Prosopis alba Grisebach
Algarrobo Blanco, Ibope, Igope, Tacu
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
All information, especially early information, on Prosopis spp. is only
tentatively assigned to one or the other species of Prosopis. Taxonomic
identities were extremely confused until Burkart's monograph. Much of the
early chemical, ecological, and ethnobotanical data may be masquerading under
the wrong name. Burkart (1943) describes several beverages made from the
fruits, including a coffee substitute made from toasted pods. A very important
tree in arid lands, similar in value to Prosopis chilensis, P.
nigra, or P. pallida. In northeastern Argentina, native people
frequently call it "el arbol", the tree, because of its usefulness and
abundance. It is cultivated to a limited extent. In the Chaco it furnishes
timber of high value for construction, doors, premanufactured houses, etc.
Trees with straight trunks 8 to 10 m occur, but these are becoming extremely
rare, from being cut in preference to the other shorter ones. Thus a negative,
artificial selection is taking place, which should be counteracted by genetic
up-building of the best lines in experimental plots (Burkart, 1976). According
to NAS (1980a) this valuable food tree is also used for fodder, roadside
planting, timber, and windbreaks. Streets of Buenos Aires are lined with these
trees in the belief that they subdue vehicular noises (Burkart, 1943). The
fruit is milled into a baking flour for human consumption. Though difficult to
work, the wood is used for flooring, paving blocks, shoe lasts, and wine casks.
Sawdust, like the fruits is used for tanning.
Reported to be astringent, lithontriptic, and tonic, the white algarrobo is a
folk remedy for ophthalmia.
Per 100 g, the pericarp only (of P. alba and P. velutina) is
reported to contain 4 g H2O, 10 g protein, 40 g sugar, and 19 g fiber. "Patay"
is the sweet floury paste of the pods, ground up and dried, serving as the
basis for many popular Argentine dishes. Patay contains 9.6% water, 6.7% ash,
43.9% sugar, 10.4% starch, 5.9% cellulose (we need it), 4.3% protein, 1.2%
fats, and 3.5% pentosans. While high in calories, the patay is deficient in
certain proteins, vitamin A, C, and D (Burkart, 1943). Like P.
chilensis, this species contains apigenin 8-glucoside, apigenin
6-glucoside, quercitin 3-glucoside, quercitin 3-rhamnoside, quercitin
3-rutinoside, and traces of myricetin 3-rhamnoside, luteolin, kaempferol-3-OMe
quercetin, and quercitin 3-OMe (Simpson, 1977). Pipecolic and 4-hydroxy
pipecolic acid also occur in both, but varying concentrations of pipecolic
acid and proline are interpreted as reflecting a plastic response to changing
environmental conditions. The consistent patterns of flavonoid distributions
in several species groups, on the other hand, apparently reflects genetic
fixation independent of known environmental factors (Simpson, 1977). Pods
contain ca 711% protein, 2528% sugar (Simpson, l977; Burkart, 1943).
Tree 515 m tall, in age the short trunk possibly reaching 1 m in diameter;
treetop rounded; branchlets drooping; spines scarce and small, only on strong
shoots, 24 cm long, geminate. Leaves large, uni- to trijugate, glabrous;
petiole (including the rachis) 0.58 cm long; pinnae 614 cm long, with 25 to
50 pairs of leaflets, these linear, acute or subacute, in some forms nearly
obtuse, 0.51.7 cm long x 12 mm broad, scarcely nerved below, approximate,
1.56 mm between pairs. Racemes spikelike as in similar species, 711 cm long;
florets greenish-white to yellowish, small; calyx 1 mm long, puberulous;
corolla 33.2 mm; stamens 4.5 mm; pistil 5 mm long. Legume falcate to
ring-shaped (ring ca 7 cm in diameter), linear, compresses with parallel
margins, straw-yellow, stipitate and acuminate, 1225 cm long x 1120 mm broad
x 45 mm thick, with 12 to 30 subquadrate endocarp segments broader than long,
ca 0.6 x 1 cm (Burkart, 1976).
Reported from the South American Center of Diversity, white algarrobo, or cvs
thereof, is reported to tolerate drought, salt, and sand, but it will withstand
only a few hours of mild frost, prolonged cold (-6°C) killing most
seedlings. Said to hybridize with P. flexuosa, P. nigra, and P.
ruscifolia. In terms of chromosome number and morphology, there seem to be
few genetic or chromosomal barriers to hybridization between various species of
Prosopis. Sympatry, partial overlap of flowering time, and little
specific discrimination by pollinating insects also facilitate hybridization
(2n = 28) (Simpson, 1977).
