3014

11: Auxiliary plants

Gliricidia sepium (Jacq.) Kunth ex Walp.

Repertorium bot. syst. 1: 679 (1842).

LEGUMINOSAE - PAPILIONOIDEAE

2n=20

Gliricidia maculata (Kunth) Kunth ex Walp. (1842).

Gliricidia, mother of cocoa, Mexican lilac (En). Quickstick (Am). Indonesia: gamal, liriksidia (Javanese). Malaysia: bunga jepun (also used for Thevetia spp.). Philippines: kakawate (general), madre-cacao, balok-balok (Tagalog). Laos: kh'è: no:yz, kh'è: fàlangx. Thailand: khae-farang. Vietnam: anh d[af]o g[is]a, s[as]t thu, h[oo]ng mai.

Gliricidia is a native of the seasonally dry Pacific Coast of Central America. It has long been cultivated and is naturalized in tropical Mexico, Central America and northern South America. It was also introduced to the Caribbean and later to West Africa. The Spaniards took it to the Philippines in the early 1600s. From Trinidad it was taken to Sri Lanka in the 18th Century; from there it reached other Asian countries including Indonesia (about 1900), Malaysia, Thailand and India.

Gliricidia is considered to be the most widely cultivated multipurpose tree after leucaena (Leucaena leucocephala (Lamk) de Wit). In former times it was mainly used as a shade tree in plantation crops, but more recently it has become a widely cultivated multipurpose tree integrated into several cropping systems, e.g. as a shade tree in tea, cocoa or coffee plantations, as live stakes to support black pepper, vanilla and yam (in West Africa), as a hedge and green manure crop in intercropping systems such as alley-cropping systems. It has also been planted to stabilize soil, to prevent erosion and to reclaim denuded land or land infested with Imperata cylindrica (L.) Raeuschel. In this last respect gliricidia has been found to be more effective than leucaena. The wood is often utilized as firewood, for charcoal production or as posts and farm implements, and locally for furniture, construction and railway sleepers. Gliricidia provides useful forage in the form of leaves, green stem and bark, and is commonly used to supplement poor quality, low protein roughage, especially in dry seasons when it may become a major source of feed for goats and cattle in dryland cropping areas. Its forage has been reported to be toxic to horses, but clear confirmation is lacking. Leaf meal can also be fed to poultry and rabbits. Flowers are a source of nectar for bees. Seeds, bark, leaves and roots may be used as a rodenticide and pesticide after fermentation. Gliricidia is often planted as an ornamental. The juice of the leaves, bark and roots is used as a traditional anti-dermatophyte to control eczema and to alleviate itches and wounds.

Gliricidia prunings have a low C/N ratio, a low content of lignins, silica and polyphenols, and a high nutrient level. When applied as green manure they quickly decompose; in one trial gliricidia residues had a half-life of 20 days, which is shorter than that of other green manure crops such as Leucaena leucocephala or Flemingia macrophylla (Willd.) Merr. Consequently, gliricidia mulch has only a short-lived effect on soil temperature and moisture content. Analyses of gliricidia prunings (leaves and twigs) grown on an alfisol in Nigeria indicated a nutrient content per 100 g dry matter of: N 3.1—3.6 g, P 0.13—0.20 g, K 2.6—2.7 g, Ca 1.2—1.6 g, Mg 0.3—0.45 g, lignin 11.6 g, cellulose 19.4 g, hemicellulose 12.2 g, polyphenols 1.6 g and a C/N ratio of about 13. Water extracts of both fresh and dried gliricidia leaves have been found to produce some allelopathic effect caused by phenolic acids. The effect does not last long and can be eliminated by applying gliricidia mulch at least one week before planting.
Forage quality varies with age, plant part, season and genotype. It is highest in the youngest leaves; with maturity N concentrations decrease slightly and crude fibre increases. The leaves contain 3—5% N, 13—30% crude fibre and 6—10% ash. Digestibility ranges from 48—77%. In 3-month-old growth, gliricidia bark had lower N concentrations than the leaves, but higher levels than the stem. Palatability is problematical, as the forage contains some anti-nutritional factors, with 1—3.5% flavonol and 3—5% total phenols on a dry matter basis. Ruminants unaccustomed to eat the foliage may initially refuse it. However, once they have overcome their initial aversion they will eat a high proportion in their diet for extended periods of time. In some cases it has been observed that one-day-old wilted leaves are preferred to fresh leaves; also silage is more palatable than fresh foliage.
Gliricidia has light-brown sapwood and dark-brown heartwood turning reddish on exposure to air. It is hard, coarse-textured with irregular grain, very durable and termite-resistant. The wood has a high density of up to 750 kg/m³ and proves difficult to work. The wood of young coppices is less dense, about 500 kg/m³. As the bole seldom has a diameter of more than 40 cm and a length of 8 m, especially in coppiced trees, timber of large dimensions is rare. The heartwood of gliricidia burns slowly thus producing good embers, and gives off little smoke or sparks; its energy value is 19 800—20 600 kJ/kg. The weight of 1000 seeds is about 125 g.

