Identification of Bark in Raw Cottons1
- P. R. Morey,
- D. F. Wanjura and
- R. V. Baker2
The presence of the trash component ‘bark’ reduces lint quality, but the constituents that make up the bark fraction have not been clearly identified. Botanical identification of bark constituents might lead to practices that reduce the presence of this trash material in lint. The objective of this study was to determine the botanical nature and the origin of the trash material that a Cotton Classer identified as bark in field-grown Upland Cotton (Gossypium hirsutum L.) lint. Most barklike strands removed from lint at the wagon and at the feeder apron were identified in transverse sections as phloem fiber groups. A few barklike strands from the same samples were found to be wood fragments. The Shirley Analyzer was used to estimate the nonlint content of raw cotton. Ninety % of the barklike strands removed from visible Shirley Analyzer wastes of raw cotton consisted of phloem fiber groups. Anatomical study of transverse sections taken from the pedicel, fruiting branch, and main stem of three lots of cotton plants field grown on Amarillo loam (Aridic Paleustalfs) collected just prior to machine harvest showed that visual rating of barkiness in lint could not be associated with an excessive amount of phloem fibers in any one of these plant parts. The bark content in visible Shirley Analyzer wastes was determined by removing and weighing all barklike strands with a width greater than 25 µm and a length greater than 500 µm. Visual rating of degree of barkiness (DB) of lint at various stages of gin processing and total weight of visible Shirley Analyzer wastes did not accurately predict the content of barklike strands in visible Shirley Analyzer wastes. Stick content at the wagon and at the feeder apron was found to be the most accurate parameter for estimating bark content in visible Shirley Analyzer wastes of raw cottons.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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