Search

We evaluated spray coverage on grape leaves and bunches by a high-volume sprayer (HVS), an air-assisted, low volume knapsack sprayer (LVS), and a motorized knapsack dust applicator modified to spray liquid formulations (common sprayer – CS). At the full development of the vine canopy 1400, 250 and 150 L ha−1 were applied via HVS, CS and LVS, respectively. Sprayer type, leaf or bunch orientation, leaf position and leaf side significantly affected spray coverage (P < 0.001). Mean spray coverage on leaves or bunches was below 21% for CS, and above 40 and 55% for LVS and HVS, respectively. Downy mildew leaf infection was below 5% throughout the season, with a significant effect of sprayer, time and an interaction between sprayer and time (P < 0.001). Grape berry moth damage did not differ between sprayers and the untreated control. The current work suggests that LVS might be a viable alternative to HVS, but further work is needed to establish whether differences in spray coverage affect biological efficacy. [ABSTRACT FROM AUTHOR]

• Data base of 17 composting plants, 8 years, more than 2000 registers. • Biowaste, green waste, compost, refuse and improper material mass assessment. • Data-base indicators can help to assess composting efficiency of industrial plants. • Influence of size and technology in plant efficiency and compost quality. This study aims to assess composting efficiency and quality of compost through the study of the parameters of the Catalan Waste Agency (ARC) data-base by developing indicators useful for industrial sector. The study includes 17 composting plants for an 8-years period (2010–2017), the quantities of materials treated and generated in these plants: biowaste, yard trimmings, refuse and compost, as well as chemical characterization of compost: moisture, total organic matter, organic nitrogen, pH, electrical conductivity, self-heating test, pollutants and ammonium. Plant were sorted into 4 size classes depending on size capacity and into 4 technologies employed during thermophilic phase. Different indicators were developed related to improper fraction content, yard trimmings ratio, mass losses, compost production, refuse generation and plant saturation. The main average results indicate that improper fraction is 10%, process losses 68%, refuse generated 25% and saturation 79%. Differences were observed in size and technology; for instance, smaller plants presented lower improper content, refuse and saturation and higher losses while plants with turned windrows during decomposition presented higher improper, yard trimmings ratio and plants with vessel technology showed lower losses and higher saturation. Also, the compost quality is higher if the plant saturation and improper fraction are below 90% and 7%, respectively. The indicators were useful to assess the process and were related to the compost quality obtained. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • DOSAVIÑA is a newly developed DSS giving optimal volume rates/PPP doses in vineyards. • A modified leaf wall area method integrates canopy density/width and sprayer type. • Accurate volume rates from the DSS allow good coverage and uniformity over the canopy. • DSS achieves 20% drop in volume rate and pesticide use while reducing contamination. • DOSAVIÑA is available for IOS and Android; a web version is also available. Abstract DOSAVIÑA is a new tool (website and app for smartphones) developed for calculating the optimal volume rates and pesticide doses to apply during spray application processes in vineyards. DOSAVIÑA also calculates and recommends the optimal working parameters for working pressure, forward speed, and number and types of nozzles. DOSAVIÑA was developed by the Unit of Agricultural Machinery at the Universitat Politècnica de Catalunya, and is available for iOS and Android devices. It is also available on the DOSAVIÑA website (https://dosavina.upc.edu). The developed tool can be used also for the calibration of spray applications on fruit trees (as well as on citrus orchards, olive trees, almond trees, and many other vertical crops) once the volume rate has been established. The system, which is based on a modified version of the leaf wall area (LWA) method, calculates the optimal volume rate for vineyards by considering the effects of leaf density, canopy width, and sprayer type. System testing took biological efficacy into consideration and measured the main factors used for characterizing spray processes, coverage, and distribution over the entire canopy. Results showed that water and pesticide use could be reduced by more than 20% while still meeting economic, environmental, and food quality requirements. The design of the tool is aligned with European requirements concerning pesticide use, as established in the European Directive for a Sustainable Use of Pesticides. [ABSTRACT FROM AUTHOR]

The current standard for the field measurements of spray drift (ISO 22866) is the only official standard for drift measurements in field conditions for all type of crops, including bushes and trees. A series of field trials following all the requirements established in the standard were arranged in a traditional olive grove in Córdoba (south of Spain). The aims of the study were to evaluate the applicability of the current standard procedure to the particular conditions of traditional olive trees plantations, to evaluate the critical requirements for performing the tests and to obtain a specific drift curve for such as important and specific crop as olive trees in traditional plantations, considering the enormous area covered by this type of crop all around the world. Results showed that the field trials incur a very complex process due to the particular conditions of the crop and the very precise environmental requirements. Furthermore, the trials offered a very low level of repeatability as the drift values varied significantly from one spray application to the next, with the obtained results being closely related to the wind speed, even when considering the standard minimum value of 1 m·s −1 . The collector's placement with respect to the position of the isolated trees was determined as being critical since this substantially modifies the ground deposit in the first 5 m. Even though, a new drift curve for olive trees in traditional plantation has been defined, giving an interesting tool for regulatory aspects. Conclusions indicated that a deep review of the official standard is needed to allow its application to the most relevant orchard/fruit crops. [ABSTRACT FROM AUTHOR]

Because of variations in environmental conditions, spray-drift field measurements following ISO 22866:2005 involve complicated and time-consuming experiments often with low repeatability. Therefore, simple, repeatable, and precise alternative drift assessment methods that are complementary to the official standards are required. One of the alternatives is the use of a drift test bench for field crop sprayers. Previous studies have demonstrated that the drift test bench can be considered an adequate complement to existing standard protocols for field drift measurements. In this study, in order to further improve the methodology and to evaluate the possibility of classifying different field-crop-sprayer settings according to drift risk using a test bench, a series of tests were performed in a test hall. A conventional mounted Delvano HD3 crop sprayer (Delvano, Kuurne, Belgium) equipped with an 800-l spray tank and a 15-m-wide stainless steel spray boom was used. Eight different sprayer setups were tested, involving three nozzle types (TeeJet XR 110 04, Agrotop TDXL 110 04 and Micron Micromax 3) and three boom heights (0.30, 0.50, and 0.70 m). For the drift classification, the reference sprayer drift behaviour was defined as that obtained using conventional flat fan TeeJet XR 110 04 nozzles operated at 0.30 MPa and at a boom height of 0.50 m. The different sprayer setups were successfully assigned to different drift reduction classes, and the results underlined the effects of nozzle type and boom height on the potential drift. The feasibility of the test-bench methodology for classifying field-crop-sprayer drift according to ISO 22369-1:2006 was demonstrated. [ABSTRACT FROM AUTHOR]

Canopy characterization is essential for pesticide dosage adjustment according to vegetation volume and density. It is especially important for fresh exportable vegetables like greenhouse tomatoes. These plants are thin and tall and are planted in pairs, which makes their characterization with electronic methods difficult. Therefore, the accuracy of the terrestrial 2D LiDAR sensor is evaluated for determining canopy parameters related to volume and density and established useful correlations between manual and electronic parameters for leaf area estimation. Experiments were performed in three commercial tomato greenhouses with a paired plantation system. In the electronic characterization, a LiDAR sensor scanned the plant pairs from both sides. The canopy height, canopy width, canopy volume, and leaf area were obtained. From these, other important parameters were calculated, like the tree row volume, leaf wall area, leaf area index, and leaf area density. Manual measurements were found to overestimate the parameters compared with the LiDAR sensor. The canopy volume estimated with the scanner was found to be reliable for estimating the canopy height, volume, and density. Moreover, the LiDAR scanner could assess the high variability in canopy density along rows and hence is an important tool for generating canopy maps. [ABSTRACT FROM AUTHOR]

In 2009, the European Directive for a Sustainable Use of Pesticides (128/2009/CE) established important mandatory actions to be accomplished by all Member States (MS) in the European Union. The main objective is to achieve the sustainable use of pesticides by reducing their risks and impacts on human health and the environment. Among other important actions, drift reduction measures are essential to avoid the entry of plant protection products (PPP) in water or other undesirable areas. As the risk of environmental contamination is directly related to the spray application technology, there is a strong need for objective methods for drift evaluation as well as robust procedures for the classification of sprayers according to their risk of contamination. For this purpose, and as a complementary tool to actual drift measurement methodologies in the field or in laboratory conditions, a new method has been proposed for the quantification of the potential drift generated by horizontal boom sprayer systems using an ad hoc test bench. This study aims to evaluate the influence of wind velocity and wind direction on the drift potential value (DPV) using the proposed methodology and test bench. The results indicated that wind velocities below 1.0 m s −1 have a negligible influence on the DPV. Front wind led to higher DPVs than lateral wind. A global analysis of data indicates that the proposed methodology and test bench are interesting tools for the quick and objective evaluation of the potential drift if used in appropriate environmental conditions. [ABSTRACT FROM AUTHOR]

Spraying techniques have been undergoing continuous evolution in recent decades. This paper presents part of the research work carried out in Spain in the field of sensors for characterizing vineyard canopies and monitoring spray drift in order to improve vineyard spraying and make it more sustainable. Some methods and geostatistical procedures for mapping vineyard parameters are proposed, and the development of a variable rate sprayer is described. All these technologies are interesting in terms of adjusting the amount of pesticides applied to the target canopy. [ABSTRACT FROM AUTHOR]

The use of a scanning Light Detection and Ranging (LIDAR) system to characterize drift during pesticide application is described. The LIDAR system is compared with an ad hoc test bench used to quantify the amount of spray liquid moving beyond the canopy. Two sprayers were used during the field test; a conventional mist blower at two air flow rates (27,507 and 34,959 m³·h-1) equipped with two different nozzle types (conventional and air injection) and a multi row sprayer with individually oriented air outlets. A simple model based on a linear function was used to predict spray deposit using LIDAR measurements and to compare with the deposits measured over the test bench. Results showed differences in the effectiveness of the LIDAR sensor depending on the sprayed droplet size (nozzle type) and air intensity. For conventional mist blower and low air flow rate; the sensor detects a greater number of drift drops obtaining a better correlation (r = 0.91; p < 0.01) than for the case of coarse droplets or high air flow rate. In the case of the multi row sprayer; drift deposition in the test bench was very poor. In general; the use of the LIDAR sensor presents an interesting and easy technique to establish the potential drift of a specific spray situation as an adequate alternative for the evaluation of drift potential. [ABSTRACT FROM AUTHOR]

The use of electronic devices for canopy characterization has recently been widely discussed. Among such devices, LiDAR sensors appear to be the most accurate and precise. Information obtained with LiDAR sensors during reading while driving a tractor along a crop row can be managed and transformed into canopy density maps by evaluating the frequency of LiDAR returns. This paper describes a proposed methodology to obtain a georeferenced canopy map by combining the information obtained with LiDAR with that generated using a GPS receiver installed on top of a tractor. Data regarding the velocity of LiDAR measurements and UTM coordinates of each measured point on the canopy were obtained by applying the proposed transformation process. The process allows overlap of the canopy density map generated with the image of the intended measured area using Google Earth®, providing accurate information about the canopy distribution and/or location of damage along the rows. This methodology was applied and tested on different vine varieties and crop stages in two important vine production areas in Spain. The results indicate that the georeferenced information obtained with LiDAR sensors appears to be an interesting tool with the potential to improve crop management processes. [ABSTRACT FROM AUTHOR]

Canopy characterization is a key factor to improve pesticide application methods in tree crops and vineyards. Development of quick, easy and efficient methods to determine the fundamental parameters used to characterize canopy structure is thus an important need. In this research the use of ultrasonic and LIDAR sensors have been compared with the traditional manual and destructive canopy measurement procedure. For both methods the values of key parameters such as crop height, crop width, crop volume or leaf area have been compared. Obtained results indicate that an ultrasonic sensor is an appropriate tool to determine the average canopy characteristics, while a LIDAR sensor provides more accuracy and detailed information about the canopy. Good correlations have been obtained between crop volume (CVU) values measured with ultrasonic sensors and leaf area index, LAI (R2 = 0.51). A good correlation has also been obtained between the canopy volume measured with ultrasonic and LIDAR sensors (R2 = 0.52). Laser measurements of crop height (CHL) allow one to accurately predict the canopy volume. The proposed new technologies seems very appropriate as complementary tools to improve the efficiency of pesticide applications, although further improvements are still needed. [ABSTRACT FROM AUTHOR]

An orchard sprayer prototype running a variable-rate algorithm to adapt the spray volume to the canopy characteristics (dimensions, shape and leaf density) in real-time was designed and implemented. The developed machine was able to modify the application rate by using an algorithm based on the tree row volume, in combination with a newly coefficient defined as Density Factor (Df). Variations in the canopy characteristics along the row crop were electronically measured using six ultrasonic sensors (three per sprayer side). These differences in foliage structure were used to adjust the flow rate of the nozzles by merging the ultrasonic sensors data and the forward speed information received from the on-board GNSS. A set of motor-valves was used to regulate the final amount of sprayed liquid. Laboratory and field tests using artificial canopy were arranged to calibrate and select the optimal ultrasonic sensor configuration (width beam and signal pre-processing method) that best described the physical canopy properties. Results indicated that the sensor setup with a medium beam width offered the most appropriate characterization of trees in terms of width and Df. The experimental sprayer was also able to calculate the application rate automatically depending on changes on target trees. In general, the motor valves demonstrated adequate capability to supply and control the required liquid pressure at all times, mainly when spraying in a range between 4.0 and 14.0 MPa. Further work is required on the equipment, such as designing field efficiency tests for the sprayer or refining the accuracy of Df. [ABSTRACT FROM AUTHOR]

