LEGUMINOUS GROUND COVERS AND GREEN MANURES
This group includes any rapidly growing crop that covers and protects the soil and that can be left as a mulch or plowed under to enrich the soil. Legumes are emphasized because of their ability to fix nitrogen. These crops are adapted principally to the hot, somewhat moist, tropics, but some are adapted to all tropical climates. They can all be established by seed, but some root at the nodes and can be established from cuttings. We have a general Technical Note on Green Manure Crops available.
Seeds are available to members of our network.
To find out how to request seeds, click here.
Beach Bean | Butterfly Pea | Desmanthus | Flemingia | Forage Cowpea | Hairy Indigo | Jack Bean | Lablab | Lupine | Sunnhemp | Sword Bean | Tarwi | Tephrosia | Tropical Kudzu | Velvet bean | Winged Bean
Canavalia ensiformis Elevation: up to 1,800m
Jack Bean LL, MS, SA, H
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Plant Pod Flower
Very young pods edible; mature beans are highly toxic, but heat treatment eliminates the toxic effects; very drought-tolerant valuable green manure and cover crop species; ideal pH 5-6; will grow on impoverished tropical soils where other pulses will not grow. It has been a useful species in tropical soil reclamation efforts because of its deeply penetrating root system (affording high drought tolerance), its nitrogen fixation capabilities (providing for soil nutrient improvement) and its tolerance of a wide range of soil acidity and salinity conditions; can be used as a forage crop for ruminant (cud-chewing) animals. Soil pH: 4.3-8.0.
Canavalia gladiata Elevation: up to 1,500m
Sword Bean MS, LL, RF, H
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Uncooked seed is toxic at any stage, BUT young tender immature pods are edible after being boiled and water poured off. Do not eat in large quantities and do not eat mature seeds, even after boiling! Drought-tolerant, green manure; seeds germinate readily. Optimum growth occurs in full sunlight but sword beans are tolerant of some shade. Preferred environmental conditions are found in the humid lowland tropics but these beans may be grown with success in tropical elevations to 1,000 m (3,000 ft). Sword Bean thrives in tropical climates exhibiting moderately high temperature (15-30°C/59-86°F) environments. Sword Bean is tolerant of a wide range of rainfall conditions (from 700-4,200 mm or approximately 27-165 in). Sword Bean is well adapted to growth and survival in low-quality soils.
Soil pH: 4.3-7.5.
Canavalia maritima SA, LL, MS, RF
Beach Bean, Bay Bean
Image (Australian National Botanic Gardens)
A salt tolerant green manure, cover & forage crop. Used for beach soil stabilization. Young seeds are eaten cooked. Scarify seed before planting. Requires a longer growing season. It thrives in warm climates similar to those required for growing cotton plants.
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Clitoria ternatea Elevation: 0-1800m
Butterfly Pea SA, MS, LL, RF, H
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Very drought-tolerant, but does not compete well with weeds, some weed control can be achieved by mowing the crop; flowers are used to give blue tinge to rice; young pods eaten like string beans; can be grown with tall grasses for rotational grazing, hay, or silage. Butterfly Pea, a climbing vine, is also used as a cover crop or green manure. It is well adapted to a variety of soil types (pH 4.5 – 9.0), including calcareous soils, survies both extended rainfall and prolonged periods of drought.
Crotalaria spp. Elevation: 0-1500m
Sunnhemp MS, LL, RF, SA, H
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An excellent versatile green manure crop, which can be used as a feed (ochroleuca), or used as a weed suppressant and erosion control. The juncea species was traditionally used as a source for fiber in the manufacturing of twine and cord. Soil pH: 5.0-8.4.
C. juncea: toxic to livestock if more than 10% of diet; may suppress nematodes; some drought resistance. Although it is adapted to hot climates, this plant will endure slight frost; a good source of fiber for the manufacture of twine and cord; fixes up to 67 kg (147 lb) of nitrogen per acre.
C. ochroleuca: forage before it goes to seed, not poisonous to livestock; upright, non-vining legume; good for intercropping; green manure crop used to improve the soil, suppress weeds, feed livestock, and control erosion; especially suited for fruit groves; some usefulness in suppressing nematodes when used in rotation with other crops. The seeds are used to keep weevils from stored rice and maize. It is fairly drought tolerant.
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Desmanthus virgatus Elevation: 0-2500m
Wild tantan/Dwarf koa/slender mimosa/ bundleflower. SA, MS,LL
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A nitrogen-fixing tropical shrub that can be used as a green manure/cover crop and as fodder for livestock. Native to the American tropics and subtropics, it can grow up to 3 meters high. Grows back quickly and can tolerate drought. Also used as a living fence or for alley cropping. Soil pH: 4.5-7.5.
Flemingia macrophylla Elevation: 0-2000m
Wild Hops (Flemingia) H, MS, LL
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A woody, leguminous, deep-rooted shrub native to Asia, but now found in Sub-Saharan Africa and Malaysia. Useful in erosion control, for shade or shelter and for soil improvement. Wild hop leaves are slow to decompose and are an effective weed suppressant. Can also be used for fuelwood or fodder. Dried pods produce a powder that is used as an orange dye for silks. Roots used for medicinal purposes against ulcers and swelling. Sol pH: 4.6-7.5.
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Indigofera hirsuta Elevation: 0-1350m
Hairy Indigo MS
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Reseeding annual; nematode-suppressant; tolerates a wide range of soils, but prefers well-drained soils; used for hay and grazing. Plants grow from 0.6 – 2.3 m (2-7 ft) tall. Good ground cover and green manure; sensitive to cold. It grows as far as 30 degrees south and as far north as 32 degrees N in the USA and from sea level to 1350 m (4429 ft) in Africa.
Soil pH: 4.5-8.0.
Lablab purpureus Elevation: sea level up to 2,100m
Lablab Bean/ Hyacinth Bean MS, LL, H, SA
Image: Pods (Red) Used as a spring cover crop at ECHO
Lablab Bean is capable of growing in a wide range of climatic conditions and soil types, depending upon the variety chosen. Lablabs have been grown from sea level to 2,000 m (6,000 ft) in tropical regions. It tolerates drought periods well but has been grown successfully in climates ranging from 200-2500 mm (8-100 in) annual rainfall. Lablabs prefer well-drained soils with a pH range from 4.4-7.8. Lablab has been grown both in nutrient-poor soils and those high in some minerals such as aluminum. Dark-seeded cultivars have high levels of both cyanogenic glucoside and a trypsin inhibitor and must be cooked, sprouted, or fermented before eating. Soil pH: 4.5-8.0.
Refer to Pulses (grain legumes) section for varieties available.
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Lupinus albus Elevation: 0-740m
Sweet Lupine/ White Lupine H, T, MS
Image (Courtesy of Net-Garden.de.www.net-garden.de)
The planting date is the most important factor in lupine production, a grain legume. It should be planted so that it grows during the coolest period of spring. It is drought-tolerant and moderately frost tolerant. Hot temperatures can inhibit pod production. Also used as a ground cover and green manure. Performs better than other pulses on marginal soils. This is a cool climate legume lacks bitter saponins found in other lupines. Cook seed like beans or grind and mix 30% with flour for high-protein pasta. Soil pH: 4.8-8.2.
Lupinus mutabilis Elevation: 0-3800m
Tarwi/Andean Lupin/Tarhui T, H, MS
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This crop is from the central Andean region of South America. Mature plants tolerate frost, but do not produce a good crop of seed under high humidity or if drought occurs during flowering. Tarwi can produce a crop in poor soils but it yields the best in well-drained, sandy soils. The seeds are soaked in water for several days to remove bitter alkaloids. They are a good source of high protein and oil for humans as well as livestock. It can also be used as a green manure crop, adding as much as 400kg of nitrogen per hectare.
Mucuna pruriens Elevation: 0-2100m
Velvet Bean MS, LL, RF, H
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Velvet bean can tolerate drought, low soil fertility, and acidic soil, although it is sensitive to frost and does not grow well in cold, wet soils. It grows best at altitudes under 1,500m (4,500 ft). All varieties from ECHO's seed bank grow vigorously and thrive in areas with full sun and high rainfall, which can cause velvet bean to be weedy. Mucuna requires a long growing season. It serves as a good green manure, but is not recommended for human consumption. Soil pH: 4.0-7.5.
90-Day: Day-length neutral; less vigorous than tropical variety; has irritating hairs, must protect skin during harvesting. Grows well in temperate areas.
Bush: Bushy growth; compact; short-day plant. Image
ECHO 1: A bush type selected by the University of Florida, from seeds from ECHO, for high pod set.
Tropical: Requires short days for flower and pod production. Image
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Psophocarpus tetragonolobus Elevation: 0-2000m
Winged Bean/ Goa Bean MS, RF, LL, T
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Climbing vine does best in hot, humid zones; edible pods, beans, leaves, tubers, and flowers; plant in a sunny location, frost sensitive; does well in a variety of soils except sands or high salinity environments; drought sensitive. Soil pH: 4.3-8.5.
Refer to Pulses (grain legumes) section for varieties available.
Pueraria phaseoloides Elevation: 0-2000m
Tropical Kudzu MS, LL, RF,H
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Used as a nitrogen-fixing green manure, cover crop, or pasture crop. It is a vigorous legume with runners up to 25 feet (8-9 meters) long. It is slow to establish for the first 3 to 4 months. An excellent crop to minimize erosion. This crop tolerates high water levels (even occasional water logging), grows well in dry season, tolerates acidic soil and shade. Soil pH: 4.0-8.0.
Note: This is NOT Georgia kudzu
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Tephrosia spp.
Tephrosia candida (White Hoarypea) Elevation: 0-1600m MS, LL
First grown in India, this species has a dense leaf canopy with greater leaf biomass than T. vogelii. The leaves are high in protein and can be used as food supplement for pigs and cattle but not humans. Insecticidal properties are not as well documented as for T. vogelii; however, roots (ground to powder) have shown activity against Diaprepes Root Weevil and dry leaf powder is said to inhibit weevils.
Tephrosia vogelii (Tephrosia/Fish Bean) Elevation: 0-2100m MS, LL
Image: Pods/leaves Plant
A small bush used as green manure that contains rotenone in leaves and beans. Crushed leaves used for insecticide; beans and leaves are poisonous to fish; used for erosion control and for mulch; Do NOT use as a fodder for animals or as a fish poison in ponds or streams. Soil pH: 4.5-7.0.
See Industrial Crops.
Vigna unguiculata Elevation: 0-2000m
Forage Cowpea SA, MS
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‘ILCA’: This forage plant can also be used as a green manure and cover crop; drought-tolerant forage/edible pulse; bush plant with compact pods; succeeds best in warm weather surviving some drought conditions and even some shade. It is not particular to soil types, will thrive where soil is well drained, properly inoculated and moderately rich with lime. Soil pH: 4.3-8.8.
Refer to Pulses (grain legumes) section for varieties available.
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