august, 1987 - ttu-ir.tdl.org
TRANSCRIPT
EFFECTS OF SHORT-DURATION GRAZING TRAMPLING ON
SEEDLING EMERGENCE AND SOIL STRENGTH
by
JEFFREY RICHARD WEIGEL, B.A.
A THESIS
IN
RANGE SCIENCE
Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for
the Degree of
MASTER OF SCIENCE
August, 1987
1 •" ^ . i
thr t\U ff^r-^ ACKNOWLEDGEMENTS
I thank Dr. Carlton M. Britton, chairman of my graduate
cor:r.-:ittee, for his support and friendship during this study.
The members of my graduate committee, Drs. Bill E. Dahl,
B.L. Allen, and David B. Wester offered invaluable and much
appreciated assistance. Mr. Dan Griffis generously enabled
use of his ranch as a study site. John Pitts of the Texas
Tech Experimental Ranch provided welcome logistical support.
For their friendship, encouragement, and help I thank Guy
McPherson, Allen Rasmussen, Perry Grissom, Bob Masters,
Gretchen Scott, Craig Olawsky, Sheila Merrigan, Colleen
Schreiber, Sergio Soltero, Tony Leif, Meg Addison, Greg
Reeves, Jim Bergan, Doug Sheeley, and Jim Walters.
Financial support for this study was provided by the
Texas Noxious Brush and Weed Control line item. Dr. Henry
A. Wright also provided financial assistance.
I would like to thank my colleagues at The Nature
Conservancy for encouraging me to return to school and for
arranging my leave of absence.
I wish also to thank my parents, Richard and Elizabeth
Weigel, for their constant support. Finally, special thanks
and love to Mary and Moses Robert Candee for all they have
given.
11
TABLE OF CONTENTS
ACKNOWLEDGEMENTS ii
ABSTRACT v
LIST OF TABLES vi
LIST OF FIGURES viii
CHAPTER
I. EFFECTS OF SHORT-DURATION GRAZING TRAMPLING ON SEEDLING EMERGENCE OF BROADCAST-SEEDED KLEINGRASS
(PANICUM CQLQRATUM L.) 1
Materials and Methods 3
Results and Discussion 9
Conclusions 15
II. EFFECTS OF SHORT-DURATION GRAZING ON ANNUAL FORB
AND GRASS SEEDLING EMERGENCE 17
Materials and Methods 19
Results and Discussion 23
Conclusions 27
LITERATURE CITED 28
APPENDICES
A. SOIL PROFILE DESCRIPTIONS 34
B. SOIL TEXTURE DATA 3 9
C. BASAL COVER OF PERENNIAL GRASS SPECIES 41
D. PRECIPITATION, TRAMPLING TRANSECT, AND KLEINGRASS EMERGENCE DATA, AND KLEINGRASS ANALYSIS OF VARIANCE TABLES 4 3
E. ANALYSIS OF VARIANCE TABLES FOR SOIL STRENGTH DATA 50
1 1 1
F. FREQUENCY DATA FOR ANNUAL FORB AND GRASS SPECIES 53
IV
ABSTRACT
Emergence of broadcast-seeded kleingrass (Panicum
COloratum L. 'Selection 75') and of native annual forbs and
grasses was compared for two seasons in short-duration
grazed areas and ungrazed exclosures. Stocking rate in
short-duration grazed areas was 2.0 and 1.5 times recommen
ded in 1985 and 1986, respectively. Kleingrass emergence
was similar between treatments in both years. Emergence was
unrelated to percent foliar cover of preexisting vegetation.
In both study years, soil strength was greater in grazed
areas. Short-duration grazing provided no beneficial effect
on kleingrass emergence or soil strength in either year.
Emergence did not differ by treatment in either year for
five of ten species of annual forbs and two species of
annual grass. Common broomweed fXanthocephalum dracuncu-
loides (DC.) Shinners.], Texas filaree (Erodium texanum
Gray.), and meadow flax FLinum pratense (Nort.) Small.] were
more abundant in the grazed treatment in one year, while
bitterweed (Hymenoxys odorata DC.) emerged more frequently
in ungrazed areas in one season. Short-duration grazing at
the stocking rates used did not consistently improve or harm
emergence of any of the annual species studied.