Pesticide application equipment (PAE) is the last part of the chain during the plant protection process. The use-phase of plant protection products (PPP) has been addressed in two EU Directives: 128/2009/EC and 127/2009/EC. This last one covers all the mandatory technical requirements to be fulfilled by new sprayers prior to their placement in the market. The objective of this research was to develop a potential decision support system (DSS) to evaluate and quantify the degree of implementation of all the required characteristics of new sprayers, including not only the mandatory requirements but also specifications widely described in the corresponding harmonized standard ISO 16119. It includes 10 independent elements of the sprayer, including a list of technical specifications listed in the applied standards ISO 16119 and ISO 16122. The relative influence of every one of the different elements has been quantified based on previous research. The algorithm enables the establishment of an objective relative classification of the sprayers to differentiate among different machines, mainly based on their quantified environmental contamination risk. The DSS can also discriminate among sprayers that should not reach the market due to their non-compliance with any of the mandatory requirements. [ABSTRACT FROM AUTHOR]

New spraying systems embedded with different technologies have been developed for pesticide application in 3D crops. However, while applied to specific tree crops, the potential spray drift mitigation for advanced spraying systems needs to be classified due to the great variability of spray equipment and canopy structure. Here a precision spraying system was developed and compared with two typical spraying systems (conventional system, optimized system following the best management practices) for the applied volume/pesticide and spray drift in an apple orchard at two growth stages following the ISO22866-2005 protocol. Compared to the conventional system, the other two advanced systems significantly reduced the amount of ground drift (> 60%) at most of the sampling distances at the growth stage BBCH 72, while the precision system demonstrated the best drift mitigation (57.3% reduction) at the stage BBCH 99. For the airborne drift, a remarkable drift reduction was also achieved with the two advanced systems. Specifically, the optimized spraying system exhibited a drift reduction by approximately 80% at the first growth stage, and the precision application demonstrated its considerable advantages in minimizing drift loss for the sparse canopy at the stage BBCH 99. Moreover, the saving of applied volume/pesticide was achieved by 12% with the optimized system and 43% with the precision system. This study revealed the necessity and prospect of the advanced spraying systems to reduce the environmental contamination and health risk from pesticide applications in fruit tree production. [ABSTRACT FROM AUTHOR]

In landscape-scale ecological restoration, there is an urgent need to develop participatory systematic planning strategies and prioritization schemes that are operational under current technical and legal constraints. Different stakeholder groups may differ in their choice of criteria to define critical areas for restoration. Analyzing the correspondence between stakeholder characteristics and their expressed preferences is key to understand their values and facilitate consensus among the different groups. We analyzed the participatory identification of critical areas for restoration in a Mediterranean semiarid landscape of southeastern Spain by means of two Spatial Multicriteria Analyses. The first one included 33 ecological and socioeconomic prioritization criteria. The second included 24 ecosystem services. Prioritization criteria and services and their weights were based on the preferences of 46 stakeholders. We distinguished three stakeholder groups, according to their approach to ecological restoration. Stakeholders showed similarities regarding the most important criteria and services assessed. Yet, we found contrasted opinions between the group labeled as Biodiversity, who showed preference for Regulating Services and Ecosystem Functions, and the two groups labeled as Environment, and Agriculture & other occupations who assigned the highest importance to Provisioning and Cultural Services, along with highly Anthropized Environments. Maps integrating criteria and services weighted by the different groups of stakeholders were largely coincident, because of their overall agreement and the high number of criteria and services included in the analysis. Our approach allowed the identification of consensual critical areas for restoration, which were mainly covered by shrublands and rainfed crops, and mostly characterized by low to medium supply of ecosystem services. Our study emphasizes the need to recognize and integrate different social perspectives when identifying critical areas for restoration and highlights the importance of using complementary approaches as decision-making support tools to define these areas. • Stakeholders identified a long list of criteria to define restoration priorities. • Stakeholder groups showed an agreement in the subset of the most valued criteria. • The location of critical areas for restoration was similar across stakeholder groups. • Critical areas for restoration showed low to medium supply of ecosystem services. • Focusing on relevant restoration criteria facilitates consensus among stakeholders. [ABSTRACT FROM AUTHOR]

Landscape‐scale prioritization models are powerful decision‐making tools in ecological restoration. Yet, they often fail to integrate multi‐stakeholder perspectives and socio‐ecological criteria.We designed a new methodology to identify high‐priority areas for landscape‐scale restoration. This participatory cost‐effectiveness analysis model is based on execution and maintenance costs and the potential increase in the supply of multiple ecosystem services.We tested the model in a 181,000 ha heavily anthropized semi‐arid landscape in southeastern Spain. Restoring the whole area would cost 221 million EUR and enhance the supply of ecosystem services by 39%. The cost‐effectiveness of restoring pine forest and abandoned and irrigated crops were higher than restoring other Landscape Units. Restoring the least degraded sites was more cost‐effective than the most degraded areas or randomly selecting sites, even when potential recovery was incomplete.Synthesis and applications. The cost‐effectiveness of restoration actions depends on the type of ecosystem and degradation state. Visualizing the outcomes of alternative restoration scenarios needs participatory prioritization maps based on financial costs and the potential supply of ecosystem services. We propose a participatory prioritization protocol that is flexible and adaptable and can help government agencies, environmental managers, investors, consultancies and NGOs' plan restoration actions at the landscape scale and optimize the effectiveness of restoration programs. [ABSTRACT FROM AUTHOR]

An orchard variable-rate sprayer applies the appropriate amount of plant protection products only where they are needed based on detection data from advanced sensors, a system that has attracted increasing attention. The latest developments in the detection unit, variable control unit, and signal-processing algorithm of the variable-rate sprayer are discussed. The detection of target position and volume is realized with an ultrasonic sensor, a laser scanning sensor, or other methods. The technology of real-time acquisition of foliage density, plant diseases and pests and their severity, as well as meteorological parameters needs further improvements. Among the three variable-flow-rate control units, pulse width modulation was the most widely used, followed by pressure-based, and variable concentration, which is preliminarily verified in the laboratory. The variable air supply control unit is tested both in the laboratory and in field experiments. The tree-row-volume model, the leaf-wall-area model, and the continuous application mode are widely used algorithms. Advanced research on a variable-rate sprayer is analyzed and future prospects are pointed out. A laser-based variable-rate intelligent sprayer equipped with pulse width modulation solenoid valves to tune spray outputs in real time based on target structures may have the potential to be successfully adopted by growers on a large scale in the foreseeable future. It will be a future research direction to develop an intelligent multi-sensor-fusion variable-rate sprayer based on target crop characteristics, plant diseases and pests and their severity, as well as meteorological conditions while achieving multi-variable control. [ABSTRACT FROM AUTHOR]

