Scielo RSS <![CDATA[Engenharia Agrícola]]> vol. 37 num. 2 lang. en <![CDATA[SciELO Logo]]> <![CDATA[PHYSIOLOGICAL RESPONSES OF DAIRY COWS AS A FUNCTION OF ENVIRONMENT IN HOLDING PEN]]> ABSTRACT This research aimed to assess the climatization configuration in a holding pen for dairy cattle considering physiological responses of animals and thermal comfort indexes. Experimental design consisted of 16 cows in a Latin square design containing four groups of four animals (G1, G2, G3 and G4) and four periods (P1, P2, P3 and P4), in which four environments were used as treatments: EXT – external environment (control); SHA – shading with polypropylene mesh, 80% light interception; S+S – shading and water sprinkling; and S+S+V – shading, sprinkling and ventilation. Dry and wet bulb temperature, black globe temperature, wind speed and humidity were recorded during the climatization process, between October 13 and December 7. Subsequently, temperature-humidity index (THI), black globe temperature and humidity index (BGTHI), radiant heat load (RHL) and heat load index (HLI) were calculated. After climatization, respiratory rate (RR), surface temperature (ST), and rectal temperature (RT) were recorded. Animals submitted to EXT presented physiological responses that indicated heat stress. The best physiological response was found in S+S+V, which reduced RR by 58.6% when compared to the other environments. <![CDATA[EFFECT OF AUDITORY ENRICHMENT (MUSIC) IN PREGNANT SOWS WELFARE]]> ABSTRACT Studies have shown that the benefits from music can improve the welfare conditions of laboratory, pet and production animals. The study aimed to evaluate the influence of music (Antonio Lucio Vivaldi compositions) on behavior aspects (position, activity, stereotypes, social and agonistic behavior) and physiological responses (respiratory rate and rectal temperature) in gestating sows in individual cages (stage 1), and collective stalls (stage 2). 28 animals were studied, 14 belonged to music group, and 14 to the control group (without music).The respiratory rate had the lowest averages in the group with music, for example, in stage 1, time 1, values of 19.28 and 21.50 mov.min−1. In stage 2, the values found in the same time were 20.36 and 24.16, and in time 2, values of 24.37 and 27.18 mov.min−1. These findings follow in stage 2 until time 4.Behaviors position, activity, stereotypes and agonistic interaction with the researcher were also influenced by the music. We concluded from the results that music influenced the behavior of animals, providing greater relaxing and reduce stereotypes aspects related to a better welfare. <![CDATA[DAIRY PRODUCTION OF ‘SAANEN’ GOATS BASED ON METEOROLOGICAL VARIABLES AND FUTURE CLIMATE SCENARIOS]]> ABSTRACT This study aimed to modeling and bioclimatic zoning of ‘Saanen’ goat milk production in northeastern Brazil. Data were obtained from a 14-year dairy control program for 246 ‘Saanen’ goat matrices. Dairy production meteorological influence and mathematical modeling were assessed through statistical analyses such as Pearson’s correlation matrix and path analysis. Bioclimatic zoning for current and future scenarios, with climate changes, were delineated using inverse-square distance (ISD) and spherical model (kriging) interpolations. Results showed maximum air temperature to contribute substantially to goat dairy production; therefore, its modeling was based thereon. Current and future dairy production maps highlighted Maranhão and Piauí as regions of limited ‘Saanen’ milk production. Furthermore, we should emphasize that temperature rises in further scenarios may have significant impact on the potential of dairy farming for the region under study. <![CDATA[EFFECT OF THERMAL STIMULATION IN EMBRYOS FROM COBB<sup>®</sup>GENETIC STRAIN UNDER COMMERCIAL SCALE]]> ABSTRACT Studies aimed at producing stronger birds and with better growth performance are being developed involving artificial incubation. To that extent, thermal stimulation by the heat of 1.39 ºC and 1ºC above the standard, and by cold of 36 ºC fixed, were applied in the last week of the embryonic development (day 14 to day 18) to Cobb® strain birds of 33 to 53 weeks age. With the purpose of evaluating the behavior of the embryos facing these temperature stimuli to identify what is the best amplitude, frequency and the most appropriate period to perform temperature variation, obtaining more adapted birds to the field. It has been observed that heat or cold stimulation did not cause embryo mortality and did not affect the hatching and the quality of the chick for this strain negatively. The weight of the pullet, the residual weight of the yolk, and the peak of birth were not modified. The thermal stimulation during the last week of the birds' incubation is an available tool to improve hatchery production, quality and performance. However, several variables must be tested. <![CDATA[PRODUCTIVITY AND NUTRITIVE VALUE OF TIFTON 85 IN SUMMER, WITH AND WITHOUT IRRIGATION UNDER DIFFERENT NITROGEN DOSES]]> ABSTRACT The pasture irrigation has expanded, mostly in small areas in order to boost the production system, along with the use of soil improvement techniques and high-productivity grasses. Thus, this study, carried out on a small dairy farm property, aimed to evaluate the productivity, botanical composition and nutritive value of Tifton 85 with different nitrogen (N) doses, in the presence and absence of irrigation. The experimental design was a randomized block in a split-plot design with four replications, plots Non-irrigated and Irrigated. The subplots consisted of nitrogen doses: 25 kg ha−1 cycle−1 of N, 50 kg ha−1 cycle−1 of N, 75 kg ha−1 cycle−1 of N and 100 kg ha−1 cycle−1 of N. The irrigation increased the productivity in an average of 3,626.5 kg ha−1 cycle−1, with higher leaf stem ratio of 1.3, increasing the crude protein content of the pasture. The productivity responded quadratically to nitrogen fertilization with increases up to 84 kg N ha−1 cycle−1 with slight linear decrease of dead matter. There were linear increments of crude protein and digestibility “in vitro” of dry matter in function of applied nitrogen. <![CDATA[ESTIMATE OF REFERENCE EVAPOTRANSPIRATION THROUGH CONTINUOUS PROBABILITY MODELLING]]> ABSTRACT This study aimed at testing the fit of continuous probability distributions to a daily reference evapotranspiration dataset (ET0) at a 75% probability level for designing of irrigation systems. Reference evapotranspiration was estimated by the Penman-Monteith method (FAO-56-PM) for eight locations, within the state of Espírito Santo (Brazil), where there are automatic gauge stations. The assessed probability distributions were beta, gamma, generalized extreme value (GEV), generalized logistic (GLO), generalized normal (GN), Gumbel (G), normal (N), Pearson type 3 (P3), Weibull (W), two- and three-parameter lognormal (LN2 and LN3). The fitting of the probability distributions to the ET0 daily dataset was checked by the Kolmogorov-Smirnov's test. Among the studied distributions, GN was the only one to fit the ET0 data for all studied months and locations. We should also infer that continuous probability models have a good fit to the studied ET0 dataset, enabling its estimation at 75% probability through a Generalized Normal distribution (GN). Therefore, it can be used for the sizing of irrigation systems according to a given degree of risk. <![CDATA[WATER RELATIONS AT THE INITIAL SUGARCANE GROWTH PHASE UNDER VARIABLE WATER DEFICIT]]> ABSTRACT This study aimed to quantify water deficit levels that compromise sugarcane initial growth exposed to different availability soil depths. The experiment was conducted in a greenhouse by using 100-liter capacity asbestos-cement boxes filled with different soil layers simulating depths of 10, 20, 30, and 40 cm. Water deficit levels were represented by accumulated reference evapotranspiration of 0, 40, 80, 120, 160, 200, 240, and 280 mm, which was considered from planting to irrigation return. Soil moisture at field capacity at planting time was sufficient to promote sprouting and emergence regardless the water deficit level that was subsequently exposed. For soil depths of 10 and 20 cm, a 160-mm water deficit level caused total plant death. On the other hand, for soil depths of 30 and 40 cm, a 200-mm water deficit level promoted plant death. A water deficit level from 40 mm significantly reduced plant growth regardless soil depth. <![CDATA[PERFORMANCE AND EMISSION OF POLLUTANTS OF AN AGRICULTURAL ENGINE WITH TWO POWER TAKE-OFF SETTINGS]]> ABSTRACT Farming operations are usually performed implements driven by a power take-off (PTO) from tractors. Some manufacturers offer PTO settings named as economic (540E). Such configuration drives implements at lower tractor’s engine rotation, thus providing lower fuel consumption. An engine performance using standard (540) or 540E settings are different and poorly studied. The amounts of pollutants emitted by engines vary mainly with the applied load and rotation. The aim of this study was to compare the performance and exhaust emissions of a farming tractor engine under different PTO loads, using both standard (540) and 540E settings. Specific fuel consumption using 540E was an average 14.7% less than the standard setting. However, 540E promoted increasing levels of gas opacity, CO, CO2, NOx, and HC for the highest PTO power demands. <![CDATA[PESTICIDES DEPOSITION IN VINEYARDS ON DIFFERENT CONDITIONS OF LEAF WETNESS]]> ABSTRACT The high susceptibility to diseases of fine table grapes cultivars demand intensive use of pesticides, and the presence of water on the leaf surface can worsen the deposition of these products. The