Scielo RSS <![CDATA[Engenharia Agrícola]]> vol. 37 num. 6 lang. es <![CDATA[SciELO Logo]]> <![CDATA[BIOGAS PRODUCTION FROM DAIRY CATTLE MANURE, UNDER ORGANIC AND CONVENTIONAL PRODUCTION SYSTEMS]]> ABSTRACT The purpose of this study was to evaluate the production of biogas, as well as the biogas production potential resulting from the anaerobic biodigestion of dairy cattle manure under organic (CMOS) and conventional (CMCS) production system. Also, the concentration of thermotolerant coliforms was evaluated after the biodigestion process. Therefore, bench biodigesters prototypes were supplied with CMOS and CMCS for 30 weeks. The experimental design was completely randomized with four repetitions for each treatment. Analysis of total solids (TS), volatile solids (VS), biogas production potential, most probable number (MPN) of thermotolerant coliforms were made. The cumulative biogas production was 6.18 L and 11.15 L, when using the CMOS and CMCS, respectively. Average biogas production potential of CMCS were 0.2; 2.6 and 2.9 L kg-1 substrate, ST and SV added, respectively and for CMOS 0.1; 1.4 and 1.9 L kg-1substrate, ST and SV added, respectively. After the anaerobic biodigestion process of CMOS and CMCS, it was observed that the concentrations of thermotolerant coliforms were well below than the limit established by law. <![CDATA[ESTIMATION OF THE KINETIC HEAD COEFFICIENT (k) BASED ON THE GEOMETRIC CHARACTERISTICS OF EMITTER PIPES]]> ABSTRACT: The objective of this study was to determine the variability of the head loss as a function of the emitter geometry as well as to develop a relation between local head loss caused by the emitter insertion and geometric characteristics of the emitter pipe, using index of obstruction for dripper pipes with non-coaxial emitters. For this, an experimental bench was developed to control the system and obtain the variables pertinent to the study. From the value of the total head loss in the emitter pipe and the value obtained with calculation of the distributed head loss in the pipe, the difference of these values was local head loss caused by the insertion of the emitter. Total head loss in the emitter pipe and local head loss on the emitter presented a potential relation with flow rate. The kinetic head coefficient (k), for each emitter studied, was obtained from the local head loss on the emitter and the kinetic head. A model for estimating the k coefficient based on the obstruction index was then generated. <![CDATA[FUZZY MODELING ON WHEAT PRODUCTIVITY UNDER DIFFERENT DOSES OF SLUDGE AND SEWAGE EFFLUENT]]> ABSTRACT: This study aimed to evaluate the effects of fertilization with composted sewage sludge and irrigation with drinking water (DW) and fertigation with wastewater (WW) in wheat crop using fuzzy rule-based system. The experiment was conducted in the Department of Soil and Environmental Resources, of FCA, UNESP - Botucatu, with factorial 6 × 2, which were applied 6 doses of sewage sludge (0, 50, 100, 150, 200 and 250% of nitrogen recommendation) and two types of effluents (treated water and sewage). In the developing of the system based in fuzzy rules, it was used the Mamdani inference method, where the input variables were sewage sludge doses and water types and the output variables used were the number of tillers, length and number spike per plant; number of spikelet per plant, grain mass per spike and dry mass of the aerial parts. It can be seen that the sewage sludge and the effluent contributed to the higher increase of production, and at 150% sludge dose occurred higher production. <![CDATA[REFERENCE EVAPOTRANSPIRATION FORECASTING BY ARTIFICIAL NEURAL NETWORKS]]> ABSTRACT: Evapotranspiration (ET) is the main component of water balance in agricultural systems and the most active variable of the hydrological cycle. In the literature, few studies have used the forecast the day before via Artificial Neural Networks (ANNs) for the northern region of São Paulo state, Brazil. Therefore, this aimed to predict the reference evapotranspiration for Jaboticabal, the major sugarcane-producing region of São Paulo state. We used a historical series of data on average air temperature, wind speed, net radiation, soil heat flux, and daily relative humidity from 2002 to 2012, for Jaboticabal, SP (Brazil). ET was estimated by Penman-Monteith method. To forecast reference evapotranspiration, we used a feed-forward Multi-Layer