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Unmanned aerial vehicles have been developed and applied to support agricultural production management. Compared with piloted aircraft, an Unmanned Aerial Vehicle (UAV) can focus on small crop fields at lower flight altitudes than regular aircraft to perform site-specific farm management with higher precision. They can also “fill in the gap” in locations where fixed winged or rotary winged aircraft are not readily available. In agriculture, UAVs have primarily been developed and used for remote sensing and application of crop production and protection materials. Application of fertilizers and chemicals is frequently needed at specific times and locations for site-specific management. Routine monitoring of crop plant health is often required at very high resolution for accurate site-specific management as well. This paper presents an overview of research involving the development of UAV technology for agricultural production management. Technologies, systems and methods are examined and studied. The limitations of current UAVs for agricultural production management are discussed, as well as future needs and suggestions for development and application of the UAV technologies in agricultural production management.

This work reports droplet-size data measured as part of a collaborative testing program between the US Department of Agriculture, Agricultural Research Service, and the US Navy, Navy Entomological Center for Excellence. This is an ongoing relationship that seeks to test new and revised spray technologies that may potentially be used by deployed personnel. As new equipment comes to market or when existing equipment is modified they are all integrated into this annual testing. During the 2011 equipment evaluations, 24 sprayers were operated across their range of available settings (pressure and flow rate), using both water and oil solutions. Droplet-size data as measured with laser diffraction ranged from 4 to 223 microns (volume median diameter). Generally, as the spray rate increased, droplet size increased, and as the pressure increased at a given same spray rate, droplet size decreased. This information allows users to set up and operate these sprayers in a manner such that a particular droplet size is applied optimizing efficiency and efficacy of applications., Journal of the American Mosquito Control Association, v28 n2 p93-101, 2012.

This study investigated three different types of multispectral imaging systems for airborne remote sensing to support management in agricultural application and production. The three systems have been used in agricultural studies. They range from low-cost to relatively high-cost, manually operated to automated, multispectral composite imaging with a single camera and integrated imaging with custom-mounting of separate cameras. Practical issues regarding use of the imaging systems were described and discussed. The low-cost system, due to band saturation, slow imaging speed and poor image quality, is more preferable to slower moving platforms that can fly close to the ground, such as unmanned autonomous helicopters, but not recommended for low or high altitude aerial remote sensing on fixed-wing aircraft. With the restriction on payload unmanned autonomous helicopters are not recommended for high-cost systems because they are typically heavy and difficult to mount. The system with intermediate cost works well for low altitude aerial remote sensing on fixed-wing aircraft with field shapefile-based global positioning triggering. This system also works well for high altitude aerial remote sensing on fixed-wing aircraft with global positioning triggering or manually operated. The custom-built system is recommended for high altitude aerial remote sensing on fixed-wing aircraft with waypoint global positioning triggering or manually operated. Keywords: airborne remote sensing, multispectral imaging, agricultural production management

The first variable-rate aerial application system was developed about a decade ago in the USA and since then, aerial application has benefitted from these technologies. Many areas of the United States rely on readily available agricultural airplanes or helicopters for pest management, and variable-rate aerial application provides a solution for applying field inputs such as cotton growth regulators, defoliants, and insecticides. In the context of aerial application, variable-rate control can simply mean terminating spray over field areas that do not require inputs, terminating spray near pre-defined buffer areas determined by Global Positioning, or applying multiple rates to meet the variable needs of the crop. Prescription maps for aerial application are developed using remote sensing, Global Positioning, and Geographic Information System technologies. Precision agriculture technology has the potential to benefit the agricultural aviation industry by saving operators and farmers time and money.

Soft computing is a set of “inexact” computing techniques, which are able to model and analyze very complex problems. For these complex problems, more conventional methods have not been able to produce cost-effective, analytical, or complete solutions. Soft computing has been extensively studied and applied in the last three decades for scientific research and engineering computing. In agricultural and biological engineering, researchers and engineers have developed methods of fuzzy logic, artificial neural networks, genetic algorithms, decision trees, and support vector machines to study soil and water regimes related to crop growth, analyze the operation of food processing, and support decision-making in precision farming. This paper reviews the development of soft computing techniques. With the concepts and methods, applications of soft computing in the field of agricultural and biological engineering are presented, especially in the soil and water context for crop management and decision support in precision agriculture. The future of development and application of soft computing in agricultural and biological engineering is discussed.

Numerous spray machines are used to apply pesticides for the control of human disease vectors, such as mosquitoes and flies, and the selection and setup of these machines significantly affects the level of control achieved during an application. The droplet spectra produced by 9 different ultra-low? volume sprayers with oil- and water-based spray solutions were evaluated along with 2 thermal foggers with the use of diesel-based spray solutions. The droplet spectra from the sprayers were measured with the use of laser diffraction droplet sizing equipment. The volume median diameter from the sprayers ranged from 14.8 to 61.9 mm for the oil-based spray solutions and 15.5 to 87.5 mm for the water-based spray solutions. The 2 thermal foggers generated sprays with a volume median diameter of 3.5 mm. The data presented will allow spray applicators to select the spray solution and sprayer that generate the droplet-size spectra that meet the desired specific spray application scenarios., Pub. in Journal of the American Mosquito Control Association, v25 n3, p332-337, 2009.

The EPA's proposed Drift Reduction Technology DRT low-speed wind tunnel evaluation protocol was tested across a series of modified ASAE reference nozzles. Both droplet size and deposition and flux volume measurements were made downwind from the nozzles operating in the tunnel at airspeeds of 1 m/s and 2.5 m/s, following the prescribed protocol. Overall, the data followed anticipated trends with a few unanticipated results observed, which could be addressed in future iterations of the protocol. There were some difficulties meeting the proposed protocol data quality requirements. Refined quality requirements would address this with no detrimental effect to the overall data set. Major concerns, at this point, are the feasibility of the overall protocol as well as the applicability of the final collected data. The protocol was tailored such that the collected data would directly input into a dispersion model most likely WTDISP. However, not having access to such a model puts into question the validity and practicality of the protocol in its present form. Given the time requirements, which require approximately nine times that of the high speed protocol 90 min versus 10 min, unpublished data, there is a definite need to modify the existing protocol to insure equitable implementation of the overall DRT program., Published in the Journal of the ASTM International v6 n4 (JAI 102129).

Application of crop production and protection materials is a crucial component in the high productivity of American agriculture. Agricultural chemical application is frequently needed at specific times and locations for accurate site‐specific management of crop pests. Piloted agricultural aircraft are typically used to treat large, unobstructed, continuous acreage crops and are not as efficient when working over small or obstructed plots. An Unmanned Aerial Vehicle (UAV), which can be remotely controlled or fly autonomously based on pre‐programmed flight plans, may be used to make timely and efficient applications over these small area plots. This research developed a low volume spray system for use on a fully autonomous UAV to apply crop protection products on specified crop areas. This article discusses the development of the spray system and its integration with the flight control system of a fully autonomous, unmanned vertical take‐off and landing helicopter. Sprayer actuation can be triggered by preset positional coordinates as monitored by the equipped Global Positioning System (GPS). The developed spray system has the potential to provide accurate, site‐specific crop management when coupled with UAV systems. It also has great potential for vector control in the areas that are not easily accessible by personnel or equipment.

Minerals and organic matter in spray carrier water can reduce the effectiveness of some plant protection products. Water hardness has been found to have a significant impact of the efficacy of some crop protection materials and has shown conflicting influence on spray droplet size. The objectives of this study were to determine the effects of water hardness on spray droplet size produced by two commonly-used aerial spray nozzles with and without the addition of an invert suspension adjuvant to the tank solution under aerial application conditions. Water hardness levels from 0 to 800 ppm and/or the addition of a spray adjuvant to a spray solution had a significant effect on spray droplet size. The spray adjuvant, an invert suspension, increased most spray droplet size parameters and decreased the percent of spray volume contained in droplets less than 200 micrometre as long as the water hardness did not exceed 200 ppm. The spray adjuvant had little effect on relative span when the spray was released at a 45 deg angle to the high speed airstream, but lowered the relative span for sprays orientated 0 deg or straight back relative to the high speed airstream. Aerial applicators should test the water used in making tank solution for water hardness before the addition of spray adjuvants., Published in Applied Engineering in Agriculture, v24 n1 p11-14, 2008.