT: This study aimed to evaluate the effect of variations in organic load (hydraulic retention times - HRTs: from 2 to 0.5 day) and in alkalinity (NaHCO3 from 4,000 to 1,000 mg.L−1) on methane production. Biomass of sewage sludge was inoculated and stabilized on 1" polypropylene rings. The rings were immersed in the liquid phase (8.41 L) of an upflow anaerobic filter reactor (12.22 L). A solution of 5 g of whole milk powder per liter was used to simulate effluent from the dairy industry. Process effectiveness was measured by chemical oxygen demand reduction, biogas production, and biogas methane content. Biogas production started at a 2-day HRT and synthetic effluent alkalinization with 4,000 mg.L−1 NaHCO3. The best operation condition was at 1-day HRT and with the addition of 4,000 mg.L−1 NaHCO3. Biogas production reached 1.5 NL of biogas per L of reactor liquid phase, with 68% of methane and a concomitant reduction in COD of 57%. <![CDATA[METHODOLOGY FOR DIMENSIONING OF A CENTER PIVOT IRRIGATION SYSTEM OPERATING WITH DRIPPER TYPE EMITTER]]> ABSTRACT: In Brazil, the conventional center pivot is widely used for irrigation of agricultural crops and its use has grown continuously. However, when improperly managed, it facilitates the development of diseases in all parts of the plant, with a direct effect on productivity, besides favoring losses of water by evaporation. The drip may be an alternative, since it minimizes the losses and does not wet the aerial parts of the plants, thereby reducing the incidence of diseases. A new system called localized mobile drip irrigation (IRGMO) is being developed in an attempt to combine the practicality and rusticity of the center pivot with the efficiency and water savings of the dripping irrigation systems. This fusion system is the central pivot with drip irrigation system for water distribution in the soil surface. This study aims to present a calculation methodology for the design of IRGMO system and compare it with conventional systems. It is concluded that this methodology allows the design of the IRGMO and that this new technology allows a savings of approximately 99% in a number of drip tubes compared to the conventional system with fixed drip irrigation lines in the field. <![CDATA[FINANCIAL ANALYSIS OF THE INVESTMENT IN PRECISION AGRICULTURE TECHNIQUES ON COTTON CROP]]> ABSTRACT: The aim of this study was to evaluate a financial analysis by the use of precision agriculture (PA) techniques on cotton crop. The experiment was carried out in a cotton field of 91 ha and its result compared to another field with similar area, cultivated with the conventional agricultural techniques. The financial analysis was extrapolated to the total farm area of 3,500 ha. All agricultural inputs applied, during the 2013/14 cotton crop season were analyzed, as well as their costs. The use of precision agriculture techniques over the cotton crop reduces production costs in 6.6%, increases the profitability index and operating profit in 3.3% and 7.9% respectively, when compared to conventional agriculture. The fertilizer application in variable rate, using precision agriculture, provides 41% of costs reduction with these inputs. Profitability and investment analysis indicators demonstrate economic feasibility and return over investment to both production systems (precision agriculture and conventional) over the cotton crop production, however, the use of precision agriculture techniques shows higher economic viability and smaller return over investment time, even having higher initial costs with machines, sensors and maps production.