THE INFLUENCE OF PLANT MATURITY ON KENAF YIELD COMPONENTS

Authors: BLEDSOE, VENITA - TEXAS A&M - COMMERCE, TX; Webber Iii, Charles

Submitted to: Kenaf Association International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Kenaf is a warm season annual that is closely related to cotton and okra. The bark of the kenaf stalk contains a long fiber called bast fiber, while the woody core contains short core fibers. The kenaf fibers, bast and core, can be pulped as a whole stalk or separated and pulped individually. This research is the first phase of a three-part study to determine the effect of kenaf plange age on its yield components, plant fiber composition, and paper quality. The objective of this research was to determine the effect of kenaf plant age on kenaf yield components. Kenaf variety 'SF459' was planted at Lane, OK, on April 30, 1996 on 30-cm row spacing at 100,000 plants/a. Kenaf plots were harvested at four harvest dates, 60 days after planting (DAP), 90 DAP, 120 DAP, and 150 DAP. Harvest age (60, 90, 120, and 150 DAP) did not affect plant populations, but did have a significant affect on all other yield measurements. Even though the rate of growth of the kenaf plants either leveled off or decreased after the 120 DAP harvest, the stalk yields continued to increase until the 150 DAP harvest. Stalk yields (stalks only, oven dried) increased from 60 DAP (1.7 t/a) to 150 DAP (8.6 t/a). The significant increase in stalk yields after 120 DAP justify the additional 30 days of growth. The second and third phase of this research will determine the effect of the different harvest dates on plant fiber composition and paper quality.

Technical Abstract: Kenaf (Hibiscus cannabinus L.) bast and core fiber can be pulped separately or in combination to produce kenaf paper. It is often advantageous to harvest kenaf earlier than 150 days after planting (DAP). This research is the first phase of a three-part study to determine the effect of kenaf plant age on its yield components, plant fiber composition, and paper quality. The objective of this research was to determine the effect of kenaf plant age on kenaf yield components. Kenaf variety 'SF459' was planted at Lane, OK, on April 30, 1996 on 76-cm row spacing at 247,100 plants/ha. Kenaf plots were harvested at four harvest dates, 60 DAP, 90 DAP, 120 DAP, and 150 DAP. At each harvest date, a 3-m length of plant row was cut at ground level and used to determine plant population, stalk height, percentage stalk by weight, percentage leaves by weight, and stalk yield. The experiment was a randomized complete block design with five replications. Harvest age (60, 90, 120, and 150 DAP) did not significantly affect plant populations, but did have a significant effect on all other yield parameters. The kenaf stalk yield and stalk biomass percentage were the only yield components which continued to have significant increases after 120 DAP. Although the growth rates did level off or even decrease after 120 DAP, the significant increase in stalk yields after 120 DAP justify the additional 30 days of growth. Stalk yields ranged from 3.8 mt/ha for 60 DAP to 19.3 mt/ha for 150 DAP.