Several fungicides, such as copper and organic products (synthetic or natural), are currently being used in vineyards to control downy mildew (Plasmopara viticola) resulting in soil, surface water, and groundwater pollution. This study aims to assess the effectiveness of using cover crops as an agricultural practice in vineyards to protect soil and groundwater pollution. For that purpose, we performed different soil column studies to quantify soil leaching of selected fungicides (copper, dimethomorph, oxathiapiprolin, zoxamide, acibenzolar-s-methyl, and laminarin) following a rainfall event after a conventional fungicide vineyard application. Two types of vineyard soils (loam and sandy-loam soil textures) and three ground covers (bare ground, monoculture cover, and polyculture cover) were assessed. These studies were completed with hydroponic assays to check the effectiveness of cover roots in the fungicide degradation. Mass balance results show that whereas 3 fungicides (Cu, zoxamide, and dimethomorph) were leached through sandy soil columns, only copper was leached from loam soil columns. The effect of cover crops was only significant for Cu and zoxamide when fungicides were applied 24 h before the rain event, reducing the fungicide leaching by 30%. Hydroponic studies showed that cover roots enhanced the kinetic rates of almost all tested fungicides by 5–467%, suggesting that they are relevant to improving the degradation of fungicides in the soil column. These results are relevant to drawing up recommendations on the use of cover crops to protect soil and groundwater pollution by fungicides. [Display omitted] • Fungicide soil leaching was highly affected by soil texture. • Crop covering reduced fungicide soil leaching. • Rhizosphere interaction time is key for reducing fungicide leaching. • Crop roots enhanced the depletion kinetic rates of almost all tested fungicides. [ABSTRACT FROM AUTHOR]

Olive is a key crop in Europe, especially in countries around the Mediterranean Basin. Optimising the parameters of a spray is essential for sustainable pesticide use, especially in high-input systems, such as the super-intensive hedgerow system. Parameters may be optimised by adjusting the applied volume and airflow rate of sprays, in addition to the liquid to air proportion and the relationship between air velocity and airflow rate. Two spray experiments using a commercial airblast sprayer were conducted in a super-intensive orchard to study how varying the liquid volume rate (testing volumes of 182, 619, and 1603 l ha − 1 ) and volumetric airflow rate (with flow rates of 11.93, 8.90, and 6.15 m 3 s − 1 ) influences the coverage parameters and the amount and distribution of deposits in different zones of the canopy.. Our results showed that an increase in the application volume raised the mean deposit and percentage coverage, but decreased the application efficiency, spray penetration, and deposit homogeneity. Furthermore, we found that the volumetric airflow rate had a lower influence on the studied parameters than the liquid volume; however, an increase in the airflow rate improved the application efficiency and homogeneity to a certain threshold, after which the spray quality decreased. This decrease was observed in the high-flow treatment. Our results demonstrate that intermediate liquid volume rates and volumetric airflow rates are required for the optimal spraying of pesticides on super-intensive olive crops, and would reduce current pollution levels. [ABSTRACT FROM AUTHOR]

Integration of variable-rate disc-core nozzles in orchard sprayers is the optimal solution to achieve precision spray applications of agrochemicals; however, little information is available on the droplet size distribution and classification for these hollow-cone nozzles. Investigations were performed for the comprehensive understanding of spray droplet size spectrum discharged from hollow-cone nozzles which were manipulated with pulse width modulation (PWM) valves to produce variable flow rates. Test variables included five disc-core hollow-cone nozzle sizes (D2-DC25, D2-DC45, D4-DC25, D4-DC45, and D5-DC25), two 10-Hz PWM valve designs, five operating pressures (276, 414, 552, 689, and 827 kPa), and 10 duty cycles (DUCs) ranging from 10% to 100% at 10% intervals. Droplet diameters were measured with a laser imaging particle system. Volumetric diameters (DV0.1, DV0.5, and DV0.9) varied greatly with the nozzle orifice size, operating pressure, and DUC, and varied slightly by PWM valve type. Higher operating pressures and larger nozzles generated droplets with more consistent size distributions across DUCs from 10% to 100%. The differences in relative spans among DUCs increased with the nozzle size increase and the operating pressure decrease. Droplet size classifications from very fine to coarse, based on ASABE 572.3 standard definitions, varied with the nozzle size and operating pressure but were similar for two PWM valve designs at all DUCs. Spray volume fractions also varied with the droplet size range, DUC and pressure. For droplets smaller than 100 µm, the volume fraction remained relatively consistent or slightly decreased as DUC increased, but increased as the pressure increased. In comparison, the fraction increased as both DUC and pressure increased for droplets between 100 and 300 µm and decreased for the portion of droplets greater than 300 µm. As a result, the discovered information would be implemented for the improvement of precision variable-rate spray systems equipped with PWM valves. [ABSTRACT FROM AUTHOR]

Pulse width modulation (PWM) solenoid valves are used for controlling flowrates of hollow-cone nozzles on variable-rate air-assisted orchard sprayers. However, little information is available on the spray characteristics of these PWM-controlled nozzles. Laboratory tests were performed to evaluate the influences of duty cycles of two different design PWM solenoid valves along with five operating pressures on spray characteristics of five hollow-cone nozzles with different disc-core combinations. Parameters of the spray characteristics investigated were nozzle flowrates, upstream and downstream pressures of the PWM valves, nozzle activation pressures and times, and spray angles of water discharged from nozzles. Test results illustrated that these parameters except for the spray angle were greatly affected by the operating pressure, nozzle selection (disc orifice size and quantity of holes on core), PWM duty cycle and solenoid valve design. Spray angles were affected by the duty cycle but not by the PWM valve design. In general, nozzles with larger disc orifice and higher operating pressures resulted in higher flowrates as expected, whilst the nozzle activation pressure and the spray angle decreased as the duty cycle decreased. Thus, when designing orchard sprayers for precision variable-rate pesticide applications, variations in spray characteristics of disc-core type hollow-cone nozzles controlled by PWM solenoid valves should be considered and minimised. This prospect could be facilitated by establishing a digital database of these characteristics. • Spray parameters were measured for PWM-controlled disc-core hollow-cone nozzles. • Pressures acting on PWM valves and nozzle orifices were significantly different. • Nozzle activation pressures decreased as duty cycles decreased. • PWM valve design affected nozzle pressures and flowrates but not spray angles. • Digital tables were established for improvement of precision variable-rate sprayers. [ABSTRACT FROM AUTHOR]

Abstract: Despite technological progress in pesticide application equipment, chemical crop protection continues to contribute to environmental pollution. Water is at risk of contamination with pesticides from point and diffuse sources and could be reduced to a great extent with a better sprayer design. The sprayer manufacturers and pesticide applicators need to take more responsibility for the prevention of water pollution and therefore they have to make environmentally responsible decisions at different stages, from designing to servicing sprayers. The objective of the presented work was to develop an interactive application that would support decisions made by sprayer manufacturers during the production process, and by pesticide applicators when selecting and operating the sprayers. The EOS (Environmentally Optimised Sprayer) is an application evaluating the risk mitigation potential of sprayers based on their technological features, within five risk areas, representing sources of pollution: (i) Inside Contamination; (ii) Outside Contamination; (iii) Filling; (iv) Spray Loss & Drift; (v) Remnants. The evaluator completes the EOS questionnaire by checking for the technical solutions identified in the evaluated sprayer and the result reflects the sprayer quality in terms of potential environmental risk mitigation. The EOS tool also proved its awareness raising facility and educative value when used during training activities and university courses. [Copyright &y& Elsevier]