Perceptron (MLP), which is a traditional Artificial Neural Network. Numerous topologies and variations were tested between neurons in intermediate and outer layers until the most accurate were obtained. We separated 75% from data for network training (2002 to 2010) and 25% for testing (2011 to 2013). The criteria for assessing the ANN performance were accuracy, precision, and trend. ET could be accurately estimated with a day to spare at any time of the year, by means of artificial neural networks, and using only air temperature data as an input variable. <![CDATA[PEANUT CULTIVARS SUBMITTED TO IRRIGATION LEVELS AND NITROGEN ADUBATION IN TROPICAL CLIMATE]]> ABSTRACT: The objective of this study was to define the best irrigation level in a sprinkler system, submitted to nitrogen doses in covering in the municipality of Tangará da Serra - MT, for two cultivars of peanut (Arachis hypogaea L.). The experiment was carried out in the experimental field of the State University of Mato Grosso (UNEMAT), located geographically in latitude 14°39′S; Longitude 57°25′W, at 440 meters of altitude. The climate is classified as tropical humid megathermal (Aw), with annual average rainfall of 1,830 mm and average temperature of the air 24.4°C. The soil is classified as Dystroferric Red Latosol. The experimental design was in randomized blocks where 4 levels (30, 70, 110 and 150% of the reference evapotranspiration, ET0) were determined. In each level, 0, 30, 60, 90 and 120 Kg ha-1 of nitrogen were applied in two peanut cultivars IAC Tatu ST and IAC Runner 886. Each plot had 24 lines per 12 m length, 4 lines for each dose of N in each level and cultivar with 0.45 m spacing between lines. The irrigation level that provided the highest productivity in the development cycle for both peanut cultivars was 110% of ET0. While the levels of 30 and 70% of the ET0 allowed greater growth in height, but smaller productivities, the 150% ET0 level showed higher yields in the husk, and lower grain yield due to the high germination rate of the grain yet in the plant. For Tatu cultivar, doses of 60 to 90 kg ha-1 of N increase productivity, whereas for Runner cultivar nitrogen fertilization did not affect productivity. <![CDATA[SUPPLEMENTATION OF NUTRIENTS FOR TABLE BEETS BY IRRIGATION WITH TREATED DAIRY EFFLUENT]]> ABSTRACT: This study was conducted to evaluate the nutritional status of table beet plants cultivated in a greenhouse irrigated with treated dairy effluent at different irrigation depths. The experimental design used was a randomized block in a 3 x 3 + 1 factorial arrangement with four replications and conducted in a greenhouse. The treatments consisted of three types of water sources and three irrigation depths applied by drip irrigation: anaerobic effluent; anaerobic/aerobic effluent; tap water, and irrigation for replenishment 50; 100 and 150% of the crop evapotranspiration (ETc). All these treatments were applied in combination with 50% of the recommended nitrogen fertilization for the table beet cultivation. A control treatment was irrigated with tap water with irrigation depth equal to 100% ETc and received the complete dose (100%) of mineral nitrogen fertilizer. Table beet seedlings were arranged in 40 fiberglass boxes with a base area of 1 m2. Table beets were harvested 72 days after transplanting (DAT) when the leaves and roots were analyzed. Irrigation with wastewater promoted appropriate levels of macronutrients, distributed between the leaves and roots. The sodium was increased significantly in the leaves and roots of table beets in effluent treatments at increasing irrigation depths, which was antagonistic to the absorption of potassium. <![CDATA[DISTRIBUTION OF MAIZE SEED IN A SEEDING LINE PROTOTYPE USING MICROCONTROLLED DATA ACQUISITION SYSTEMS]]> ABSTRACT: The aim of this study was evaluate the longitudinal distribution of maize seeds using a seeding line prototype, whit a microcontroller data acquisition system, at different speeds and types of horizontal feeder discs. Initially it was constructed a prototype simulator of seeding line, in the laboratory, and mounted two systems of microcontroller data acquisitions with infrared sensors for maize seeds counting. A test was conducted in a completely randomized design in split plots with factorial scheme of treatments 5 x 2 x 2, being the parcel two types of microcontroller data acquisition systems (infrared