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Regrowth of 'Ladak' Alfalfa on PinyonJuniper Rangelands Following Various
Timing and Types of Spring Use
Richard Stevens
Scott C. Walker
Stuart Wooley
Abstract-Drought tolerant alfalfa is the most abundantly seeded
forb on Utah pinyon-juniper ranges. It is eagerly sought after by all
classes of grazing animals. Generally, mule deer and elk utilize
areas seeded to alfalfa during winter, early spring and fall, whereas,
cattle and sheep generally use the same areas during mid spring to
early summer and fall. Alfalfa in some seedings has been lost
through year after year late May and June use. In order to properly
manage and maintain alfalfa on rangelands it is imperative we
know the effect of timing, type, and amount of use on regrowth and
subsequent plant vigor. On a deer and elk winter and spring pinyon
juniper range that had been chained and seeded 20 years earlier,
sheep were grazed at differing periods. Grazing effect on alfalfa
forage regrowth and seed production was evaluated. With grazing
of alfalfa up to May 15, some regrowth offorage and seed production
did occur. Little regrowth was evident when grazing occurred after
May 15. Lack of regrowth does not allow alfalfa plants to maintain
and replenish themselves and to produce seed.
For over 40 years, drought tolerant range alfalfa has been
the most abundantly seeded forb on western pinyon-juniper
ranges receiving over 25 cm annual precipitation (Rumbaugh
and Townsend 1985; Stevens and Monsen In press). The
most commonly seeded rangeland cultivar is 'Ladak'. The
most persistent and best performing cultivars have been
'Ladak' and 'Nomad.' These cultivars have persisted on
many seedings for over 28 years (Kilcher and Heinrichs
1965; Rosenstock and Stevens 1989), however on some
seedings their persistence has been somewhat less. The
decrease in density that occurred, has been a result of
continuous heavy rabbit use and continual spring sheep and
cattle use (Stevens and Monsen In press; USDA 1971).
Rangeland cultivars are especially well adapted to the
sagebrush grass, pinyon-juniper, and mountain brush types.
They have also been seeded and have done fairly well in the
aspen, spruce-fir, and subalpine types (Stevens and Monsen
In: Monsen, Stephen B.; Stevens, Richard, comps. 1999. Proceedings:
ecology and management of pinyon-juniper communities within the Interior
West; 1997 September 15-18; Provo, UT. Proc. RMRS-P-9. Ogden, UT: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research
Station.
Richard Stevens was Project LeaderlResearch Biologist (retired); Scott C.
Walker is Research Biologist, Division of Wildlife Resources, Great Basin
Experiment Station, Ephraim, UT 84627; Stuart Wooley is a graduate
student, Brigham Young University, Provo, UT.
352
In press). Once established, alfalfa can be very persistent
and can produce adequate seed to maintain itself(Rumbaugh
1982). However, little reproduction has occurred from established stands on rangeland sites due to poor seed production
and consumption of seed by rabbits, rodents, livestock and
big game (Rosenstock and Stevens 1989). Rhizomatous forms
do however spread vegetatively, even under arid conditions
and grazing pressure. In fact, grazing has been shown to
stimulate rhizome production (Rosenstock and Stevens 1989).
Drought tolerant alfalfa cultivars have not exhibited much
regrowth or subsequent seed production following moderate
to heavy spring use. Spring use could result in very few seeds
being produced. Big game, livestock, and rodents readily
consume seed heads in the fall. These two factors, combined
with the fact that alfalfa seed requires seed coverage adversely affects sexual reproduction.
Alfalfa is sought out extensively by cattle, sheep, deer, elk,
rodents and rabbits. Basal leaves can be green throughout
winter months. New growth starts prior to snow melt and
generally becomes available mid February to early March.
Big game generally migrate off pinyon-juniper areas by mid
May. Livestock grazing generally occurs from May through
June. Fall use by big game and livestock most often starts in
early October. It has been observed that when extended
spring use occurs, there is little or no succulent forage
available in the fall and that little if any seed is produced.
Succulent fall forage is a key to healthy big game and for
keeping big game out of cultivated fields.
Methods -----------------------------------Two hundred hectares of pinyon-juniper east of Ephraim,
Utah were chained and seeded to a mixture of grasses, forbs,
and shrubs in 1969. The area receives an average annual
precipitation of 32 cm. 'Ladak' alfalfa was a major component (2.8 kglha) of the seeding. In 1989, 20 years after
seeding, this study was conducted. Deer and some elk
utilized the seeding throughout the winter and spring. Even
with the late spring, a majority ofthe deer and all the elk had
left the area by May 15. Sheep were allowed on the area
May 15 through June 25. Eighteen baskets were set out on
four different dates between September10, 1989 and June 4,
1990 (total 72 baskets). Each basket was randomly placed
over one to five alfalfa plants. Adjacent to each basket a like
number of alfalfa plants were identified and marked. Baskets were round, rodent proof, and 1.5 m in diameter. Dates
baskets were placed, moved and removed determined grazing periods. Grazing treatments were:
USDA Forest Service Proceedings RMRS-P-9. 1999
Treatment
Date
baskets on
A
Sept. 10, 1989
Sept. 15, 1990 No use all year
B
May 15, 1990
Sept. 15, 1990 Spring deer and elk
use to May 15
C
June 4, 1990
Sept. 15, 1990 Spring deer and elk
use to May 15; and
May 15 to June 4
sheep use
D
May 15, 1990
June 4, 1990
Spring deer and elk
use to May 15 and
June 4 to June 24
sheep use
No baskets
No baskets
Year long use;
sheep, deer, and elk
Control
Date
baskets off
and elk (Treatments B,C,D and Control) showed extensive
use and averaged less than 20 mm in height. On June 24
when the sheep were removed, grazed alfalfa plants averaged less than 15 mm in height. No use occurred after June
24 to harvest on Sept. 15.
