1. Multipurpose legumes in smallholder farming systems in east Africa
Tarirai Muoni, Ingrid Oborn, Andrew Barnes, Goran Bergkvist, Christine Watson, Alan Duncan

2. Introduction Objectives
Multipurpose legumes play crucial role in smallholder farming systems as good source of: food, feed, income, soil fertility build-up, soil erosion control and fuel.
Multipurpose legumes can be classified into grain legumes, herbaceous legumes and tree legumes.
The legumes in these classes contribution to different functions vary
Objectives
To validate the legume expert scoring on different functions, using literature findings.

3. Materials and methods Literature search was done using
Scopus® data base
Google Scholar search engine
The legume expert scoring data used was done during previous Legume CHOICE workshops
The other data on feed quality was collected on the Ethiopian Feed Composition Database by ILRI and Feedipedia database

4. Grain legumes
Grain legumes provide grain seed that is used as food by humans, feed for livestock and nitrogen through BNF.
The grain yield can be as high as 3400 kg/ha (eg Faba bean and Field pea) while the majority of the grain legumes here are between kg/ha

5. Mature plants CP (g/kg) Soil fertility (BNF/ha/season)
The straw of the grain legumes have low crude protein (CP). This is important when farmers are considering to feed the crop residues to livestock
Some grain legumes take more nitrogen than they fix!!!
 Legume species
Mature plants CP (g/kg)
Grain legume CP (g/kg)
Nitrogen taken in seed
Soil fertility (BNF/ha/season)
Remaining nitrogen
Phaseolus vulgaris 68
248 45 41 -4
Vicia faba 74
290
156
117
-39
Pisum sativum 46
245
133
101
-32
Vignia unguiculata
145
220 36 61 25
Arachis hypogea
163
247
141 67
Cicer arietinum
228 -5
Glycine max
244
378 96
100 4
Vigna radiata
171
275 51 40
-11
Cajanus cajan
217 53 8
Lens culinaris Medik 82
311 56 24
-33

6. Nitrogen in biomass (kg/ha) Soil fertility (BNF/ha/season)
Herbaceous legumes
These legumes are generally used for livestock feed and soil fertility improvement
Legume name
Food (kg/ha)
Biomass (kg/ha)
Crude Protein (g/kg)
Nitrogen in biomass (kg/ha)
Soil fertility (BNF/ha/season)
Mucuna pruriens
1438
6380
160
163 97
Lablab purpureus
856
4674
184
188
Carnavalia ensiformis
3649
4635
292
298 40
Desmodium uncinatum
1498
151
154
178
Desmodium intortum
155
158
Trifolium resupinatum
12059
216
220 80
Vicia sativa
7369
230
235
105
Medicago sativa
310
13904
183
187
199
Crotalaria ochroleuca
7800

7. Both the grain and herbaceous crops have more nitrogen in the seed and straw than the fixed N
This reduces the amount of the nitrogen that remains in the soil, thus has an effect on soil fertility build up.
Retaining crop residues to the field is crucial when low soil fertility is a problem in the smallholder farming sector.

8. Tree legumes
This group plays a role in providing livestock feed, soil erosion control soil fertility improvement and fuel among other benefits.
Legume name
Forage (kg/ha)
Fuel (kg/ha wood)
Soil fertility (BNF/ha/season)
Calliandra calothyrsus
4240
4379 68
Gliricidia sepium
9451
12314 51
Leucaena leucocephala
4943
7988
115
Sesbania sesban
2000
4100
282
Acacia angustissima
2220

9. Legume attributes scoring
Legume name
Food_prov
Feed_prov
Income_prov
Erosion control_prov
Fuel_prov
Soil fertility_prov
Pigeon pea 4 2 3
Common bean 1
Groundnuts
Soybean
Faba bean (Vicia faba) – low
Cowpea (Vigna unguiculata
Bambara nut
Chickpea (Cicer arietinum L.)
Green grams/Mung bean (XX) - low
Lentils (xx)
Lupins – low, sweet lupin (new)
Field Pea – low, high (Pisum sativum)
Grass pea – low (Lathyrus spp)
Alfalfa/lucerne (Medicago sativa)
Velvet bean (Mucuna pruriens)
Lablab cv xx
Calliandra
Gliricidia
Leucaena leucocephala
Sesbania
Tephrosia (Tephrosia vogelii)

10. Conclusions
Most of the grain and herbaceous legumes have high nitrogen in the grain and the crop residues.
This has a direct effect on soil fertility improvement. The soil fertility build up is dependent on the management of crop residues. The more the crop residues retained, the better the soil fertility improvement.
Herbaceous legumes main function is provision of livestock feed and soil fertility improvement.