sensors in parallel and an diffuse infrared sensor), the factors were two feeder discs of maize seeds (inclined and normal) and five sowing speeds (3.0, 4.0, 5.0, 6.0, and 8.0 km h-1), with three replications, totaling 60 plots. The results showed that the data acquisition systems presented efficiency higher than 93% in the perception of the seeds. The lower speeds provided a seed distribution closer to the desired. The spacing average error between seed with the microcontroller data acquisition system with diffuse sensor was 0.0206 meters and the system with infrared sensors in parallel was 0.0158 meters. <![CDATA[PERFORMANCE OF FERTILIZER METERING MECHANISMS OF PLANTERS AS A FUNCTION OF LONGITUDINAL INCLINATION]]> ABSTRACT: Sowing occurs in agricultural areas with irregular relief, influencing the quality of seed and fertilizer distribution. The aim of this study was to analyze the performance of different fertilizer metering mechanisms of planters as a function of longitudinal inclination. The experimental design was a completely randomized design with five treatments and six replications. Treatments consisted of five longitudinal inclinations to the metering mechanism (−10, −5, 0, 5, and 10 degrees). The mass of fertilizer collected per minute was considered as a replication. We worked with two types of fertilizers: a mixture of granules and powder. Metering mechanisms used were a horizontal toothed rotor, helical without flow restrictor, helical with lateral overflow, and helical with longitudinal overflow. The longitudinal inclination of ±10° in relation to the leveling altered the metered amount of both fertilizers used in all metering mechanisms. The helical with lateral overflow was the metering mechanism that obtained the smallest amount variation of fertilizer distributed in the different longitudinal inclinations, followed by the helical with longitudinal overflow, horizontal toothed rotor, and helical without flow restrictor. <![CDATA[SPRAY DRIFT AND CATERPILLAR AND STINK BUG CONTROL FROM AERIAL APPLICATIONS WITH ELECTROSTATIC CHARGE AND ATOMIZER ON SOYBEAN CROP]]> ABSTRACT: The use of aerial application with electrostatic charge is an alternative to improve the quality of insecticide applications in soybean crop. The objective of this study was to evaluate the drift and chemical control of the caterpillar and stink bug complex promoted by aerial applications of insecticide in the soybean crop, using electrostatic spray system and rotary atomizers. The insecticide Thiamethoxam + Lambda cyhalothrin was applied with a Cessna 188 Ag Truck agricultural aircraft in two treatments: SPE® electrostatic system, with 54 SPE-5 nozzles and 10 L ha-1 application rate, and Travicar model® 05165 rotary atomizer, with 55° angle blades and application rate of 20 L ha-1. Drift was evaluated through quantification of active ingredient, by means of liquid chromatography, on nylon strings set 20, 40, 80, 160 and 320 m downwind from the applied area. Control efficiency was measured by counting caterpillars and stink bugs found five days after application. The droplet spectrum was also evaluated through water sensitive papers placed in the target area. It was verified that the hydraulic nozzles, associated with the electrostatic system, generated lower drift, but there was no difference in pest control efficiency, in relation to the rotary atomizers. <![CDATA[QUALITY OF MECHANICAL SOYBEAN HARVESTING AT TWO TRAVEL SPEEDS]]> ABSTRACT: Soybean harvesting is the last operation performed in the field and therefore has high added value. Quantitative losses during this process should therefore be minimized to achieve maximum quality and increase the sustainability of the production system. The aim of the present study was to determine and characterize the quantitative losses and operational characteristics of an axial-flow combine harvester, using tools from Statistical Quality Control to determine the quality of the harvesting operation. The experiment was designed in accordance with the assumptions of statistical process control, with a total of 40 sampling points monitored over time. Quality indicators of harvester performance and crop agronomic characteristics were evaluated at two harvester travel speeds (5 and 7 km h-1). The stability of the process was confirmed for the variables indicated by the analysis of run charts for the variables engine water temperature