Water Sensitive Paper Research Articles

Droplet Distribution of an Autonomous UAV-based Sprayer in Citrus Tree Canopy

Although Unmanned Aerial Vehicles (UAVs) are developed for military missions originally, they have been used widely in civil activities for several decades globally. In agricultural, UAVs have been developed as an efficient sprayer for pesticide application since 1987. UAV-based sprayers are popular for the prevention and control of pests and diseases in field crop in many countries recently. Some of the UAV-based sprayers are developed to be equipped with fruit tree mode aiming at solving droplet penetration in the inside and bottom part of the fruit tree canopy. In this study, a newly released UAV-based sprayer (i.e., T30) equipped fruit tree mode is chosen as spraying platform to optimize the spraying parameters for practical application. The flight velocity and application rate are the variables, while droplet coverage, density, size, and penetration are the observed metrics. Three treatments with different flight velocities (2 m s-1 or 3 m s-1) or application rates (60 L ha-1 or 75 L ha-1) are arranged to collect the droplets for assessment. Water Sensitive Papers (WSPs) are placed in the outside, bottom, and inside layers of the canopy to collect droplets. The results show that the treatment combined a flight velocity of 2 m s-1 and an application rate of 60 L ha-1 obtains the most droplets among all the variables based on the values of droplet coverage and density. The treatment with a flight velocity of 2 m s-1 and an application rate of 75 L ha-1 has the best penetration, while the treatment with a velocity of 2 m s-1 and an application rate of 60 L ha-1 takes the second place according to the percentages of droplet deposition in the three layers. Overall consideration of the total droplet distribution and penetration of the application parameters, a flight velocity of 2 m s-1 and an application rate of 60 L ha-1 are recommended to get an ideal droplet distribution in tree canopy when UAV-based sprayer T30 equipped with fruit tree mode flies at 1.6∼2 m above the citrus tree canopy.

Feasibility study on hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard

Aim: To study the feasibility of hexacopter UAV based sprayer for application of environment-friendly biopesticide in guava orchard. Methodology: Field experiments were conducted in Punjab (India) during 2020. UAV was evaluated for spraying environment-friendly bio-pesticidein guava orchard. UAV was operated at 2.0 m height above the tree top.The water and oil sensitive papers were fixed on the outer side as well as inside of selected guava trees at four different canopies. Organic neem seed kernel based azadirachtin 0.15% EC biopesticide was used at recommended dose. After spraying, all water and oil sensitive papers were collected for further laboratory analysis. All spray quality parameters, i.e., coverage (%), droplet density (droplets cm-2), droplet size (µm) and uniformity coefficient were determined. For the efficacy of drone sprayer insects were counted before and 1, 2, 7 days after spray (DAS) and reduction in number of insects was calculated. Results: The on-flight field capacity of spraying with UAV was 3.0-3.3 ha h-1 whereas actual field capacity was found to be 2.0-2.3 ha h-1. The total mean coverage area was found in the range of 2.67-10.67%. The maximum coverage was at the top canopy (inner and outer) of tree which was significantly higher than all other observation points on the canopy. The mean droplet density was found in the range of 14.67-28.33 droplets cm-2. The highest droplet density (28.33 droplets cm-2) was found at the top outer side of the tree canopy. The volume median diameter was found in the range of 208.0-418.3 µm whereas, number median diameter was in the range of 138 to 269 µm. The percent reduction in aphid population 1, 2 and 7 days after spray (DAS) was 38.06, 68.28 and 62.69%, respectively whereas it was 47.95, 78.69 and 70.90% with knapsack sprayer. Interpretation: Hexacopter UAV sprayer is effective in terms of quality of spray and effective control of aphid population.