A small deciduous tree up to 12 m tall with a short trunk up to 50 cm in diameter, with smooth or slightly fissured, whitish-grey to light brown bark, often branching from the base; the mature tree has an irregular spreading crown of thin foliage. Leaves alternate, pinnate, 15—40 cm long; petiole 5 mm long; rachis slender, yellow-green, finely hairy; leaflets 7—17 per leaf, opposite except in upper part of rachis, elliptical or lanceolate, 3—6 cm x 1.5—3 cm, rounded or cuneate at base, acuminate at top, thin, dull green and glabrous above, grey-green and often pubescent beneath. Flowers in a 5—12 cm long, axillary raceme, about 2 cm long, on an 8—12 mm long, slender pedicel; calyx campanulate, 5-toothed, light green tinged with red; corolla whitish-pink or purple, with a broad standard, folded back and yellowish near the base, 2 oblong, curved wings, and a narrow keel; stamens 10, white, 9 united in a tube and 1 free; pistil with stalked, narrow, red ovary and whitish, curved style. Pod narrow, flat, 10—15 cm x 1.2—1.5 cm, yellow-green when immature, turning yellowish-brown, shortly stalked and with a short mucro, splitting open at maturity, 4—10-seeded. Seed ellipsoid, about 10 mm long, shiny, dark reddish-brown.

Seeds germinate in 3—10 days. Early seedling growth is slow, but once established, growth is fast and the annual increase in height may be as much as 3 m. The root system is relatively weakly developed and does not extend strongly laterally. Flowering may start at the age of 6—8 months; abundant flowering takes place during the dry season if the tree has not been coppiced or pruned, after it has shed its leaves. Flowers are insect-pollinated; a wide variety of insects, often large bees, are attracted to the abundant nectar. These may distribute pollen over several kilometres. Pods ripen 40—55 days after flowering, the seeds are mature when the pods turn yellow-brown. Fruiting is relatively uniform, with about 20 days from first to last seed dehiscence. In its native area seed production is usually abundant and can be predictably timed. In more humid areas, shoot growth tends to be continuous and the evergreen tree flowers only sporadically on the basal parts of twigs from which the leaves have fallen.

Gliricidia maculata has been used extensively as a synonym for Gliricidia sepium. Gliricidia maculata has been recently proposed as a distinct species with a different natural geographical distribution. i.e. Yucatan Peninsula, northern Guatemala and Belize. It differs from Gliricidia sepium in having white flowers and smaller pods and seeds. Most gliricidia planted as exotics can be attributed to Gliricidia sepium, but former introductions of Gliricidia maculata cannot be ruled out.

In its native range the climate is relatively uniformly sub-humid with an annual rainfall of 900—1500 mm and a five-month dry period. Gliricidia has been introduced successfully in more humid zones with up to 3500 mm annual rainfall and without a marked dry season. In its native range the mean annual temperature varies from 20—29°C, the mean maximum temperature of the hottest month from 34—41°C, the mean minimum temperature of the coldest month from 14—20°C. Light night frost is tolerated, but not prolonged frost. Gliricidia occurs naturally in early and middle successional vegetation types on disturbed sites such as coastal sand dunes, river banks, floodplains and fallow land, from sea level up to 1500 m altitude. It can tolerate a wide range of soil types, both alkaline and acidic, but prefers free drainage. It is also more tolerant of acid and low fertile soils than leucaena, but will respond to fertilizer application on such soils. It is not as well adapted to the subtropics as leucaena; leaves are shed with the onset of lower temperatures during winter, and plants are less resistant to frost. It is, however, more tolerant of waterlogged conditions than leucaena. In its native, seasonally dry habitat, trees are often exposed to annual fires. Gliricidia tolerates such fires well and trees quickly resprout when the rains start, which explains the abundance of the tree in secondary vegetations and fallows.