at a travel speed of 5 km h-1; engine oil pressure, fuel consumption and cutting height at a travel speed of 7 km h-1; and losses at both speeds, indicating that these were only affected by natural causes. <![CDATA[SPRAYING QUALITY OF CROP PROTECTION PRODUCTS USING TWO DROPLET SPECTRA IN THREE PERIODS OF THE DAY]]> ABSTRACT: Spraying of crop protection products can be affected by weather conditions and spray nozzles, altering deposition patterns and coverage of the target surface. The objective of this research was to analyze the quality of sprayings performed in three periods of the day (9:00 am, 2:00 pm, and 6:00 pm), using two different droplet sizes (fine and coarse) in soybeans. Coverage and deposition were evaluated in the upper, middle, and lower portion of soybean canopy. Spraying the products at 2:00 pm increased leaf coverage in the medium portion but also increased losses to the soil. Spray nozzles with fine droplet sizes provided greater coverage and deposition in the medium and upper portion of the crop for the sprayings performed in the morning. If compared to coarse droplets, fine droplets increased leaf coverage and had no interference with the losses to the soil. <![CDATA[IDENTIFICATION OF DESERTIFICATION- SENSITIVE AREAS IN THE BRAZILIAN NORTHEAST THROUGH VEGETATION INDICES]]> ABSTRACT: The aim of this study was to identify areas susceptible to drought and under desertification in the Brazilian Northeast, more specifically in the states of Alagoas, Pernambuco, and Sergipe. The study was based on the 2000-2014 time period, relative frequency, Vegetation Condition Index (VCI) dataset derived from MOD13Q1 products (vegetation indices derived from the Moderate Resolution Imaging Spectroradiometer sensor). The areas located within the desertification nucleus of Cabrobó, in the southwestern of Pernambuco and surrounding the Águas Belas municipality were considered susceptible to drought and desertification. Some municipalities in the countryside of Alagoas showed a very low relative frequency of VCI data (45-50%), and occurrence of areas between 55-60%. Tthe Sergipe state presented a relative frequency VCI data around 50% only in the Poço Verde municipality. Among the areas with low rates of VCI and the most frequently identified in this research, therefore, with greater frequency of droughts, the Southwestern and the Southern Pernambuco hinterlands were not considered as pilot areas by MMA (Brazilian Environment Ministry) in its desertification studies and were included as susceptible for desertification in this study. The results suggest the use of this methodology to subsidize formulations of public policies with application in land use and land cover studies or sustainable development and environmental risk analysis. <![CDATA[MILK PRODUCTION AS AN INDICATOR OF DROUGHT VULNERABILITY OF CITIES LOCATED IN THE BRAZILIAN SEMIARID REGION]]> ABSTRACT Several spectral indices have been used to estimate droughts, however, these indicators only give evidence of a dry spell leaving out its impacts on significant economic activities performed in a given region. In this context, livestock breeding in one of the most important activities to analyze in the Brazilian semiarid region. The aim of this study was to evaluate the relationship between the drought indices, obtained through remote sensory devices, and annual milk production (2004 – 2014), identifying the most affected cities by the drought and were considered the most vulnerable and in need of special attention during dry periods. In order to analyze the data, the hierarchical grouping technique and correlation analyses between milk production and VCI - Vegetation Condition Index, TCI - Temperature Condition Index, VHI - Vegetation Health Index, PCI - Precipitation Condition Index and SDCI - Scaled Drought Condition indices were used. The intense correlation between milk production and the drought indices may be related to the dependency of the cities’ economies on natural resources. On the other hand, the diversification of the cities’ economic activities may enable access to various resources and drought vulnerability reduction. <![CDATA[USE OF ACTIVE OPTICAL SENSOR IN THE CHARACTERISTICS ANALYSIS OF THE FERTIGATED BRACHIARIA WITH TREATED SEWAGE]]> ABSTRACT Through the use of remote sensing, the productivity and the nutritional state of the plants can be estimated in relation to the nitrogen