Relationship Between Three Cotton Trash Measurements: HVI, SA, and AFIS

Presence of trash in commercial cotton bales at varying amounts degrades their market values and further influences the end-use qualities. In order to ensure a fair trading, USDA’s AMS has introduced the high volume instrument (HVI) measurement as an universal standard index. Compare to HVI’s geometric method that represents the trash portion only on samples’ surface, gravimetric-based Shirley analyzer (SA) and advanced fiber information system (AFIS) have also been utilized to yield the trash contents considerably in cotton industry. With the increasing acceptance of HVI readings in the domestic and international trading, there is a continued interest in the relationship between HVI trash and SA trash from cotton customers and regulators. Due to the complexity of not only trash type, size, and presence but also the nature of HVI and SA tests, it is understandable that there has been no such a study available trying to bridge two types of trash readings and, apparently, this is a challenge. Further, with the suggestion from Dr. James Knowlton of AMS, who talked his latest foreign trip to promote the HVI and mentioned one concern on HVI trash during the 2011 Beltwide Cotton Conference, we voluntarily performed this study by analyzing the data collected over a 4-year span at the house.  As a result of new strategy, we not only proposed the conversion between HVI and SA trash from the simple statistic approach, but also confirmed this tactic from independent NIR measurement.