Gliricidia can be propagated easily by seed and cuttings. Direct seeding is seldom used, and potted plants or bare-rooted stock are raised in nurseries. Fresh seed or seed that has been preserved in cold storage has a germination percentage of 80—90%. Seed may be sown directly in nursery beds or in polythene bags. Seed pretreatment is not necessary. Nursery stock can be transplanted after 10—12 weeks. Vegetative propagation is by large cuttings, 3—6 cm thick and 0.5—2 m long; the bark may be incised to promote rooting. Cuttings should be taken from mature branches with brownish-green bark and planted fresh. Rooting starts 6—7 weeks after planting. Plants grown from cuttings may have 50—150 root nodules after 3 months, compared with 20—70 nodules after 6 months on plants from seed. Trees obtained from cuttings have shallower roots than trees grown from seed. Inoculation with an appropriate strain of Bradyrhizobium and fertilization can stimulate growth on degraded lands. On soils with low P content gliricidia is mycorrhiza-dependent; inoculation with ectomycorrhizal fungi (Boletus suillus) or vesicular-arbuscular mycorrhizal fungi (VAM) may enhance plant growth.
Gliricidia may be planted in hedges spaced 4—10 m apart with 25—100 cm between trees in the rows, or as live fences with 10—25 cm spacing. When it is used for live posts for black pepper or vanilla the crops can be planted at the same time as the tree. In fodder plots spacings of 0.25 m x 1.0 m or wider may be used; yields of leaves are little affected by planting densities ranging from 5000—40 000 trees/ha. Sometimes, trees are planted at wider spacings (e.g. 10 m x 10 m) over pasture lands. Where animals are grazed in young plantations, young trees must be protected. In woodlots spacings of 1.5—2 m x 2—2.5 m are common.

Gliricidia can be managed for either wood or foliage (green manure, fodder) production, for shade, fencing or for live posts. It may be planted in pure stands for the production of fuelwood, as protein banks which are periodically harvested for fodder, or for land reclamation. Hedges may be planted around homesteads, in pastures and along the contours in fields to serve as erosion barriers and be managed for green manure production. Sometimes some of the tree prunings obtained from the alley-cropping system are fed to animals. Experimental data indicate that at low crop yields and low crop response to mulching, feeding part of the tree foliage to small ruminants is economically gainful. Gliricidia hedgerows for fodder production may also be established in existing pastures and interplanted with pasture grasses. In Sri Lanka the tree has been integrated in pastures under coconut to produce dry season fodder. In Bali, Indonesia, gliricidia has been incorporated in a 'Three Strata Forage System'' consisting of a strip of 5 m wide, in which fodder trees (Ficus subcordata Blume, Lannea coromandelica (Houtt.) Merrill, Hibiscus tiliaceus L.), shrub legumes (Gliricidia sepium, Leucaena leucocephala, Acacia glauca (L.) Moench) and grasses and herbaceous legumes (Cenchrus ciliaris L., Panicum maximum Jacq., Stylosanthes spp.) are combined. Cattle feed mainly on the grass-legume stratum in the wet season, the shrub legumes in the mid-dry season and leaves from the fodder trees in the late dry season.
A wide variety of agricultural crops or fodder grasses and legumes can be grown together with gliricidia. Although the competitive effect of the tree on crop and pasture grass production depends on the species, site conditions and management it seems to be limited. Due to its open crown and thin foliage and weakly developed root system the tree does not provide heavy competition. In alley-cropping experiments it was found that crop growth next to the hedges is depressed less by gliricidia than by alternative hedge species such as Erythrina poeppigiana (Walpers) O.F. Cook. Similarly, when used as living posts for yam cultivation, tuber yields were higher with gliricidia than with leucaena. In pastures, gliricidia may be combined with Panicum maximum Jacq. var. trichoglume Robijns, Cenchrus ciliaris, Urochloa mosambicensis (Hack.) Dandy, Stylosanthes scabra Vogel, and Stylosanthes hamata (L.) Taub. Even if grass production is depressed, gliricidia production may compensate for this loss, because the total production is more evenly distributed over the year. Gliricidia has improved the survival of ewes and lambs, lambing percentage, and birth weight and growth of lambs when fed as a supplement to poor quality grass. It is normally recommended that gliricidia be used mixed with either grass, straw or other roughages. When fed to poultry in place of lucerne (Medicago sativa L.), levels not exceeding 2—4% are recommended.