objective of this study was to evaluate the spray deposition in vine leaves in different conditions of leaf wetness, and test the effectiveness of an artificial ventilation method to remove water on the leaf surface. We evaluated the spray deposition in vine applied over: wet canopy (presence of high leaf wetness); canopy dried artificially (dried with air jet from air-assisted sprayer, wind speed of 25 km h−1) and canopy dried naturally (naturally dried leaves and free of water on its surface). Saline marker was used in the spray and the deposition on the canopy was determined by conductimetry. A pesticide application in vine, with the presence of water in the leaf surface, causes losses by run-off and reduces the deposit of spraying. The use of air jet formed by air-assisted sprayer fan is efficient for the removal of water on the vine leaf surface and its use can increase the favorable period for the application of pesticides without causing dilution and losses by run-off of the applied product. <![CDATA[DROPLET SPECTRA AND SURFACE TENSION OF SPRAY SOLUTIONS BY BIOLOGICAL INSECTICIDE AND ADJUVANTS]]> ABSTRACT Biological insecticides can be another pest control method used in integrated pest management; hence there is a demand for scientific information about these products to understand the appropriate application technique. The aim of this study was to evaluate the spray spectra data by different nozzle types using biological insecticide isolated and with adjuvants, as well the surface tension of these spray solutions. For droplet spectra data, a particle size analyzer was used and for surface tension of the spray solution, the method of pendant drop was used. Among the nozzles tested, ADI 11002 provided greater droplets median diameter volume, a lower percentage of droplets with diameters less than 100 μm and also the highest coefficient of uniformity. In general, the addition of adjuvants reduced the median droplet diameter and increased the proportion of drops susceptible to spray drift. By adding adjuvants to the spray solution there was a lower surface tension, which were dependent of the adjuvant chemical group. The Silwet L-77® adjuvant showed the lowest surface tension among the spray solutions evaluated. <![CDATA[PERFORMANCE OF DIESEL ENGINE FUELLED WITH FOUR VEGETABLE OILS, PREHEATED AND AT ENGINE WORKING TEMPERATURE]]> ABSTRACT With the rise of restrictions imposed by law for gases emission, several technologies both for petrodiesel (PD) or diesel engines are been applied, such as the sulfur reduction and the injection electronic command, followed of gases recirculation and/or after-treatment. The utilization of biofuels is considered as an interesting option for pollutants reduction. In this study was evaluated the performance on short duration tests (minor period than the factory indication of the lubricant lifespan) of the Diesel engine fueled with four vegetable oils. With the aim to select the most interesting oils for future evaluations in long duration tests. The analyzed variables were fuel consumption, power relative loss and opacity, for oils of linseed, crambe, rapseed, jatropha , with 100 °C preheating and engine work temperature (60 °C) comparing those with the PD. It was verified that the vegetable oils, on average, present a lower consumption than the PD for the cases of working without load, however with load, they presented higher consumption. In addiction were observed that the oils show a higher relative power loss in relation of PD and provides lower emission of particulate matter. Crambe and canola presented the best performance among the evaluated oils. <![CDATA[STATISTICAL CONTROL OF PROCESSES APLIED FOR PEANUT MECHANICAL DIGGING IN SOIL TEXTURAL CLASSES]]> ABSTRACT The digging of peanut, which has the pod production in the subsurface, is directly affected by soil conditions, physical or environmental characteristics, at the time of operation and may be the cause of unwanted losses. Therefore, the quality of the operation is very important for minimizing these losses. Thus, this study aimed to evaluate the quality of mechanized digging operation of peanut according to three soil textural classes (Sandy, Medium and Loamy) and their water content conditions at operation through statistical process control. The experiment was conducted at three locations in the state of São Paulo, Brazil, under sampling scheme arranged in tracks and 40 sampling points for each textural class of soil, using the mechanical digging variables as indicators of quality. We found that the mechanized digging operation in Sandy soil was the most critical, just meeting the specifications of quality indicators, reflecting higher losses and lower quality of the operation. Medium soil showed at the digging good and homogeneous conditions in relation to water content in