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LEAFLET 87 DECEMBER 1973
Effect of Cutting and Irrigation
on Seed Yields of
Interstate Sericea Lespedeza
HOMER C. ADAMSON and E. D. DONNELLY'
SINCE ITS RELEASE in 1969 (3), Inter-
state sericea lespedeza has been widely
planted in t h e Southeastern United
States on highway rights-of-way and on
other areas where an attractive, low
growing perennial is needed for conser-
'Former Graduate Research Assistant, De-
partment of Agronomy and Soils, and now
Management Trainee, Gold Kist, Inc., Head-
land, Alabama; and Professor, Department
of Agronomy and Soils.
vation. Unfortunately, seed supply has
not been large enough to meet demand
for the new variety.
Lack of rainfall during critical growth
periods, a serious problem with many
crops in the Southeast, has limited Inter-
state seed production. Although sericea
can withstand relatively dry conditions,
irrigation could be expected to increase
seed yields in years of drought.
Sericea seed yields reported by sev-
AGRICULTURAL EXPERIMENT
R. Dennis Rouse, Director AUBURN UNIVERSITY
STATION
Auburn, Alabama
eral workers show wide variations. Un-
hulled seed yields were 400 to 600
pounds in Georgia (1) and 1,600
pounds per acre in Virginia (9). Yield
of hulled seed was reported to range
from 150 to 1,500 pounds in Tennes-
see (8).
Good sericea hay yields have been
reported, ranging from 2 tons per acre
when cut once a year at 12-inch height
(6) to 5 tons when cut twice a year
(2,7). In previous research at Auburn
(4,6), cutting hay early in the season
decreased seed yields. However, irri-
gation was found to increase seed pro-
duction (4).
Objectives of this study were to de-
termine the influence of cutting and ir-
rigation on seed yields of Interstate seri-
cea lespedeza.
EXPERIMENTAL PROCEDURE
Seed yield experiments were conduct-
ed during 1971-72 on 5-year-old stands
Water, inches
9.0 -
2.6
2.4
2.2 r
2.0
1.4
1.2 -
0.8-
0.6-
0.4-
0.2J
0
9.
I.
Rainfall
----Irrigation
I
I r II 1 ll 0 - I
July I b II 1 0 l 1 .. 1
total August
of Interstate sericea on Lucedale fine
sandy loam soil at the Foundation Seed
Stocks Farm, Thorsby, Alabama. A
large field of established sericea was
necessary so seed could be harvested
with a combine to duplicate farm condi-
tions. The only field of adequate size
available for this study was planted
partly broadcast and partly in 27-inch
The experimental area was divided
into plots of 20 x 150 feet. There were
four replicated plots - two broadcast
and two in wide rows - for each irri-
gation and cutting treatment. A split-
plot design was used. Seed were har-
vested from the following treatments:
(1) No hay cut - irrigated.
(2) Hay cut once when 12 to 15
inches tall - irrigated.
(3) No hay cut - not irrigated.
(4) Hay cut once when 12 to 15
inches tall - not irrigated.
I
I 6 II 16 21 27
October
S6 11 16 21 26
September
FIG. 1. Rainfall and supplemental irrigation from July until seed
of irrigation water is an average of four replications.
[2]
harvest in 1971. Amount
I , I, L J : IIl
bCCCVI~IILC ~-~rr ~V Irs~VCIV Uuu -v ~-----I
I A I L-.J-
Il
I I I I
Water, inches
1.8
1.6- -
1.4-
1.2
1.0
0.8
0.6
0.4
0.2
0-
July 
I
total
Rainfall
-- Irrigation
I I i
I I 
I
I I I I
I I I
I I I I
I 
I 
I
I 
I 
I 
I
I 
I II
1 ' L
II I
i I i I I I
6 11 16 21 26 31 I 6 II 16 2126
August September
FIG. 2. Rainfall and supplemental irrigation from July 
until seed harvest in 1972. Amount
of irrigation water is an average of four replications.