Few serious diseases and pests have been recorded. Some problems with foliar diseases caused by Pellicularia filamentosa (India) and Colletotrichum gloeosporioides and Cercosporidium gliricidiasis (Nigeria) have been noted; in Trinidad a root fungus attacks the tree, but not very seriously. In the Caribbean a number of insects, such as aphids, mealy bugs and scale insects attack the tree. One of the reasons for the popularity of gliricidia is its complete resistance to the leucaena psyllid (Heteropsylla cubana), which seriously attacks many cultivars of Leucaena leucocephala. When intercropped the tree may affect crop pests positively or negatively. In several cases the tree has been reported to control pests, e.g. termite damage to tea was minimized in Sri Lanka, as was stem-borer damage to rice in the Philippines. In India on the other hand, it was found to increase the number of aphids (Aphis craccivora) causing rosette disease in groundnut; in Indonesia, this aphid adversely affected buffelgrass (Cenchrus ciliaris) intercropped with gliricidia.

The first harvest of gliricidia can be as early as 6—8 months from plants grown from cuttings and 12—16 months from plants grown from seedlings. There should be only one or two harvests per year during the first 2 years. Harvesting should be less intensive (every 3—4 months) in the dry season than during the rainy season (every 2—3 months). Regrowth should be 1—2 m in height before each harvest. To obtain fodder during the dry season the trees should be cut about 3 months before the onset of this season. If trees are not cut 4—6 months before the dry season they will shed their leaves during the dry season. Cutting heights commonly range from 0.5—2 m. Trees grown along contours and in fodder banks are usually cut lower than those cultivated in living fences or as shade trees in pastures, where browsing cattle may interfere with regrowth.
Forage from gliricidia is usually cut by hand and left on the ground for grazing or carried to paddocks or livestock sheds. Acceptable silage can be prepared using standard techniques; the chopped forage may be mixed with grasses or maize and additives such as molasses and sugar cane or formic acid (0.85%) should be added to provide fermentable carbohydrate.
In woodlots the first harvest can be carried out after 3—4 years, giving wood yields of 8—15 m³/ha. From then on, coppicing is done every 2—3 years yielding up to 40% more than the first harvest.

Under average conditions yields of 3—4 kg dry matter per tree per harvest may be obtained. In Nigeria gliricidia hedgerows interplanted with 4 rows of Panicum grasses yielded 20 t/ha per year of mixed dry matter, which was sufficient to feed 3 head of cattle. Annual yields of 9—16 t/ha of leaf dry matter or up to 43 t/ha fresh leaves have been obtained in fodder plots.
In woodlots coppiced every 2—3 years the wood yield varies from 10—20 m³/ha. Wood production in living fences has been reported at 9 m³/km per year. Harvested produce is usually used locally.
Marked differences in yield have been found between different provenances (e.g. up to 500% for biomass production).

Major germplasm collections are being maintained at the Oxford Forestry Institute in the United Kingdom, the Centro Agronómico Tropical de Investigación y Enseñanza (CATIE, Turrialba, Costa Rica), and at the Humid Zone Programme of the International Livestock Research Institute (ILRI, Ibadan, Nigeria). In Asia, collections have been made by the Visayas State College of Agriculture (VISCA, Leyte, the Philippines). The Oxford Forestry Institute administers an international network of provenance evaluation involving 29 provenances from 8 Latin American countries. CATIE collected 49 provenances from Costa Rica; the ILRI Humid Zone Programme has developed a high yield bulk composite from four Costa Rican accessions.