Performance Evaluation of a Wheel Operated Boom Sprayer

A wheel operated boom sprayer working on the principle of eccentric mechanism was evaluated on the independent parameters like nozzle type i.e. flat fan nozzle, hollow cone nozzle and flood jet nozzle in combination with the three different heights of the boom (H1=400 mm, H2=500 mm and H3= 600 mm) and three different type of boom carrying two, three and four nozzles. The dependent parameters studied were nozzle discharge (l h-1), swath width (cm), spray overlap (%), spray coverage (%), size of droplets (µm) and droplet density (droplets/cm2). The study involved the use of dropleaf software, which analysed the spray pattern obtained on water sensitive papers (WSP) used during the study to measure various spraying characteristics of the sprayer. The nozzle discharge (l h-1), swath width (cm) and size of droplets (µm) increased with the increase in the number of nozzles on boom while as the spray overlap (%) and droplet density (droplets cm-2) decreased with an increase in the number of nozzles on boom. The swath width, spray overlap (%) and size of the droplets (µm) increased with an increase in the height of the boom while as nozzle discharge (l h-1), spray coverage (%) and droplet density (droplets cm-2) decreased with the increase in the height of boom.

Intelligent Sprayer Spray Rates Optimization to Efficiently Apply Chemicals in Modern Apple Orchards

Highlights Intelligent sprayers require crop canopy-specific base spray rate (SR) adjustments. SRs can be estimated by Tree Row Volume (TRV) and Unit Canopy Row (UCR) methods. This study formulated TRV and UCR based SRs for modern apple orchard canopies. Field trials evaluated spray deposition and coverage variations for these rates. TRV and UCR based treatments had comparable spray performance to the grower-adapted application rate. Abstract. The efficiency of air-assisted sprayer-based chemical applications in horticultural crops is dependent on several factors, including that of the application rate as the amount of liquid per ground area (L ha-1 or gal acre-1 [GPA]). In contrast to the conventional GPA-based application rates, recently developed intelligent and precision sprayers use the input spray rate (SR) as the amount of liquid volume (L) required to spray one cubic meter of crop canopy (L m-3 or ounces per cubic foot). This input rate ranges between 0.06 and 0.13 L m-3 depending on the architecture and canopy size. However, the exact value of input SR is decided based on grower experience and manufacturer recommendation and can often be a broad estimation. Therefore, this study was conducted to explore methods that could be used to have a precise estimate of the input SR related to the canopy being sprayed for optimal spray applications. Tree row volume (TRV) and unit canopy row (UCR) methods were used to estimate input SRs and the sprayer field efficiency was evaluated in a vertical fruiting wall-trained commercial apple orchard, typical in the State of Washington, USA. Field spray trials were conducted in the full canopy growth stage, spraying a mix of fluorescent tracer dye of 2 g L-1 concentration at a calibration speed of 1.50 m s-1. Spray deposition and coverage were evaluated in replicated field trials using deposit samplers (mylar cards and screen) and water-sensitive papers, respectively. Test results demonstrated that both TRV (SR: 0.09 L m-3) and UCR (SR: 0.10 L m-3) were effective methods to calculate the spray rates since their spray deposition and coverage were comparable to that of the grower-adapted application rate (935 L ha-1). While the spray rates calculated by both methods provided better application efficiency, an SR of 0.09 L m-3 calculated by the TRV method would be preferable in spray applications of fully foliated fruiting wall-trained apple trees as it sprayed less liquid. Although the TRV method could potentially be applicable for estimating SR with an adjustment factor to compensate for the pruning level, crop-specific further evaluations are suggested for different canopy training systems. Keywords: Intelligent sprayer, Modern orchard systems, Spray rate, Tree row volume, Unit canopy row.