Seed from each plot were combine
harvested in October each year, and
yields are reported in pounds per acre
of hulled, cleaned seed. To estimate seed
loss during combining, small sub-plots
in each plot were hand harvested just
before combining in 1972. Thus, ac-
tual yields could be compared with com-
bine-harvested yields to provide loss fig-
ures.
Irrigation was done during August
and September each year, figures 1 and
2, with 50 per cent available moisture
level set as the point at which water
would be added. At field capacity, the
average available water per foot of soil
was 1.2 inches. Water loss under ser-
icea is about 0.2 inch per day on this
soil type (5). Therefore, if 1.5 inches
of rain fell in 1 day, irrigation would
be necessary approximately 7 days later
if no more rain fell during this 7-day
period. However, if the 1.5 inches were
followed by 2 inches of rain 1 or 2 days
later, much of the latter rainfall would
run off. Nevertheless, the soil most
likely would have reached field capac-
ity. Thus, the 0.2 inch per day water-
loss count would begin at 1.2 inches.
The moisture would be sufficient for
about 6 days, at which time supple-
mental irrigation again would be needed.
RESULTS AND DISCUSSION
Such weed species as fall panicum,
prickly sida, crabgrass, ragweed, and
signalgrass were abundant between rows
on plots that were cut for hay, particu-
larly in 1971 when there was more rain-
fall. In fact, weeds were already taller
than sericea when irrigation treatments
were begun on these plots in August
1971. The next summer was rather dry,
and weeds were no taller than the ser-
icea when 1972 irrigation treatments
were begun. There was no appreciable
weed competition on the uncut, wide-
row or on the cut or uncut, broadcast-
planted plots, Figure 3.
Combine-Harvested Seed Yields
Broadcast sericea that was neither
cut nor irrigated produced 860 pounds
of hulled, cleaned seed per acre in 1971
and 431 pounds in 1972, an average of
645 pounds, figures 4 and 5. As an
[31]
I 6 II
October
FIG. 3. Weed competition in Interstate sericea lespedeza varied according to treatment.
Uncut wide row (lower photo, left) and cut wide row (lower photo, right) are contrasted
with uncut broadcast (upper photo, left) and cut broadcast (upper photo, right). Photo-
graphed in mid-August, just after beginning of irrigation treatments.
average for the 2-year period, irrigation
increased the yield of broadcast, uncut
sericea by 33 per cent. During the dry
season of 1972, the increase from irri-
gation of broadcast, uncut sericea was 74
per cent, or 317 pounds.
Generally, seed yields from broadcast
sericea were higher than from wide-
row sericea, figures 4 and 5. This higher
yield is attributed to greater weed com-
petition in wide-row sericea, Figure 3.
Considering an average of both 
years,
irrigation did not increase seed yields
from wide-row sericea. During the dry
year of 1972, however, 
irrigating uncut,
wide-row sericea increased seed yields
by 7:3 per cent. This was a 269-pound
difference because of irrigation.
A single hay cutting each year in
May reduced average seed yields of
broadcast sericea from 751 to 340
ponds per acre, a 55 per cent de-
crease. On wide-row sericea the de-
crease amounted to 66 per cent, from
542 to 182 pounds per acre.
FIG. 4. Effects of cutting and irrigation on FIG. 
5. Effects of cutting and irrigation on
combine-harvested seed yields of Interstate 
combine-harvested seed yields of Interstate
sericea lespedeza in 1971 are illustrated sericea 
lespedeza in 1972 are illustrated
here. 
here.
Hand-Harvested Seed Yields
Hand-harvested seed yields were ex-
cellent, Figure 6. Despite the dry sum-
mer of 1972, broadcast sericea that was
not cut for hay produced 621 pounds
per acre of hulled, cleaned seed without
irrigation. Irrigation pushed this to
1,347 pounds, giving a 117 per cent
increase from the irrigation. Wide-row
sericea made higher seed yield than
broadcast sericea when hand-harvested,
except for the cut and irrigated treat-
ment.