Previous studies have revealed that for some perovskite compositions, power conversion efficiencies (PCEs) improved after storing the devices in different ambient conditions. With the aim of better understanding such improvements, we focus our attention on the carrier/ionic dynamic kinetics of fresh and aged PSCs with different perovskite compositions (MAPbI3 and MAPbBr3) and using spiro‐OMeTAD as HTM. For that, we use transient photovoltage (TPV), a technique used to analyse the different recombination kinetics at equilibrium and at different illumination times. We observe that the aging treatment causes significant changes on the kinetics behaviour for bromide‐based devices, resulting in a positive influence on the cell performance (from 3.5 % to 6.1 % PCE, in reverse scan). However, the kinetics for those iodide‐based perovskite solar cells remains unchangeable (from 16.3 % to 15.0 % PCE, in reverse scan). [ABSTRACT FROM AUTHOR]

Canopy characterisation is a key factor for the success and efficiency of the pesticide application process in vineyards. Canopy measurements to determine the optimal volume rate are currently conducted manually, which is time-consuming and limits the adoption of precise methods for volume rate selection. Therefore, automated methods for canopy characterisation must be established using a rapid and reliable technology capable of providing precise information about crop structure. This research providedregression models for obtaining canopy characteristics of vineyards from unmanned aerial vehicle (UAV) and satellite images collected in three significant growth stages. Between 2018 and 2019, a total of 1400 vines were characterised manually and remotely using a UAV and a satellite-based technology. The information collected from the sampled vines was analysed by two different procedures. First, a linear relationship between the manual and remote sensing data was investigated considering every single vine as a data point. Second, the vines were clustered based on three vigour levels in the parcel, and regression models were fitted to the average values of the ground-based and remote sensing-estimated canopy parameters. Remote sensing could detect the changes in canopy characteristics associated with vegetation growth. The combination of normalised differential vegetation index (NDVI) and projected area extracted from the UAV images is correlated with the tree row volume (TRV) when raw point data were used. This relationship was improved and extended to canopy height, width, leaf wall area, and TRV when the data were clustered. Similarly, satellite-based NDVI yielded moderate coefficients of determination for canopy width with raw point data, and for canopy width, height, and TRV when the vines were clustered according to the vigour. The proposed approach should facilitate the estimation of canopy characteristics in each area of a field using a cost-effective, simple, and reliable technology, allowing variable rate application in vineyards. [ABSTRACT FROM AUTHOR]

The traditional use of copper as a fungicide in vineyards has raised concerns among authorities as it increases environmental pollution. As a result, new regulations have been enacted to reduce the use of plant protection products while encouraging the use of biological pesticides, which are less harmful to the environment. In this study, we surveyed two of the most relevant countries in terms of vine cultivation: Spain and Portugal. The objective of this study was to analyse the factors influencing the use of copper-based fungicides and their biological alternatives to provide a framework for state-of-the-art downy mildew control. This has led to some forward-thinking on the applicability of EU objectives. A probabilistic LogiT model was used to observe the field and exploitation variables that influenced winegrowers' use of biopesticides. Given its great reliance on copper, it can be concluded that copper is still a necessary product for viticulture. Moreover, because the use of synthetic products is prohibited in organic vineyards, more copper treatments are carried out. Although the intention to use biopesticides exists, this did not result in actual use. The most influential factor in the probability of biopesticide use is knowledge of the legislation; however, it is also important to have watercourses near the field and to have the necessary technology. These results are relevant for formulating recommendations to ensure that all information reaches small farmers, as this would be key to more sustainable agriculture in Europe. • Organic farmers use more copper-based products than conventional ones. • Growers are aware of the existence of biopesticides, but their use is not widespread. • Knowledge of the current European copper legislation is the main factor for increasing the use of biopesticides. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the inhibitory effects of resveratrol (RSV) in A375 and A431 melanoma cells, by assessing cell viability (CCK-8 assay), apoptosis through flow cytometer and cell morphology, cell cycle assay by flow cytometer and western blot (Cyclin D1, Rac1 and PCDH9). Our results demonstrated that RSV strongly inhibited A375 cells proliferation, by decreasing cell viability, promoting apoptosis and arresting cell cycle. Besides, to clarify the main factor - duration or concentration of RSV, the double variance analysis of independent factors was operated after Bartlett's test for homogeneity by R project. According to the outcomes obtained from statistical analyses, Cyclin D1 and PCDH9 were strongly affected by RSV duration while Rac1 was not influenced. In conclusion, RSV can inhibit A375 proliferation and trigger apoptosis by influencing cell cycle proteins; for these effects, treatment duration of RSV played more important role than concentration. [ABSTRACT FROM AUTHOR]

Site-specific management of crops represents an important improvement in terms of efficiency and efficacy of the different labours, and its implementation has experienced a large development in the last decades, especially for field crops. The particular case of the spray application process for what are called "specialty crops" (vineyard, orchard fruits, citrus, olive trees, etc.) represents one of the most controversial and influential actions directly related with economical, technical, and environmental aspects. This study was conducted with the main objective to find possible correlations between data obtained from remote sensing technology and the actual canopy characteristics. The potential correlation will be the starting point to develop a variable rate application technology based on prescription maps previously developed. An unmanned aerial vehicle (UAV) equipped with a multispectral camera was used to obtain data to build a canopy vigour map of an entire parcel. By applying the specific software DOSAVIÑA®, the canopy map was then transformed into a practical prescription map, which was uploaded into the dedicated software embedded in the sprayer. Adding to this information precise georeferenced placement of the sprayer, the system was able to modify the working parameters (pressure) in real time in order to follow the prescription map. The results indicate that site-specific management for spray application in vineyards result in a 45% reduction of application rate when compared with conventional spray application. This fact leads to a equivalent reduction of the amount of pesticide when concentration is maintained constant, showing once more that new technologies can help to achieve the goal of the European legislative network of safe use of pesticides. [ABSTRACT FROM AUTHOR]

