{"metadata":{"id":"0012643aa33c6d3df497119f6f3b0743","source":"gardian_index","url":"https://cgspace.cgiar.org/rest/bitstreams/901f4942-ff2a-44ff-a5f4-2a22cb93f94c/retrieve"},"pageCount":8,"title":"Leucaena in Latin American Farming Systems: Challenges for Development","keywords":[],"chapters":[{"head":"","index":1,"paragraphs":[{"index":1,"size":180,"text":"The genus Leucaena is native to the New World and extends from Southern United States through middle South America. Presently, there are 22 species identified (Bray et al. 1997); however L. leucocephala (Lam) de Wit is the species more investigated and utilized (Casas and Caballero 1996), followed by L. diversifolia (Schlecht) Benth (Salazar 1986). For centuries indigenous people of the American tropics, have used Leucaena species as a source of edible pods, as forage for domestic animals, as poles for construction, as firewood and as shade in permanent plantations. But despite the diverse uses of leucaena, and the convinced research results that show significant increases in animal products, improvement of the soil through nitrogen fixation and the possibilities of using this legume in alley cropping systems, there is not an intensive use of leucaena in the region. In this review we discuss the present status of leucaena in the region and comment on some of the reasons for the poor adoption of the legume in a wide and intensive scale; the potential and recommendations for future developments is also presented."}]},{"head":"Traditional use of Leucaena","index":2,"paragraphs":[{"index":1,"size":76,"text":"The species presently recognize of Leucaena have a long history of human use by indigenous communities of Mexico and Central America. Usually the Leucaena species are protected in traditional agroforestry systems (Hughes 1993), for example five taxa are reported to be utilized by Indian groups of Mexico, these are L. lanceolata, L. confertiflora subsp. adenotheloidea, L. esculenta subsp. paniculata, L. esculenta subsp. esculenta, L. leucocephala subs. leucocephala and L. leucecephala subsp. glabrata (Casas and Caballero 1996)."},{"index":2,"size":308,"text":"The more widely cultivated species of Leucaena in Mexico by indigenous people are L. esculenta subsp. esculenta and L. leucocephala subsp. glabrata. The former is called guaje rojo (red guaje) and local people, mainly of the Mixtec group, gather pods, seeds and young leaves for human consumption. The seeds are eaten raw, roasted, cooked in stews or milled and added to traditional chilli sauces (Casas and Caballero 1996). The cultivation of leucaena is not intensive; edible parts are gathered from individuals planted in home gardens, from wild populations or from selected individuals spared in crop lands. L. leucocephala is widely distributed in the region; the subsp. glabrata has naturalized in Honduras. Other species native to this country are L. salvadorensis, L. diversifolia, L. shannonii subsp. shannonii and L. lempirana (Ponce 1995). Indigenous people of Honduras have also managed the leucaena trees for a long time and use them as a source of edible pods, as forage for pigs, rabbits and cattle, for firewood, for construction, as living fences, as shade and as green manure. Similar use of leucaena is practiced by small farmers of Guatemala (Arias 1994), Costa Rica (Camacho 1989) and in other countries of the region. A more detailed used of Leucaena species by local people is presented in Table 1. However, it needs to be clarified that this use of leucaena is part of a diversified practice for family subsistence of indigenous people that take advantages of all available plant resources in the local environment to fill particular needs, it does not mean that presently exists an intensive use of leucaena in the region. The interspecific crosses between L. leucocephala and L. diversifolia, to obtain hybrids tolerant to acid soils, continues in Brazil (Schifino-Wittmann et al. 1995); however, although superior acidity-tolerant phenotypes have been selected, no cultivar has been released up to date (Hutton 1995)."