LIST OF TABLES
1.1 Rainfall prior to kleingrass emergence events in 1985 and 1986, and deviation from long-term average. 10
1.2 Hoofprint intercept means (SE) by date and mean (SE) kleingrass seedling density by date and treatment, 1985 and 1986. 11
1.3 Mean (SE) soil strength by date, grazing cycle stage, and treatment, 1985 and 1986. 13
1.4 Mean (SE) soil strength by date in hoofprints and areas without hoofprints, 1986. 14
2.1 Scientific, common, and code names of annual forbs and grasses studied, 1985-1987, 22
2.2 Percent frequency of annual forb and grass species
by season and treatment, 1985-1987. 25
B.l Soil texture data for study site soils. 40
C.l Percent basal cover of bare ground, mulch, and perennial grasses by study block, 5 August 1986. 42
D.l Kleingrass seeding and emergence dates and precipitation by day. Spring 1985 and 1986. 44
D.2 Trampling intensity in grazing cycles before
kleingrass emergence dates, 1985 and 1986. 45
D.3 Kleingrass emergence data for 25 May 1985. 46
D.4 Kleingrass emergence data for 25 April 1986. 47
D,5 Kleingrass emergence data for 6 June 198 6. 48
D.6 Analysis of variance tables for kleingrass emergence data, 1985 and 1986. 49
E.l Generalized analysis of variance table for soil strength data, 1985 and 1986. 51
E.2 Analysis of variance table for soil strength data by date, 1985 and 1986. 52
VI
F.l Frequency data for rabbit's tobacco, common broom-weed, and woolly plantain, 1985-1987 54
F.2 Frequency data for red-seeded plantain, spurge, and bitterweed, 1985-1987. 55
F.3 Frequency data for Astragalus, Gordon's bladder-pod, and Texas filaree, 1985-1987. 56
F.4 Frequency data for meadow flax, little barley, and six-weeks fescue, 1985-1987. 57
Vll
LIST OF FIGURES
1.1 Steers grazing near exclosures in study block six, 10 June 1985. 6
1.2 May 31, 1986 photo of study plot 81G2. 7
2.1 Deviation from average precipitation by quarterly phenological stage of annual species studied, 1985-1987. 24
Vlll
CHAPTER I
EFFECTS OF SHORT-DURATION GRAZING TRAMPLING
ON SEEDLING EMERGENCE OF BROADCAST-SEEDED
KLEINGRASS (PANICUM CQLQRATUM L.)
Hooves of grazing animals impart physical impact on
rangeland soils and vegetation. Kind of animal, season and
intensity of grazing, soil characteristics, and plant
community influence the type and degree of impact. Range-
lands do not benefit from long-term, excessive physical
animal impact (Lull 1959, Reynolds and Packer 1963, Black
burn et al. 1982, Blackburn 1984) .
Proponents of intensive rotational grazing systems cite
beneficial effects from increased stocking densities. The
"hoof action" of concentrated animals is said to improve
soil hydrologic properties by breaking up crusts and
increasing infiltration, thereby enhancing seedling emer
gence (Howell 1978, Savory and Parsons 1980, Walter 1984),
Recent studies of intensive rotational grazing systems have
demonstrated detrimental impacts on soil hydrologic proper
ties such as infiltration rate, sediment production, and
runoff (Blackburn 1984; Gamougoun et al, 1984; McCalla et
al. 1984a, 1984b; Thurow et al. 1986; Warren et al. 1986a,
1986b, 1986c, 1986d; Weltz and Wood 1986).
2
Germination of a surface-lying seed depends on escape
from predation and placement on a site which provides appro
priate moisture and temperature conditions (Harper et al.
1965, Sheldon 1974, Harper 1977). Modifications of soil
structure and/or microtopography by animal trampling can
influence the number of available microsites for germina
tion. Trampling may improve the suitability for germination
of one type of microsite but reduce the suitability of
another (Stephens 1980, Eckert et al. 1986).
The ability of a seedling to emerge out of or push roots
through soil depends on relative soil strength and moisture
content as well as the emergence force exerted by the
seedling (Hanks and Thorp 1956, 1957; Taylor et al. 1966;
Taylor 1971; Jensen et al. 1972). As the soil surface
dries, soil strength increases, and emergence declines
(Stephens 1980, Hillel 1982). Trampling may increase
emergence of some species but decrease emergence of others
(Stephens 1980, Wood et al. 1982, Dahl 1986, Eckert et al.
1986, Norton and Owens 1986). Factors other than trampling
also influence seedling emergence. Wood et al. (1982) and
Dahl (1986) considered the presence or absence of competing
vegetation, and Stephens (1980) and Eckert et al, (1986)
considered soil microsite characteristics important in
determining emergence and establishment. Soil moisture
before emergence and the ability of a species to germinate
3
under a wide variety of conditions may also exert greater
influence than trampling (Graff 1983, Dahl 1986).
This study evaluated selected impacts of short-duration
grazing on western Texas rangeland. Our hypothesis stated
that short-duration grazing trampling does not enhance
seedling emergence; this was tested using broadcast-seeded
kleingrass (Panicum coloratum L. 'Selection 75') as a
bioassay. Short-duration grazing impacts on soil compaction
were also documented.
Materials and Methods
Research was conducted in 1985 and 1986 at the Texas
Tech Experimental Ranch (101° 11' W., 32° 58' N.) 10 km
southeast of Justiceburg, Garza County, in the Texas Rolling
Plains (Gould 1969). Regional climate is semiarid, with
most of the 4 90 mm of average annual precipitation falling
from May to October (NOAA 1985) . Study plots were located
on a clay flat range site dominated by tobosagrass FHilaria
mutica (Buckl,) Benth.] and alkali sacaton rSporobolus
airoides (Torr.) Torr.] with scattered honey mesquite (Pro-
SODIS glandulosa var. glandulosa Torr.) and plains prickly-
pear (Opuntia polyacantha Haw,) (Britton and Steuter 1983) .
Soils were nearly level Stamford clays (fine, montmorillon-
itic, thermic Typic Chromusterts) with a high shrink-swell
potential, intermixed with small areas of Vernon clay loams
4
(fine, mixed, thermic Typic Ustochrepts) (Richardson et al.
1965) ,
Before 1984, the site was moderately and continuously
grazed. It was burned in February 1983 and sprayed in July
1983 with triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy]
acetic acid}. In 1984 a six-pasture short-duration grazing
system was initiated. The 14-ha study pasture was stocked
with Hereford/Angus crossbred steers at 1.7 AUM/ha in 1985
and 1.2 AUM/ha in 1986 for three grazing cycles between
mid-April and mid-July each year. Recommended stocking for
moderate, yearlong-continuous grazing on this site is about
0,8 AUM/ha. Sixty and 42 yearling steers were used in 1985
and 1986, respectively. Stocking rate each year and grazing
and rest period lengths within years were adjusted based on
forage availability. In both years, the first two grazing
periods were seven days, followed by rest periods of 35 and
21 days in 1985 and 33 and 30 days in 1986. A final grazing
period of three days in 1985 and two days in 1986 occurred
before removal of all animals.
Immediately before grazing each season 128, 0,28-m^
plots arranged in a randomized, complete block design with
eight blocks were broadcast-seeded with kleingrass at 8,6 kg
pure live seed/ha. Kleingrass was selected because of its
adaptation to the soil and rainfall conditions of the site.
Seeding rate was intentionally heavy to insure adequate
5
emergence to test treatment effects. Half the plots in each
block were located in randomly-placed ungrazed exclosures
(Figure 1.1) . Blocks were relocated and new plots estab
lished for the second grazing season. Plots were located in
a 2-ha area about 550 m from the watering point of the 800-m
long triangular pasture. Grazed plots were marked below-
ground with metal stakes to avoid artificially attracting
cattle and augmenting trampling. A metal detector was used
to locate plots on sampling dates (Weigel and Britton 1986).
Kleingrass was seeded into greenhouse pots to aid field
identification. Plots were monitored twice-weekly for
kleingrass and seedlings were counted following each
emergence.
Vertical black-and-white photographs taken with a 35-rpjn
camera and 50-mm lens from 1.5 m above each plot were used
to estimate foliar cover of individual plots (Figure 1.2).
A dot-grid overlay (50 dots/grid) was used to estimate cover
on each photograph. These data were used as a covariate to
evaluate the effect of vegetative cover on kleingrass
emergence.
A proving-ring.penetrometer (Soiltest CN-970) was used
to measure soil strength (MPa) before and after each grazing
cycle each year. Soil strength is strongly correlated with
soil bulk density, a measure of soil compaction (Gifford er
al. 1977). Balph and Malachek (1985) found that livestock
G •H
CO (U U P CO
o rH C) X <1)
near
o c
- H N (d M
CO 4-> O
<-{
Cu -o <U N trt 5-1
cn c; D
85
.
CT* rH
<U C P
Cni-D
CO
u <i) <D 4-» Ul
• rH
• i H
0) M
o i H
^ X
- H CO
^ O O
rH X>
• CO <D U P C/J U
rH
u X (i)
mes
h
- H ?
0) x: .p
(1) T5 - H ro G
- H
-d 0) 4-> OJ
o O
>1rH P -o O^ P
-H
fc 1 +J 1 CO
<U u (0
7
(1) 4-> O
CM 73 2 • O 0) ^ rH CO <U (30 P • -M
4-> CO O ^ O n3 rH U -H 5 a O, M
O JG ^ > i 4 J U ?
T3 O (TJ O p x : (u •-•
CO 14H TJ
.G O 5 M-l U (^ O fO M
0) <U - P o > ' -f 4-) M O <i O 0) O -H .£: > a o M M "X) T 3 -H 5 cr> (1) rH O cn o O rH <-H 03 ^H
.H 4-)
rH C CO > i (D 0) j j
(d O rH O >1rH JH X3 rH td M <U -H f l , 2 <u a CO
> -H G O 0) > o
CM 73 (d CO CO . -H >H .p 4J
^ M P G G cr> O - H <U
(1) I - H M g M 4-J Cd CU 0) 3 O O 4H M C P T J O U
-H O O G tn < 4-> x : M
u
0) 5H
(d
0) g (d 5H
8
in a short-duration grazing system avoided trampling
elevated grass tussocks, so penetrometer sarr.ples were taken
only from bare soil interstices. Immediately before and
after each grazing cycle, 640 penetrometer readings
(80/block) were taken in groups of 20 closely-spaced
samples. In 1986, three of every 20 readings on dates after
grazing began were taken in visible cattle hoofprints. This
frequency of sampling corresponded to actual percent cover
of hoofprints estimated by line-intercept sampling.
Kleingrass emergence and soil strength data were
averaged over subsamples (four plots/average for kleingrass
and 20 penetr'jmeter readings/average for soil strength) ;
these data were tested for normality at each date with the
Shapiro-Wilk W-statistic (Shapiro and Wilk 1965). Block-
treatment interaction for each date was tested using Tukey's
single-degree-of-freedom test for nonadditivity at the 90%
level of significance (Steel and Torrie 1980) . Three of
four 1985 soil strength data sets demonstrated significant
interaction and were transformed using the Anscombe-Tukey
power transformation (Anscombe and Tukey 1963) . Kleingrass
emergence and soil strength data were evaluated using
analysis of variance for a randomized, complete block design
with a sampling error. Duncan's New Multiple Range Test was
used to compare soil strength data when treatments were
divided into hoofprint and non-hoofprint means. Analysis of
9
covariance was used to assess the effect of foliar cover on
seedling emergence.
Trampling intensity was estimated by measuring hoofprint
intercepts along 16 randomly-located lO-meter line transects
immediately following the first two grazing periods each
year. Duncan's New Multiple Range Test was used to compare
hoofprint intercept means for each date. Means for the
grazing period immediately prior to each emergence event are
reported.
Results and Discussion
Adequate precipitation before and after seeding is
critical in stimulating germination (Bewley and Black 1985,
Wester et al. 1986). Precipitation during this period was
average in 1985 and above average in 1986 (Table 1.1).
Three distinct emergence events occurred during the study:
one in 1985 and two in 1986. Trampling intensity before the
single 1985 emergence was higher (P<0.05) than for the two
1986 emergences (Table 1.2) because of the higher stocking
rate in 1985.
No difference (P>0,18) in seedling emergence between
grazed and ungrazed treatments was found in either year
(Table 1.2) . Percent foliar cover of individual plots was
not a significant covariate (P>0.15) for any date,
indicating that emergence was not related to foliar cover.
In contrast, Graff (1983) obtained little or no emergence of
10 0
G -H
CO -P G <U > (U
0) o G 0) cn u 0) g 0)
CO CO fd u cn G
- H
.H
..^
O -P
pri
or
rH rH (d
4H G
- H (d fri
• rH
• vH
<U rH XI Cd H
• (U cn (d M (U > cd
e u (]) X)
1 cn G
o rH
g o
MH
G
via
tio
(1) -o T3 G fd
^ UD CX)
cn rH
-d G fd
LO (X)
cn rH
00
r-CM
00
\o
CX)
CM
cn
in CX)
CX) CM
CX)
V£)
I \0 ^
00
i n CM
LO 00 "^ LO
CM
l O
00 00
r i (v^
CO LO
I
00 00
r- l pr^
LO LO 00 00
c^ ^ LO
(U -p fd Q
cn G
- H
-d (U (U w
. . Q) -P Id Q
<D O G 0) cn u <D g W
-d o - H M <u CM
rH r^i
(d <4H G
- H fd pcj
00 LO U5 ro rH +
00
00
CN
LO
+
cn
o
to
H .—. 1 H rH r-i fd
^H G
- H fd M
CM
o\o
G O
- H -P fd
- H > 0) -d
o •p - H OT
6 o M
4-1
X) - H OT
l|H
o
J-)
o c g
CM CO
c o
- H . p (TJ 4-) OT
O
M O
4-1
.i<
00 .
o
-0 0) -d M O o o a:
d) cn <n u Q) > <o .
u > 1
o ro
Csl
11
CO rn
ng
rai
- H
CD r H
M
^ - v
w w
G td
g
Ti ' f d C O
cn 0) ' " I
(d "^ -d ^
fd
O LO 0 0
CO >—^ ^
4-> CO G
G ^ fd g <U - I - ' g (
<D
^ .1 cu o "d U G (U fd
G 0 ) - H - P
fd A-> ' d G
- H > i
p. •^-I > 1 O +J O -H aa CO
G fU
• -d CN
• cn r H G
- H (U r H
r H - d ^ 0) fd cu
E H CO
hi
A
O
CU
CM
g 0 0 CM
O
^ s ^
> 1
- p - H
CO
G (1) Q
0^ G
- H r-\ Ti CD CD
C/2
T? CD N fd u cn G D
- d <D
fd
M O
rH
a\P
4J ^ G
-H -P
a 0) 4 H O
O >-i
O <D K -P
G M
CD O G CD cn U <D CD 4 J
g (d u Q
CM
CO
G
r-o CN
• O
_ >^
" o >_
U3
• VD
r-
o
VO
. t ^
fd
VO
• CN
CN .
0 0 r H
LO 0 0 cn r-{
> 1 fd
l O CM
CO
G
O cn CM CM
• o
^ ro
• r'{ _
r-•
o rH
r-\
r H
l O
. 0 0
X»
CO
• r-\
CO .
r H r H
VD 0 0
cn r-i
rH •ri u
<
LO CM
CO
G
o VO 0 0 r-i
• o
^ ^ 0 0
• o >
LO
• CM r-i
0 0
O
ro •
o r-{
JO
VO
• r-\
r-i .
r-t
VO 0 0 cn r-i
(D G P T>
VO O
^» • v LO
4-) O c • 0) o O A U Oi 0) - -
a x>
x> C a, Q) 0) U O <D M L|-|
U - H C T)
- H
4J O
c c - H M 0) a M
MH (0 o o u
JC a) 4J
II -U OJ
- . ^ H
g O (U - - g
j : : OT
cn 0) 0) xi
H
4-) jQ
o a> X ) OT (P
(tJ o M rH X) H
O rH IM (0
o g 4J 3
H \ O
O
'-» g c O - H
OT +J C a fo (U (U
o g 0) .V 4J C C (d
- H 0) g
X) -^ C OT
- H +J H O
a o MH OT
o C O (tJ
j : : M 4-)
rH (tJ U3 4-) rH O II
EH C
rH
• C (0
g
VO II
i n o
o A CXi
C 0) )-i 0)
%i MH - H XJ
4-) o c 0)
(d
3
o M
(0 OT
c - H
OT C (0 0) g
G - H rH - d 0)
CO Cvl
12
several broadcast-seeded grass and forb species subjected to
two levels of short-duration grazing trampling unless
competing vegetation was suppressed with herbicide prior to
seeding. In this study, no kleingrass survived to estab
lishment in either year, probably as a consequence of
insufficient post-emergence rainfall. Virtually all seed
lings on all emergence dates died three to seven days after
emergence.
Soil strength did not differ (P>0.40) between treatments
before grazing in 1986 (Table 1.3). There was no pre-
grazing sampling in 1985. Once grazing began, soil strength
in the grazed treatment was higher (P<0.0001) than in
ungrazed areas for all 1985 dates and four of five 1986
dates. Uniformly low soil strength in both treatments on 31
May 1986 was attributed to very wet soil conditions from
over 80 mm of rain received immediately before sampling.
On four of five 1986 post-grazing sample dates, soil
strength in hoofprints was greater (P<0.05) than in
untrampled areas within the grazed treatment (Table 1.4) ,
Soil strength in grazed, untrampled areas was not different
from ungrazed areas on three of five dates, Overall soil
strength differences between treatments (Table 1.3) were
apparently caused by the contribution of a few high-strength
hoofprints in the grazed treatment.
13
-d G fd
^ CD cn fd 4-) CO
<D r H
O > i
o
cn G
-H N fd u cn
»ite
CD 4 J fd -d
> i
X>
^ 4-)
cn G CD >H 4-» CO
r-i - H O y)
-—~ w Ul " ^ • " ^
G fd CD 2
CO •
r H
CD r-i
J3 fd H
, VO 0 0 (Ti r-i
T5 G fd
LO 0 0 cn r-i
-p G CD g
4-> (d (D M
Xi
PM
A
Xi O U Oi
H
fd
2
-G 4-)
Cr G CD U
4-) CO
r H - H
0 CO
T3 CD N fd u cn G D
-d (D N fd u (L9
(D Cn
tj> fd G 4-J
-H CO N fd CD U --i o o
> 1 o
CD 4-) fd Q
fd CD
>H
ro r-o o
o
r-i
o
o
CN ^
o
r-i
o
o
LO LO
o
r-i
1 .P CO
O
a
> i
fd 2
VO
o
CM r-i
O
O
O
o
r-i O
O
0 0 ^
o
r-i O
O
CN VO
O
CM
1 CD U Q,
CD G P
^O
cn o
Cvl r-i
O
O
o
o
r-i O
O
CN VO
O
r-i
o
o
0 0 0 0
/pre-3
0,
CM 1
4-) CO
O Qi
CD G P
1 ^
0 0 r H
LO 0 0
cn
eg r-i
o o o
o
r H O
O
r~ VO
o
r H
o
o
CN
cn
o
ro 1 1
-P CO 0 Qi
> i
<-i P •^
0 0
o
^ VD
O " S ^ *
o
r-i O
O
c~-0 0
o
r-i O
o
VO
0 0
aze
0,
cn 1 CD u Qi
x: o u fd 2
o CM
r-i
"^ 0 0 (T>
O
r H O
O
0 0 VO
o
r H O
o
0 0 VD
aze
0,
u cn 1 CD U Qi
r-i - H M
a <
0 0 r H
r H
O
O
o
o
r-i O
o
0 0 LO
o
ri O
O
VD VO
o
t-i
1 -p CO
o Qi
r-i - H ^ Qi <
0 0 CN
r H
o o o
o
r-i
o
o
r H
r-
o
r-i
o
o
0 0
cn
/pre-2
0.
r-i 1
4-) CO
O Qi
> i
fd 2
"^
1986
1
r-i
CD
O
O
O
r-i O
o
LO LO
o
r-i O
O
O
r
o
CM
1 CD u a
> l
fd 2
LO CM
r-i
"^ o CM
O
r H O
o
r-i CM
O
r-i O
o
CM CN
/pre-3
0.
CN 1
4-> CO
O Qi
> 1
fd 2
r-i OO
r-i
CD
O
O
O
r-i O
O
LO 0 0
O
r-i
o
o
0 0 r-i
r-i
00 1 1
4-) CO O Qi
> i
,-i P
VD r H
Q) X) M O a d) u OT
c (T3 0) g -0 31 g M O
4H OT
c (tJ M
J J C 3
«. C tcJ 0)
e x: o (d 0)
)-i
o 4-1
O ^ V£> II C
fO 4-> (0 -0
X5 a) g M
o 4H OT C (T3 U -u) 1 S-l 0) 3 O Q.
C
o OT
- H OT > i
r H (T3
c <
Csl
14
- d G fd
CO 4-)
G •r-i
U
a M H
o o
G -H
(D 4-) td -d
> i
JO
.G 4-> cn G CD
- p CO
VD 0 0
cn
- H
U U)
-—» PLJ Ul """"
G td CD
2
• -vT
• r-i
<D r-i XI fd EH
CO 4-> G
- H h Qi
MH O O
4:^
4-) P 0
^ 4-) - H
:s CO fd (D u fd
fd cu 2
-P Cn G CD U 4-) CO
- H
o Ul -d
CD N td u (3
- d (D N fd u cn G D
4-> G
-H
a O O
I G O
4-)
G - H M
4H O O
CD 4J td Q
XI
X
o
CM fd
-H
a <:
00 CM
O
fd
td 2
XJ
td
> i fd 2
10 CN
fd
td
fd
fd 2
00
o
rH 0
0
00 LO
r-i 0
0
r-r~
r-i CD
0
LO LO
r-i 0
0
rH CM
r-i 0
0
LO 00
XI
r-i 0
0
CT\ LO
r-i 0
0
^ CO
r-i 0
0
0 VD
r-i 0
0
CM CM
r-i 0
0
VD 0
fd
00 0
0
r-0
CM 0
0
00 ^
00 0
0
^ CM
r-i 0
0
^ CN
00 0
0
^ LO
p
VO
<]) x> (tJ -o iH
a c g 4J (d 0) M
4-)
fU
a o VO
-d c (d
LO
4-) o C
0) M (d
0) X> 4-» CD
fU g fd
OT
CU
x: 4J > i
J3 -o <D
O
O 4H
p U-,
(d
c -H x: - H
OT C
o A
C CD M 0)
*4H (d 4H 0) 2
-H -d
CM
15
The duration of trampling impact on soil strength was
not investigated. However, evidence of recovery from
compaction between years was found. Soil strength in
second-year plots, all located in areas grazed during year
one, did not differ (P>0,40; Table 1,3) prior to second-
year grazing. This recovery was attributed to the high
shrink-swell potential of the clayey Vertisols of the site
(Larson and Allmaras 1971), Other studies of compaction
froni grazing have demonstrated recovery after rest (Warren
et al. 1986c), although more than one season may be needed
to return to the pre-compaction condition (Orr 1975,
Stephenson and Veigel 1987),
Conclusions
Suggesting that soil hydrologic condition and subsequent
seedling emergence is universally improved by livestock
trar.pling ignores the effects of soil type, soil water
consent, stocking rate, and vegetation type (Warren et al.
