Brian D Luck

Reducing Pesticide Over-Application with Map-Based Automatic Boom Section Control on Agricultural Sprayers

The use of precision agriculture technologies such as automatic guidance and map-based automatic boom section control on agricultural sprayers has increased substantially over the past few years. The purpose of these systems is to decrease pesticide application inaccuracy by reducing pass-to-pass overlaps or by turning boom sections off when the boom passes over previously covered areas or beyond field boundaries. The objectives of this study were to compare areas treated by a sprayer before and after the addition of an automatic boom section control system and determine if there was a relationship between field shape factors, specifically perimeter-to-area (P/A) ratio, and pesticide over-application. Coverage files were downloaded from a self-propelled agricultural sprayer with a 24.8 m boom divided into five manually controlled sections. Prior to the subsequent cropping season, automatic boom section control (seven sections) was installed on the sprayer. Application inaccuracy was calculated for the 21 study fields by comparing the actual sprayed area (based on boom section control state: on/off) versus the total projected field area. A comparison between the average percent over-application from fields during season one (12.4%) and season two (6.2%) revealed a significant reduction in off-target application. This reduction represents savings to agricultural producers, potentially justifying the purchase and implementation of this technology. Further analysis indicated an increasing trend in over-application for manual and automatic boom section control as the P/A ratio increased for the study fields. Over-application increased at a greater rate with manual boom section control, which suggests that as field inclusions (grassed waterways or other obstacles) increase, automatic boom section control will provide a greater opportunity for producers to reduce these errors.

Computational model of methane and ammonia emissions from dairy barns: Development and validation

Abstract The increased global demand for milk and other dairy products over the past decades is a cause for concern due to the potential for environmental impact. Ammonia produced by housed dairy cows can contribute to the formation of particulate matter and nitrous oxide which both contribute to the greenhouse effect. The methane produced by these cows also contributes to the greenhouse effect. Scientists and engineers face the challenge of developing methods to reduce the environmental impact of dairy production while not inhibiting the ability of producers to keep up with demand. Emission of methane and ammonia are highly dependent on feed composition, barn design and operation, manure management making this a challenging topic to study experimentally. Using computational models to simulate the generation and dispersion of gaseous species within dairy housing can facilitate the exploration of cost-effective gas mitigation strategies. Thus a steady-state computational fluid dynamics (CFD) model capable of simulating biologically based generation of methane, ammonia, and heat and their transport within the domain was developed and validated. The effect of buoyancy forces on the accuracy and stability of the solutions was explored. The model was validated with experimental data collected from emission chambers located at USDA-ARS Dairy Forage Research Center in Wisconsin, USA. Concentration of ammonia and methane, due to controlled injections from cylinders and biological generations from a dairy cow, were measured in the chambers using a FTIR gas analyzer. Results of the validated CFD model could be used to predict gaseous emissions under a range of environmental, design, and experimental treatment parameters.

Assessing Cross-Sectional Air Velocity Uniformity in Commercial Broiler Houses via the Traverse Method

Abstract. Air velocity is a contributing factor to maintaining a production environment that promotes production efficiency, thermal comfort, and animal well-being. Variations in size, design, and equipment of production facilities contribute greatly to the air velocity generated. This study assessed mean cross-sectional air velocities and total air flow of two broiler production facilities. Test facility 1 was an 18.3 A— 170.7 m smooth sidewall broiler production facility and test facility 2 was a 12.19 A— 121.9 m curtain sidewall broiler production facility. Air velocity was characterized down each house with a Scalable Environment Assessment System (SEAS). Cross-sections were measured at 2.44 m and 3.05 m intervals in the axial direction for test facility 1 and 2 respectively. Total air flow was measured with Fan Assessment and Numeration System (FANS) units. Normalized cross-sectional air velocity was plotted against proportion of total house length to compare the cross-sectional air velocity of the two facilities. Test facility 1 showed 26.5% of the total house length below superficial velocity while test facility 2 only had 17.5% below superficial velocity. Test facility 1 demonstrated 11.4% of the facility length below normalized superficial velocity for temperature control at the exhaust fan end of the facility. Physical arrangement of the feed hoppers, heating systems, and tunnel fans are important for improving uniformity of air velocity in commercial broiler houses.

Improving Commercial Broiler Attic Inlet Ventilation through CFD Analysis

The use of solar heated attic air is an area of increasing interest in commercial poultry production. Attic inlets satisfy the demand for alternative heating while being simple to implement in an existing poultry house. A number of demonstration projects have suggested that attic inlets may decrease the amount of fuel required to raise minimum ventilation air to set point temperature by tempering the inlet air. However, little attention has been given to the configuration of the attic space and its influence on thermal energy extraction. The objectives of this study were as follows: 1) Collect data for the operation of attic inlets in a commercial broiler house, 2) develop a two-dimensional computational fluid dynamic (CFD) simulation model using experimental data, and 3) Use the simulation to investigate the efficiency of attic inlet system configurations. Field data collected during the operation of attic inlets in an east-west oriented broiler house illustrated the asymmetric heating and stratification of air temperature. A two dimensional CFD simulation model was developed for attic inlet system operation using field data to develop boundary conditions. The simulation demonstrated that the strategic placement of a simple 2.44 m ridge cap diverter and a central inlet riser (1.3 m high) may increase thermal energy extraction by 55% and 68% (30 s and 60 s fan runtimes, respectively) over the measured attic inlet system.

Air Velocity Distribution in a Commercial Broiler House

Increasing air velocity during tunnel ventilation in commercial broiler production facilities improves production efficiency, and many housing design specifications require a minimum air velocity. Air velocities are typically assessed with a hand-held velocity meter at random locations, rather than systematic traverses. Simultaneous measurement of air velocity at multiple locations in the facility would provide a more accurate estimation of mean velocity. Objectives of this study were to develop a multi-point air velocity measurement system and map air velocity in a tunnel ventilated broiler house. An array of hot-bead type anemometers was placed in a commercial broiler production facility measuring 12.9 x 121.9 m with curtain side walls; the house was equipped with ten 121.9 cm exhaust fans. Cross-sectional velocity measurements were taken in increments of 12.19 m starting at 12.19 m from the end wall of the house and ending at 12.19 m away from the exhaust fans; one cross section of the house was tested at a time. The sensors were allowed a 2 min settling time before 5 min of data collection at each location. Air velocities were compiled at 45.7, 106.7, 167.6 and 213.4 cm above the litter. Mean velocities ranged from 1.94 m/s to 3.06 m/s (382 ft/min to 602 ft/min) across all cross-sections measured. All location contributions to the ANOVA were significant (P = 0.0185) and regression results showed a quadratic relationship between transverse location and air velocity.

Technical Note: Evaluation of a Rhodamine-WT Dye/Glycerin Mixture as a Tracer for Testing Direct Injection Systems for Agricultural Sprayers

The purpose of this study was to provide valuable insight regarding the use of Rhodamine WT (red) dye as a tracer for evaluating injected concentrations. More specifically, the effects of mixing the dye with glycerin to simulate the viscosity of a pesticide (e.g., glyphosate) or injecting the dye/glycerin mixture into deionized (DI) versus tap water on developing appropriate calibration equations were evaluated. Test results indicated that mixing the dye in a solution of glycerin and DI water significantly affected absorbance measurements compared to the dye mixed solely in DI water. The error in estimating absorbance was 7.4% between the two calibration equations. Therefore, any calibration curves must include a solution containing glycerin to compensate for this. Absorbance results also indicated that potable tap water could be used to simulate the spray carrier as opposed to the DI water. A calibration curve was developed for the simulated pesticide (dye/glycerin/DI water solution) injected into the carrier (tap water) for solutions ranging from 2,000:1 (carrier:pesticide) to 500,000:1; an overall dilution range of 250:1. This dilution range exceeded typical pesticide tank-mixed dilutions which were on the order of 11:1 for the application of glyphosate for corn or soybeans. The regression model standard error for predicting the dye concentration based on absorbance measurements was 5.3x10-6.

Assessment of Air Velocity Sensors for Use in Animal Production Facilities

Ventilation is an integral part of thermal environment control in animal production facilities. Accurately measuring the air velocity distribution within these facilities is cumbersome using the traverse method and a distributed velocity measurement system would reduce the time necessary to perform an accurate traverse. Ideally, a network of these sensors would be placed in several locations throughout the facility to simultaneously measure airflow in real time at multiple points in the building. The performance of low-cost thermo-anemometers was assessed in a wind tunnel and in a poultry research facility. A small scale wind tunnel was constructed and calibrated to assess the performance of the anemometers at velocities ranging from 0.25 to 5.1 m/s. Standard errors of the estimates when comparing the two types of sensors were less that 5% of full scale and did not exceed 0.254 m/s (50 ft/min). Once the initial assessment and calibration of the sensors was completed, the sensors were placed in an environmentally controlled air-velocity research facility housing broilers at seven weeks of age. Sensor performance was degraded as dust and feathers collected on the sensors. A cleaning method was developed using a small compressed air tank, solenoid valve and several small nozzles directed at the sensors. A study was conducted to determine the optimal cleaning interval to maintain measurement accuracy. Visual assessment of the data showed a cleaning interval of 10 min. to be satisfactory. With further investigation a cleaning interval of 30 min. may prove to be sufficient.

Effects of Field Shape and Size on Application Errors Using Manual and Automatic Boom Section Control on a Self-Propelled Agricultural Sprayer

Past studies have been conducted to determine how the shape or size of a field may affect field efficiency and overlap errors. Typically these studies have been conducted using actual field boundaries, with assumed field coverage paths, implement types, and overlap widths. The information gained from some of these studies, while often based on hypothetical situations, can be beneficial to producers who want to reduce application errors. The goal of this study was to utilize actual field application data collected from a self-propelled agricultural sprayer to compare errors resulting from manual and automatic boom section control. Application errors resulting from both boom section control scenarios were evaluated versus field size and shape factors to identify if any trends existed as these parameters vary. Results of the statistical analysis indicated a relationship existed between field perimeter-to-area ratio and over-application resulting from manual (R2 of 0.57) and automatic (R2 of 0.56) boom section control for both sprayers. The reduction in over-application with the addition of automatic boom section control also demonstrated an increasing trend as the field perimeter to area ratio increased (R2 of 0.61). Errors increased at a greater rate using manual boom section control which suggests that as field inclusions (grassed waterways or other obstacles) increase or the field boundary becomes more complex, automatic boom section control will provide a greater opportunity for producers to reduce over-application.