Results were different with combine-
harvested sericea in 1972. More seed
were harvested from broadcast than from
wide-row sericea except for one treat-
ment (cut, nonirrigated). This reversal
was caused by weeds in the wide-row
plots. On wide-row plots that were
hand harvested, only sericea was 
cut
and weeds between rows were left.
With combine harvesting, however, all
plant material (sericea plus weeds) was
cut and forced through the combine.
Many of the seed were lost as excess-
ive plant material passed through the
combine.
In irrigated plots (where 
weeds pre-
sented the greatest problem), 
hand-har-
vested, wide-row sericea produced 
39
pounds more seed per acre than 
broad-
cast sericea, Figure 6. When 
combine
harvested in 1972, however, 
wide-row
sericea produced 79 fewer 
pounds of
seed per acre than broadcast 
sericea,
Figure 5. Approximately twice 
as much
seed was produced on uncut, 
wide-row
sericea when irrigated than if 
nonirri-
gated, (1,463 vs. 753 pounds 
per acre),
Figure 6. Weed competition 
was much
less on wide-row sericea that was 
uncut
than on the cut treatment, Figure 
3.
One hay cutting in May 
reduced seed
yields considerably on both 
broadcast
and wide-row sericea, Figure 
6. Broad-
cast sericea left uncut (average 
of irri-
gated and nonirrigated) produced 
984
pounds per acre of hulled, cleaned 
seed.
When cut, however, broadcast 
sericea
made only 309 pounds, 
a 675-pound
yield reduction. Wide-row 
sericea suf-
fered even more pronounced 
yield re-
[51
FIG. 6. Effects of cutting and irrigation on
hand-harvested seed yields of Interstate
sericea lespedeza in 1972 are illustrated
here.
duction from cutting. Uncut sericea
produced 1,108 pounds of seed while
that cut yielded only 376 pounds, a de-
crease of 732 pounds. These data indi-
cate that sericea in rows as wide as
those in this experiment should not be
cut for hay.
Considering all treatments in 1972 on
both broadcast and wide-row sericea, an
average of 391 pounds of hulled, cleaned
seed was combine harvested, Figure 5.
Hand-harvested sericea, however, pro-
duced an average of 694 pounds, Figure
6. This indicates that slightly more
than half of the seed produced (56 per
cent) were harvested by the combine.
The remaining 44 per cent may be ac-
counted for partially through shatter
loss from the combine reel and cutter
bar and inefficiency of the combine in
separating seed from the remaining
plant parts.
In 1972, hand harvest of nonirrigated,
uncut, broadcast sericea produced 621
pounds of hulled, cleaned seed per acre,
Figure 6. When combine harvested,
yield was 431 pounds per acre of seed,
Figure 5. This indicates that only 69
per cent of the seed actually produced
were combined.
Forage dry matter yield from one hay
cutting each May of the 2-year period
averaged 3,000 pounds per acre.
Results of this study indicate that
several factors are important in efforts
to get maximum Interstate sericea seed
yields.
(1) Broadcast plantings were less
weedy than wide row sericea, and weed
competition interferes with sericea seed
harvest.
(2) Yield data indicate it would be
more profitable to harvest Interstate
for seed only. Hay from a May cutting
would be much less valuable than seed
that would be sacrificed by the hay cut-
ting.
(3) Proper timing of seed harvest and
combine efficiency also must be consid-
ered. Optimum seed harvest time in
central Alabama is October 10 to 15.
(4) Results also indicate that irriga-
tion can effectively increase seed yields
during seasons of low rainfall or poor
rainfall distribution. Droughty condi-
tions such as prevailed in the summer
of 1972 might be expected in 5 of 10
years in central Alabama (10).
