Sesbania (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Sesbania Adanson

Protologue: Fam. pl. 2: 326 (1763) (Sesban), corr. Scopoli, Intr.: 308 (1777), nom. cons.

Family: Leguminosae - Papilionoideae

Chromosome number: x= 6; S. bispinosa: 2n= 12, 14, 24; S. cannabina: 2n= 12; S. sericea: 2n= 12, 24

Major species and synonyms

• Sesbania bispinosa (Jacq.) W.F. Wight, U.S. Dept. Agr. Bur. Pl. Ind. Bull. 137: 15 (1909), synonyms: Aeschynomene aculeata Schreb. (1770), A. bispinosa Jacq. (1792), Sesbania aculeata (Willd.) Pers. (1807).

• Sesbania cannabina (Retz.) Poiret, Encycl. 7: 130 (1806), synonyms: Aeschynomene cannabina Retz. (1789), Sesbania australis F. Mueller (1855).

• Sesbania rostrata Bremek. & Oberm. - see separate article.

• Sesbania sericea (Willd.) Link, Enum. Hort. Berol. 2: 244 (1822), synonyms: Coronilla sericea Willd. (1809), Sesbania pubescens DC. (1825), S. polyphylla Miq. (1855).

Vernacular names

• General: Sesbania (En). Sesbane (Fr.)

• S. bispinosa : Prickly sesban, sesbania pea (Australia)(En)
• Laos: sanô: (general), sanô s'a:ngz (Louang Prabang), kho:ng kh'wa:y (Houa Phan)
• Thailand: sano-khangkhok (central)
• Vietnam: rút (Hanoi, Thanh Hoa), (cây) diền diễn, diền sội.

• S. cannabina Yellow pea bush (Australia), dhaincha (India) (En). Sesbane chanvré (Fr)
• Malaysia: turi
• Philippines: balakbak (Tagalog), ganai (Bisaya), rubau (Ilokano).

• S. sericea : Malaysia: turi
• Vietnam: (cây) diền diền.

Origin and geographic distribution

Sesbania comprises about 50 species and occurs throughout the tropics and subtropics; it is richest in Africa. S. bispinosa is widespread from Africa and Madagascar, through India and Pakistan to China and South-East Asia; although its origin is unknown it is thought to have been introduced in much of its range. S. cannabina occurs naturally in Australia, Papua New Guinea and eastern Indonesia. It is probably introduced in other areas of South-East Asia and in South Asia (from India up to Iraq) and is also cultivated in other tropical areas. S. sericea occurs in tropical Africa and southern Arabia, China, Indo-China, Thailand, Java and New Guinea. It was introduced into the West Indies and northern South America.

Uses

Sesbania yields light, small sized firewood, while green branches and leaves are used as green manure in the production of food crops, especially rice. In north-eastern India, it is also widely grown as green manure in tea estates. Sesbania is planted as temporary shade and grown as hedges, it is also used as a wind-break. Shade plants and wind-breaks also provide seed for green manure crops. The stems of S. bispinosa and S. cannabina yield a phloem fibre used mainly in northern India as a substitute for sunn hemp (Crotalaria juncea L.) or jute (Corchorus spp.) in making ropes, cordage for fish nets, and sails; the fibre is also used in paper manufacture. The leaves are used as fodder. A galactomannan gum obtained from the seed is used as a substitute for gum from Cyamopsis tetragonoloba (L.) Taubert. In traditional medicine, seed mixed with flour is used for treatment of ringworm and other skin diseases and wounds.

Properties

The green parts of S. sericea contain per 100 g approximately: water 82 g, crude protein 4.5 g, ether extract 0.7 g, N-free extract 6.8 g, crude fibre 4.3 g, ash 1.6 g, P 0.05 g, Ca 0.2 g. The composition of the seed approximates per 100 g: crude protein 35 g, ether extract 5 g, N-free extract 45 g, crude fibre 11 g, ash 5 g, P 0.6 g, Ca 0.4 g. The fibre is suitable for making paper. The endosperm of the seed contains per 100 g 25-30 g gum made up of galactose and mannose in the approximate proportion 1:1.5. It is water-soluble and produces a smooth, light coloured, coherent and elastic film used for sizing textiles and paper products and for thickening and stabilizing solutions.

