Theme 14: Advances in Forage Legumes
Description
Forage tree legumes benefit agriculture through their multi-purpose contributions to livestock feeding, to productivity of farming systems, and to protection of the environment.
Of the several hundred forage tree legume species regarded as having potential for forage only c. twenty are in common use. These are listed together with their agroecological range and tolerance of adverse environments including acid soils, cool temperatures, low rainfall, poor drainage and high salinity. The value of many species to ruminants is limited due to low nutritive value arising from low protein availability and low acceptability caused principally by high condensed tannin content. Only 10 of the 20 listed species are considered to have a high nutritive value viz. Albizia lebbeck, Chamaecytisus palmensis, Cratylia argentea, Desmodium rensonii, Desmanthus virgatus, Gliricidia sepium, Leucaena leucocephala, Leucaena diversifolia, Sesbania grandiflora,and Sesbania sesban.
The germplasm in commercial use worldwide is often inferior and with a narrow genetic base. The need for farmer access to a greater diversity of planting material and improved varieties through better distribution systems is highlighted. However, plant improvement is often limited due to taxonomic confusion in many genera e.g. Albizia, Prosopis, and farmer access to new varieties is limited by lack of information and lack of resources to purchase high quality seeds. There is debate over whether to use fast growing exotic species or slower growing native species. There are as many as 150-200 M people use Gliricidia sepium worldwide but there is minimal use in its native range. Conversely, native Acacia communities are over-exploited in their native range with minimal use elsewhere. Conservation of native range is critical and in situ, ex situ and circa situm approaches are suggested. Issues of weediness potential are paramount when using exotic species requiring greater care in the evaluation of risk factors.
Finally, the reasons for successes and failures in promotion of forage tree legume use in world farming systems are analyzed and suggestions made to extend the utilization of this important group of legume species.
Included in
Advances in Forage Legumes: Shrub Legumes
Forage tree legumes benefit agriculture through their multi-purpose contributions to livestock feeding, to productivity of farming systems, and to protection of the environment.
Of the several hundred forage tree legume species regarded as having potential for forage only c. twenty are in common use. These are listed together with their agroecological range and tolerance of adverse environments including acid soils, cool temperatures, low rainfall, poor drainage and high salinity. The value of many species to ruminants is limited due to low nutritive value arising from low protein availability and low acceptability caused principally by high condensed tannin content. Only 10 of the 20 listed species are considered to have a high nutritive value viz. Albizia lebbeck, Chamaecytisus palmensis, Cratylia argentea, Desmodium rensonii, Desmanthus virgatus, Gliricidia sepium, Leucaena leucocephala, Leucaena diversifolia, Sesbania grandiflora,and Sesbania sesban.
The germplasm in commercial use worldwide is often inferior and with a narrow genetic base. The need for farmer access to a greater diversity of planting material and improved varieties through better distribution systems is highlighted. However, plant improvement is often limited due to taxonomic confusion in many genera e.g. Albizia, Prosopis, and farmer access to new varieties is limited by lack of information and lack of resources to purchase high quality seeds. There is debate over whether to use fast growing exotic species or slower growing native species. There are as many as 150-200 M people use Gliricidia sepium worldwide but there is minimal use in its native range. Conversely, native Acacia communities are over-exploited in their native range with minimal use elsewhere. Conservation of native range is critical and in situ, ex situ and circa situm approaches are suggested. Issues of weediness potential are paramount when using exotic species requiring greater care in the evaluation of risk factors.
Finally, the reasons for successes and failures in promotion of forage tree legume use in world farming systems are analyzed and suggestions made to extend the utilization of this important group of legume species.
