Kenaf

KENAF

Scientific classificationKingdom:Plantae

Division:MagnoliophytaClass:Magnoliopsida

Order:MalvalesFamily:Malvaceae

Genus:HibiscusSpecies:H. cannabinus

Binomial nameHibiscus cannabinus

Introduction

• Kenaf is a 4,000 year old ‘new’ crop with origin in ancient Africa. It offers a way to make paper without cutting trees.

• a member of the hibiscus family (Hibiscus cannabinus L), it is related to cotton, okra and hibiscus.

• grows quickly, rising to heights of 5 - 6 m in as little as 6 to 8 months.

• yields to about 30 tons metric of dry fiber per hectare per year can be obtained

• leading producers: India, Thailand, & China.

Contd/-

The stalk of the kenaf plant consists of two distinct fiber types:- The outer fiber is called "bast" and comprises roughly 40% of the stalk's dry weight. The refined bast fibers measure 2.6 mm and are similar to the best softwood fibers used to make paper.

- The whiter, inner fiber is called "core", and comprises 60% of the stalk's dry weight. These refined fibers measure 0.6mm and are comparable to hardwood tree fibers, which are used in a widening range of paper products.

Contd/-

• Upon harvest, the whole kenaf plant is processed in a mechanical fiber separator, similar to a cotton gin.

• The separation of the two fibers allows for independent processing and provides raw materials for a growing number of products including paper, particle board, animal bedding and bioremediation aids. 

Crop Culture

• An annual, short-day, herbaceous plant of the Malvaceae family, cultivated for its stem fibers.

• The genus Hibiscus has approximately 200 species, of which one, roselle

(H. sabdariffa var. altissima), also is occasionally referred to as kenaf.

• The leaves either are entirely heart shaped or display radiating lobes occurring mainly near the stalk top.

• Kenaf usually grows up to 5 m in height, and is cylindrical and either branched or without branch.

• The stem is composed of two fibers, bast and core. The bast fibers, located in the bark, are long compared to the core fibers, produced in the stem interior.

• Flowers, typically yellow with deep red or purple centers, are borne on short stalks growing from the upper angles between leaf stalks and stems.

• While the flowering can last 3 to 4 weeks, or more, per plant, each individual flower blooms for only one day.

• After blooming the flower drops off, leaving a seed pod behind.

• Wild forms of kenaf are found in east and central Africa, where for several centuries kenaf has been used for both fiber and food.

• Selection and breeding have developed varieties with higher fiber yields, improved disease resistance, and reduced branching.

1. Ecology

• Kenaf, although adaptable to various soils, grows best in well-drained, sandy loam and requires a warm, moist climate, tropical or subtropical, without excessively heavy rains or strong winds.

• Some varieties need at least 12 hours of light each day throughout the growing season.

• Kenaf can adapt to a wide range of climates and soils. However, because it cannot tolerate frost, planting should not occur at temperatures below 0°C.

• most of the recent kenaf varieties and technologies favour growing at low elevations between 37" N and S latitudes.

• Most varieties of kenaf are photoperiod sensitive, and vegetative growth increases until the daylight period becomes less than 12 h 30 min.

• Flowering is then initiated and the vegetative growth rate declines.

• It grows well on flat land and to a gradient of 12% with good drainage, sandy loam soils with good amount of humus and not waterlogged.

• Suitable on peat soil, and not on sandy or heavy clay. It can withstand saline and highly acidic conditions.

• Requires high RH (>85%) and a rainfall regime of 20 - 25 cm during the 4 – 5 months growing period.

Cultivars

• Currently, the principal commercial varieties are: accessions K465/118, K465, HW 1 Kirlin, Everglades 71, Tainung 2 and Khon Kaen 60.

• Growth cycle varies between varieties: - a. early maturing - 75-105 days,

b. intermediate - 105-120 days,

c. late maturing - 120-150 days.

Production Practices

• Kenaf is direct seeded with conventional grain drills. The germination rate of the seed should be at least 75 to 80%.

• Land preparation is similar to other agronomic crops, e.g., cotton, etc. Fertilizer and irrigation should be applied as needed.

• Seeds is either sown manually or by a 4-row seeder machine. With a speed of 60 m/hr the machine is able to sow seeds in 1 hr for 1 hectare

• Seed rate is 10kg/ha and drilled to a depth of 1 – 2 cm with a planting distance of 70 x 10 cm giving a density of 250,000 plants per hectare.

• Fertilization: Nitrophoska green (NPK = 15:15:15) is recommended with 25% of the total supplied at time of planting (about 200 - 300 kg/ha) and the remainder (about 400 - 500 kg/ha) after the plants have reached 4 – 6 weeks stage.

• Liming with GML of 1 – 2 tons/ha is normally applied 1 month before sowing seeds.

• Early planting maximizes yields by increasing the growing season.

• Kenaf is propagated by seed and must be replanted annually. Dense plant populations generally produce greater total and bast fiber yields, reduce weed populations, and improve harvesting efficiency.

• It reaches maturity in about 150 days

• Kenaf is less demanding on the soil than jute and may be grown in rotation with other crops.

• Dense sowing is common, except when cultivation is for seed production.

• Crops are hand or machine-harvested, yielding the best fibre at the flowering stage.

Fibres are usually separated from the stalks mechanically, although in some areas retting (rendaman), followed by hand stripping, is still practiced.

The fibre strands,

about 0.9 metre long,

are pale in colour and

lustrous, with strength

comparable to that

of jute.

Yield Harvest

• The plants are harvested for their stalks from which the fiber is extracted.

Grower interest in kenaf arises primarily from its potential as a commercial fiber crop.

Harvesting of kenaf stems

Water separation process of fiber

Uses: Automotive products

Uses:

Uses: As animal feed

Assignment

Compare and contrast the botanical description of kenaf and that of roselle. (Hint: Tabulate your description of each morphological feature and support with suitable diagrams, if any)

Date of submission: 23 December 2012

7 Dec 2011