A computational fluid dynamics (CFD) model for simulating the air flow produced by an air-assisted sprayer can be developed according to any one of several sets of criteria and for various specific applications. Thus far, most CFD models have focused on the characterization of the air flow generated by the sprayer. However, such models may not be the best when assessing the effectiveness of air-assisted sprayers adapted to crop geometry, such as those used in vineyards. In this study, the air flow produced by an air-assisted sprayer adapted to the geometry of a vineyard was simulated using four CFD models: Model 1 was designed to simulate air velocity measurements at the outlets; Model 2 was designed to simulate air velocity measurements at a certain distance from the outlets; Model 3 was dedicated to the modelling of the internal geometry of the air ducts rather than the characterization of the air flows generated by the sprayer; and Model 4, which was developed as a variant of Model 3, was created to perform the same calculation in several stages. The models were validated with actual measurements of the air velocity near the sprayer outlets. The results showed that although Models 1 and 2 (both of which have been used in most existing studies) simplified the calculation, they are impractical for simulating different air flows. By contrast, Models 3 and 4 provided complex meshes that complicate the convergence of the calculation and require a suitable treatment of both the viscosity and the flow near the walls. Model 3 showed the smallest error (16%) in the air velocity estimated in the treatment plane. Model 4 showed potential for future implementation of the dispersed phase and crop-air interaction because it mitigated the problems arising from the complexity of the meshes. It should also be noted that there are errors inherent to the implementation of the CFD model, errors related to inaccuracies in the geometry of the air ducts, inaccuracies related to the measurement of the air velocities, inaccuracies in the quantification of the air flow, and simplifications linked to the turbulent model. [ABSTRACT FROM AUTHOR]

• Variable Rate Application Technology (VRA) • Copper reduction. • Remote Sensing. • UAV. • Vineyard. Reduction of Plant Protection Products (PPP) has become a priority in agriculture, led by European directives and regulations due to the negative impacts and social awareness that pesticides have raised in the population. In viticulture, the use of copper to control Downy Mildew (Plasmopara viticola) is posing severe problems of soil, water and environment contamination, and European Commission is regulating its use through the EU regulation 2018/1981. A targeted spraying management can be done benefiting from the novel development of variable rate application (VRA) technology for orchard sprayers, resulting in savings of PPP. In this research, the quality of the application in terms of copper deposit in leaves of two VRA strategies where compared versus the conventional strategy performed by the farmer (REF). In each of the two VRA strategies, copper dosage was selected 1) maintaining copper dose per hectare (VRA) and 2) following the copper concentration listed in the product label (VRA [Cu]). Drone based NDVI maps from three commercial vineyards were used to characterize the structure of the vegetation in every vigour zone and manual measures in field were used to determine the most appropriate spraying volume rate according to canopy characteristics. Results show that a reduction of 33 and 44 % of copper used per hectare did not have significant impact on the quality of the application. On the contrary, while leaf deposit was comparable to that achieved by REF strategy, the product was better distributed across the entire canopy. Savings of 40 % of copper could be achieved in in the PPP application calendar along the season 2019 with no influence in disease control. Impact of PPP can be reduced by incorporating digital technologies, and the objectives of the Farm to Fork strategy and the European Green Deal can be met ensuring a more sustainable agri-food production. [ABSTRACT FROM AUTHOR]

• Effect of fan settings and nozzle size on leaf coverage in a treatment was studied. • The higher the airflow rate and droplet size, the bigger the homogeneous coverage. • The finest droplets distribution showed a large dependence on initial fan setup. • Canopy resistance behavior was related with the turbulence intensity of air currents. • A larger turbulence intensity did not imply a better spray coverage on the trees. Air assistance and droplet's characteristics influence on the pesticide deposit and its distribution over the intended target during the spray application process. The present research work is focused on the characterization of the leaf coverage and the overall spray distribution within the whole canopy by combining different settings of air assistance with different nozzles, generating different droplet's sizes. A new designed air-assisted orchard sprayer was tested, presenting a wireless remote-regulation system to control the airflow rate from the fan by adjusting the blade pitch. In this way, five airflow rates were obtained by combining the gearbox position and the blade pitch. For each one of these five air settings, three droplet sizes (F-Fine, M−Medium, and C-Coarse) were combined and evaluated over a set of artificial apple trees. The evaluation was divided in two parts: a) a whole characterization of the airstream generated by the five air settings was performed for the two sprayer's sides using a 3D-ultrasonic anemometer and placing the sprayer in front of the artificial trees and b) a coverage tests for each nozzle-air settings combination by using water sensitive papers (WSP) placed at different heights and depths evenly distributed across the canopy, the WSP's were analyzed by a processing image software. The results demonstrated that ultrasonic anemometers were helpful to characterize the airstream and to analyze its effect on leaf coverage. Experimental data showed that a higher airflow rate and a larger droplet size generated a more homogeneous coverage on both sides of the sprayer. In this line, the turbulence intensity data suggest that larger variations in the air velocities increase the drag coefficient. Which meant that the canopy resistance to the air stream increased. In addition, an increase of turbulence intensity generated higher spray coverage. Therefore, a higher turbulence intensity did not imply a better spray coverage. It was also observed that the droplet size was critical on regulating the airflow influence on spray coverage. Coarse droplet size did not present any relation with the airflow changes. While the fine droplet size presented a high dependency on airflow conditions. [ABSTRACT FROM AUTHOR]

Accurate crown characterization of large isolated olive trees is vital for adjusting spray doses in three-dimensional crop agriculture. Among the many methodologies available, laser sensors have proved to be the most reliable and accurate. However, their operation is time consuming and requires specialist knowledge and so a simpler crown characterization method is required. To this end, three methods were evaluated and compared with LiDAR measurements to determine their accuracy: Vertical Crown Projected Area method (VCPA), Ellipsoid Volume method (VE) and Tree Silhouette Volume method (VTS). Trials were performed in three different kinds of olive tree plantations: intensive, adapted one-trunked traditional and traditional. In total, 55 trees were characterized. Results show that all three methods are appropriate to estimate the crown volume, reaching high coefficients of determination: R² = 0.783, 0.843 and 0.824 for VCPA, VE and VTS, respectively. However, discrepancies arise when evaluating tree plantations separately, especially for traditional trees. Here, correlations between LiDAR volume and other parameters showed that the Mean Vector calculated for VCPA method showed the highest correlation for traditional trees, thus its use in traditional plantations is highly recommended. [ABSTRACT FROM AUTHOR]

The photocatalytic and electrocatalytic conversion of CO2 has the potential to provide valuable products, such as chemicals or fuels of interest, at low cost while maintaining a circular carbon cycle. In this context, carbon dots possess optical and electrochemical properties that make them suitable candidates to participate in the reaction, either as a single component or forming part of more elaborate catalytic systems. In this review, we describe several strategies where the carbon dots participate, both with amorphous and graphitic structures, in the photocatalysis or electrochemical catalysis of CO2 to provide different carbon-containing products of interest. The role of the carbon dots is analyzed as a function of their redox and light absorption characteristics and their complementarity with other known catalytic systems. Moreover, detailed information about synthetic procedures is also reviewed. [ABSTRACT FROM AUTHOR]

Electronic canopy characterization is an important issue in tree crop management. Ultrasonic and optical sensors are the most used for this purpose. The objective of this work was to assess the performance of an ultrasonic sensor under laboratory and field conditions in order to provide reliable estimations of distance measurements to apple tree canopies. To this purpose, a methodology has been designed to analyze sensor performance in relation to foliage ranging and to interferences with adjacent sensors when working simultaneously. Results show that the average error in distance measurement using the ultrasonic sensor in laboratory conditions is ±0.53 cm. However, the increase of variability in field conditions reduces the accuracy of this kind of sensors when estimating distances to canopies. The average error in such situations is ±5.11 cm. When analyzing interferences of adjacent sensors 30 cm apart, the average error is ±17.46 cm. When sensors are separated 60 cm, the average error is ±9.29 cm. The ultrasonic sensor tested has been proven to be suitable to estimate distances to the canopy in field conditions when sensors are 60 cm apart or more and could, therefore, be used in a system to estimate structural canopy parameters in precision horticulture. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, LIDAR (light detection and ranging) sensors have been widely used to measure environmental parameters such as the structural characteristics of trees, crops and forests. Knowledge of the structural characteristics of plants has a high scientific value due to their influence in many biophysical processes including, photosynthesis, growth, CO2-sequestration and evapotranspiration, playing a key role in the exchange of matter and energy between plants and the atmosphere, and affecting terrestrial, above-ground, carbon storage. In this work, we report the use of a 2D LIDAR scanner in agriculture to obtain three-dimensional (3D) structural characteristics of plants. LIDAR allows fast, non-destructive measurement of the 3D structure of vegetation (geometry, size, height, cross-section, etc.). LIDAR provides a 3D cloud of points, which is easily visualized with Computer Aided Design software. Three-dimensional, high density data are uniquely valuable for the qualitative and quantitative study of the geometric parameters of plants. Results are demonstrated in fruit and citrus orchards and vineyards, leading to the conclusion that the LIDAR system is able to measure the geometric characteristics of plants with sufficient precision for most agriculture applications. The developed system made it possible to obtain 3D digitalized images of crops, from which a large amount of plant information – such as height, width, volume, leaf area index and leaf area density – could be obtained. There was a great degree of concordance between the physical dimensions, shape and global appearance of the 3D digital plant structure and the real plants, revealing the coherence of the 3D tree model obtained from the developed system with respect to the real structure. For some selected trees, the correlation coefficient obtained between manually measured volumes and those obtained from the 3D LIDAR models was as high as 0.976. [Copyright &y& Elsevier]

The use of a low-cost tractor-mounted scanning Light Detection and Ranging (LIDAR) system for capable of making non-destructive recordings of tree-row structure in orchards and vineyards is described. Field tests consisted of several LIDAR measurements on both sides of the crop row, before and after defoliation of selected trees. Summary parameters describing the tree-row volume and the total crop surface area viewed by the LIDAR (expressed as a ratio with ground surface area) were derived using a suitable numerical algorithm. The results for apple and pear orchards and a wine producing vineyard were shown to be in reasonable agreement with the results derived from a destructive leaf sampling method. Also, good correlation was found between manual and sensor-based measurements of the vegetative volume of tree-row plantations. The Tree Area Index parameter, TAI, gave the best correlation between destructive and non-destructive (i.e. LIDAR-based) determinants of crop leaf area. The LIDAR system proved to be a powerful technique for low cost, prompt and non-destructive estimates of the volume and leaf-area characteristics of plants. [Copyright &y& Elsevier]

Objectives: The purpose of this study was to assess the value of the serum levels of α-L-fucosidase activity in the diagnosis of patients with colorectal cancer. Methods: Using a fluorometric method we analyzed the α-L-fucosidase activity in preoperative sera from 137 colorectal cancer patients and in sera from 232 donors. Results: The enzymatic activity of α-L-fucosidase was significantly lower (p < 0.001) in patients (4.8 ± 3.09 U/ml) than in donors (10.5 ± 5.46 U/ml). Using the ROC curve, the ideal cut-off for the diagnostic value of α-L-fucosidase activity was determined to be 5.6 U/ml. The diagnostic efficiency for colorectal cancer of α-L-fucosidase activity was higher than that observed for carcinoembryonic antigen (cut-off 5.0 ng/ml), especially for tumors at an early stage. Conclusions: Our results suggest that preoperative serum α-L-fucosidase activity may be used as a cheap and easy complementary test, in addition to standard clinical procedures routinely used for the diagnosis of colorectal cancer.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Visual navigation is developing rapidly and is of great significance to improve agricultural automation. The most important issue involved in visual navigation is extracting a guidance path from agricultural field images. Traditional image segmentation methods may fail to work in paddy field, for the colors of weed, duckweed, and eutrophic water surface are very similar to those of real rice seedings. To deal with these problems, a crop row segmentation and detection algorithm, designed for complex paddy fields, is proposed. Firstly, the original image is transformed to the grayscale image and then the treble-classification Otsu method classifies the pixels in the grayscale image into three clusters according to their gray values. Secondly, the binary image is divided into several horizontal strips, and feature points representing green plants are extracted. Lastly, the proposed double-dimensional adaptive clustering method, which can deal with gaps inside a single crop row and misleading points between real crop rows, is applied to obtain the clusters of real crop rows and the corresponding fitting line. Quantitative validation tests of efficiency and accuracy have proven that the combination of these two methods constitutes a new robust integrated solution, with attitude error and distance error within 0.02° and 10 pixels, respectively. The proposed method achieved better quantitative results than the detection method based on typical Otsu under various conditions. [ABSTRACT FROM AUTHOR]

We evaluate the potential of using a process-based ecosystem model (BEPS) for crop biomass mapping at 20 m resolution over the research site in Manitoba, western Canada driven by spatially explicit leaf area index (LAI) retrieved from Sentinel-2 spectral reflectance throughout the entire growing season. We find that overall, the BEPS-simulated crop gross primary production (GPP), net primary production (NPP), and LAI time-series can explain 82%, 83%, and 85%, respectively, of the variation in the above-ground biomass (AGB) for six selected annual crops, while an application of individual crop LAI explains only 50% of the variation in AGB. The linear relationships between the AGB and these three indicators (GPP, NPP and LAI time-series) are rather high for the six crops, while the slopes of the regression models vary for individual crop type, indicating the need for calibration of key photosynthetic parameters and carbon allocation coefficients. This study demonstrates that accumulated GPP and NPP derived from an ecosystem model, driven by Sentinel-2 LAI data and abiotic data, can be effectively used for crop AGB mapping; the temporal information from LAI is also effective in AGB mapping for some crop types. [ABSTRACT FROM AUTHOR]

