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Agronomy Research Report AY83-10
Plant Nutrient.and Quality Analysis of A Wild Legume From The
Highland Rim Area of Central Tennessee '
-BY .. .
Raymond Noel Gallaher and K. L.- Buhr, Associate and- Assistant
Professors of Agronomy, Department of Agronomy, Institute of Food and
.Agricultural Sciences, University of Florida, Gainesville, Fl. 32611.
SLegumes have long been valued for their capacity to supply their
own N requirements through the symbiotic'relationship with N-fixing
bacteria (Rhizo biumn).,: The-'legume family comprises a large group of
plants that are utilized by. man as-a source of high quality dietary
Protein .and as a soruce of high quality forage for domestic animals.
S: .For: these reasons'man.. has long sought, selected and improved plants
:.i found growing rin 'the.wi:ld.'j-- .: ; :..
: This study was undertaken to analyze-and report -on a wild
legume, :thought to be --a summer annual, found 'growing -in .the Highland
Rim:area -of Central Tennessee. .. :-. t
MATERIALS AND IETHDDS
In early -September of .1979, vegetative and reproductive samples
'of the wild legume were collected on the Gallaher Angus Farms near
Waynesboro, Tennessee. Residents of the -area. refer to the plant as
"wild pea" and in other areas it has been referred to as "hog
peanut". Long time -residents of- the Waynesboro, Tennessee area
report that before domestic animals were confined to fenced pastures,
sheep and cattle sought out this wild legume.: No analytical analyses
or animal studies are known to exist to explain this grazing
: .preference:by riuminants.;: : -,-" :_ ---
: .About 50 -plants were sampled i from near ran old stream where the
.--:senior authors has .known of :-the-legurre growing through volunteer
S:- reestablishment ifor over ,30. .years. ISamples 'of both ,above-'and below
': ground:parts were- collected;F Additional sampling and collection of
seeds .was -. accomplished iLin 1980, by the -senior author's mother
S(Margaret Gallaher) -and .'stored for later use. Samples were preserved
and transported to the University of Florida for *analysis and
testing. Ten whole plant samples were.separated into :leaf, stem, and
Soot :divisions; -In: separate experiments- at' the -University of
-Florida, plants-of peanut (Arachis hypogaea:L. "Florunner"), soybean
Si (Glycinemax 'L. Merr;. "Cobb".), hairy vetch- (Vicia villosaa, Roth),
-oats (Avena sativa L.'"Florida 301"),'. wheat -(Triticum aestivum L.
"Holley"), and rye (Secale cereale L. "Wrens-Abruzzi) were collected
at-the'early bloom stage and separated into leaf,:stem,-and :roots for
.; comparison in-dry matter-ratios and :chemical analyses. ;.
-. .. -.. -. .. ...- -'. ." .'
S" .. ... .
The plant parts and additional whole plants were dried at 70 C
for 48 hours in a forced air oven and weighed. The leaf to stem ratio
was determined followed by the grinding of sample to pass a 1 nm
stainless steel screen using a Wiley mill. Dry ground samples were
stored in air tight plastic containers for subsequent laboratory
analyses. For plant mineral analysis, samples were ashed in a muffle
furnace at 480 C for a minimum of 4 hours, treated with H-1, and
subsequently brought to volume using 0.1 NI HCl. Phosphorus was
determined colorirnetrically, K by flame emission spectrophotometry,
and Ca, Mg, Zn, Cu, Mn, and Fe by Atomic Absorption
Spectrophotometry. Nitrogen was determined by an automated procedure
after treatment according to Gallaher et. al (1975 and 1976). A
S 100-rg sample of .the dry, ground ,.tissue was placed into 75-ml pyrex
test tubes. IThese samples were ,digested in a mixture, of 10 ml
concentrated H2S4, .2 ml of H202, and 3.2 g of a salt-catalyst
mixture (90% K2504: 10% CuS04) with three boiling chips for 2.5 hours
S .on an aluminum block heated to 385 -C. The digested liquid was then
:diluted' to 75 ml with.distilled water and analyzed- for N. the
invitro organic matter digestibility. .(IVCMD) was determined in the
Agronomy Research Support Laboratory, University of Florida, Using
modifications. of the Tilly and Terry (1963) two. stage invitro
digestion procedure. The IVOMD, and CM was not determined on peanut
and soybean, the K, Ca, Mg, Cu, Zn, Mn, and Fe were not determined on
vetch, oats, wheat, and rye.