doses due to the modification of the canopy reflectance. In this study, values of the normalized difference vegetation index (NDVI) obtained by a terrestrial optical sensor were correlated with productivity and contents of nitrogen (N) and of foliar crude protein (CP) of Brachiaria brizantha cv. Marandu, fertigated with doses of sewage treatment effluent (STE) The NDVI average rates of the forage were obtained by the active terrestrial sensor (GreenSeeker) before the harvests that were realized every 28 days in 2014. Five fertigated treatments with the following fractions of STE in water were evaluated: E5 = 1.0; E4 = 0.87; E3 = 0.60; E2 = 0.31; and E1 = 0.11. During the 12 months of experiment, the treatment E5 received 1,132 kg ha-1 of N and the others received quantities proportional according to the application fractions defined in each treatment. The increasing application doses of STE resulted in higher yields of dry biomass and better leaf qualities in N and crude protein (CP). The productivity, the foliar N content and the NDVI index were increasing due to the gradual application of applied STE. There was a high linear correlation among the NDVI indexes and the productivity (r&gt;0.9256) and with the N content (r&gt;0.9570) and also for CP (r&gt;0.8421) and leaf N (r&gt;0.8339), demonstrating that the method can be used to estimate forage productivity and quality. <![CDATA[PERCOLATE QUALITY IN SOIL CULTIVATED WITH APPLICATION OF WASTEWATER FROM SWINE SLAUGHTERHOUSE AND DAIRY PRODUCTS]]> ABSTRACT The objective of this study was to evaluate the quality of the percolate in soil columns cultivated with Tiffon-grass 85 under different wastewater rates from swine slaughterhouse and dairy. The experiment was conducted at the Department of Engineering at the Federal University of Lavras, in PVC columns with 0.30 m of diameter and 1.2 m deep, filled with Dark Red Latosol cultivated with Tifton-grass 85. The treatments consisted of a (AQT0) control with recommended chemical fertilization for Tifton-grass 85 (300 kg ha-1 year-1 of N), and four doses of SSW and DPW (100, 200, 300 and 400% of the recommendation) in a CRD with 3 replications. The samples of percolated were collected and characterized weekly. The treatments of highest dosage have obtained COD, after 120 days, of 47.7 mg L-1 (AAT3) and 38.6 mg L-1 (AAT4). Although nitrate concentrations were elevated on the earlier months, the greater assimilation of nutrients by the Tifton-grass 85 and the reduction of the mineralization of organic material resulted in lower nitrate concentrations of 10 mg L-1. <![CDATA[EFFECT OF AERATION AND RECIRCULATION IN THE REMOVAL OF NITROGEN AND CHEMICAL OXYGEN DEMAND FROM SANITARY SEWAGE IN A STRUCTURED BED REACTOR]]> ABSTRACT This study aimed to evaluate a structured bed reactor with intermittent aeration in the simultaneous removal of Chemical Oxygen Demand (COD) and Total Nitrogen (TN) from sanitary sewage. The reactor was operated for 339 days with a Hydraulic Retention Time (HRT) of 12 hours, temperature of 30 ± 1°C and continuous feeding. Nine trials were carried out in which three different effluent recirculation flow (Qr), 3, 2 and 1 time the incoming flow, were evaluated in three different aeration times, of 1h, 2h, and 3h, in 3 hour cycles. The results showed that different recirculation flows and aeration times did not influence the removal of COD, which reached 89%±12. It was observed that the efficiency of TN removal was higher in the tests with higher COD/TKN ratio, between 7.2 and 7.8, reaching TN effluent values of 17 mg.L-1, being 5 mg.L-1 of N-NH4+, 2 mg.L-1 of N-NO2 and 10 mg.L-1 of N-NO3-. It was verified that it is possible to remove the COD and nitrogen from sanitary sewage in a structured bed reactor with intermittent aeration. <![CDATA[CHEMICAL PROPERTIES OF SOIL FERTIRRIGATED WITH DAIRY AND SLAUGHTERHOUSE WASTEWATER]]> ABSTRACT The aim of this study was to evaluate the soil chemical properties submitted to fertigation with slaughterhouse (SW) and dairies (DW) wastewater. 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 years-1 of N) consisted of four doses of SW and DW (100, 200, 300 and 400% of the recommendation) and AQT0 control at random. The soil was collected at a depth of 0.30 m and, subsequently, characterized in terms of physical, chemical and physicochemical. The application of treatment of the largest irrigation of DW provided, after 120 days of monitoring, N concentration of 1.85 g kg-1. However, the treatment with AQT0 obtained N concentration of 0.81 g kg-1, in the soil. We observed that the largest irrigation of SW provided increases of 2.62 and 5.49 g kg-1, respectively, in the P and K concentrations of the soil. There was quadratic increase in the N concentration in the 0.30 m soil depth of the columns with the increase in the applied irrigations of SW and DW, being obtained maximum values of 1.85 and 1.02 g kg-1 that were obtained in the relative irrigation of the application dose of 600 kg ha-1 of N. <![CDATA[RESIDUE ANALYSIS OF ORGANOCHLORINE AND ORGANOPHOSPHORUS PESTICIDES IN URBAN LAKE SEDIMENTS]]> ABSTRACT The knowledge of pesticide residual concentrations in the environment is important to understand the threats to the environment and human health, especially when natural resources are used for human consumption. In this context, this study aimed to assess the potential ecological risk and respective sources of sediment contamination by organochlorine and organophosphorus pesticides. The study site was an urban lake located in Cascavel city, western Paraná state, Brazil, where the history of land use and occupation in the urban environment is typically agricultural. Surface sediment samples were collected every three months from April 2010 to June 2013 at five different collection points, totaling 65 samples. Analyses showed that contamination by organochlorine pesticides is related to agricultural activities in the past, with a low ecological risk to benthic organisms. Conversely, organophosphorus pesticides presented a recent and continuous contamination from urban activities, with a risk coefficient, especially for disulfoton, indicating a significant potential adverse effect on organisms. However, in general, the obtained results did not indicate an immediate risk to public health. <![CDATA[ASSEMBLY OF A REMOTELY PILOTED AIRCRAFT OF LOW COST APPLIED TO AGRICULTURE]]> ABSTRACT: The remotely piloted aircraft (RPA) have great applicability in agriculture. Although it is a technology that has been developed for many years, in the field of agriculture it passed unnoticed for a long time. The high cost of acquisition is still a limiting factor for small and medium-sized farmers. In this way, this study had as objective to develop a low cost RPA for agriculture application. In the present study, the development and the assembly of an RPA prototype of a quadcopter type is presented, consisting of four engines and of vertical propulsion, capable of moving without human intervention, that is, autonomous flight, applied to agriculture and low cost investment. In it was boarded a data control and processing system collected from sensors and cameras, using hardware and software from a free platform (Open Source). The assembly equipment showed to be robust, with a payload of approximately 1,000 grams, with an acquisition cost (R$ 2,393.16), included the camera module, much lower than those commercially available and suitable for the agricultural application, as acquisition, processing and interpretation of digital images, due to the quality of the images obtained. <![CDATA[ERRATUM]]> ABSTRACT: The remotely piloted aircraft (RPA) have great applicability in agriculture. Although it is a technology that has been developed for many years, in the field of agriculture it passed unnoticed for a long time. The high cost of acquisition is still a limiting factor for small and medium-sized farmers. In this way, this study had as objective to develop a low cost RPA for agriculture application. In the present study, the development and the assembly of an RPA prototype of a quadcopter type is presented, consisting of four engines and of vertical propulsion, capable of moving without human intervention, that is, autonomous flight, applied to agriculture and low cost investment. In it was boarded a data control and processing system collected from sensors and cameras, using hardware and software from a free platform (Open Source). The assembly equipment showed to be robust, with a payload of approximately 1,000 grams, with an acquisition cost (R$ 2,393.16), included the camera module, much lower than those commercially available and suitable for the agricultural application, as acquisition, processing and interpretation of digital images, due to the quality of the images obtained.