1919

4: Forages

Sesbania sesban (L.) Merrill

Philipp. J. Sci., Bot. 7: 235 (1912).

LEGUMINOSAE

2n = 12

Aeschynomene sesban L. (1753), Sesbania aegyptiaca Poiret (1806) (as 'Sesban aegyptiacus').

Sesban (En). Indonesia: jayanti (Sundanese), janti (Javanese), puri. Philippines: katuray (Tagalog, Bikol), katodai (Ilokano). Burma: yay-tha-kyee (Burmese), yethugyi. Cambodia: snaô kôôk. Laos: sapao lom. Thailand: sami (central), saphaolom (northern). Vietnam: dien-dien.

The exact origin of Sesbania sesban is unknown, but it is widely distributed and cultivated throughout tropical Africa and tropical Asia. It has been introduced into tropical America.

The leaves and young twigs of sesban are used as fodder for ruminants. The thick branches and stems serve as fuelwood or are used as construction material. Sesban is frequently used to improve soil fertility, either through direct N fixation or through the incorporation of foliage as a green manure to the soil. Sesban can be grown to provide shade (e.g. in coffee, cocoa, turmeric), and as a live support (e.g. in pepper and betel vine) or windbreak for other crops (e.g. banana). Sesban is also used by humans for food from the edible leaves and flowers, for fibre from the bark, for traditional medicines from leaves and flowers, and for gum from the seeds and bark.

The N concentration of sesban leaves ranges between 3.0 and 4.5% of DM. In vitro DM digestibility often exceeds 65% because of a relatively low fibre content. Anti-nutritional factors such as polyphenolic compounds may sometimes have an adverse effect on the digestibility of sesban, but their role is not clearly understood. In view of reported negative effects of sesban in monogastric animals, especially poultry, it is less suitable to be used in diets for these animals. Phosphorus concentrations in the edible portion are generally adequate for animal nutrition. Sesban has 55—80 seeds/g.

Shrub or short-lived tree up to 8 m tall. Stem up to 12 cm in diameter, usually pubescent, sometimes becoming glabrous. Leaves, including a short petiole, 2—18 cm long, pinnately compound; leaflets in 6—27 pairs, linear oblong, up to 26 mm x 5 mm, glabrous or almost so above, sometimes pubescent beneath, often pilose at the margins; stipules narrowly triangular, up to 7 mm long, pubescent. Racemes 2—20 flowered, up to 20 cm long, glabrous or sparsely pilose; peduncle up to 5 cm long; pedicels 4—12 mm long, glabrous; bracts and bracteoles linear lanceolate, 3—5 mm long, subglabrous or pilose, very early caducous; calyx up to 6.5 mm long, the tube glabrous, the teeth broadly triangular with an acuminate point 0.5—1 mm long, marginally pubescent; standard ovate, 11—20 mm x 13—21 mm, cordate at the base, yellow and commonly speckled or flecked with violet-purple, claw up to 4 mm long, appendages with acuminate free tips 2—5 mm long; wings 15—19 mm x 4.5—7 mm including a claw of 4—6 mm, yellow, with a broad tooth or short hook at the base; keel 11—21 mm x 6.5—9 mm, including a claw of 6—9 mm, yellow or creamish, basal tooth acute at 0—20 degrees to the claw; staminal tube (9—)12—13(—17) mm long; ovary glabrous or rarely somewhat pilose; style glabrous, 5 mm long. Pod subcylindrical, straight or slightly curved, up to 20—30 cm x 2—5 mm, straw-coloured, often with a brown blotch over each septum or reddish-brown, 10—50 seeded, glabrous; septa 4—8 mm apart. Seed subcylindrical, 3—4.5 mm x 2 mm x 2 mm, olive-green or brown, usually mottled.

Sesban germinates and grows rapidly; plants can reach a height of 1.5—2 m in 10—12 weeks after sowing under favourable conditions. It usually flowers and produces ripe pods within the first year after planting. The flowers are mostly visited and pollinated by members of the Hymenoptera.

Sesbania sesban is subdivided into two subspecies, ssp. sesban and ssp. punctata (DC.) J.B. Gillett, of which the latter occurs only in West Africa from Senegal to the Sudan. The main difference is the length of the staminal tube: 15—17 mm in ssp. punctata and 9—13 mm in ssp. sesban. The specimens in South-East Asia belong to ssp. sesban.
Based on flower colour and hairiness, ssp. sesban has been further divided into 4 botanical varieties, which are, however, without much practical value because the distinguishing characters are weak and unstable.

Sesban grows in areas with a semi-arid to sub-humid climate, with a rainfall between 500 and 2000 mm per year. In East Africa it grows up to an altitude of 2300 m as it can withstand cool temperatures, but not frost. It grows in a wide range of soil types ranging from loose sandy soils to heavy clays. It tolerates saline (1.0% salt concentration in seedling stage to 1.4% at maturity), alkaline (pH(H₂O) < 10) and acidic soils as well as waterlogging and flooding. However, sesban cannot withstand waterlogging immediately after germination or in the early stages of seedling development. Although sesban tolerates low P levels, the application of P has a positive effect on its growth and nodulation.

