Author
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Thomson, Steven |
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Submitted to: Agricultural Aviation
Publication Type: Trade Journal Publication Acceptance Date: 4/17/2007 Publication Date: 9/30/2007 Citation: Thomson, S.J. 2007. Agricultural Aircraft for Site-Specific Agriculture. National Agricultural Aviation Association 34(5):28-29 Interpretive Summary: Precision agriculture is a method by which pesticide, fertilizer or other field inputs are applied only where they are needed. This saves on chemical and farm resources, and reduces environmental loading. Agricultural aircraft provide a convenient platform to aid in detecting areas in the field to treat (remote sensing), and applying these field inputs in a variable fashion (variable-rate flow control). Data from remote sensing can be used by itself or to provide data for variable-rate flow control. An exciting stand-alone remote sensing application uses thermal imagery to detect the onset of crop water stress. Global positioning systems (GPS) on aircraft are used to locate areas to apply field inputs, but they are also used to trigger remote sensing cameras. Thus, these systems have to be evaluated for positioning accuracy so that cameras can be triggered at the right time and field inputs are applied in a timely fashion. Automatic flow control devices are the heart of variable-rate application systems used on agricultural aircraft, and they are continually being evaluated for accuracy and response time when application flow is changed. Research is being conducted to assist the system manufacturer in improving an automatic variable-rate flow control system, and new variable rate nozzles will be required in the future to assure proper spray droplet size is delivered at all system pressures. These pressures and flowrates change as some parts of the field require different amounts of chemical. Keeping a constant droplet size range will assure that off-target spry drift is minimized. Technical Abstract: Agricultural aircraft provide a convenient platform to aid in precision agriculture, in which pesticide, fertilizer or other field inputs are applied only where they are needed. This saves on chemical and farm resources, and reduces environmental loading. Remote sensing is used to spot areas of the field to treat, and variable-rate application systems on board the aircraft can vary the amount of field input to select sections of the field, according to need. Both remote sensing and variable rate application can be accomplished using agricultural aircraft. An exciting stand-alone remote sensing application uses thermal imagery to detect the onset of crop water stress. Researchers with the USDA ARS Application and Production Technology Research Unit (APTRU) in Stoneville Mississippi have installed thermal imaging cameras on agricultural aircraft to accomplish this. Global positioning systems (GPS) on aircraft are used to locate areas to apply field inputs, but they are also used to trigger remote sensing cameras. Thus, these systems have been evaluated for positioning accuracy so that cameras can be triggered at the right time and field inputs are applied in a timely fashion. Automatic flow control devices are the heart of variable-rate application systems used on agricultural aircraft, and they are continually being evaluated for accuracy and response time when application flowrates are changed. Research is being conducted to assist the system manufacturer in improving the automatic variable-rate flow control system. In order for variable rate aerial application systems to be practical, new spray nozzles that maintain a relatively constant spray droplet size regardless of system pressure are a must so that off-target spray drift is minimized and the spray application is effective for the crop and pest control. |