SUMMARY
Cutting and irrigation treatments were
applied to established broadcast and 27-
inch row stands of Interstate sericea
lespedeza to determine their influence
on seed yields. Seed were both com-
bine and hand harvested.
Irrigation increased 2-year average
combine-harvested seed yields of uncut,
broadcast sericea 211 pounds per acre
(857 vs. 646 pounds) but had no
effect on wide-row sericea. With well-
distributed rainfall in 1971, there was
no increase from irrigation on either
broadcast or wide-row sericea. In 1972,
however, rainfall was limited and irri-
gation increased combine-harvested seed
yields of uncut sericea from 431 to 748
pounds per acre. Generally, combine-
harvested seed yields were higher from
broadcast than from wide-row sericea.
[61
Irrigation more than doubled the
hand-harvested seed yields from uncut,
broadcast sericea. Production was 621
pounds per acre without irrigation and
1,347 when irrigated.
For the 2-year period, one hay cut-
ting in May each year reduced combine-
harvested seed yields of broadcast se-
ricea from 751 to 340 pounds per acre;
the reduction on wide-row sericea was
from 542 to 182 pounds.
Hand-harvested yields showed that
only about half of the seed actually
produced in 1972 were gathered by the
combine. The other half was lost
through shatter loss from the combine
reel and cutter bar and inefficiency of
the combine in separating the seed from
other plant material.
Forage yields from one hay cutting
in May averaged 3,000 pounds of dry
matter per acre during the 2 years.
Acknowledgments
Sincere appreciation is expressed to
Basil D. Doss, Soil Scientist, USDA,
ARS, and to G. T. Sharman, Jr., Super-
intendent, and other employees of the
Foundation Seed Stocks Farm, Thors-
by, Alabama, for their assistance in con-
ducting the research. Thanks also are
due the reading committee for their
suggestions in preparing this manuscript.
Literature Cited
(1) BAILEY, R. Y. 1951. Sericea in Con-
servation Farming. USDA Farmers
Bull. 2033.
(2) DONNELLY, E. D. 1963. Serala - A
New Sericea Variety. Auburn Univ.
(Ala.) Agr. Exp. Sta. Leaf. 70.
(3) . 1971. Registration
of Interstate Sericea Lespedeza. Crop
Sci. 2:601-602.
(4) AND R. M. PATTER-
SON. 1969. Effect of Irrigation and
Clipping on Seed Production and
Chasmogamy of Sericea Genotypes.
Agron. J. 61:501-502.
(5) Doss, BASIL D., O. L. BENNETT, D. A.
ASHLEY, AND H. A. WEAVER. 1962.
Soil Moisture Regime Effect on Yield
and Evapotranspiration From Warm
Season Perennial Forage Species. Agron.
J. 54:239-242.
(6) DUGGAR, J. F. 1936. Studies on Les-
pedeza Sericea. Ala. Poly. Inst. (Ala.)
Agr. Exp. Sta. Ann. Rpt. 47.
(7) HOVELAND, C. S., W. B. ANTHONY, AND
F. T. GLAZE. 1972. Managing Seri-
cea for Forage. Auburn Univ. (Ala.)
Agr. Exp. Sta. Highlights of Agr. Res.
Vol. 19, No. 1
(8) MOOERs, C. S. AND H. P. OGDEN. 1935.
Lespedeza Sericea. Tenn. Agr. Exp.
Sta. Bull. 154.
(9) PIETERS, A. J., P. R. HENSON, W. E.
ADAMS, AND A. P. BARNETT. 1950.
Sericea and Other Perennial Lespedezas
for Forage and Soil Conservation.
USDA Cir. 863.
(10) WARD, HENRY S., C. H. M. VAN BAVEL,
J. T. COPE, JR., L. M. WARE, AND
HERMAN BOUWER. 1959. Agricultural
Drought in Alabama. Ala. Poly. Inst.
(Ala.) Agr. Exp. Sta. Bull. 316.
[7]