1918

4: Forages

Sesbania grandiflora (L.) Poiret

Lamk, Encycl. Méth. Bot. 7: 127 (1806) ('Sesban').

LEGUMINOSAE

2n = 24

Robinia grandiflora L. (1753), Aeschynomene grandiflora (L.) L. (1763), Agati grandiflora (L.) Desv. (1813).

Agati sesbania, West-Indian pea (En). Fagotier (Fr). Indonesia: turi (Sundanese), toroy (Maduranese), tuwi (Balinese). Malaysia: sesban, kacang turi (Peninsular), petai belalang (Sabah). Philippines: pan (Tagalog), gauai-gauai (Visaya), katuday (Ilokano). Cambodia: 'ângkiëdèi. Laos: kh'ê: kha:w. Thailand: khae, khae-ban. Vietnam: so d[u]a.

The exact country of origin of Sesbania grandiflora is not known (India or Indonesia have been suggested) but it is considered native to many South-East Asian countries. It is widely distributed through the tropics from southern Mexico to South America and has been planted in southern Florida and Hawaii. It has been cultivated for at least 140 years in West Africa and more recently in East Africa.

The leaves and fruits are used as forage and green manure. The tree can be used as an ornamental, a shade tree, a windbreak, a living fence, a live support for crops like pepper and vanilla, and for the reforestation of eroded areas. In South-East Asia it has long been used for fuelwood. The young leaves, flowers and tender pods are used as a vegetable for salads, curries and soups. The tree is used as a pulp source for the paper industry, especially in East Java. The light wood is used in floating fishing nets. The extracts from leaves, flowers, bark and roots are known for their traditional medicinal uses (e.g. the root is a well known medicine for malaria). The bark, when cut or damaged, exudes a clear gum which has some potential in the food and non-food industries.

Many reports indicate that Sesbania grandiflora is a very palatable fodder with a high feeding value for ruminants. The N concentration of the seeds is up to 6.5% and it ranges from 3.0—5.5% in the foliage. This makes it a very suitable supplement for poor quality roughages. The DM digestibility of foliage ranges between 65% and 73%; it generally has a low crude fibre content (5—18%) and a relatively high P concentration (0.30—0.45%). The information on anti-nutritional factors is limited and although the foliage contains saponins and tannins it has no known toxic reaction to ruminants. However, caution should be used in feeding it to monogastric animals as it has caused mortality in chickens. Sesbania grandiflora has 14—20 seeds/g. The wood is white and soft and not durable. Its low specific gravity of 0.42 kg/dm³ makes it also a poor fuelwood.

A loosely branching tree, up to 15 m tall and about 30 cm in diameter. Roots are normally heavily nodulated with large nodules. The tree can develop floating roots and aerenchyma tissue. Stems tomentose, unarmed. Leaf pinnately compound, up to 30 cm long, including a petiole of 7—15 mm long; the rachis slightly pubescent or glabrous; leaflets 20—50, in pairs opposite to alternate on the same leaf, oblong to elliptical, 12—44 mm x 5—15 mm, rounded to obtuse to slightly emarginate at the apex, slightly asymmetrical at the base, glabrous or sparsely pubescent on both surfaces; stipels filiform, 0.75—1 mm long, pubescent, persistent; stipules broadly lanceolate, 8 mm long, early deciduous. Raceme axillary, 2—4 flowered, rachis up to 65 mm long; peduncle 15—35 mm long, tomentose; pedicels 15—18 mm long, pubescent; bracts lanceolate, 3—6 mm long, early deciduous; bracteoles broadly lanceolate, 4—6 mm long, deciduous; flower white, yellowish, rose-pink or red; calyx 15—22 mm long, closed in young buds, splitting or breaking in various ways at anthesis, the basal part persistent in fruit; standard up to 10.5 cm x 6 cm, no appendages at the claw; wings up to 10.5 cm x 3 cm without a basal tooth; keel up to 10.5 cm x 4.5 cm with basal tooth; staminal tube 10—12 cm long, curved for most of its length; ovary and style glabrous. Pod linear to slightly falcate, 20—60 cm x 6—9 mm with broad sutures, 15—50 seeded, septa 7.5—10 mm apart, glabrous, hanging vertically, indehiscent. Seed subreniform, 6.5 mm x 5 mm x 2.5—3 mm, dark brown.

