Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 20, 2009
Publication Date: May 26, 2009
Citation: Byler, R.K., Pelletier, M.G., Baker, K.D., Hughs, S.E., Buser, M.D., Holt, G.A., Carroll, J.A. 2009. Cotton Bale Moisture Meter Comparison at Different Locations. Applied Engineering in Agriculture. 25(3): 315-320. Interpretive Summary: Cotton is marketed by weight without regard to the moisture content (mc) but excessive moisture is not allowed and will lead to quality degradation during storage. Recently excessive moisture has been defined as mc greater than 7.5% wet basis at any point in the bale at the gin. Unfortunately there has been no meter for determining the mc of cotton in the bale for which the accuracy has been documented. In this study seven commercially available portable moisture measurement devices, consisting of a bale probe and display, were purchased and used to make measurements of cotton bales by each of the three Agricultural Research Service Cotton Ginning Units. A total of 96 bales, formed using different regimes designed to achieve different mc, were obtained. Each bale was measured in six locations with the seven measurement devices, lint samples obtained from the same locations, and the mc determined by the oven drying method separately by one of the Ginning Units. The resulting 7000 meter readings were compared with the oven-based mc. The best standard error of the un-calibrated meters was found to be over 1 percentage point showing that these meters are not as accurate as would be desired. A properly documented commercially available cotton bale moisture meter is necessary to deal with the requirement of keeping the mc below 7.5% and the marketability of the US crop will be enhanced by keeping the bales below this upper limit.
Technical Abstract: Seven commercially available portable cotton bale moisture content (mc) meter-probe combinations were purchased by each of the three Agricultural Research Service Cotton Ginning Research Units and examined for repeatability and accuracy when used with commercially ginned cotton. The devices were used to measure the mc at the same six locations on a total of 96 cotton bales. Lint samples were obtained from the same locations in the bales for mc determination by the oven method resulting in more than 7000 meter readings with corresponding reference mc values. Based on oven-mc, the lint samples had mc in the range 2.3% to 9.4% wet basis. The oven-mc wet basis for the different samples in the same bale had a repeatability of 0.16. The different meters produced significantly different readings from each other, and these were significantly different from the oven-based mc. The AquaBoy meter with the twin electrode probe was the most accurate without calibration of the Lubbock and Mesilla Park meters when compared to moisture data using their technique but the Delmhorst meter was the most accurate without calibration with data collected at the Stoneville laboratory. If the meters were calibrated before use the Strandberg Digital meter with long twin electrodes would be the most accurate, although several of the others were not significantly less accurate, and still had a standard error of over 2 percentage points. It is unknown if these corrections would be applicable to other meters of the same model and manufacturer.