}]},{"head":"Utilization in production systems","index":3,"paragraphs":[{"index":1,"size":264,"text":"Leucaena -particularly L. leucocephala -has the potential to be used in a diversity of production systems of the region, either leucaena-based pastures (Faría-Mármol and Morillo 1997) or in crop production activities such as shade in perennial crops, for erosion control planted as hedges in hillsides, as mulch and green manure, for wood, firewood and fence posts. However, the reality is that despite positive research findings that show the potential that leucaena has to improve different agropastoral production systems of the region, its use by farmers is limited. In Brazil, Venezuela, Colombia, Mexico and countries of Central America and the Caribbean, L. leucocephala is planted in small scale as forage plant (protein banks or associated with grasses) mainly as part of a research or development project, and in few cases planted by the own initiative of the farmer; figures of the total area planted are not available. L. leucocephala planted on strips into existing grasses in Campo Grande (Brazil) has increased beef production threefold (P. Rayman pers. comm.); however, no more than 500 ha are presently planted and farmers show little interest in this technology for reasons listed below. In the Cerrados and Northwest of Brazil leucaena has been promoted to be used as windbreak and protein bank among small farmers, but it is use only in small scale (M. Soter and C. T. Karia pers. comm.). Similarly occurs around the Maracaibo Lake in Venezuela with the use L. leucocephala (D. Urbano pers. comm.), in the Cauca Valley of Colombia (Shultze -Kraft 1994) and in the State of Chiapas in Mexico (I. Carmona pers. comm.)."},{"index":2,"size":75,"text":"L. diversifolia is used and prefered over other species by local farmers of Guatemala as firewood, because it splits easily, burns slowly and produces little smoke. The hardwood is used to make axe handles and to built attics for drying tabacco. Also L. leucocephala is used in a small scale by farmers of Nicaragua as windbreak planted together with Tecoma stands and Eucalyptus camaldulensis, thus offering a better foliar surface for wind control (CATIE 1986)."},{"index":3,"size":84,"text":"Regional projects, such as Madeleña (CATIE -ROCAP) and COHDEFORD in Honduras have encouraged during the last years the use of leucaena (mainly native lines) in agroforestry systems and as live fences among indigenous people (Ponce 1995); however, statistics on the degree of success are not available. Similarly, CATIE has researched the use of leucaena in ally cropping systems in Nicaragua and Costa Rica (Viques 1995), but the utility and advantages of the system are not known nor it is a popular practice among farmers."}]},{"head":"Limitations to Adoption","index":4,"paragraphs":[{"index":1,"size":74,"text":"Research and promotion in the region have centered on L. leucocephala, which is known by its deficient cold tolerance, heavy defoliation during prolonged dry periods, poor growth on acid soils, heavy pod production, low wood durability and susceptibility to a defoliating psyllid (Hughes 1993), although its high forage quality is well recognized. Therefore, there are inherent factors to the species that limit its adoption, but there are additional ones that merit to be mentioned:"},{"index":2,"size":156,"text":"• There are not well supported transfer programs to promote the utilization of leucaena in the region. • Farmers do not understand or are not fully aware of the benefits of using leucaena as a fodder plant or in agroforestry systems. • Traditionally for a cattle farmer a pasture is formed by pure grass only and has difficulties accepting a pasture formed by trees. • Technical information on establishment at low cost and management methods to regenerate plantations is scarce. • Leucaena-based pastures need intensive management under rotation, a practice that is not generalized among cattle farmers of the region. • Ants and termites are a problem during the establishment phase of L. leucocephala in areas like the Cerrados of Brazil. • There are not studies that show the economic impact of using leucaena at the farm and community level, and the contribution of the legume to the cycling of nutrients and improvement of the soil."}]},{"head":"Potential and Recommendations for Development","index":5,"paragraphs":[{"index":1,"size":94,"text":"With the present technology available, large areas of the Latin American tropics could be planted with L. leucocephala, particularly areas of the region with medium to good fertility soils and a well defined dry season. According to Lascano et al. (1995), these areas are present in the southern part of Mexico, in some island of the Caribbean, along the Pacific coast of Central America, parts of Colombia, Venezuela, Guyana, Ecuador, Bolivia, Paraguay, northern Argentina and east and northeast of Brazil. Generally, these areas hold already a high population of beef and dual purpose cattle."