Timing of use significantly influenced the amount of
regrowth that occurred. Plants that were not grazed all year
(Treatment A) produced an average of 318 grams of stem,
leaves, and seed (table 1). Plants only exposed to deer and elk
use up to May 15 (Treatment B) produced significantly less
(104 grams) regrowth than plants protected all year (Treatment A), and significantly more than those exposed to use
after May 15 (Treatments C and D), and year long use
(Control) (table 1). Ungrazed plants (Treatment A) produced
produced more seed (111 grams) than plants that were
grazed (treatments B, C, D, and Control) (table 1). Leaf
and stem production accounted for the majority of the
regrowth on grazed plants (table 1). Ifplants were grazed in
the spring or year round grazed, little seed (0.7 to 14 grams
depending on treatment) was produced (table 1).
Grazing date
On September 15, 1990, identified alfalfa plants under
baskets and adjacent to them were clipped to ground level.
Number of stems with seeds were identified. Leaves and
seeds were removed from stems. The length of each stem was
determined. Stems, leaves, and seeds were air dried and
weighed. Data was analyzed with one way ANOVA (p < .05).
Results
Conclusions -----------------------------'Ladak' alfalfa can and has been maintained in pinyonjuniper chainings and seedings for over 30 years. Year after
year, continued early to late spring use by livestock has
resulted in loss of alfalfa in some seedings.
When alfalfa is grazed into the spring, little regrowth
takes place which is needed to maintain and replenish the
------------------------------------
All elk and essentially all deer had moved off the area by
May 15. When the sheep (ewes with lambs) were put in the
area on May 15 alfalfa plants that had been available to deer
Table 1-'Ladak' alfalfa growth and regrowth. Average total leaf, stem and seed production, length of stems. and number of stems with seeds
per plant on September 15 as influenced by five grazing treatments.
Grazing
treatment
Leaf
production (g)
Stem
production (g)
Seed
production (g)
Stem
length (mm)
No. stems
with seed
318 A*
77 A
130A
111 A
287 A
5.10A
104B
38 M
52 B
14B
197B
0.95 B
C:
Spring
deer and elk
use to May
15 and May
15 to June 4
sheep use
34 c
15B
18c
0.7B
93c
0.07B
D:
Spring
deer and elk
use to May
15 and June
4 to June 24
sheep use
48 c
19B
26 c
3B
100c
0.18 B
Control:
Year round use
35 c
14B
14c
1B
59 D
.07B
A:
Total
production (g)
No use
all year
B:
Spring
deer and elk
use to May 15
'Number within column followed by the same letter are not significantly different (p < .05).
USDA Forest Service Proceedings RMRS-P-9. 1999
353
plant through the summer, fall, and winter, and to produce
seed for reproduction. Likewise, with no spring regrowth,
little forage or seed is available for fall and winter use by big
game and livestock.
This study demonstrates that grazing to May 15 significantly reduced subsequent regrowth of forage and seed
production and use after May 15 reduced forage and seed
production even further. Early and late spring grazing
results in essentially no seed production. In order to maintain vigorous plants of drought tolerant alfalfa cultivars, it
is recommended that spring grazing by livestock should not
extend beyond May 15 and not occur in consecutive years.
Acknowledgments
::'-
Funds were provided through Federal Aid in Wildlife
Restoration Project W82R, Study 8 and Rocky Mountain
Research Station, Forest Service, U.S. Department of Agriculture, Provo, Utah.
354
References __________
Kilcher, M. R; Heinrich, D. H. 1965. Persistence of alfalfa in
mixtures wi th grasses in a semiarid region. Canadian Journal of
Plant Science. 46:163-167.
Rosenstock. S. S.; Stevens, R. 1989. Herbivore effects on seeded
alfalfa at four pinyon-juniper sites in central Utah. Journal of
Range Management. 42(6):483-490.
Rumbaugh, M. D. 1982. Reseeding by eight alfalfas populations in
a semiarid pasture. Journal of Range Management. 35:84-86.
Rumbaugh, M. D.; Townsend, C. E. 1985. Range legume selection
and breeding in North America. In: McArthur, E. D.; Carlson, J.
R, eds. Proceedings selected papers presented at the 38th annual
meeting of the Society for Range Management; 1985 Feb. 11-15,
Salt Lake City, UT. Denver, CO: Society for Range Management.
137-147.
Stevens, R; Monsen, S. B. In press. Alfalfa. In: Monsen, S. B;
Stevens, R, eds. Restoration and revegetation of western ranges
and wildlands. Rocky Mountain Research Station, Gen. Tech.
Report.
U.S. Department of Agriculture. 1971. Management and use of
alfalfa. In: Conservation Plant Handbook. Washington, DC: U.S.
Department of Agriculture, Soil Conservation Service.
USDA Forest Service Proceedings RMRS-P-9. 1999