Resumo em Inglês:

ABSTRACT The aim of this work was to evaluate the effects of variations in soil compaction on the stability of the slope embankments of fish farms used in aquaculture. Computational modeling was performed using the RocScience Slide 6.0 program, simulating filling scenarios, fast lowering and stationary regimes for the full operation of the fish farms. The data used in these simulations were obtained from soil characterization tests in the laboratory. The geometry of the levees, the inclination of the slopes and the crest width and height, also necessary for modeling, were obtained from field data and technical projects. The modeling generated a safety factor (SF) for the upstream and downstream slopes of the levees, considering different upstream slopes, for three types of levees (L1, L2 and L3). The results have shown that the variation in soil compaction, regardless of the upstream inclination of the slopes, maintains the stability of the levee slopes, as it generated safety factors above the acceptable minimum (> 1.5). Decreasing the speed of lowering the water column in the fish farm does not compromise the stability of the embankments of the levees. The construction of superficial pond levees for aquaculture can be performed at points below the optimum water contents for compaction since the stabilization of these structures showed SF values above the minimum required.

Resumo em Inglês:

ABSTRACT This research was conducted with the objective of evaluating the thermal inertia and hysteresis of the following materials in a wind tunnel: hollow copper sphere with 150.0 mm diameter used as standard in globe thermometers, hollow brass sphere with 75.0 mm diameter, and two hollow plastic spheres with 115.5 and 69.7 mm diameter. The results showed that the thermal inertia and hysteresis for the hollow copper sphere were approximately 24 and 28 min, respectively; these values were bigger than those obtained for the other spheres, implying faster responses of these. While there were no statistical differences in the measurements conducted by globe thermometers which are used to indicate the black globe temperature with the different types of spheres mentioned above under indoor environment conditions, i.e., with no wind and solar radiation, the wind causes faster cooling in smaller spheres under outdoor environment conditions, which may denote erroneous interpretations of the measurements at those instants. It was concluded that it is possible to replace the hollow copper sphere of diameter 150 mm by other types of spheres to measure the black globe temperature. However, this requires knowledge of the response times of the spheres as well as corrections to be made in the measurements with respect to the globe thermometer standard.

Resumo em Inglês:

ABSTRACT Plant yield is strongly influenced by the amount of water used by it. In this sense, yield response factor (Ky) allows evaluating the decrease in yield as a function of the evapotranspiration that occurs, which may be an important tool for harvest forecasting. Therefore, this study aimed to determine Ky for winter corn crop grown in the region of Dourados, MS, Brazil. The yield function analysis based on the water factor, which requires actual (Ya) and maximum (Ym) yield data, as well as actual (ETa) and maximum (ETm) evapotranspiration, was used to adjust Ky. Ym was assumed to be 8,820 kg ha−1, while Ya was obtained for each season from the database SIDRA from IBGE. ETm and ETa were estimated by sequential daily water balance, considering four different sowing dates (all in the off-season). In total, seasons from 2001 to 2013 were analyzed. The high Ky value obtained (1.22) for winter corn crop showed its high sensitivity to water deficit. Its yield is strongly influenced by water availability so that for every 1% reduction in evapotranspiration, there is a 1.22% yield reduction.

Resumo em Inglês:

ABSTRACT The answers to when and how much to irrigate orchards can be obtained based on the measurements of plants' transpiration and leaf temperature. This study aims to determine the leaf temperature and sap flow of the pequi tree (Caryocar brasiliense Camb.), both with and without water restriction. Further, the leaf temperature was measured by infrared thermometry and estimated transpiration using the Granier method, where the thermal dissipation probes are inserted into the plant stems. The experiment was conducted in a 120-plant orchard located in Goiânia-GO, Brazil, from which seven of the plants (3 irrigated and 4 non-irrigated; aged 6.6–7.4 years) were evaluated for eight months (October 2015 to May 2016). The soil was characterized as a dystrophic red latosol, and its water content was determined using the EC-5 capacitance sensors. The results denoted that the leaf temperature of the irrigated plants was lower than the median air temperature during summer and the transition period into the dry season, and the non-irrigated plants exhibited shortage of water availability during the dry season. In dryland conditions, the average transpiration was 24.09 L plant−1 day−1 and, when irrigated, became 42.29 L plant−1 day−1.

Resumo em Inglês:

ABSTRACT Paricá (Schizolobium amazonicum) can be used for rehabilitation of degraded lands, timber manufacturing markets. However, for its planting, high-quality seedlings should be used. Thus, this study aimed to evaluate the effect of different types of paclobutrazol (PBZ) application and two shading levels on high-quality seedling production. As there was no replication of cultivation environments, we considered each one of them as an experiment. For each environment (35 and 50% shading screen), a completely randomized design was adopted, testing combinations of two types of PBZ application (direct seed immersion in 0.005% PBZ solution; substrate hydration with 0.005% PBZ solution; and 50% seed hydration and 50% substrate hydration; plus, a control), with five replications and five seedlings per plot. The environments were evaluated by analysis of groups of experiments. Seedling growth was evaluated. Under 50% shading, Paricá seedlings had better growth conditions. Application of 100% PBZ in substrate provided compact seedlings with larger dry root phytomass, besides being more practical.

Resumo em Inglês:

ABSTRACT Seasonal changes in agricultural soil use due to agroclimatic conditions affect the water cycle in watersheds. This study aimed to understand the temporal variation of runoff inherent to the seasonal occupation dynamics of the agricultural soil in the basin that drains the upper valley of the Marrecas River, upstream of the urban perimeter of Francisco Beltrão, PR. The effects of runoff were verified through flow peaks simulated by the HEC-HMS model in twelve monthly soil use scenarios, under seven precipitation return periods. The results indicated a strong relationship between bare soil and flow peaks, temporally delimiting April and March as the largest runoff generators and January and August as the smallest ones. The ratio quantified by rates of increase in flow peaks ranging from 0.78 to 1.64 m3 s−1 per km2 of bare soil. In addition, the survey of historical precipitation data also warns of the generation of large runoff volumes in October. Therefore, the strong correlation between the increase in flow peaks and occupation by bare soil can be quantified with good precision, but it is also necessary to consider historical precipitation records to understand the temporal distribution of runoff and flood risks.

Resumo em Inglês:

ABSTRACT Adjuvants are tools to maximize pesticide spray quality. This study aimed to evaluate the interaction effects between adjuvants and the fungicide azoxystrobin + benzovindiflupyr on the physicochemical characteristics, droplet evaporation time, and spray droplet size. The experiment was carried out using a 2×6 factorial scheme, in which the first factor was the absence or presence of the fungicide mixture (water or water + fungicide) and the second factor was the presence of different adjuvants (water and five adjuvants). The parameters evaluated were surface tension, pH, viscosity, electrical conductivity, droplet evaporation time, volume median diameter, percentage of droplets smaller than 100 μm, and relative amplitude of the droplet spectrum. The silicone and propionic acid + soy lecithin adjuvants reduced the pH of the spray solution, and the sodium lauryl ether sulfate, propionic acid + soy lecithin, and orange essential oil adjuvants reduced droplet evaporation when mixed with the fungicide. All tested adjuvants improved spray quality related to the characteristics of the droplet spectrum, reducing the percentage of droplets smaller than 100 μm, and allowing more uniform droplet size. The fungicide azoxystrobin + benzovindiflupyr affected droplet evaporation time.

Resumo em Inglês:

ABSTRACT The soil management system affects physical attributes, and the forward sowing speed can increase or decrease its results. Thus, this work aimed to evaluate management systems before and after soil mobilisation and forward sowing speed on soil physical attributes. Thus, an experiment was conduct in a completely randomized block design with four replications and six soil management systems: no tillage (NT), medium harrowing (MH), subsoiling operation (S), subsoiling and medium harrowing operations (S+MH), cross-subsoiling and medium harrowing (S+MH), and ploughing and two medium harrowing (P+2MH), and four forward sowing speeds: 3.1, 5.1, 5.8, and 7.9 km h−1, applied in the subplots. Soil management affects soil penetration resistance (PR) values, pointing out the highest PR occurring in no-tillage beyond critical limits. Soil bulk density (sD) is affected by management and forward sowing speeds. The medium harrowing operation has higher sD and the ideal forward sowing speed range to mitigate this effect would be 5.0 to 7.0 km h−1. Moreover, it also presents a higher amount of macropores in the 0.20–0.30 m layer. Management system without soil mobilisation favours an increase in soil microporosity, and the use of subsoiler as tillage equipment should be carried out at slower speeds to favour the increased micropores.

Resumo em Inglês:

ABSTRACT The mechanized harvesting process of sugarcane seedlings affects the mechanized planting operation in the sense that straw adhered to the billet can reduce the quantity of non-viable gems obtained as a result of mechanical damage sustained during the mechanized operation. This study proposes a method to improve the quality of the implantation of sugarcane crop by prevention of damages caused mainly during October/November, when adverse climatic conditions of higher water stresses and high temperatures exist. The objective of this study is to evaluate the quality of the sugarcane planting operation using seedlings with and without straw, distributed by planters and distributors of chopped sugarcane, and comparing their performance to that of semi-mechanized planting. The study was conducted at Fazenda Santa Clara, located in Pradópolis - São Paulo, Brazil and considered five processes: mechanized planting of seedlings without straw, mechanized planting of seedlings with straw, mechanized distribution of seedlings without straw, mechanized distribution of seedlings with straw, and semi-mechanized planting. Fifty sample points were used to collect data for each process, as per the principles of Statistical Process Control. The number of unfeasible gems and faults in the stand reduced with the presence of straw in the grinding wheel, in addition to less variability being presented. The presence of straw in the billet enabled the best overall quality of sugarcane plantation.

Resumo em Inglês:

ABSTRACT Agricultural spray adjuvants (ASA) are widely used in pesticide applications to enhance the performance of pesticides. The aim of this research was to investigate the effects of ASA on static surface tension (SST) and foliar spray retention on coffee leaves. The SST of ASA at different concentrations was determined by the drop weight method. Spray retention on adaxial and abaxial coffee leaf surfaces was performed using a micro-sprayer at solution concentrations of 0, 0.01, 0.1, 0.5, and 1.0% v v−1. The ASA assessed were: polyether-polymethylsiloxane-copolymer (PPC); Nonylphenol ethoxylate; nonyl polyethylene glycol ether; mineral oil; nonylphenoxy polyethoxy ethanol; carboxyl copolymer of styrene and butadiene; primary aliphatic oxyalkylated alcohol plus carboxyl copolymer of styrene and butadiene; and soyal phospholipids and propionic acid. All ASA reduced the SST of the aqueous solutions. PPC provided the best performance in decreasing SST, reaching values below 20 mN m−1 at a concentration of 0.05% v v−1. Spray retention on leaves was influenced by adjuvant type as well as concentration. A very strong positive correlation between SST and spray retention on coffee leaves was observed. Decreasing the SST of the solution provided a reduction of spray retention when spraying was performed until run-off point.

Resumo em Inglês:

ABSTRACT This work aimed to study the immediate and latent effects of different relative humidities on the quality of dried coffee fruits, describe the drying kinetics of natural immature coffee (Coffea arabica L.), and evaluate the mathematical model that best fits the experimental drying data. The drying was carried out in a fixed layer dryer coupled to a composite air conditioning system in which the drying air was controlled with an air flow of 20 m3.min1.m−2, at a temperature of 40 °C, and at relative humidities of 10%, 17.5% and 32.5%. Manually harvested coffee fruits were used and dried to a mean water content of 0.120 dry basis (d.b). After drying, the kinetic curve and the physical and physiological properties were determined. The coffee was stored in permeable packs for 6 months. The electrical conductivity, potassium leaching, and colour analysis were performed every 2 months. For the modelling adjustment, the models were tested, and the Midilli model had the best fit with the drying kinetics of the immature coffee. No immediate damage was observed in the physical and physiological quality of the coffees, and latent damage was perceived after 120 days of storage for the natural immature coffees.

Resumo em Inglês:

ABSTRACT We propose a segmentation algorithm for raisin extraction. The proposed approach consists of the following aspects. Deep learning is used to predict the number of raisins in each connected region, and the shape features such as the roundness, area, X-axis value for the centroid, Y-axis value for the centroid, axis length and perimeter of each region will be used to establish the prediction model. Morphological analysis, based on edge parameters including the polar axis, polar angle and angular velocity, is applied to search for the suitable break points that are useful for identifying the dividing lines between two adjacent raisins. To make our segmentation more accurate, some machine-learning algorithms such as the random forest (RF), support vector machine (SVM) and deep learning (deep neural network, DNN) are applied to predict the number of raisins and to decide whether the raisins need more segmentation. The performance of the three models is compared, and the DNN is the most accurate.

Resumo em Inglês:

ABSTRACT Grain drying processes have been improved to reduce costs and losses of coffee beverage quality. The objectives of this study were to evaluate the quality of coffee dried using air partially dehumidified before entering drying units (DUs) in four coffee-producing farms, as well as the effects of such process on coffee commercial value. The method consisted of obtaining three samples (triplicates) of coffee dried in both DUs and concrete terraces (control) for mean multiple comparisons. The following variables were analyzed for sieve #13 and hand-picked beans: defect number, cupping test, and pricing. Evaluations were carried out by three professional graders. The results showed that coffee dried in the DUs presented fewer broken grains, higher cupping score, and less negative factors of handsorting and defects. As a conclusion, it should be emphasized an average increase of 12.11% in price for coffee beans previously dehumidified.

Resumo em Inglês:

ABSTRACT This study aimed to assess the drying kinetics of red and yellow chili peppers, “dedo-de-moça” variety, at different temperatures (35, 45, 55, and 70 °C) and model this phenomenon mathematically. We also evaluated the effect of these drying air temperatures on pepper fruit color. Pepper fruits were dried in a forced-air circulation dryer. Ten mathematical models were fitted to the experimental data by nonlinear regression analysis. After drying, pepper samples were analyzed for the following colorimetric parameters: lightness (L*), chroma or saturation (c), and hue angle (h), in order to determine the influence of drying air temperature on fruit coloration. Our findings showed that the higher the air temperature, the faster the drying process. Midilli model fitted well to all temperature data and best represented the drying kinetics of “dedo-de-moça” chili peppers. Moreover, fruit color was affected by the drying air temperatures, in which the higher the drying air temperature, the greater the color variation.

Resumo em Inglês:

ABSTRACT Constructed wetland systems have been used to treat different wastewater; among their essential components are the cultivated plant species and type of substrate used to fill them. The choice of plant species and type of substrate are important for the good system performance in wastewater treatment. This study aimed to evaluate the extraction capacity of Napier and Tifton 85 grasses when cultivated at different positions in horizontal subsurface flow constructed wetlands (HSSF-CWs) filled with different substrates in wastewater treatment from a bulk milk-cooling tank (MTWW). The experimental unit consisted of four HSSF-CWs, in which an average surface organic loading rate of 318 kg ha−1 d−1 of BOD5,20 was imposed and a hydraulic holding time of 1.8 and 3.0 d, respectively, in units filled with gravel or crushed PET bottles. Tifton 85 grass presented the highest Na extraction capacity, with better results obtained in HSSF-CWs filled with crushed PET bottles, while Napier grass was more effective in extracting N, K, and P from MTWW. When cultivated in the second half of gravel-filled HSSF-CWs, both grasses provided higher average N extractions when compared to those filled with crushed PET bottles, which had higher extractions in the first half of HSSF-CWs.

Resumo em Inglês:

ABSTRACT The delimitation of management classes is critical for successful precision agriculture. This process involves choosing the variables to use and analyzing the spatial variability of the variables. Thus, the objective of this study was to analyze the correlation between management class maps generated from orbital images and yield maps. A 95-hectare area of rainfed grain was evaluated. Yield maps were obtained for the 2015/2016 and 2016/2017 soybean crops. Orbital images were used from two dates for each crop to generate vegetation index maps. The spatial correlation between the vegetation indices and the yield maps was obtained using a bivariate Moran index. The delineated management classes were compared using the Kappa index. This study demonstrated that the Kappa values resulting from the comparison between the management class maps generated from the soybean yield and the vegetation index ranged from 5% to 67% depending on the number of delineated classes. The highest Kappa values were observed when the area was delineated into three classes.