One of the characteristics of Sesbania grandiflora is its rapid early growth, reaching heights of up to 2 m in 12 weeks, 4—5 m in one year and about 8 m in 3 years. It is able to produce ripe pods nine months after planting. Sesbania grandiflora seeds lose their viability after about one year when stored at ambient conditions. It improves soil fertility, although the ability to fix N may be suppressed by nematodes or high acidity of the soil. It has responded to the inoculation of soil with Vesicular-Arbuscular Mycorrhizal (VAM) fungi (Glomus fasciculatum and Glomus mossaeae). This treatment could facilitate the introduction of this species to P-deficient soils. The tree has a lifespan of about 20 years. It is not wind resistant.

A closely related species, Sesbania formosa (F. Mueller) N. Burbridge, is native to northern Australia.

Sesbania grandiflora is only suitable for the lowland tropics, up to 800 m above sea-level, as it is frost-sensitive and cannot tolerate cool temperatures over an extended period. Although it has been successfully grown in arid areas with only 800 mm annual rainfall it is best adapted to places with an annual rainfall between 2000—4000 mm. It can be grown in a wide range of soils including those that are poor and waterlogged. It tolerates saline and alkaline soils and has also some tolerance to acidic soils down to pH(H₂O) 4.5. Sesbania grandiflora is able to tolerate flooding over long periods.

Sesbania grandiflora is easily propagated by direct seeding. Although scarification might have some positive effects the seeds usually germinate promptly without any treatment. Seedlings nodulate on most soils without inoculation. Because of its rapid early growth, it can compete very well with weeds. Vegetative propagation by cuttings is possible but seldom practised. Occasionally seedlings raised in polythene bags or other containers are used, to ensure a better establishment. Sesbania grandiflora is often planted as individual trees or in rows (spaced 1—2 m apart) along fence lines, field borders and the bunds of rice paddies.
For wood production it can be planted very densely. Over 3000 stems per ha have been used in Australia and India.

The foliage of Sesbania grandiflora is generally used in a cut-and-carry system. It is usually fed fresh as a supplement to other roughages, but it can also be dried. Although there are several reports that it is browsed, the reaction to and recovery of bushes after direct grazing has not been studied. Fertilizers are rarely used and therefore their effects are not well known.

Little information is available on the occurrence and importance of diseases and pests in Sesbania grandiflora. Reports on the fungus Pseudocercospora sesbaniae (grey leaf-spot) are only from India, as is the occurrence of the sesbania mosaic virus. The stem-borer Azygophleps scalaris has caused some damage in India. Larvae of the insect Bruchophagus mellipes infest and damage seeds. Susceptibility to nematodes has been reported.

Sesbania grandiflora does not tolerate frequent, complete defoliation; this will cause high mortality rates. Initially the side branches of a tree may be cut, leaving the main growing point untouched. After the tree has reached a height of 3 m or more, the leader can be cut back to heights above 1.5 m.

Forage yields of Sesbania grandiflora depend very much on soil fertility and the management imposed. When side branches are lopped periodically a tree can yield up to 27 kg of fresh green leaves per year.
Wood yields of 20—25 m³/ha per year are commonly achieved in Indonesia. For green manure, yields of 55 t/ha green material have been obtained in Java in 6—7 months.

Small germplasm collections are available at the University of Hawaii (Waimanalo, United States), ILCA (Ethiopia) and ATFGRC (CSIRO, Australia).

No breeding work is being carried out.

This species is widely grown in the tropics and has potential for wider use, although prospects for improvement as a livestock fodder are limited. The research needs are: to collect germplasm of Sesbania grandiflora, to document diseases and pests, to quantify the yield of forage from border plantings and fences, and to study the anti-nutritional factors that affect ruminants and monogastric animals.

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. pp. 27-68.
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.
National Academy of Sciences, 1979. Tropical legumes: resources for the future. National Research Council, Washington. pp. 185-193.
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. 56-62.

J.H. Heering & R.C. Gutteridge

Heering, J.H. & Gutteridge, R.C., 1992. Sesbania grandiflora (L.) Poiret. 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