},{"index":2,"size":103,"text":"To this areas we need to add millions of hectareas of very acid oxisol and ultisols with pH < 5 and Al saturation of 47-87 percent that cover around 55 percent of South America and 68 percent of Brazil (Hutton 1995). These areas could be planted with acid-tolerant hybrids of L. leucocephala x L. diversifolia that are well advanced in Brazil (Schifino-Wittmann et al. 1995), or with newly identified species presently under evaluation (Argel and Pérez 1996). However, for this potential to be realized a series of problems and limitations need to be overcome with relation to the present available lines of leucaena:"},{"index":3,"size":203,"text":"• Improve the growing methods, focusing on establishment and soil nutritional requirements of L. leucocephala. Farmers have to wait too long from planting to the first grazing. Appropriate planting techniques are needed, together with the selection of robust genotypes of faster growth. • Organize and establish transfer programs that incentive farmers participation in the planting, growing and management of leucaena. A government incentive may be considered such as one that is presently in place in Mexico, where the state covers to a farmer around 60 percent of the cost of establishment of a new pasture (usually the seed cost of a grass). • Improve the dissemination of technical information on the potential and limitations of leucaena-based systems to farmers, extension agents and policy makers. This can be assisted by establishing a regional network to share germplasm, experimental results and experiences with farmers. The present chain of experiments already underway in Latin America with new species of leucaena supported by the Oxford Forestry Institute in collaboration with CIAT, may be the base for a future regional network. • Incentive programs to identify new lines tolerant to high Al saturation and low Ca soil concentration either by breeding or selection from new species of leucaena."}]},{"head":"Conclusions","index":6,"paragraphs":[{"index":1,"size":137,"text":"Leucaena species are utilized for different uses by indigenous people of Latin America as part of a diversified practice that takes into account all plant resources available for subsistence in the local environment. L. leucocephala is the species more widely distributed and researched, however there is no wide utilization of this species in agropastoral system of the region. New species of leucaena are still in an early phase of evaluation. The potential of leucaena to increase animal production, as well as to contribute to more sustainable crop practices, is enormous, but there are several factors that limit adoption (lack of effective transfer programs, farmers traditions, slow establishment, poor growth in acid soils), that need to be resolved if an intensive use in different production systems of this important legume, is to be achieved in the near future."}]}],"figures":[{"text":"Table 1 . Main use of native Leucaena species by indigenous people of Mexico and Central America (Adapted from Hughes 1993). Species Main use SpeciesMain use  "},{"text":"Table 2 . Growth and regrowth yields of L. diversifolia in La Garita de Alajuela, Costa Rica (Adapted formSalazar et al. 1987).  Regrowth harvests  Regrowth harvests Variables First harvest* 1 st 2 nd Total production VariablesFirst harvest*1 st2 ndTotal production  (2.6 years) (0.8 yrs) (1 yr)** (4.4 years) (2.6 years)(0.8 yrs) (1 yr)**(4.4 years) Total height (m) 6.0 5.3 5.3 - Total height (m)6.05.35.3- dbh (cm) of main stem 4.7 2.9 2.8 - dbh (cm) of main stem4.72.92.8- Foliar DW (mton/ha) 13.9 10.3 18.9 43.1 Foliar DW (mton/ha)13.910.318.943.1 Firewood DW 23.4 14.9 7.6 45.9 Firewood DW23.414.97.645.9 (mton/ha)     (mton/ha) DW standing 37.3 25.2 26.5 89.0 DW standing37.325.226.589.0 biomass (mton/ha)     biomass (mton/ha) Specific gravity 0.54 0.54 - - Specific gravity0.540.54-- (g/cm3)     (g/cm3) * Harvest of the original stand     * Harvest of the original stand ** Harvest of regrowth at 10 to 12 month intervals    ** Harvest of regrowth at 10 to 12 month intervals  "}],"sieverID":"106ba2d6-a045-4b21-af35-931da74ba7fb","abstract":"Different species of Leucaena have been used traditionally by indigenous people of Mexico and Central America, as part of their subsistence activities that take advantages of all plant resources available in the natural environment; however, this does not implies an intensive use of leucaena in their farming systems. L. leucocephala is the species more widely used, but it has limitations such as slow growth during establishment, deficient cold tolerance, poor growth on acid soils and susceptibility to defoliating psyllid. These inherent problems of leucaena added to deficient transfer programs, poor diffusion of technical information and farmers tradition, are some of the reasons for the poor farmer adoption in a wide scale. With the present technology available on L. leucocephala productivity of large areas of the region can be improved either by incorporating leucaena in grazing systems or into crop lands, however, to realize this potential technical and transfer problems must be solved."}