The Effects of Crosswind Speed on the Droplet Deposition Distribution of Thrush 510G Aircraft

HighlightsThe penetration ability of droplet in the crop canopy was in a negative correlation with wind speed.The high wind speed was conducive to the deposition of droplet on the crop canopy in the deposition area.The smaller the wind speed was, the more uniform the distribution of droplets became, and the worse the uniformity of droplet penetration.Abstract. Large plant protection fixed-wing aircrafts are widely used for crop spraying in Northeast China, because their working efficiency matches farm size. However, the spray droplet deposition and drift associated with manned fixed-wing aircraft has not been fully understood in China. The objectives of this study were to quantify effects of the small gradient crosswind speeds of 1.10, 0.83, and 0.58 m/s on the distribution and drift of droplets on soybean in the field. Water-sensitive paper (WSP) was used to collect the droplets on the upper canopy and lower parts of the plant. The results showed that the percentage of droplet deposition (the percentage of droplet deposition on the lower layer to that on the canopy of soybean plant) negatively correlated with the crosswind speeds. The crosswind speed had a significant influence on the deposition of droplets on the canopy and penetration performance. When the crosswind speed was 1.10 m/s, the deposition of droplet on the canopy was maximum and the average value of droplet penetration percentage was minimum, which was 6.11 µL and 50.6%, respectively. The average volume median diameters (VMD or DV0.5s) from all in-swath WSPs of three treatments were all smaller than that of droplet spectrum. The variation coefficients of droplet density in three treatments were 46.8%, 39.6%,and 34.1%, respectively, which indicated that the smaller the wind speed was, the more uniform the distribution of droplets became. The results revealed the influence of crosswind speed on the droplet distribution of large fixed-wing aircraft, which was of great significance to improve the operation. Keywords: Droplets distribution, Penetration, Uniformity performance, Wind speed.

Effect of Emitter Modifications on Spray Performance of a Solid Set Canopy Delivery System in a High-Density Apple Orchard

Optimally configured solid set canopy delivery systems (SSCDS) can provide adequate spray performance in high-density apple orchards with a minimized risk of off-target pesticide drift. SSCDS configured in a shower-down emitter arrangement have been reported to be the simplest and most economical system. However, existing off-the-shelf emitters used in shower-down configurations have resulted in minimal deposition in lower canopy zones. Therefore, this study was focused on the modifications of off-the-shelf emitters to obtain a desirable spray pattern for adequate spray deposition in all the canopy zones. The modifications include redesigning the impact plate of two existing micro-emitters. Field tests were conducted to evaluate the spray performance of SSCDS with the non-modified emitters (treatment: SD1 and SD3) and contrast the results with modified emitters (treatment: SD2 and SD4). While the treatments SD1 and SD3 had off-the-shelf emitters with swivel plate and static spreader, respectively, the treatment SD2 and SD4 had similar emitters with modified impactor plates. In each treatment block, the apple canopy was divided into six zones and sprayed with a 500 ppm fluorescent tracer solution. Mylar cards and water-sensitive paper samplers were placed on the adaxial and abaxial leaf surfaces in each canopy zone to quantify spray deposition and coverage, respectively. The SSCDS treatments retrofitted with modified emitters, i.e., SD2 and SD4, were observed to have uniform and numerically higher deposition and coverage compared to SD1 and SD3. The SSCDS treatment with modified static spreader (i.e., SD4) resulted in the highest overall spray deposition (1405.7 ± 156.4 ng cm−2 [mean ± standard error]) with improved mid (1121.6 ± 186.9 ng cm−2) and bottom (895.6 ± 149.3 ng cm−2) canopy deposition. Overall, the proposed emitter modification assisted in improved SSCDS spray performances and may be a way forward toward large-scale emplacements of such systems.

Development of sensor system for real-time measurement of droplet deposition of agricultural sprayers

During the chemical application process, droplet deposition on a target is an important reference indicator for evaluating the spraying technique and its performance. In order to quickly obtain deposition results in the field, this study proposed a novel system based on surface humidity sensors. The basic principle is to convert the measured physical quantity change into a capacitance change, thereby realizing the physical quantity to electrical signal conversion. An Android application for mobile terminal and the corresponding coordinator were developed, which allowed operators to control multiple sensors simultaneously through the Bluetooth. The soluble tracer detected by spectrophotometer was used to calibrate the system. The obtained results indicated a good correlation between deposition volume and voltage increment output from the newly developed system (R2 of the six nozzles with Dv0.5 ranging from 107.28 μm to 396.20 μm were 0.8674-0.9729), and a power regression model based on the least squares technique (R2=0.8022) was developed. In the field test, the system exhibited an optimal performance in predicting the deposition volume. Compared with the conventional method of measuring tracer concentration, the deviation was less than 10%. In addition, the system exhibited good fitting curve of the deposition distribution with droplet number results measured by the water sensitive paper method. Keywords: deposition measurement, agricultural sprayer, droplets, intelligent sensor DOI: 10.25165/j.ijabe.20211405.5528 Citation: Li L L, Zhang R R, Chen L P, Yi T C, Xu G, Xue D X, et al. Development of sensor system for real-time measurement of droplet deposition of agricultural sprayers. Int J Agric & Biol Eng, 2021; 14(5): 19–26.

Efficacy of the Prototype Electrostatic Nozzle for Cotton Crops

A prototype of an electrostatic nozzle was developed for spraying cotton crops in a project titled ‘Design and development of an electrostatic nozzle for agricultural applications’. The study was carried out to evaluate the locally-developed electrostatic nozzle and compare its performance with an imported electrostatic nozzle and solid cone nozzle (conventional knapsack sprayer) in the cotton crop at the departmental research farm of Punjab Agricultural University, Ludhiana, India. Different spray performance parameters, i.e. number median diameter (NMD), volume median diameter (VMD), uniformity coefficient, droplet density, the volume of spray deposition, and area covered with droplets were determined with the help of water-sensitive paper (WSP) method of deposition collection. There was comparatively less variation in uniformity coefficient with the imported and locally-developed electrostatic nozzles than the solid cone nozzle at a 5 % level of significance. The average droplet density obtained with both the imported and locally-developed electrostatic nozzles was significantly more compared to the solid cone nozzle. The area covered by the droplets of the locally-developed prototype of the electrostatic nozzle was more than the solid cone nozzle. The volume of spray deposition differed significantly for all three treatments at a 5 % level of significance. Overall, there was no significant difference in the performance of both electrostatic sprayers, but they were found to be more effective than the solid cone nozzle.

Reducing ground and airborne drift losses in young apple orchards with PWM-controlled spray systems

Pulse Width Modulated (PWM) solenoid valves can be used to control nozzle flow rates for precision spray applications to reduce pesticide use, thereby reducing environmental risk and production cost. Field tests in a two-year-old young apple orchard were conducted to investigate spray losses to the ground and in the air for an air-blast sprayer equipped with three spray systems: 1) manually controlled constant-rate system enabled with the PWM spray system (Manual-PWM), 2) laser-guided variable-rate system enabled with the PWM spray system (Laser-PWM); and 3) conventional constant-rate system with disabled PWM valves (Disabled-PWM). Artificial targets (plastic plates and water sensitive papers) were placed under twelve trees randomly selected from four rows of the orchard to collect spray losses to the ground. Airborne spray losses were determined by using nylon screens, mounted at five heights on each of seven poles distributed at different distances from the first sprayed row. Laser-PWM and Manual-PWM produced significantly lower airborne and ground spray drift losses inside and outside the orchard than Disabled-PWM, and these losses decreased significantly as the distance away from the first sprayed row increased. Laser-PWM reduced the total airborne drift by 90.3% and total ground loss by 85.0% compared to Disabled-PWM whereas Manual-PWM decreased the same airborne and ground drift by 84.1% and 7.9%, respectively. Disabled-PWM produced detectable airborne losses that reached 88.4 m away from where the sprayer was operated. Thus, the air-blast orchard sprayer equipped with PWM solenoid valves controlled by either the automatic laser-guided system or manual system would have great potentials to improve pesticide application efficiency with significant reductions in both pesticide consumption in young apple orchards, and off-target drift loss to the environment.

Synergistic dispersal of plant pathogen spores by jumping-droplet condensation and wind

Plant pathogens are responsible for the annual yield loss of crops worldwide and pose a significant threat to global food security. A necessary prelude to many plant disease epidemics is the short-range dispersal of spores, which may generate several disease foci within a field. New information is needed on the mechanisms of plant pathogen spread within and among susceptible plants. Here, we show that self-propelled jumping dew droplets, working synergistically with low wind flow, can propel spores of a fungal plant pathogen (wheat leaf rust) beyond the quiescent boundary layer and disperse them onto neighboring leaves downwind. An array of horizontal water-sensitive papers was used to mimic healthy wheat leaves and showed that up to 25 spores/h may be deposited on a single leaf downwind of the infected leaf during a single dew cycle. These findings reveal that a single dew cycle can disperse copious numbers of fungal spores to other wheat plants, even in the absence of rain splash or strong gusts of wind.

Field assessment of a pulse width modulation\xa0(PWM) spray system applying different spray volumes: duty cycle and forward speed effects on vines spray coverage

The pulse width modulation (PWM) spray system is the most advanced technology to obtain variable rate spray application without varying the operative sprayer parameters (e.g. spray pressure, nozzle size). According to the precision agriculture principles, PWM is the prime technology that allows to spray the required amount where needed without varying the droplet size spectra which benefits both the uniformity of spray quality and the spray drift reduction. However, some concerns related to the effect of on–off solenoid valves and the alternating on/off action of adjacent nozzles on final uneven spray coverage (SC) have arisen. Further evaluations of PWM systems used for spraying 3D crops under field conditions are welcomed. A tower-shaped airblast sprayer equipped with a PWM was tested in a vineyard. Twelve configurations, combining duty cycles (DC: 30, 50, 70, 100%) and forward speeds (FS: 4, 6, 8 km h−1), were tested. Two methodologies, namely field-standardized and real field conditions, were adopted to evaluate the effect of DC and FS on (1) SC variability (CV%) along both the sprayer travel direction and the vertical spray profile using long water sensitive papers (WSP), and (2) SC uniformity (IU, index value) within the canopy at different depths and heights, respectively. Furthermore, the SC (%) and deposit density (Nst, no stains cm−2), determined using short WSP, were used to evaluate the spray application performances taking into account the spray volumes applied. Under field-controlled conditions, the pulsing of the PWM system affects both the SC variability measured along the sprayer travel direction and along the vertical spray profile. In contrast, under real field conditions, the PWM system does not affect the uniformity of SC measured within the canopy. The relationship between SC and Nst allowed identification of the ranges of 200–250 and 300–370 l ha−1 as the most suitable spray volumes to be applied for insecticide and fungicide plant protection products, respectively.

Physical and Biological Performance Evaluation of Disinfection Systems for Transportation Vehicles against AI Virus.

To prevent the outbreak of infectious diseases that inflict huge economic and social losses, domestic livestock farms and related facilities have introduced automatic and semiautomatic disinfectant solution-spraying systems for vehicles. However, the facility standards and specifications vary by manufacturer, and no scientific performance evaluation has been conducted. The puropose of this study is to develop physical and biological evaluation methods. Physical and biological appraisals were conducted using two types of disinfection facilities (tunnel- and U-type) and two types of vehicles (passenger car, truck). Water-sensitive paper was used to evaluate the physical performance values for the disinfection facilities. In addition, to assess their biological performance, carriers containing low-pathogenic avian influenza virus were attached to vehicles, and the viral reduction was measured after the vehicles moved through the facility. The tunnel-type had rates of coverage in the range of 70-90% for the passenger car and 60-90% for the truck. At least 4-log virus reduction after spraying for 1-5 min was shown for both vehicles. For the U-type facility evaluation, the coverage rates were in the range of 60-90% for the passenger car and at least 90% for the truck. More than 4-log viral reduction was estimated within a spraying time of 5 min. To reduce viruses on the surface of vehicles by at least 4 log within a short period, the disinfectant solution should cover at least 71% of the pathogens. In conclusion, we were able to assess the physical and biological performance criteria for disinfection facilities aboard transportation vehicles.

Deposition of sprayed drops in soybean in function of sowing spacing

To reach all parts of the plants can be a difficult achievement faced by the drops in several crops. Strategies in crop management such as an increment in the plant spacing can contribute to the spray application's success. This study aimed to evaluate the droplets deposition in soybean, using three different spray nozzles and application rate, in two soybean rows spacing. The experimental design used was the randomized blocks, with treatments arranged in a split-plot scheme. The plots were the interrow spacing (0.45 and 0.76 m), the subplots were the spray nozzles (JA-2 and Magno 11002 BD), and the sub-subplots were the application rate (120, 200 and 280 L ha-1). Droplets coverage was evaluated in the upper, middle and lower thirds of soybean plants. Water-sensitive papers were installed in the adaxial part of plant leaves to analyze the spray technology and evaluated using E-Sprinkle® software. Spraying was performed in plants at the R5.3 soybean stage. This experiment evaluated the following parameters: the volume median diameter, the density of droplets per cm2, the droplet coverage area, and the droplet percentage less than 150 µm. The increase in the soybean row spacing combined with the spray volume increase provided greater droplet coverage in the middle third in soybean crop. The Magno 11002 BD droplet nozzle provided the higher droplet coverage in the row spacing of 0.76 m. The spray rate of 280 L ha-1 provided the highest density of droplets per cm2 in the lower third and greater coverage in the middle-third.

Effect of geometrical parameters of air-induction nozzles on droplet characteristics and behaviour

Delivering pesticide droplets accurately to a target has always been a challenge for crop spraying. Pesticide spray that drifts or runs-off the crop are major sources of soil and groundwater pollution and encourage pesticide overuse. This study optimised an agricultural air-induction nozzle to overcome these difficulties. Various configurations were designed and manufactured to investigate the geometrical parameters. A range of experiments were designed and carried out to simulate field conditions and examine spray structure, stability, droplet size range, and the probability of microbubbles to determine correlations between droplet size and spray drift and droplet rebound potential with or without entrained microbubbles. The performance of the designed nozzle was compared to that of commercial nozzles. Optical diagnostic methods, including high-speed photography, laser diffraction-based droplet sizing, and microscopic flow visualisation, were employed to perform accurate investigations of droplet size range and microbubble presence potential. In addition, the spatial distribution of spray influenced by lateral wind was investigated in an open-type wind tunnel and measured using a 2-dimensional patternator and water-sensitive papers. The rebound potential of the droplets was investigated using high-speed photography for artificial leaves. The results demonstrate the significance of geometrical design factors on the performance of nozzles and the effectiveness of induced air on the reduction of drift and rebound potential. Droplets including microbubbles were found to distribute across the surface of the target leaves on impact and exhibit increased rebound resistance. • Agricultural nozzles with coarser sprays have less drift potential. • Jet pump geometry controls ALR where the tip V-cut angle controls the spray angle. • Injection pressure enhances the atomization quality and degrades the uniformity. • Droplet air inclusion leads to better coverage. • Larger droplets including air bubbles have less rebound potential.

Nozzle Type and Driving Speed Effects on Spray Density of Aerial Application According to the Wind Tunnel Measurements

Spray density (Number of droplets/cm2) is an important component of agricultural spraying processes. In the field, assessment of the spray density under effect of a number of variables such as nozzle type and driving speed without take in account the effect of cross wind speed is insufficient. In this study, to simulate field spray operation, tests were carried out in wind tunnel using automatic spraying mechanism to investigate and to clarify effect of three types of flat fan nozzle tip spray at three driving speeds under effect three cross wind speeds on spray density. Water sensitive papers (WSPs) were used to collect spray density data. Spray density was calculated through image processing program software. Performance of spray nozzles was validated relative to experimental data of a TP11003 reference nozzle. Results indicated that XR11003 nozzle behavior was to some extent similar to that TP11003 nozzle under effect slow wind speed. It is also noticed that the spray density value decreased with increasing driving speed and wind speed, the spray density value with driving speed of 2.2 m/s and wind speed of 1 m/s was the best, reaching 64.3 droplet /cm2. While the spray density value with driving speed of 5.5 m/s and wind speed of 3 m/s was the least, reaching 3.8 droplet /cm2. The current study presents that the use of DG11003 nozzle gives the best control spray density data under effect very windy conditions to the reference nozzle.

Study on Water Distribution of Spraying Drone by different Speed and Altitude

The application of unmanned aerial vehicles (UAV) in Malaysia, or best known as a drone, is changing from time to time. Today, drones are used not only in the military, but also in agriculture. The use of drones became common in agriculture due to a reduction in cultivated land, labour shortages and obsolete methods. The spraying of pesticides and herbicides may also be carried out using drones. Furthermore, the time-consumed using drone is faster compared to the conventional method. On the market, there are different kinds and types of drone sprayers. Although the manufacturer has set the Standard Operating Procedure (SOP) for drone usage, the efficacy of spraying should first be examined because of Malaysia's weather and environmental factors which vary from other countries. The purpose of this paper is to investigate the effects of altitude and speed of the drone onto the coverage area during spraying application. In this study, a plot consisting of 0.5 Hectares situated at MARDI Seberang Perai was used. Three different speeds of 2 m/s, 3 m/s, and 4 m/s and three altitudes measured in heights of 1.5 m, 2.0 m, and 2.5 m from the top of the crop were tested. Wind speed and direction were recorded using an anemometer during the study. Water-sensitive paper was used during the experiment to examine the effect on spraying. In order to calculate the coverage area percentage, the spraying effect on water sensitive paper was analysed using ImageJ software. The results are expected to show which speed and altitude may contribute to the largest area of coverage percentage. The appropriate altitude and speed for the spraying operation on the basis of crop requirements can be concluded from the result which is 2 m from above crop at speed of 2.5 m/s.

Numerical and experimental analyses for the improvement of surface instant decontamination technology through biocidal agent dispersion: Potential of application during pandemic.

The transmission of SARS-CoV-2 through contact with contaminated surfaces or objects is an important form of transmissibility. Thus, in this study, we evaluated the performance of a disinfection chamber designed for instantaneous dispersion of the biocidal agent solution, in order to characterize a new device that can be used to protect individuals by reducing the transmissibility of the disease through contaminated surfaces. We proposed the necessary adjustments in the configuration to improve the dispersion on surfaces and the effectiveness of the developed equipment. Computational Fluid Dynamics (CFD) simulations of the present technology with a chamber having six nebulizer nozzles were performed and validated through qualitative and quantitative comparisons, and experimental tests were conducted using the method Water-Sensitive Paper (WSP), with an exposure to the biocidal agent for 10 and 30 s. After evaluation, a new passage procedure for the chamber with six nozzles and a new configuration of the disinfection chamber were proposed. In the chamber with six nozzles, a deficiency was identified in its central region, where the suspended droplet concentration was close to zero. However, with the new passage procedure, there was a significant increase in wettability of the surface. With the proposition of the chamber with 12 nozzles, the suspended droplet concentration in different regions increased, with an average increase of 266%. The experimental results of the new configuration proved that there was an increase in wettability at all times of exposure, and it was more significant for an exposure of 30 s. Additionally, even in different passage procedures, there were no significant differences in the results for an exposure of 10 s, thereby showing the effectiveness of the new configuration or improved spraying and wettability by the biocidal agent, as well as in minimizing the impact caused by human factor in the performance of the disinfection technology.

Evaluation of Drift-Reducing Nozzles for Pesticide Application in Hazelnut (Corylus avellana L.)

Spraying pesticides using air induction nozzles is a well-known method to reduce drift. These drift-reducing nozzles have been tested on many different tree crops (such as apples, citrus, and grapes), but we are still lacking information on their utilization on hazelnut (Corylus avellana L.) groves, although hazelnut is a major nut crop in Italy, and in recent years its cultivated area has been constantly growing. This paper reports a comparison between treatments carried out with cone and flat-fan low-drift nozzles versus two conventional nozzles. The distribution quality, the number of droplets per cm2 of the target area, and the drift in non-target trees adjacent to those treated were evaluated by analyzing the impact of the droplets on water-sensitive papers placed on the tree canopies. The results show that because no significative differences in terms of application quality were found between the tested nozzles, low-drift nozzles can be a good alternative to the standard nozzles to reduce the drift of pesticide applications in hazelnuts without altering the chosen distribution of the pesticide.

Effects of position angles in twin-jet spray applications on droplet penetration of hydraulic nozzles

This study was conducted to determine the effects of different position angles in twin-jet spray applications on droplet penetration of different nozzle types. Seven different nozzle types (standard flat fan, ST; narrow flat fan, STN; multirange, LU; low-drift potential, AD; air-induction, IDK; twin-jet air-induction, IDKT) were used and nozzles were positioned +15° along the forward direction, perpendicular to ground surface 0? and reverse direction of forward -15°. Spray experiments at 100 L/ha constant application volume were conducted under controlled conditions of a closed facility. Water sensitive paper (WSP) was used as sampling surface. WSP samples were placed vertically and horizontally over both the metal frames and root collar of artificial plants. The present findings revealed that transport potential of spray droplets was quite lower on vertical planes than on horizontal planes. The greatest coverage was achieved with ST, STN, LU, and SC-type nozzles producing fine droplets. Compared to open targets, the coverage ratios around the root collars were quite low and insufficient. In all spray treatments, coverage ratio on the vertical planes was 86.1% lower than the coverage ratio on the horizontal plane. In other words, coverage ratio on the horizontal plane was 7.2 times greater than the coverage ratio on the vertical plane. Transfer efficiency of medium and coarse droplet-producing nozzles to root collars was greater than the transfer efficiency of fine droplet-producing nozzles. Such a ratio for AD, IDKT, and IDK-type nozzles was determined as 37.06, 37.85, and 41.02% respectively. According to the present findings, effects of nozzle position angle on droplet penetration were not found to be significant. However, nozzle position angle along the forward direction increased coverage ratios on the vertical planes.

Reduction of Pesticide Use in Fresh-Cut Salad Production through Artificial Intelligence

Incorrect pesticide use in plant protection often involve a risk to the health of operators and consumers and can have negative impacts on the environment and the crops. The application of artificial intelligence techniques can help the reduction of the volume sprayed, decreasing these impacts. In Italy, the production of ready-to-eat salad in greenhouses requires usually from 8 to 12 treatments per year. Moreover, inappropriate sprayers are frequently used, being originally designed for open-field operations. To solve this problem, a small vehicle suitable for moving over rough ground (named “rover”), was designed, able to carry out treatments based on a single row pass in the greenhouse, devoted to reduce significantly the sprayed product amount. To ascertain its potential, the prototype has been tested at two growth stages of some salad cultivars, adopting different nozzles and boom settings. Parameters such as boom height, nozzle spacing and inclination, pump pressure and rover traveling speed were studied. To assess the effectiveness of the spraying coverage, for each run several water-sensitive papers were placed throughout the vegetation. Compared to the commonly distributed mixture volume (1000 L/ha), the prototype is able to reduce up to 55% of product sprayed, but still assure an excellent crop coverage.