Sesban is propagated by seeds. Scarification of the seeds, using hot water or acid, improves germination. The seeds are sown in a well prepared soil. The planting distance depends on the purpose: as a fence, planting is in rows with a spacing up to 1—2 m; as an alley crop, rows (single or double) are planted 2—10 m apart with a spacing of 25—50 cm between plants; as a fodderbank, rows are 1—2 m apart and plants 25—50 cm apart. Seedlings will normally form root nodules with native rhizobia within 3—4 weeks after planting. Where the effective rhizobia are absent and effective nodulation does not take place, inoculation with an appropriate Bradyrhizobium strain is necessary. Sesban has rapid early growth and therefore overcomes weed competition easily and usually requires little maintenance. If necessary, the selective herbicide fluazifop can be used post-emergence at 2 kg of active ingredient/ha to control grass weeds. Vegetative propagation using stem cuttings is possible but rarely practised.

Sesban is normally used by cutting the foliage and carrying it to the animals for fodder or to neighbouring fields for green manure. Natural stands of sesban are known to be browsed by ruminants. Limited experience with the effects of direct grazing by cattle have shown that stems are quite brittle and are easily broken but regrowth below the break is rapid. Direct grazing by goats, however, resulted in over 80% plant mortality because of ringbarking 8—20 cm above ground level. Although it responds to fertilizers, especially P and farmyard manure, their application is not a common practice.

In general the reduction in yield caused by diseases and pests is not large and very few reports are available from South-East Asia. Larvae of the Azygophleps scalaris are reported to tunnel in the stem. Seeds can be infested with larvae of Bruchophagus mellipes (Hymenoptera) which reduce the seed yield. Nematodes can reduce the growth of the plants. In East Africa, larvae of a leaf-feeding beetle Mesoplatys ochroptera can completely defoliate and kill sesban. In Australia, larvae of the moth Orgyia australis have caused leaf rolling and drop of young leaves. In cool moist conditions in south-eastern Queensland, lesions of the fungus Botrytis cinerea girdled the stem resulting in death of leaf and stem above the lesion.

Sesban can be cut after it reaches 1—2 m height. Leaving the first cutting until it is > 4 m tall may even be detrimental. Cutting frequency depends on use, soil type and climate but can be as much as 5 times per year. A cutting height of 75—100 cm is best. Too low (< 50 cm) and too frequent cutting decreases the lifespan of plants. In order to increase longevity, it is advisable to leave some foliage on the plant when harvesting. Although usually fed fresh as a supplement, sesban can also be dried.

The fodder yields of sesban depend on soil type, soil fertility and moisture, climate and on management factors, such as planting distance, cutting height and frequency. Under favourable conditions DM yields of 20 t/ha per year have been obtained. The edible fraction (leaves and young twigs) ranges from 30—60% depending on the growing conditions and cutting frequency. In a subtropical environment DM yields of 5 t/ha over 6 months have been obtained at a cutting height of 100 cm and cutting frequency of 8 weeks.
Seed production depends on growing conditions but can be as much as 1—2 t/ha.

Sesban is the most widely collected species of the genus Sesbania Adanson, but only few accessions are of Asian origin; most were collected in Africa. Germplasm collections are available at ILCA (Ethiopia), ATFGRC (CSIRO, Australia) and the University of Hawaii (Waimanalo, United States).

No breeding programmes have been started.

It is only recently that sesban has received international attention as fodder. Research priorities are to collect germplasm, especially in South-East Asia, to establish proper management systems for alley cropping, to investigate the role of anti-nutritional factors in animal feeding and to develop a proper feeding strategy. The outcome of this research will determine further use of sesban.

Evans, D.O. & Macklin, B. (Editors), 1990. Perennial Sesbania production and use. A manual of practical information for extension agents and development workers. NFTA, Waimanalo, Hawaii. 41 pp.
Evans, D.O. & Rotar, P.P., 1987. Sesbania in agriculture. Westview Tropical Agriculture Series No 8. Westview Press, Boulder, Colorado. 192 pp.
Gillett, J.B., 1963. Sesbania in Africa (excluding Madagascar) and southern Arabia. Kew Bulletin 17: 91-159.
Lewis, G.P., 1988. Sesbania Adans. in the Flora Zambesiaca Region. Kirkia 13: 11-51.
Macklin, B. & Evans, D.O. (Editors), 1990. Perennial Sesbania species in agroforestry systems. Proceedings of a NFTA/ICRAF workshop held in Nairobi, Kenya, March 27-31, 1989. NFTA, Waimanalo, Hawaii. 242 pp.
Nguyên van Thuân, Dy Phon, P., Niyomdham, C. & Vidal, Y., 1987. Légumineuses - Papilionoïdées. In: Morat, Ph. (Director): Flore du Cambodge, du Laos et du Vietnam. Vol. 23. Muséum National D'Histoire Naturelle, Laboratoire de Phanérogamie, Paris. pp. 58-59.

J.H. Heering & R.C. Gutteridge

Heering, J.H. & Gutteridge, R.C., 1992. Sesbania sesban (L.) Merrill. In: Mannetje, L.'t and Jones, R.M. (Editors): Plant Resources of South-East Asia No 4: Forages. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea