Scielo RSS <![CDATA[Engenharia Agrícola]]> http://www.scielo.br/rss.php?pid=0100-691620160004&lang=pt vol. 36 num. 4 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[Mechanical properties of grain in silos for simulation designs]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400573&lng=pt&nrm=iso&tlng=pt ABSTRACT For the calculation of silos structures it has been used new methods and computational tools that require mechanical properties knowledge that are still unknown for most storable materials, especially grains. In this context, we aimed to determine the mechanical properties of rice and beans grains with moisture contents of 10, 12, and 14% by applying four compressive loads (5, 10, 15 and 20). The determined mechanical properties were Poisson's ratio (ν), Modulus of Elasticity (E), and the dilatancy angle (ψ). The procedure consisted in the application of the load in compression cell, adapted from MOLENDA &amp; STASIAK, aiming to simulate loading and unloading of silos. We observed that the Poisson's ratio calculated for both loading and unloading, presented higher values than the experimental values, with the increase of their moisture content; the experimental elastic modulus presented higher values than the calculated ones, and both increased their values with the increase of their moisture content; the dilatancy angle decreased with the increase of moisture content and compressive loads. <![CDATA[Thermal gradients of container and mean surface temperature of broiler chicks transported on different shipments]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400581&lng=pt&nrm=iso&tlng=pt ABSTRACT This study aimed to evaluate the thermal gradients between the container environment and the interior of chick boxes and mean surface temperature of broiler chicks during transportation on different shipments. The research was conducted in the state of São Paulo, Brazil, with the accompaniment of nine shipments with different density boxes, using an acclimatized truck with an average capacity of 380 boxes. It was selected 14 chick transportation boxes on each shipment and, subsequently, five chicks per box. It was measured the mean surface temperature of chicks (MST) in shipment (loading and unloading) by using an infrared thermometer. In the container microclimate assessment (center and inside chick boxes), it was recorded the air temperature (T), relative humidity (RH) and specific enthalpy (h). For this, 17 data loggers were placed one per box (14) and three along the container. The experimental design was the completely randomized in a 9 × 2 factorial scheme. It was found that there are two microclimates in the chick loads, being the highest averages of T, RH and h observed inside boxes. The highest values of MST occurred during the unloading of chicks. It was also observed that the chicks have undergone thermal stress during transportation. <![CDATA[Prediction of mean surface temperature of broiler chicks and load microclimate during transport]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400593&lng=pt&nrm=iso&tlng=pt ABSTRACT This study aimed to determine a model to predict mean surface temperature of broiler chicks and live load microclimate conditions during transport by using neural networks. The research was conducted in the state of São Paulo, Brazil, by monitoring nine shipments with different density of boxes using an air-conditioned truck with an average capacity of 380 boxes. Fourteen chick boxes were chosen on each shipment, assessing five chicks per box. The mean surface temperature of chicks (MST) was measured with an infrared thermometer in both loading and unloading. By assessing the container microclimate (center and inside boxes), air temperature (T), relative humidity (RH) and specific enthalpy (h) were recorded; thereby, seventeen data loggers were placed, one per box (14), and three along the container. MST and truck microclimate were analyzed using artificial neural networks with a single layer and seven neurons, which were trained with the least mean square (LMS) algorithm. MST in the unloading showed a better prediction of MST during transport. The best prediction of microclimatic conditions was obtained inside the boxes during the shipment. <![CDATA[Fuzzy modeling in the prediction of climate indices and productive performance of quails kept in climate chamber]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400604&lng=pt&nrm=iso&tlng=pt ABSTRACT With the demand in the production at large-scale food, confinement of animals has become a necessity of the productive process because of the increase in production capacity and optimization of the spaces reserved for creations. In this context, the aim of this study was the development and validation of models using fuzzy logic for predicting climate indices and productive performance of European quails kept in a climatic chamber. The model developed was analyzed from two points of view; the first one took into account the prediction of climate indexes where the input variables were the temperature (°C) and relative humidity (%) of the air. In the second, related to the prediction of productive performance, the input variables were air temperature (°C) and age of the birds (weeks) while the output variables were the food intake (FI, g), water consumption (WC, g), weight gain (WG, g) and food conversion (FC g g-1) of the birds. The Mamdani method was used for the preparation of the rules, and in the defuzzification was applied the center of gravity method. Based on the results generated by the models and compared with the experimental data it was obtained coefficients of determination (R2) of: 0.9771; 0.9897; 0.9955; 0.9995; 0.9993 and 0.9788, for BGTHI, RTL, WC, FI, WG and FC, respectively. <![CDATA[Gas emission and efficiency of an engine-generator set running on biogas]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400613&lng=pt&nrm=iso&tlng=pt ABSTRACT In Brazil there is a wide availability of residues, which have been used in the production of biogas and biofertilizers. The engine-generator by biogas is grid connected, and produce electricity for self-consumption and the surplus is inserted into the grid. The aim of the present study was to evaluate energetic efficiency and exhaust gas emission of two cases: two engine-generators sets of 100 kVA running on biogas, produced from residues of a poultry slaughterhouse unit (PSU) and swine fattening unit (SFU). Load variation in the engine-generator set was evaluated in the SMCP (system of protection and synchronism). There was an increase in the emission of nitrogen oxide, sulfur dioxide and exhaust gas temperature, in both cases. The elevation in the load of the engine-generator increased its global efficiency (mechanical plus electric), with levels between 6.12% with load of 10 kW and 20.91% with 70 kW. The average specific consumption of biogas in the load of 70 kW was 0.76 m3 kWh-1 in the swine fattening unit and 0.80 m3 kWh-1 in the slaughterhouse unit with load of 70 kW. The last results show an engine-generator on biogas of 100 kVA (load of 70 kW), spent an average of 1.4 m3 of biogas to produce 1.0 kWh of electricity. <![CDATA[Watermelon fertigation with electrical conductivity and ph monitoring in the soil solution]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400622&lng=pt&nrm=iso&tlng=pt ABSTRACT In the olericulture, in general, is practiced intensive fertilization, which creates a risk of salinization and change of high pH, ​​which if not well monitored can cause production losses, excessive spending on fertilizers and environmental contamination. We developed this study with the aim of controlling fertigation on watermelon through the behavior of the electrical conductivity (EC) and pH in the soil solution obtained through porous ceramic cups extractors. The EC and pH values ​​were corrected by the current soil moisture for the moisture field capacity, due to different moisture values ​​at the time of extraction. The monitoring comprised 19 assessments during 80 days of cultivation. We can control the pH and EC of the soil and maintain them at optimal levels for the crop through real-time monitoring of the soil solution. The monitoring enabled the achievement of a balanced fertigation. <![CDATA[Estimation of climatological water deficit in an experimental watershed in the brazilian cerrado]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400631&lng=pt&nrm=iso&tlng=pt ABSTRACT This study aimed to estimate the probability of climatological water deficit in an experimental watershed in the Cerrado biome, located in the central plateau of Brazil. For that, it was used a time series of 31 years (1982–2012). The probable climatological water deficit was calculated by the difference between rainfall and probable reference evapotranspiration, on a decennial scale. The reference evapotranspiration (ET0) was estimated by the standard FAO-56 Penman-Monteith method. To estimate water deficit, it was used gamma distribution, time series of rainfall and reference evapotranspiration. The adherence of the estimated probabilities to the observed data was verified by the Kolmogorov-Smirnov nonparametric test, with significance level (α-0.05), which presented a good adjustment to the distribution models. It was observed a climatological water deficit, in greater or lesser intensity, between the annual decennials 2 and 32. <![CDATA[Prototype for soil mechanical resistance measurement with chisel plow automated control]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400646&lng=pt&nrm=iso&tlng=pt ABSTRACT In Brazil, there are several available models and systems to measure soil compaction; however, the data generated by such equipment have to be processed and interpreted, making the process expensive. Our study aimed to evaluate a prototype of instrumented rods to identify soil compacted layers and control chiseling depth, and compared it to a conventional system at a fixed depth of 0.35 m. In order to compare them, we assessed the following parameters: hourly fuel consumption, operational fuel consumption, drawbar power, average power, average speed, slipping, tractor effective field capacity and response time. Our results showed that mechanical chiseling at variable depths reduced in 26% the operational fuel consumption and increased in 14% the effective field capacity. Furthermore, the prototype of chisel plow automated control generated maps displaying spatial variability of soil mechanical resistance with resolution, sampling density and high operating capacity. <![CDATA[Spray deposition and chemical control of the coffee leaf-miner with different spray nozzles and auxiliary boom]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400656&lng=pt&nrm=iso&tlng=pt ABSTRACT The coffee crop requires great spray ability to penetrate into the plant canopy during the application