Description

• Erect annual, or short-lived perennial, herbs or slightly woody shrubs or small trees, often producing a dark gummy juice when the bark is cut. Hairs simple, white or golden.
• Leaves paripinnate; leaflets often more than 10 pairs. Inflorescence an axillary or terminal raceme; bracts and bracteoles often early caducous.
• Calyx campanulate with 5 subequal teeth; corolla glabrous, blue, mauve, white, red or orange, or more commonly yellow; standard usually streaked and spotted or continuously veined with purple, the claw with two vertical parallel or divergent variously shaped appendages; wings with transverse lamellate sculpturing, usually toothed or hooked at the base, the claw much shorter than the blade and than that of the keel; keel rounded below, rounded or broadly pointed at the tip, usually toothed at the base, shorter or slightly longer than the claw; stamens 10, diadelphous, vexillary stamen free, bent sharply near the base; pistil subglabrous; stigma small, globose or ovoid.
• Fruit a usually long pod, dehiscent, rostrate, usually stipitate, sometimes winged, transversely septate, up to 50-seeded.
• Seed usually ellipsoid or cylindrical, hilum often surrounded by a narrow rim-aril.
• Seedling with epigeal germination; first leaf entire.

S. bispinosa

• Herb, (0.6-)1-3 m tall. Stem terete, glabrous or sparsely pilose when young, usually aculeate.
• Leaves (5.5-)9.5-29.5(-35) cm long; stipules 5-11 mm long, pilose on margins and above, late caducous; petiole 2-20 mm long; leaflets in (10-)20-50(-55) pairs, oblong to oblong-linear, 0.75-2(-2.6) cm × 1.5-3(-5) mm, base obtuse, apex obtuse, emarginate, usually apiculate, glabrescent.
• Raceme (1-)2.5-15(-16.5) cm long, 1-12(-14)-flowered; peduncle (0.5-)1.5-4(-6) cm long, glabrous.
• Calyx 3-4 mm × 3-4 mm, tube glabrous except for woolly margins, teeth triangular, 0.5-1 mm long; corolla yellow; standard rounded to obovate, 1-1.5 cm × 8-14 mm, pale yellowish, spotted brownish or purplish; wings oblong, 1-1.25 cm × 2.5-3 mm, yellow; keel straight, 1-1.3 cm × 3.5-5 mm; staminal tube up to 12 mm long, free filament parts 2-4 mm long; pistil glabrous, style 2-3 mm long, stigma capitate.
• Pod 28-45-seeded, curved, 12.5-25 cm × 2-3 mm, glabrous, constricted between the seeds.
• Seed ellipsoid, 3 mm × 1.5 mm × 1.2 mm, pale brown, olive-green or greenish-black.

S. cannabina

• Annual slender subshrub, up to 3.5 m tall. Stem terete, slightly striate, glabrescent.
• Leaves with 10-45 pairs of leaflets; stipules linear-lanceolate, up to 6 mm long, ciliate; petiole 3-15 mm long; rachis sparsely hairy; stipels subulate with gland-like tips; leaflets oblong-obtuse or truncate-apiculate or mucronate, 8-25 mm × 3-4 mm, glabrous or sparsely sericeous especially on prominent midrib on lower surface.
• Raceme about 6 cm long, 4-12-flowered; peduncle about 1 cm long; pedicel slender, shorter or a little longer than the calyx.
• Calyx 3-5 mm long; corolla yellow or orange-yellow; standard transversely oblong-orbicular, 13 mm × 15 mm, conspicuously streaked on back, pale within, claw flat and short, not thickened; wings about as long as the standard; keel slightly shorter than the wings; pistil glabrous.
• Pod very slender, 12-20 cm × 2.5-4 mm, curved or almost straight, more or less torulose when young, hardly so when mature, olive-green to brown, with darker, transverse markings corresponding to the septa.
• Seed cylindrical, about 3 mm × 1.7 mm, dark brown, shiny.

S. sericea

• Herb or subshrub, 1-3 m tall, striate and pubescent throughout except for the flower and fruit, silky when young. Stem often with minute prickles hidden amongst the hairs but not obviously aculeate, exuding bluish, slightly milky juice after cutting.
• Leaves with 20-25 pairs of leaflets; stipules linear-lanceolate, up to 6 mm long, very early caducous; petiole 0.5-3 cm long; rachis 10-15 cm long; leaflets linear-oblong, up to 2 cm × 4 mm, rounded at apex, apiculate, entire.
• Raceme lax, axillary, 1-9 cm long, 2-7-flowered; peduncle up to 2 cm long, softly silky or pilose; pedicel 3-8 mm long, sparsely silky pilose; calyx 3-4 mm × 3 mm, tube glabrous, teeth triangular, up to 0,7 mm long; corolla yellow; standard elliptical, 6-9 mm × 8-10 mm, broader than long, pale cream, slightly flecked violet or purple; wings obovate, 5-9 mm × 3-4.5 mm; keel 7-8 mm × 4-6 mm.
• Pod 15-30-seeded, straight or slightly curved, up to 16 cm × 2.5-3.5 mm, not torulose, brown, glabrous.
• Seed 3 mm × 2 mm × 1.5 mm, brown to reddish-brown, with tiny blackish spots.