soil and pods, and because it has favorable characteristics it obtained the lower total losses and higher quality of operation. Loamy soil showed satisfactory quality, meeting the specifications as well, but with poorer quality than the Medium Soil. <![CDATA[STABILITY OF PARTIAL NITRITATION OF POULTRY SLAUGHTERHOUSE WASTEWATER IN A SEQUENTIAL BATCH REACTOR]]> ABSTRACT The aim of this study was to monitor the stabilization of a sequential batch reactor (SBR) regarding the partial nitritation of poultry slaughterhouse wastewater, aiming at preparing it for a reactor with bacteria that promote anaerobic ammonia oxidation (anammox). A cylindrical reactor with a useful volume of 3.5 L, mechanical agitation (50 rpm), and suspended biomass was used in the experiment. The strategies adopted for nitrite-oxidizing bacteria (NOB) inhibition were cycle time (CT: 24, 16, 6, 5, 4 h and real-time monitoring), free ammonia accumulation, alkalinity restriction and low concentrations of dissolved oxygen (DO). The ammonification process, observed at all experimental phases, negatively influenced the control of partial nitritation process. Alkalinity restriction under low cycle times (4 and 5 h) conditions, together with low dissolved oxygen concentration, was a key factor for nitrite-oxidizing bacteria inhibition. Stability of partial nitritation was only reached by real-time monitoring, being the cycles stopped when 50% N–NH4+ and 50% N–NO2− were present in the reactor. <![CDATA[HYDRAULIC CONDUCTIVITY VARIABILITY IN HORIZONTAL SUBSURFACE FLOW CONSTRUCTED WETLANDS]]> ABSTRACT Many modifications in hydrodynamic conditions occur inside the bed of a horizontal subsurface flow constructed wetland (HSSF–CW) in operation. Studies on hydraulic conductivity measurement techniques in HSSF–CW are imperative since the monitoring of flow conditions is essential for understanding and controlling its clogging. This study aimed to assess the hydrodynamic behavior in HSSF–CW by means of saturated hydraulic conductivity (Ks) analysis. For this, six HSSF–CW were used: two non-cultivated (control), two cultivated with Tifton 85 (Cynodon spp.), and two cultivated with alligator weed (Alternanthera philoxeroides). Application of swine wastewater (SW) in HSSF–CW started on June 15, 2011, with Ks measurement period between September 9 and November 11, 2011, in which five measurements were performed in different positions along the system length and over experimental period in order to assess the effects of vegetation, position, and time factors on this variable. Ks values ranged from 1,392 to 2,834 m d−1. Plant presence led to Ks decreasing in the systems, but cultivated species had no influence on this variable. Monitoring time of HSSF–CW was no longer enough to provide a reduction in Ks, at 10% probability level. <![CDATA[CHANGES IN SOIL CHEMICAL PROPERTIES PROMOTED BY FERTIGATION WITH TREATED SANITARY WASTEWATER]]> ABSTRACT We evaluate the application of treated sanitary wastewater (TSW) to provide potassium for crops and reduce demand for fresh water and mineral nutrients. The field experiment was arranged in randomized block design with four replications and five treatments: 50, 100, 150 and 200% of potassium requirements and a control with conventional fertilizer. The TSW was applied to maize (November 2012 to February 2013), cotton (June to November 2013) and bean (April to June 2014). After bean, soil chemical properties were evaluated until 0.8 m depth. Fertigation with TSW to potassium fertilization provided about 50% of water, nitrogen and phosphorus to the bean. The soil nutrient availability and soil organic matter did not increase, whereas sodium had linear increased with TSW levels in investigated soil depth. Soil pH showed same behavior that sodium, with the highest pH level of 6.5 in 0-0.2 m soil layer. Soil nutrients and organic matter did not increase with TSW doses up to 0.8 m depth. Soil pH and sodium had linear increasing with TSW doses, respectively up to 0.6 and 0.8 m soil depth. Fertigation with potassium recommendation also provided a high content of sodium, threatening the balance of soil-plant system with continuous use. The sodium should be the first reference to permanent wastewater reuse in agriculture. <![CDATA[ECONOMIC AND FINANCIAL VIABILITY OF DIGESTER USE IN CATTLE CONFINEMENT FOR BEEF]]> ABSTRACT This research analyzes the economic and financial feasibility of implementing a biodigester for confinement of beef cattle on a farm located in the State of São Paulo, through the approach of discounted cash flow. The anaerobic digestion technology arouses interest, due to its advantages with the generation of electricity and the pollution reduction of water resources, soil and air, from the biogas and bio-fertilizer production, high value-added products to cattle raising. It was verified that the treatment system of cattle manure with biodigesters generate biogas and fertilizer as revenue, with free cash flows that enable a return on investment in 3.8 years and return an IRR 26.40% and an MIRR of 10.69%; all above than the minimum rate of attractiveness which confirmed the economic and financial viability of the investment. <![CDATA[TIMBER BEAM REPAIR BASED ON POLYMER-CEMENTITIOUS BLENDS]]> ABSTRACT This study aims to manufacture and apply polymer-cementitious blends based on a combination of epoxy polymer and Ordinary Portland Cement (OPC) for timber beam repair. The material was used to repair timber beams of “Maçaranduba” (Manilkara sp.) and “Cedro doce” (Cedrella spp) wood species. A full factorial design was conducted to investigate the effect of cement particle content (0wt%, 30wt%, 40wt% and 50wt %), type of cement (ASTM-II and ASTM-III), and pigment addition (0wt% and 0.2wt%) on the physical and mechanical properties of the blend. The cement content factor affected all properties investigated. The highest elastic modulus was achieved by the blends produced with 50wt% of cement and 0.2wt% of pigment inclusion. This condition was used to repair the timber beams evaluated under four-point bending test. The insertion of the blends in timber beams achieved superior load levels to the unreinforced woods in both species, inferior load levels to the reference condition (without defects) in “Cedro doce”, and superior to the reference condition in “Maçaranduba”. These results were justified by the low density of “Cedro doce”, providing a better blend-wood interface adhesion. <![CDATA[PHYSICO-MECHANICAL CHARACTERIZATION OF THE <em>Anadenanthera colubrine</em> WOOD SPECIE]]> ABSTRACT In Brazil, the characterization of wood is carried out in accordance with the premises established by ABNT NBR 7190standard; however, the determination of wood properties requires the use of equipment, which hinders the wood characterization for the construction professional. To circumvent this problem, the properties of wood strength and stiffness can be estimated through regression models using the apparent density as estimator, being the density a physical property of easy determination. This study aimed to determine 4 physical and 13 mechanical properties of “Angico Branco” wood (Anadenanthera colubrina), and with the aid of regression models based on analysis of variance, estimate the strength and stiffness properties as a function of apparent density. Twelve samples were produced for each test, resulting in a total of 204 experimental determinations. The results of mechanical properties showed consistent performance with other wood species studied, demonstrating their potential use in various applications. From the regression models, only the longitudinal modulus of elasticity in parallel compression to the grain showed a significant result, and the best were obtained with the linear model, which provided determination coefficient (R2) equal to 56.32%. <![CDATA[CALCIUM NITRATE CONCENTRATIONS IN FERTIGATION FOR ‘TERRA’ BANANA PRODUCTION]]> ABSTRACT The aim of this study was to evaluate the effect of calcium nitrate concentration of irrigation water on soil chemical attributes and productivity during the first ‘Terra’ banana crop cycle. The experiment followed a completely randomized design with six treatments and five replications, with six plants per plot. Treatments consisted in the use of three calcium nitrate concentrations (3.0, 10.0 and 13.0 g.L−1), applied via dripping and micro-micro-sprinkling irrigation. The results showed that the soil chemical properties under fertigation are influenced by the water and nutrient delivery system. There was a linear tendency of increase in electrical conductivity of the saturation extract and soil solution with the increase in calcium nitrate concentration in irrigation water. The banana tree productivity was influenced by the fertilizer concentration in irrigation water. <![CDATA[LOW-COST AUTOMATION OF FERTIGATION WITH PROGRAMMABLE LOGIC CONTROLLER AND GAS-FILLED SENSORS]]> ABSTRACT The aim of this study was to develop and evaluate a low-cost automation system for management of different fertigation regimes in tomato plants (Solanum lycopersicum L.) grown in a protected environment. The system consisted of an irrigation controller coupled to substrate moisture sensors and to a programmable logic controller (PLC). Four water regimes and nutrient supply levels were considered during evaluations. While developing, functional tests were performed to the automation system. Moreover, a cost-benefit analysis for the assembling of the system was carried out. As result, we noted that the automation system was efficient for controlling fertigation. It showed no problems regarding malfunction, still presenting a lower cost if compared to commercial controllers.