Early germplasm introductions in many countries usually had a very narrow genetic base and distinct types have evolved in several areas. They are largely arboreal types selected for use as shade trees, and may not be optimally suited for other uses. Provenance evaluations indicate significant differences in growth rate; local landraces in Indonesia, Nigeria, the Philippines and Sri Lanka have been outperformed by new introductions. At some sites large differences in biomass production were found, with some provenances showing superior production of leaves and wood, others with outstanding leaf production but poor wood production. This indicates the need for distinct selection programmes for high-yielding, palatable fodder cultivars, for arboreal cultivars for wood production, or for cultivars combining wood and foliage production. Recently, progeny testing with some superior provenances has started as a basis for future seed orchard establishment. Rapid genetic gains can be expected, as seed production starts early, superior types can be cloned and production cycles are short.

Gliricidia sepium is an extremely versatile multipurpose tree well adapted to a wide range of humid and sub-humid areas and soil conditions, including acid and infertile soils. Favourable properties include its versatility and ease of incorporation in a variety of agricultural production systems. It can be grown together with arable crops in alley-cropping systems, with fodder crops such as grasses or small legumes, or as shade trees in perennial crops. Its auxiliary effect on other crops is facilitated by its relatively open crown and non-spreading root system causing little competition. Plant residues of gliricidia have a relatively high nutrient level and decompose quickly thus having a high direct nutritional contribution to crops but a low mulching effect. It is also showing considerable promise as a fodder crop throughout the tropics, although the quality (anti-nutritional factors) of its forage is still being debated. Although most fodder is produced in the wet season, the tree can be managed to provide fresh leaf during the dry season. Its prospects may be further enhanced by breeding programmes to improve production and forage quality and the development of innovative production systems such as the 'Three Strata Forage System'. It has excellent properties for site reclamation, including suppression of obnoxious weeds such as Imperata cylindrica (L.) Raeuschel.

Anoka, U.A., Akobundo, I.O. & Okonkwo, S.N.C., 1991. Effects of Gliricidia sepium (Jacq.) Steud. and Leucaena leucocephala (Lam.) De Wit on growth and development of Imperata cylindrica (L.) Raeuschel. Agroforestry Systems 16: 1-12.
Budelman, A., 1990. Woody legumes as live support systems in yam cultivation. I. The tree-crop interface. II. The yam - Gliricidia sepium association. Agroforestry Systems 10: 47-59, 61-69.
Ezenwa, I., Reynolds, L., Aken'ova, M.E., Atta-Krah, A.N. & Cobbina, J., 1995. Cutting management of alley cropped leucaena/gliricidia-Guinea grass mixtures for forage production in southwestern Nigeria. Agroforestry Systems 29: 9-20.
Glover, N., 1989. Gliricidia production and use. Nitrogen Fixing Tree Association, Waimanalo, Hawaii, United States. 44 pp.
Jabbar, M.A., Cobbina, J. & Reynolds, L., 1992. Optimum fodder-mulch allocation of tree foliage under alley farming in southwest Nigeria. Agroforestry Systems 20: 187-198.
Lehmann, J., Schroth, G. & Zech, W., 1995. Decomposition and nutrient release from leaves, twigs and roots of three alley-cropped tree legumes in central Togo. Agroforestry Systems 29: 21-36.
Rao, M.R., Muraya, P. & Huxley, P.A., 1993. Observations of some tree root systems in agroforestry intercrop situations, and their graphical representation. Experimental Agriculture 29: 183-194.
Simons, A.J. & Stewart, J.L., 1994. Gliricidia sepium - a multipurpose forage tree legume. In: Gutteridge, R.C. & Shelton, H.M. (Editors): Forage tree legumes in tropical agriculture. CAB International, Wallingford, United Kingdom. pp. 30-48.
Tian, G. & Kang, B.T., 1994. Evaluation of phytotoxic effects of Gliricidia sepium (Jacq.) Walp. prunings on maize and cowpea seedlings. Agroforestry Systems 26: 249-254.
Withington, D., Glover, N. & Brewbaker, J., 1987. Gliricidia sepium (Jacq.) Walp.: management and improvement. Nitrogen Fixing Tree Association Special Publication 87-01. Waimanalo, Hawaii, United States. 255 pp.

K.F. Wiersum & I.M. Nitis

Wiersum, K.F. & Nitis, I.M., 1997. Gliricidia sepium (Jacq.) Kunth ex Walp.. In: Faridah Hanum, I & van der Maesen, L.J.G. (Editors): Plant Resources of South-East Asia No 11: Auxiliary plants. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea