Malvaceous bast fiber studies

Three malvaceous bast fiber plants, Hibiscus cannabinus L., H. sabdariffa var. altissima, and Urena Lobata L. were grown experimentally near Altmore, Ala., and studied from the standpoint of utilization as sources of bast fiber in time of a national emergency. The environmental requirements, climatic and edaphic, growth seemed adequate. However, these or other factors were able for the maturation of seed. Flowering either occurred late not at all during the period of growth. The delay in flowering until late in October confirms other investigations in reference to the influence of photoperiodism. Maximum yields in pounds per acre of mill-run fiber produced under the experimental conditions described were as follows: H. cannabinus, 3,103; var. "altissima", 2,791; Urena lobata at the 25-pound seeding rate, 1,482, and at 50-pound seeding rate, 2,016. By comparison with yields reported in some countries where these plants are grown commercially, the yields given here may be considered good. A chemical method of extraction was developed and used to follow the changes in pure fiber content of the plants throughout their growth cycle. It gave lower but consistent and reproducible results as compared to the results obtained by biological retting and subsequent mechanical extraction. A study of the progress of fiber formation during the growth and development of the plants showed somewhat similar increases in the fiber content during early growth and decrease in extractable fiber content near maturity. The results from retting tests showed that the fibers from water-retted plants were superior in strength and quality to the fibers from dew-retted plants. Retting with water was accomplished in 6 to 18 days depending on the temperature of the water in the retting tank. To ret with dew required 23 to 27 days for stalks of small diameter and up to 39 days for large stalks. Mechanical extraction of the fibers in a hemp-tow fiber mill was investigated. The stalks of var. "altissima" and Urena lobata were easily decorticated and yielded a relatively clean fiber. Many of the stalks from the late harvest of H. cannabinus were too large and too dense and did not give as clean and strong a fiber as stalks from earlier harvests. Under conditions of experimentation, the fibers of var. "altissima" and Urena lobata were superior in strength to that of H. cannabinus. Based upon the experimental data and information obtained, it would appear that the results on growth, fiber yields, mechanical processing, and fiber quality justify consideration of these malvaceous species as a domestic source of jute-like fiber if needed.