of pesticides. The aim of this study was to evaluate the spray deposition on leaves of coffee plants and the chemical control of the leaf miner provided by the application of different spray nozzles, with and without the use of an auxiliary boom. The deposition on the upper, middle and lower parts of the plants and the losses to the soil were evaluated using a tracer quantified by spectrophotometer. We also evaluated the chemical control of the leaf miner, counting the larvae, after the application of the insecticides cartap and fenpropathrin. The trial was carried out in a randomized block design, with four replications, in a factorial model (2×2+1): with and without the auxiliary boom, three spray nozzles (hollow cone – MAG 02, flat fan – AD 11002 and air induction hollow cone – TVI 8002) and a control. The use of the auxiliary boom increased the deposition in the lower part of the plants but decreased in the middle part, besides the increase in the runoff. The different nozzles do not provided differences in the deposition, showing the technical feasibility in the use of the hollow cone nozzles with coarse droplets and flat fan. All the chemical control decreased the leaf miner population, without differentiation. <![CDATA[Penetration resistance and agronomic characteristics of soybean affected by soil management and sowing speed systems]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400664&lng=pt&nrm=iso&tlng=pt ABSTRACT With the short period of the sowing process, we observed an increase in the seeder speed set in several soil management systems that may result in decreased soybean yield and problems with penetration resistance. We aimed to assess the penetration resistance (PR) and agronomic characteristics of soybean on soil tillage and sowing speed. The randomized block design in split plot with four replications was used. The treatments consisted of six management systems, applied to the plots: no tillage (NT), no tillage and chiseling (NTc), no tillage and cross chiseling (NTcc), conventional tillage (CT), reduced tillage (RT) and conservation tillage (CsT) and four speeds, (4.6; 5.5; 7,3 and 7.8 km h-1) applied in the subplot at the time of soybean seeding. We observed in the deep layers 0.0 – 0.10; 0.10 – 0.20 and 0.20 – 0.30 m significant effect of tillage systems on the PR of the soil. The NT system showed the highest value of PR compared to other management systems studied. In the NT should be used sowing speeds above 5.5 km h-1 to decrease the compression. Low speeds favor higher yield by improving pods per plant. Speeds in the working range (5-7 km h-1) promote higher productivity by improving the number of pods per plant, and provide better stand. <![CDATA[Internal environmental conditions of soybean processing plants and safety in workplace]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400673&lng=pt&nrm=iso&tlng=pt ABSTRACT Currently, the domestic agricultural sector has become increasingly professionalized; therefore, measures aimed at safety in the workplace and monitoring of environmental risks have been gaining major importance in this scenario. Thus, this study aimed at assessing internal environmental conditions of four soybean processing plants (SPPs) operating with a screen-air machine, densimetric table and with or without spiral separator. These plants are in the state of Rio Grande do Sul (Brazil), being assessed on site considering every feature related to machinery and equipment, as well as technological level. Field evaluations comprised measurements of noise, illuminance and suspended dust. Results showed that none of the SPPs is in full accordance with current laws for the investigated parameters, among which noise level is what most threatens the environmental conditions. Moreover, lightening conditions are unsatisfactory since the environments are extremely dark, not reaching minimal standard. Regarding the suspended dust is possible to claim that there is an emerging risk. <![CDATA[Geotechnology application for data acquisition for agricultural and environmental management of the municipality of Vitória Brazil-SP]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400684&lng=pt&nrm=iso&tlng=pt ABSTRACT The present study aimed at associating geoprocessing procedures for analysis of land use and native vegetation for municipal management, using an easy access and low cost methodology to the public administration of the municipality of Vitória Brazil/SP. Initially, the land use and the land occupation were evaluated, being delimited the municipal hydrographical micro basin and the permanent preservation areas (PPAs). For this purpose, multispectral images of high spatial resolution were used, available by the government partnerships between the City Hall, the state and federal authorities. From the obtained results it was possible to efficiently determine that only 3% of the original vegetation is preserved; the livestock is the main municipal occupation, covering more than 41% of the area; citrus and sugar-cane are also very expressive, occupying, respectively 13% and 7% of the area of the municipality of Vitoria; and around 70% of the municipal PPAs need hydrophilic species for its recovering. These indicators configure a data bank for consulting and supporting the public admiration, as well as a source for the administrative decision making, aiming at guiding the resources for the development of the municipal