Plains of subtropical Argentina to Uruguay, Parguay, southern Brazil to Peru
Our computer entries for Prosopis spp. are unreliable partly due to past
taxonomic confusion. I estimate that the species ranges from Tropical Thorn to
Moist through Subtropical Thorn to Moist Forest Life Zones. It will probably
tolerate annual precipitation of 1 to 20 dm, annual temperature of 18 to
28°C, and pH of 6 to 8.5. Felker et al. (1981) cite studies suggesting that
the annual minimum temperature isotherm of minus 20.5°C defines the northern
limit for Prosopis distribution generically.
Tree can be seeded directly but is best sown in a nursery and outplanted when
23 months old. For quick germination (34 days), high temperatures (night
26°C; day 32°C) are best. Running the pods through a coarse sausage
grinder both helps to separate and scarify the seed. Felker et al. (1981)
found that a coffee mill produced fewer broken seed than the other devices they
tested. Felker et al (1981) report water requirements of 478.3 cm /g DM,
making this one of the more water efficient species. Felker et al. (1981)
report the first successful rootings of mesquite cuttings. Seed need to be
inoculated with mesquite rhizobia. Competes well with grasses and shrubs.
This species, like P. nigra, has good coppicing qualities. Felker et al
(1981) project costs of $23.36 per dry ton (on the stump from tissue cultured
seedlings) for the first harvest and only $5.00 per dry ton for subsequent
coppice regrowth harvests. Firewood harvested as needed.
The three Prosopis accessions with greatest potential for woody biomass
production in semi-arid southwestern US are P. alba, P. chilensis,
and P. articulata. P. alba (#0166) had highest biomass production
of the three selections, had good coppicing characteristics, and low psyllid
insect damage. It has been successfully rooted from cuttings. Thorn free
selections have been observed. One tree survives where a 5 mm salt layer
covers the ground and a mature tree survived a -9°C (16°F) frost. It may
prove more frost hardy than either P. articulata (#0016) or P.
chilensis (#0009). Felker et al (1981) feel that progeny of
Prosopis alba accessions used for ornamentals are most promising for
woody biomass production in arid lands despite impressive biomass production by
Leucaena and Parkinsonia. They report yields of 50 MT DM/ha in 3
years or nearly 17 MT/ha/yr, a yield sufficiently high to make effective use of
harvesting and transportation equipment. Felker et al. (1981) give detailed
economic projections in their table, Projected Costs for Mesquite Pod
Production. Perhaps even more important, they talk about total use of the
pods, fractionating for mesquite pod gum, protein, and sugar to realize their
full economic potential. Galactomannan gums, estimated to constitute 25% of
the seeds of some Prosopis species have many cosmetic, chemurgic, and
food uses. The gum is fairly similar to carob gum, which commanded
$0.621.11/kg in 1970. Way back in the 40's, the mildly intoxicant beverage,
aloja, was made from fruits sold in the market for 30 Argentine centavos/kg.
The fermented aloja was further distilled into aguardiente or ethanol. To
produce a liter of absolute alcohol requires 1.7 kg fermentable sugar, which
constitute about 3/4 of the fruit's weight (Burkart, 1943).
Burkart (1943) suggests that a ton of fruit could yield 27.2 liters of absolute
alcohol. Felker et al (1981) state that the land area required for a small
commercial ethanol production plant (1,000 barrels/day) could be contained in a
circle with radius of 10.9 km assuming conversion rate of 2.6 gallons ethanol
per 55 pounds pods (much higher than Burkart's assumptions) and yields of 4,000
lb/acre. Ca 12% of the land would provide firewood for distillation. Ten year
old Argentinean plantations spaced at 2 x 2 m produced 7 m /ha/yr (NAS, 1980a).
Felker et al (1981) report yields from 9.819.2 MT/ha/yr in the Imperial Valley.
Bruchids associated with this species include Rhipibruchus,
Pectinibruchus, and Scutobruchus. Spraying cuttings with dithane
suspensions has markedly reduced problems with the fungus Alternaria (Felker et
al., 1981). Felker et al. (1981) review the pest infestations of their
Prosopis plantings with suggestions for their control.
Complete list of references for Duke, Handbook of Energy Crops
- Burkart, A. 1943. Las leguminosas Argentinas. Acme Agency. Buenos Aires.
- Burkart, A. 1976. A monograph of the genus Prosopis (Leguminosae subfam.
Mimosoideae). J. Arn. Arb. 57(3/4):219249; 450525.
- Felker, P. 1981. Uses of tree legumes in semiarid regions. Econ. Bot.
- N.A.S. 1980a. Firewood crops. Shrub and tree species for energy production.
National Academy of Sciences, Washington, DC.
- Simpson, B.B. (ed.). 1977. Mesquite, its biology in two desert scrub
ecosystems. Dowden, Hutchinson & Ross, Inc. Stroudsburg, PA.
Last update Jaunary 8, 1998 by aw