Native and Introduced Legumes in the Virgin Islands:

 Soil Improvement and Livestock Feed

 John M. Matuszak
 College of the Virgin Islands
 Cooperative Extension Service
 St. Thomas, U.S. Virgin Islands


 Steep slopes and limited water resources in the Virgin
Islands encourage the establishment of permanent pastures
and orchard crops for soil conservation while intensifying land
management. The rising costs of energy and transportation
have increased the price of both animal feeds and nitrogen fer-
tilizers, which are imported. These factors have made more
imperative the successful incorporation of N-fixing legumes
into the various farming systems. Six legumes, Leuceana


leucocephala (Lam.) DeWit, Teramnus labialis (L.f.) Spreng,
Vigna luteola (Jacq.) Benth., Macropitilium atropurpurea
(DC) Urban, Neonotonia wightii Lackey, and L. leucocephala
var. K-8, were evaluated chemically and agronomically for use
as pasture, green manure, and cover crops. In addition, 20
other native or naturalized species of legumes were suggested
for greater utilization in farm systems in the Virgin Islands and
West Indies.


 Legumes, Fabaceae syn. Leguminosae, when taken as a group
including the subfamilies: Mimosoideae, Caesalpinioideae, and
Faboideae make up the most diverse and one of the predominate
components of the natural ecosystem of the Virgin Islands. A re-
cent study (Woodbury and Weaver, 1984) lists 78 different
species of legumes as native or naturalized on St. John. Grasses,
Poaceae syn. Gramineae, were the second most diverse family
with 65 species represented.
 Legumes also play an extremely important role in the
agroecosystems of the Virgin Islands. They are important for
direct human consumption, but impact more extensively as a
livestock feed, as a soil amendment and groundcover, and
negatively as weeds, sometimes toxic to livestock (Oakes and But-
cher, 1984). Over 12,000 grazing animals (cattle, sheep and
goats) are listed in the 1982 V.I. Census of Agriculture and most
informed sources believe this estimate to be very low. Legumes
play a major role in providing the nutritional basis for this in-
dustry. Imported feed costs are high owing to the extensive ship-
ping and handling charges which are added. Similarly, fertilizer
costs for efficient crop production are high due to the size and
isolation of the islands. The soils of the Virgin Islands are catholic
in their deficiency of N and S. Many soils are low in P or Mg and
in the micronutrients Fe, Zn, Mn, and Cu. Legumes, many with
extensive root systems, can mobilize nutrients from the subsoil
for their own growth and through leaf litter or mulching as a
green manure can make these nutrients available to associated or
subsequent crops. Finally, most of the land in the Virgin Islands
is sloping and subject to high winds containing significant
amounts of marine salts. Many legumes, when properly man-
aged, can be a great help to agriculturalists in reducing the im-
pact of precipitation on the soil and reduce erosion. Shrubby
legumes can be a tremendous value as windbreaks, simultaneous-
ly reducing salt damage.


MATERIALS AND METHODS
 Seeds were obtained from the following sources:
 CARDI Antigua
 Neotonia wightii syn. Glycine wightii
 Macropitilium atropurpurea
 BARTAD Bahamas
 Leuceana leucocephala var. K8


206


 Native St. Thomas
 Vigna luteola
 Teramnus labialis
 Naturalized St. Thomas
 Leuceana leucocephala
 All materials were grown at the College of the Virgin Islands,
 St. Thomas campus, on a Glynn clay loam. Soil tests by Agroser-
 vices International and CVI/CES showed similar results with the
 following nutrients listed below optimum. Averages of the
 analyses are as follows:
 K 34.0 meg/100 ml
 N 7.5 ug/ml
 P 7.5 ug/ml
 S 15.0 ug/ml
 Cu 2.7 ug/ml
 Fe 6.7 ug/ml
 Mn 4.0 ug/ml
 Zn .9 ug/ml
 Plant tissue tests were completed at the CVI/CES laboratory.
 New growth from established plants was analyzed. No soil
 amendments were added to these plots. On similar soils all
 species have shown a response in establishment and early growth
 to 110 kg/ha superphosphate. All species were in flower when
 samples were taken 2/84. Only results of bulk leaf and petiole
 samples are listed below.
 Owing to the extremely small sizes of plots and available
material and the lack of uniformity in the time of establishment
and plant density, absolute yields are not reported. Relative
yields once established were:
K-8 > L. leucocephala > N. wightii > V. luteola > M. atropur-
purea > T. labialis

Management and Use
Leuceana leucocephala Spontaneous in most parts of the island,
this plant provides an excellent protein source for animals. It is
also high in Ca. The local variety was richer per unit analyzed in
nearly all tests, but produced less per hectare owing to the
substantially higher yields of the K-8. K-8 is slow to become
established. Once established, however, K-8 is more tolerant of
frequent cutting. As a soil amendment, Leuceana is easy to
harvest, breaks down rapidly, and provides excellent shelter to
associated crops. It can easily become weedy.

 PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY-VOL. XX