The moisture content of cotton makes significant changes in the physical properties of cotton and hence moisture content has to be known. High moisture content increases flexibility, toughness, elongation and tensile strength. If the moisture content is too high it causes difficulty in processing due to the tendency of the stock to lap-up on drafting rolls. Low moisture, on the other hand, facilitates cleaning but increases the brittleness of the fibre and results in fibre breakage during ginning, cleaning and mill processing. Low moisture also increases fly waste and may cause manufacturing difficulties due to static electricity.
Reference: A Practical Guide to Textile Testing by K. Amutha (Woodhead Publishing)