rural sector, in a more dynamic, efficient and economically viable way. <![CDATA[Variations on the expertise of two attributes of physical soil due to differences in the method of global satellite navigation]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400696&lng=pt&nrm=iso&tlng=pt ABSTRACT The mechanical resistance to penetration when related to the water content is an indicator often used of soil compaction, the use of positioning methods for greater accuracy of this review is important. In this context, this study aimed to determine the variability of positioning methods provided by GPS receivers to determine the spatial behavior of physical attributes related to soil compaction. The study area is located in the municipality of Jaboticabal, around the latitude 21º15’22”S and longitude 48º18’58”W, being characterized with a clayey Oxisol. The variables used as parameters of soil physical properties were the mechanical resistance to penetration and water content, using a sampling grid of 20 x 20 m, totaling 60 points. We used six models of GPS receivers: Garmin Etrex Vista, Garmin Etrex 30, Ashtech MM6, Trimble Nomad, Garmin Map 62 and Trimble R6, with all georeferenced points in the regular grid intersections. The georeferencing using GPS receivers (single point positioning and post-processed differential correction) interfered in characterizing the spatial variability of soil resistance to penetration, differently for some receivers to the water content attribute. Positioning methods with post-processed differential correction, using R6 and MM6 models, better define the management zones of soil resistance to penetration. <![CDATA[Composted sewage sludge in replacement of mineral fertilization on wheat production and development]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400706&lng=pt&nrm=iso&tlng=pt ABSTRACT Several research lines are required to ensure a proper disposal of sewage sludge in Brazil; among them, we may highlight agricultural use. In this sense, this study aimed at assessing the effect of exchanging nitrogen sourcing via conventional fertilization (chemical) with growing doses of composted sewage sludge (CSS) on wheat crop performance. The experiment was performed in a completely randomized design with seven treatments and ten replications, being defined as T0 (control – without fertilization); T1 (100% mineral fertilization); T2 (50% mineral + 50% CSS); T3, T4, T5, and T6 (100, 150, 200, and 250% nitrogen fertilizing from CSS). Results showed that the use of CSS increased wheat production and development, therefore enhancing its performance. Thus, exchanging mineral fertilization with CSS application raised wheat yields. <![CDATA[Influence of nails size and layout to obtain the reduction coefficient of moment of inertia for timber beams with composite cross section]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400715&lng=pt&nrm=iso&tlng=pt ABSTRACT A significant portion of rural building’s roof is supported by timber trusses. Increasing distance between the trusses can be achieved by using composite cross sections ("T" and "I") for beams. With this, it is possible to reduce the number of columns and trusses, bringing significant savings in material and the desired cost reduction, mainly using wood from planted forests. The Brazilian Code ABNT NBR 7190:1997 establishes a coefficient (αr) for the reduction of the theoretical moment of inertia (Iteo) of 0.95 and 0.85, for beams with "T" and "I" composite profile, respectively. However, no specification is showed about connections responsible for conferring such coefficients. This research aimed to investigate, based on static bending tests, analysis of variance and polynomial regression models (linear, quadratic, cubic), the precision of αr coefficients set by the Brazilian Code for Pinus sp. beams. We considered to evaluate influence of factors such as: nails number (3, 5, 9, 17, 33), nails size (19×27 mm, 19×33 mm), profile types (I, T) and calculation form to obtain the equivalent modulus of elasticity (Edeq) used to determine the cited coefficients. The highest values of αr were derived from beams with 17 and 33 nails, which provided similar results. The analysis also allowed admitting the adequacy, only to the beams with "T" section, of αr stipulated by the Brazilian Code. For "I" section, αr overestimates beams performance. Nails size and form of calculating Edeq were not significant in obtaining αr. The quadratic model showed the best results, indicating that the amount of 25 nails can provides the highest values of αr coefficients. <![CDATA[Method to evaluate the efficiency of manual overhead irrigation in citrus rootstock liner production]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400724&lng=pt&nrm=iso&tlng=pt ABSTRACT Brazil produces grafted citrus seedlings in closed screen houses to reduce pest and disease incidence. Irrigation is usually performed by hand using either breaker nozzles or drilled polyvinyl chloride (PVC) pipe wands on garden hoses. Rootstocks are produced in cone-shaped containers filled with soilless potting mix. Since the containers have a small upper diameter, nutrient solution capture is reduced with the potential to cause environmental contamination from inefficient fertigation. This study provides a method to assess the efficiency of manual overhead irrigation systems used in liner production. The method consists of determining both the volume of water applied and volume lost (i.e., directly and by percolation) in order to obtain an estimate of the percentage of water loss, irrigation efficiency, and the drainage fraction. The method was tested in a commercial facility under standard production practices. The method’s attributes included simplicity, quick sampling and data collection, and accuracy. The evaluated nursery was found to have low irrigation efficiency (27.14%) and excessive nutrient solution losses (72.86%). Considering an average production of 300,000 liners per year on 20,000 m2, we determined an annual solution loss of 221.8 m3 with an average environmental release of 158.9 kg of fertilizer. Therefore, more efficient irrigation systems are necessary for sustainable citrus rootstock liners production. <![CDATA[ERRATA]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400736&lng=pt&nrm=iso&tlng=pt ABSTRACT Brazil produces grafted citrus seedlings in closed screen houses to reduce pest and disease incidence. Irrigation is usually performed by hand using either breaker nozzles or drilled polyvinyl chloride (PVC) pipe wands on garden hoses. Rootstocks are produced in cone-shaped containers filled with soilless potting mix. Since the containers have a small upper diameter, nutrient solution capture is reduced with the potential to cause environmental contamination from inefficient fertigation. This study provides a method to assess the efficiency of manual overhead irrigation systems used in liner production. The method consists of determining both the volume of water applied and volume lost (i.e., directly and by percolation) in order to obtain an estimate of the percentage of water loss, irrigation efficiency, and the drainage fraction. The method was tested in a commercial facility under standard production practices. The method’s attributes included simplicity, quick sampling and data collection, and accuracy. The evaluated nursery was found to have low irrigation efficiency (27.14%) and excessive nutrient solution losses (72.86%). Considering an average production of 300,000 liners per year on 20,000 m2, we determined an annual solution loss of 221.8 m3 with an average environmental release of 158.9 kg of fertilizer. Therefore, more efficient irrigation systems are necessary for sustainable citrus rootstock liners production. <![CDATA[ERRATA]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400737&lng=pt&nrm=iso&tlng=pt ABSTRACT Brazil produces grafted citrus seedlings in closed screen houses to reduce pest and disease incidence. Irrigation is usually performed by hand using either breaker nozzles or drilled polyvinyl chloride (PVC) pipe wands on garden hoses. Rootstocks are produced in cone-shaped containers filled with soilless potting mix. Since the containers have a small upper diameter, nutrient solution capture is reduced with the potential to cause environmental contamination from inefficient fertigation. This study provides a method to assess the efficiency of manual overhead irrigation systems used in liner production. The method consists of determining both the volume of water applied and volume lost (i.e., directly and by percolation) in order to obtain an estimate of the percentage of water loss, irrigation efficiency, and the drainage fraction. The method was tested in a commercial facility under standard production practices. The method’s attributes included simplicity, quick sampling and data collection, and accuracy. The evaluated nursery was found to have low irrigation efficiency (27.14%) and excessive nutrient solution losses (72.86%). Considering an average production of 300,000 liners per year on 20,000 m2, we determined an annual solution loss of 221.8 m3 with an average environmental release of 158.9 kg of fertilizer. Therefore, more efficient irrigation systems are necessary for sustainable citrus rootstock liners production. <![CDATA[ERRATA]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162016000400738&lng=pt&nrm=iso&tlng=pt ABSTRACT Brazil produces grafted citrus seedlings in closed screen houses to reduce pest and disease incidence. Irrigation is usually performed by hand using either breaker nozzles or drilled polyvinyl chloride (PVC) pipe wands on garden hoses. Rootstocks are produced in cone-shaped containers filled with soilless potting mix. Since the containers have a small upper diameter, nutrient solution capture is reduced with the potential to cause environmental contamination from inefficient fertigation. This study provides a method to assess the efficiency of manual overhead irrigation systems used in liner production. The method consists of determining both the volume of water applied and volume lost (i.e., directly and by percolation) in order to obtain an estimate of the percentage of water loss, irrigation efficiency, and the drainage fraction. The method was tested in a commercial facility under standard production practices. The method’s attributes included simplicity, quick sampling and data collection, and accuracy. The evaluated nursery was found to have low irrigation efficiency (27.14%) and excessive nutrient solution losses (72.86%). Considering an average production of 300,000 liners per year on 20,000 m2, we determined an annual solution loss of 221.8 m3 with an average environmental release of 158.9 kg of fertilizer. Therefore, more efficient irrigation systems are necessary for sustainable citrus rootstock liners production.