Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2004
Publication Date: 11/14/2005
Citation: Hoffmann, W.C., Hewitt, A.J. 2005. Comparison of three imaging systems for water-sensitive papers. Applied Engineering in Agriculture. 21:961-964.
Interpretive Summary: Researchers and applicators use water-sensitive paper to help them see sprays or droplets that have been applied to crops. As the name implies, water droplets land on this paper and create blue stains that provide a method for measuring droplet sizes and deposition quality from an application of agricultural chemicals. A comparison of two commercial imaging systems and one system built by USDA personnel determined similar droplet size distributions on water-sensitive papers over a range of droplet sizes and measurement parameters from an aerial application spray test. The results from this study allow users of the three imaging systems to confidently compare and share data analyzed with any of the systems.
Technical Abstract: Water-sensitive paper is commonly used by researchers and applicators as a method for assessing the droplet size spectra and deposition quality from an application of agrochemicals. Three imaging systems (USDA-ARS and Swath Kit camera-based systems and DropletScan scanner-based system) were compared using two sets of water-sensitive papers from an aerial application spray test. Although the systems used different spread factor equations to calculate actual droplet sizes from the stain sizes on the card, and different sample definition and data processing systems, there were high correlations between the three systems for three of the droplet size spectra parameters tested (DvO.1, Dv0.5, and Dv0.9) and slight to no correlations between the systems based on the droplet spectra parameter called relative span. The information presented will allow researchers to be confident that droplet sizing data collected from either system will produce similar results and that the results can be compared.