At the time of sampling in 1979, numerous photographs were taken
of the wild legume, including leaves, -stems, roots, and reproductive
parts. By. the -use;of. photographs and preserved plants _the wild
legume was identified. i. -.- -.
RESULTS AND DISCUSSION
Phenotypic Description *
The wild legume is a twining, climbing vine-type plant, growing
to an extended height -of.1- to 2 m. iPinnately compound leaves are
primarily trifoliolate and have :-soewhat obscure stipules. The
flowers, borne in axillary racemes, are various shades I'of purple.
-Two:kinds of-fruit, one 'above and the other below ground.are produced
by the plant. -The above ground fruit is a several-seeded -pod. The
underground. form is usually -aone-seeded fruit -produced by an
Sapetalous flower. : .
Wild legumes of this plant's description appear.variously in the
literature (Britton and Brown, 1913; Fernald, i1950; Gleason and
Cronquist, 1963; Radford et al., 1965; Sanders et al.,- 1962; Small,
1903; and Wilbur, 1963). There is some overlapping of descriptions
and nomenclature. Wilbur, (1963)'describes a plant meeting this
plant's description, Amphicarpa bracteata (L.) Rickett and 'Stafleu.
* The generic name was derived from the Greek amphi, meaning "both" and
carpos -meaning."fruit", in referencento the two types ;of fruit. This
species of the wild legume hasbeen considered to be composed of two
varieties, whose ranges cover much of the eastern United States, and
Canada, from Nova Scotia and Quebec down to northern Florida, and
Amphicarpa bracteata var bracteata was describe
(1963) as follows:
"Stems capillary with closely reflexed
short-pubescence; median stipules about
3 mn long; leaflets thin and minutely
strigose on both surfaces, the terminal
mostly 2-6 an long; racemes 1-8- flowered,
usually unbranched; floral bracts 2-2.5 mn
long; the lower exceeded by the pedicels;
flower-s 9-13 rrm:long; calyx-tube 4-5 mn
long;-blade of keel-petals longer than
the claw; legumes.l.5-3 on long, glabrous
on the face, pubescence towards base
of lower suture antrorse."
Arphi'carpa bridteata var comosa was described as follows:
S "Stem coarser with spreading villous pubes- .
cence; median stipules about 4-5 mn long;
leaflets firm and densely and conspicu- --
ously pubescent, the terminal-mostly 5-10
cm long; racemes 7-17-flowered, often
branching; floral bracts 2.5-3.5 mn long,
the lower exceeding the pedicels.; flowers
" :'" '11-16 mn long; calyx-tube 4.5-6 mn long;
blade of keel-petals about equal to the
claw; legumes 2-4 on long, often with stri-
S" i gose faces, pubescence :towards the base of
the lower suture retrorse."
Reporting that although the extremes are. striking, the
intermediates are so abundant so as to defy .a distinct separation
into two groups. Wilbur concludes that a formal subspecific taxa is
Using classification nomenclature typical.- of ;the older
literature,~ -Small--(1903)- -describes- a plant -with. _the above
characteristics, listing it as Falcata cornsa.- .(L.) Kuntze,
cross-referencing-it as Amphicarpa Ell.
Chemical Analyses ---
S The leaf and stem dry matter weights of a 10 plant sample of
the'-wild legume at-'the full bloom and early pod set stage of growth
was 58.8 and 34.0 g, respectively. This .is a 1.73 leaf to stem
rat'io: Using these data, thetabove ground average weight per plant
would be 9.28 g.
Data in table I gives the breakdown for minerals and quality
relationships for the wild legume.
Table 1. Chemical analysis of Amphicarpa bracteata plants collected
from the southwest Highland Rim area of central Tennessee, during
early- pod fill stage.
Analysis Plant Part
Roots Whole Plant
M % 88.72 .91.09 87.58 90/80
CMAR % 79.24 84.82- 79.58 80.79
GO % 89.31 93.11 ..90.87 88.98
I VMD % 60.87 55.37 46.59 57.82
N % -3.68 .1.78 .2.01 2.65
P % 0.22 0.19 .,0.21 0.24
K % 1.09 1.31 :1.. 11 1.42
Ca % 2.00 1.26 1.50 1.73
-Mg % 0.50 0.42 .. :0.41 0.41
Cu ppm 22 16 23 20
Zn ppm 50 -28 30 40
Mn ppm 76 43 67- 120
Fe ppm 265 65 .480 360
Average of two replications.
One of the attributes of the wild legume may be the relatively
high whole plant percent digestibility (Table 1.). It also has a
very favorable percent crude protein of over 16% (6.25 X percent N).
The percent digestibility and crude.protein of the wild legume are
comparable to that of cultivated peanuts analyzed at a similar stage
of growth (Table 2). A comparison of N and other elements between
the wild legurme (Table 1) and -cultivated peanut show notable
' 'similarities. -
Table 2. Chemical analysis of Florunner peanut at the early pegging
stage of growth. -
Analysis : -. : Parts i
Leaf Stem Root Whole Plant
DM/plant g 12.30 9.68 0.86 23.14
O N % '-i,! '. r :3.99--: 0 1.74 2.38 .-2.94
P % 0.26 0.19 0.20 0.23
K %' 1.62 1.79 1.00 1.65
Ca % 1.56 0.71 .0.76 1.16
Mg % 0.59 0.47 0.51 0.53
Cu ppm 71 33 27 53
Zn ppm 112 91 138 103
Mn ppm 120 25 24 75
Fe ppm 245 90 348 181
Average of eight replications.
Table 3. Chemical analysis of late-planted Cobb soybeans
early pod set.
Leaf Stem i Root Whole plant
EM/Plant g 2.54* 1.29 0.96 4.79
N% 4.01 2.15 1.61 3.03
P:% 0.41 0.42 0.30 0.39
K % 2.21 2.07 1.16, 1.96 .
Ca % 1.21 .0.80 0.46 0.95
Mg % 0.42 0.36 0..17 0.35
Cu ppm 10.50 9.50 10.50 10.23
Zn ppm 48. ., 29 --, 28 39
Mn ppm 54 18 : 26 : :39
Fe ppm 345 :233 .- 731: 392
S: Average of eight replications. :
Table 4. Chemical analysis of vetch, oats, heat, and ry
early bloom stage of growth..
Analysis Plant part
Leaf Stem Root Whole Plant
Sarple DM g .-45.50 *. -51:60 -2.06 99.16
IVKMD % 78.48 63.19 r58.66 70.11
CM % 96.95 93.79, 88.35 95.14
N % 4.02 :-2.38 : ,2.12 3.13.
P % -: 0.40
Sample EM g 59.19
IVOMD % 66.04
Cl % 88.58
N % 2.02
P % 0.28
Sanple DM g ..... 64.67:
IVCMD % -: 62.61'
CM % : :;.91.68
N %' : 1.75
P % 0.29
": Wheat t
;:0.17: .- -:. 0.28
Sample EM g 96.66 73.59 27.01 194.56
IVOMD % 56.99 49.84 40.63 52.24
CM % 93.15 96.47 66.13 91.03
N % 1.54 1.22 0.70 1.32
P % 0.20 0.27 0.25 0.23
* Average of four samples.
-Analyses are given for other -domesticated legumes and grasses
that are often used for ruminant forages (Tables 3 and 4). It is
noteworthy that the wild legume (Table 1) compares favorably to these
annual -legumes- in digestibility,--elemental composition,-and crude
protein (Tables 3 and.4).
A comparison of.the wild legume with several cultivated legumes
and grasses indicate.there should be no reason why the wild legume
should not be considered for research to improve usefulness to man.
The legume.might be-much rrore competitive' than some of the cultivated
legumes because of the dual mechanism of reproduction. It thrives
well in the wild and.has been observed to maintain its growth for
over 30 years in the same area on the Gallaher Angus Farms in central
Tennessee. This would imply that the legume seeds above ground are
hard seeded which would preserve well in the soil for long periods of
time-and/or that the underground-reproductive-seeds-aid--in- survival
of this legume species. In .either-case this- would -be beneficial
under animal grazing conditions where the animal may disturb above
ground reproduction: and reseeding::could come back. from either the
hard above ground seed or from the.underground parts.
--Since-the---legume--grows--naturally along streams and -in moist
areas in the wild it may-be adapted to the vast wet -areas of the
world such as the flatwoods of Florida. One other characteristic
that may be -in the wild legume's--favor is its :tendency to vine and
twine up weeds and existingicompeting weeds. This indicates that the
wild legume would be very competitive with weeds.
Because of the favorable chemical composition, dual mechanism of
reproduction, a tendency for -.shade tolerance, and the vining
competitive nature, this wild .legume should receive -additional
research to explore its potential as a cultivated forage legume.
More work is needed to-'describe the, reproduction, growth,
germination,:and grazing aspects.of: the plant. The-authors- hope to
conduct other studies.to explore'its potential.
S. P.KNC .. EDGVENTS
Acknowledgments are :extended to the late Mr. Claude Walter
Grimes of -Waynesboro:,Tennessee-for his insistence that the senior
author -conduct research on "Wild Pea" for its potential as a
cultivated forage legume and to Mrs. Margaret Grimes Gallaher of
Waynesboro, Tennessee for her .assistance. in the collection and
storage of plant and seed material for research use by the authors.
1. Britton, Nathaniel Lord and H. Addison Brown. 1913. An
Illustrated Flora of the Northern United States, Canada, and the
British Possessions, Second Edition. Charles Scribner's Sons, New
York. Volume II. pp 418-419.
2. Fernald, Merritt Lyndon. 1950. Gray's Manual of Botany, Eighth
(Centennial) edition-Illustrated. Arerican Book Co. New york. pp
3. Gallaher, Raymond Noel, C. 0. Weldon, and 3. G. Futral. 1975.
An Aluminum Block Digester for Plant and Soil Analysis. Soil Sci.
Soc. An. Proc. 39:803-806.
4 Gallaher, Raymond Noel, C. 0. Weldon, and F. C. Boswell. 1976.
A Seniautomated Procedure for Total Nitrogen in Plant and Soil
Samples. Soil Sci. Soc. Amer. 3. 40:887-889.
D. Van Nostrand
Henry A. and Arthur Cronquist. 1963. Manual of
of Northeastern United States and Adjacent Canada.
Co., Inc. Princeton, New Jersey. p 427.
Manual of the
Albert E., Harry E.
Vascular Flora of
Press,. Chapel Hill.
Ahles, and C.
7. Sanders, Albert N., Laura Smith Ebauch, and
1962. Botanical Gardening in Greenville.
Greenville, South Carolina. p 28.
Ritchie Bell. 1965.
The University of
C. Leland Rodgers.
8. Small, 3ohn Kunkel. 1903. Flora of the Southeastern United
States. Published by the Author, Museums and Herbarium of the New
York Botanical Garden, New York. pp 650-653.
9. Tilly, 3. M. A., and R.
for the in vitro digestion
A. Terry. 1963.
of forage crops.
Br. Grassl. Soc.
10. Wilbur, Robert L. 1963. The Leguminous Plants of
Carolina. North Carolina Agricultural Experiment Station,
Carolina State University, Raleigh. pp 269, 271.