• Manuka honey reduces the volume of the entire culture of colonospheres. • Manuka honey induces apoptosis in colorectal CSCs-like from spheroids. • Manuka honey induces intracellular ROS in colorectal CSCs-like from spheroids. • Manuka honey reduces mRNA expression of ABCG2 in colorectal CSCs-like from spheroids. • Manuka honey reduces CSCs self-renewal ability by suppressing Wnt/β-catenin pathway. Chemoresistance and development of relapses are ascribable to a rare cell population of tumour mass: cancer stem cells (CSCs). Targeting CSCs could increase patients' survival rate and it is important to identify molecules that can act on the main pathways of these cells. Natural bioactive compounds, of which Manuka honey (MH) is rich, could be a good opportunity to target them. This work aims to evaluate the effect of MH on CSCs-like from human colorectal carcinoma (HCT-116 cell line) enriched through the in vitro sphere-forming assay. The results showed that MH reduced the volume of the entire culture of spheroids, affecting also their morphological parameters and induced apoptosis and ROS intracellular accumulation in CSCs-like. In addition, MH decreased the mRNA expression of one of ABC transporters (ABCG2) and affected self-renewal ability through the downregulation of the mRNA expression of one of the receptor membranes of Wnt/β-catenin pathway (Frizzled 7). [ABSTRACT FROM AUTHOR]

Agitation inside agricultural sprayer tanks can be studied while using an international standard procedure, based on obtaining internal samples of liquid. However, in practice, this test is not easy to perform. Herein, we propose the explicit study of the mixing procedure with biphasic computer simulations using Computational Fluid Dynamics (CFD). An experimental test was performed on a 3000 L tank of a commercial air-assisted sprayer, with two different agitation system configurations, in order to compare the results of several theoretical physical models of biphasic flows for CFD, both Eulerian and Lagrangian. From the analysis of these theoretical models, we conclude that the Volume of Fluid model is not viable and the Discrete Phase Model produces erroneous results, while the Eulerian and Mixture models can both be useful. However, the results obtained suggest that complex streams generated by real-world agitation systems produce more errors in calculations. Both models can be conducted in the design phase, prior to the implementation of the machine. In addition, the computer simulations allow for researchers to analyse the mixing process in detail, making it possible to evaluate the efficiency of an agitation system according to the time that is required to reach mixture homogeneity. [ABSTRACT FROM AUTHOR]

Canopy characteristics are crucial for accurately and safely determining the pesticide quantity and volume of water used for spray applications in vineyards. The inevitably high degree of intraplot variability makes it difficult to develop a global solution for the optimal volume application rate. Here, the design procedure of, and the results obtained from, a variable rate application (VRA) sprayer are presented. Prescription maps were generated after detailed canopy characterization, using a multispectral camera embedded on an unmanned aerial vehicle, throughout the entire growing season in Torrelavit (Barcelona) in four vineyard plots of Chardonnay (2.35 ha), Merlot (2.97 ha), and Cabernet Sauvignonn (4.67 ha). The maps were obtained by merging multispectral images with information provided by DOSAVIÑA®, a decision support system, to determine the optimal volume rate. They were then uploaded to the VRA prototype, obtaining actual variable application maps after the application processes were complete. The prototype had an adequate spray distribution quality, with coverage values in the range of 20–40% and exhibited similar results in terms of biological efficacy on powdery mildew compared to conventional (and constant) application volumes. The VRA results demonstrated an accurate and reasonable pesticide distribution, with potential for reduced disease damage even in cases with reduced amounts of plant protection products and water. [ABSTRACT FROM AUTHOR]

A computational fluid dynamics (CFD) model of the fluid velocities generated by the agitation system of an air-assisted sprayer was developed and validated by practical experiments in a laboratory. The model was developed considering different settings of the agitation system: Three water levels in the tank (1000, 2000, and 3000 L); two different numbers of active nozzles (2 or 4); and three working pressures of the agitation circuit (8, 10, or 12 bar). Actual measurements of the fluid velocity into the tank were taken using an acoustic Doppler velocimeter (ADV). CFD simulations made it possible to estimate fluid velocities at 38% of the measuring points with relative errors of less than 30%. Additionally, the CFD models have allowed the correct prediction of the general behavior of the fluid in the tank considering mean velocities depending on the setting parameters of the agitation system (water level in the tank, hydraulic circuit pressure, and number of active nozzles). [ABSTRACT FROM AUTHOR]

• The air generated in pesticide treatments with axial fan sprayers should be studied. • Air can be an environmental problem with the formation of atmospheric spray drift. • The air of a sprayer in static and dynamic position has been characterized. • The movement of the sprayer reinforced the asymmetric behaviour of the fan. • Vegetation can influence on the trajectories of air currents to the atmosphere. Air assisted sprayers are currently used for the applications of plant protection products in fruit trees and vineyards. However, the use of these equipment carries a high environmental risk, mainly owing to the generation of airborne spray drift in the lower boundary layer above crop canopy. Hence, many tests are currently focused on investigating several factors that affect the efficiency of the spray process, in which air assistance and air behaviour are two of the most difficult parameters to evaluate. This present work proposes a first approach on the characterization of the airflow generated by an orchard sprayer equipped with an axial fan and an air reverse system in the outlet plane of the air, while circulated through two artificial rows of canopy representing vineyard trellis, using 3D-ultrasonic anemometers to measure the experimental data. A first series of static field tests measured the air velocity at different heights on both sides of the sprayer and at both sides of every row of artificial canopy and evaluated the effect of the canopy on the sprayer airflow passing through. A second set of experiments were carried out with the sprayer moving at 4.1 km h−1 between canopy rows to simulate the normal spray process. Finally, velocity vectors and turbulent intensities were calculated. The resistance of the vegetation was also characterized by using a drag coefficient, both when the sprayer was stationary and moving. The results between the static and dynamic tests were compared. Although there were similarities between the two tests, the results indicated that when the equipment moves along the canopy rows, the axial fan asymmetry on air velocities is more noticeable and turbulence intensity increased. In addition, the vegetation received direct airflow at different times. This could affect the trajectory of the droplets. On the other hand, the resistance of the vegetation on each side was similar. The air reverse system could be affecting the airflow direction to the driving direction. Ultrasonic anemometers were successful in characterizing sprayer fan airflows but it is necessary to continue working on the descriptive analysis of the airflow in other planes different from the air outlet only and with other vineyard systems. [ABSTRACT FROM AUTHOR]

An acoustic Doppler velocimeter (ADV) was used to analyse the impact of an agricultural sprayer's agitation system settings on fluid velocities inside the tank. A 3000 L capacity sprayer equipped with a 4-nozzle hydraulic agitation system was used. ADV measurements were carried at 32 points inside the tank under the following settings: circuit pressures of 8, 10, or 12 bar; water level in the tank of 1000, 2000, or 3000 L; 2 or 4 active nozzles. An agitation test with a concentration of 0.4% copper oxychloride was employed to analyse the concentration of active matter as a function of tank fill level and number of active nozzles. All parameters significantly affected the fluid velocity, which increased with increasing pressure, but decreased with increasing water level in the tank and an increased number of active nozzles. Concentration tests showed greater active matter concentrations when higher velocities were recorded by the ADV. The ADV was shown to be a useful tool for the rapid assessment of fluid velocities; in the future, it could be used to validate the design of agitation systems, and to estimate their capacity to ensure an adequate level of active matter concentration in the fluid. [ABSTRACT FROM AUTHOR]