Growth and development

Sesbanias are normally spreading shrubs, but in dense stands they are less branched. They grow very rapidly and may reach a height of over 3.5 m in 6 months, making them very competitive with weeds. Root nodules that effectively fix atmospheric nitrogen are formed with Rhizobium. Under waterlogged conditions, the submerged part of the stem forms a spongy mass of aerenchyma. Sesbania can produce a green manure crop in 2-3 months and a fuelwood crop in 5-6 months. Leaves of sesbania follow the direction of sunlight and fold at night. The flowers are mainly pollinated by bees. Ripe pods normally do not shatter and harvesting of seed can be delayed for several months, although pods will shatter eventually and may be damaged by insects.

Other botanical information

The taxonomy of the 3 species treated here is very confused and in the agronomic literature it is often impossible to attribute information unequivocally to a single species. The differences between S. bispinosa and S. cannabina in particular are small and can mainly be found in the morphology of the keel. S. cannabina has sometimes been included in S. bispinosa and also in S. sericea. The variability of the 3 species is great, many varieties have been described, but often a clear distinction cannot be made. Only a thorough, worldwide revision of the genus might bring clarity.

In South-East Asia other Sesbania species occur with similar uses, e.g. S. grandiflora (L.) Poiret, S. sesban (L.) Merrill and S. javanica Miquel.

Ecology

Most Sesbania species are found in seasonally wet habitats in the tropics and subtropics. S. bispinosa grows along waterways, in marshes, often on disturbed sandy soils, from sea level to 1100 m altitude, in areas with an annual rainfall of up to 1200 mm. S. cannabina grows in wet areas like river beds and irrigated rice fields, up to 50 m altitude. S. sericea is tolerant of high temperatures, at least up to 40 °C, but does not tolerate even light frost. It is found up to 1250 m altitude, in Indo-China to 850 m. S. sericea grows best in locations with an annual rainfall of 500-2000 mm, is tolerant of waterlogging and also very tolerant of drought. It is adapted to clayey, moderately acid and alkaline soils. In trials in India, growth was retarded in soils with pH 5.6 and 9.3. Under irrigated conditions, sesbania, like rice, can tolerate fairly high concentrations of sodium (ESP ≥ 50).

Propagation and planting

Sesbania is propagated by seed. No seed treatment is required for S. bispinosa, S. cannabina and S. sericea. When grown as sole crop for green manure, seed requirements per ha are about 90-100 kg when broadcast, or 20-60 kg when drilled in rows. Dense stands are used to obtain tender plants for green manure. When grown as a green manure for rice, several cropping systems are used, mainly depending on the availability of time and labour. When the growing season is long enough, sesbania is grown as a sole crop in rotation with rice. This method is the least labour intensive. When time interval between rice crops is short and sufficient labour is available, sesbania is either relay sown into the standing rice crop, or even sown in a nursery and transplanted. Relay sowing is reported from northern Vietnam and southern China, transplanting from southern China. When the time interval between rice crops is even shorter, sesbania may be grown as a cut and carry green manure on field bunds or outside the paddy fields. When the water level in the rice paddy is too high for relay sowing, mounds are made at a spacing of about 100 cm × 50 cm in between the rice rows with the tops of the mounds just emerging above the water. About 3-5 seeds are sown in these mounds 6 weeks before harvesting the rice crop.

Husbandry

Because of its very fast growth, sesbania competes very well with weeds and may even suppress Imperata cylindrica (L.) Raeuschel on sites where moisture is adequate. In some areas, it is considered a weed. When grown for green manure, S. sericea is either grown in situ or in nearby fields, field bunds or waste areas to be transported and dug in the field. Decomposition of sesbania after ploughing in is rapid. As green manure it can be ploughed in just before transplanting rice. Delaying transplanting may result in a lower response to the green manure. Rice yields after a sesbania green manure crop ploughed in 60-70 days after planting are about equal to those obtained with application of about 80 kg N/ha of chemical fertilizer (on average 4.3 t/ha, compared with 3.3 t/ha without fertilizer or green manure). This is lower than has been obtained with S. rostrata . Sesbania is considered easier to grow than Azolla pinnata R. Br., but cultivated as an intercrop it competes more with the rice crop. In Vietnam, sesbania planted as a green manure crop is sometimes left to mature and produce firewood when the rains are inadequate to produce a rice crop. In Taiwan, S. sericea is grown in the interrows in banana plantations, and sown at the time of planting banana. The legume is later cut and spread out as a mulch to control weeds and used as green manure. In the foothills of the Himalayas in northern India, S. sericea is sown as a green manure in ginger (Zingiber officinale Roscoe) fields. They are progressively thinned from around the ginger plants to provide green manure or mulch, but a few plants, spaced 2-3 m apart are left to provide a light shade. Intercropping S. sericea with maize to provide green manure for a subsequent wheat crop has been tried in India. When sown simultaneously with the maize, S. sericea smothered the maize; delaying sowing S. sericea by 6 weeks did not depress the maize yield and boosted the following wheat yield by about 20-40%. In India, growing S. sericea is often combined with applications of gypsum to improve saline-sodic soils.

Diseases and pests

Damage caused by diseases is generally of limited and local importance only. A number of insect pests affect the leaves and stems, but damage is mostly minor. References to seed pests are very few, although large amounts of seed are produced and stored in India.

Yield

S. sericea can produce large amounts of organic matter in a short period. In Hawaii, several selections produced over 15 t dry matter per ha in 14 weeks, about half of it in stems. In India, sesbania grown as a sole crop produced 20-30 t/ha fresh above-ground biomass (4-6 t dry matter, containing 60-100 kg N) in 60 days. In the Philippines, the reported yields of sesbania in 60 days were even higher (7.8-9.9 t/ha of dry matter containing 170-225 kg N).

Handling after harvest

To extract the fibre of S. cannabina, stems are submerged in water for about 25 days. When fully retted, the bast is removed manually and the fibre is cleaned and dried.

Genetic resources and breeding

The Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia maintains the largest collection of Sesbania germplasm, including many accessions from Australia. Other collections are maintained at the International Rice Research Institute, Los Baños, the Philippines, and the Institut français de Recherche Scientifique pour le Développement en Coopération, Office de la Recherche Scientifique et Technique Outre-Mer (ORSTOM), Dakar, Senegal. A small collection is maintained in the United States at the Department of Agronomy and Soil Science, University of Hawaii and at the Southern Regional Plant Introduction Station, Griffin, Georgia. No breeding programme is known.

Prospects

Sesbania deserves wider attention as a green manure and firewood crop. It grows very rapidly, is tolerant to adverse soil conditions, waterlogging and moisture stress. Plant biomass decomposes rapidly after being ploughed in. Although the wood is light, large quantities are produced in a very short time. A worldwide taxonomic revision is urgently needed.

Literature

• Burbidge, N.T., 1965. The Australian species of Sesbania Scopoli (Leguminosae). Australian Journal of Botany 13: 103-141.
• Evans, D.O. & Rotar, P.P., 1987. Sesbania in agriculture. Westview Tropical Agriculture Series, Westview Press, Boulder, United States. 192 pp.
• Gillett, J.B., 1963. Sesbania in Africa (excluding Madagascar) and southern Arabia. Kew Bulletin 17: 91-159.
• Lock, J.M. & Heald, J., 1994. Legumes of Indo-China, a check-list. International Legume Database and Information Service (ILDIS). Royal Botanic Gardens, Kew, United Kingdom. pp. 126-127.
• National Academy of Sciences, 1980. Firewood crops; shrub and tree species for energy production. Vol. 1. National Academy Press, Washington, D.C., United States. pp. 60-61.
• Nguyen Van Thuan, 1987. Sesbania. In: Lescot, N. & Vidal, Y. (Editors): Flore du Cambodge, du Laos et du Vietnam. Vol. 23. Leguminosae (Fabaceae) Papilionoideae. Muséum National d'Histoire Naturelle, Paris, France. pp. 56-62.
• Pareek, R.P., Ladha, J.K. & Watanabe, I., 1990. Estimating N₂fixation by Sesbania rostrata and S. cannabina (syn. S. rostrata) in lowland rice soil by the¹⁵N dilution method. Biology and Fertility of Soils 10: 77-88.

Authors

• I.B. Ipor & L.P.A. Oyen