1986c). Trampling of sandy, crust-prone soils may reduce
compaction (Graff 1983, Tainton 1985) while finer-textured
soils may be damaged (van Haveren 1983), The impact of
trar.pling of wet soil is significantly more detrimental than
trarr.pling of dry soil (Warren et al, 1986d) ,
No beneficial effects on either emergence of broadcast-
seeded kleingrass or soil strength were realized from
seasonal short-duration grazing trampling at stocking rates
16
2.0 and 1,5 times higher than recommended in tobosagrass-
alkali sacaton vegetation on clay soils. Conversely,
trampling did not reduce kleingrass emergence relative to
ungrazed areas. Soil compaction, as measured by soil
strength, increased in grazed areas. Presumably, soil
hydrologic properties related to soil surface condition,
such as infiltration rate, sediment production, and runoff,
would be negatively affected by increases in soil strength.
Evidence of compaction recovery between years was found.
However, the short-term nature of this study is emphasized;
documentation of longer-term impacts of seasonal short-
duration grazing is needed.
CHAPTER II
EFFECTS OF SHORT-DURATION GRAZING ON ANNUAL
FORB AND GRASS SEEDLING EMERGENCE
Grazing, browsing, and trampling by domestic herbivores
alters vegetation and soils of rangeland communities.
Grazing-induced changes in species composition usually
reduce productivity, particularly under traditional
continuous grazing regimes (Sims et al. 1978, Heitschmidt et
al. 1982). Soil structure, microtopography, and hydrologic
properties are affected by animal physical impact (Reynolds
and Packer 1963, Blackburn et al. 1982, Eckert et al. 1986).
Animals graze selectively and patchily, and physically
impact soils and plants by trampling, pawing, and wallowing
(Spedding 1971, Polley and Collins 1984). This causes
heterogeneity in vegetation by altering competitive
relations and creating niches for colonizing species (Harper
1977). Species diversity often is higher in moderately
disturbed than in undisturbed communities (Huston 1979,
Crawley 1983, Belsky 1986). Annual species adapted for open
and disturbed environments (Grime 197 9) may contribute
significantly to increased diversity on disturbed sites
(Harper 1977).
Winter annual plants germinate in fall, overwinter in a
vegetative state, and flower, set seed, and die the
17
18
following spring (Newman 1963). Their life cycle is closely
tied to relatively predictable fall precipitation events
which trigger mass germination (Beatley 1967, 1974). Seed
lings develop into extremely winter-hardy basal rosettes
capable of photosynthesis at low temperatures (Bazzaz 1979) .
The winter annual strategy enables resource exploitation at
a time when dominant perennial species are largely inactive.
Range managers and researchers have directed substan
tial effort to development of rotational grazing systems
that allow forage utilization by domestic livestock while
maintaining or improving rangeland condition. Short-
duration grazing (SDG) is an intensive, rotational grazing
system which uses relatively short grazing periods, long
rest periods, and high stocking densities to manipulate
grazing pressure, forage utilization, and subsequent forage
and livestock production (Ralphs et al. 1984). Proponents
of SDG have suggested that the system closely approximates
grazing patterns of native herbivores because dense concen
trations of animals provide a beneficial physical animal
impact called "herd effect" (Savory and Parsons 1980, Savory
1983, Walter 1984). Herd effect purportedly improves range
condition by chipping the soil surface, thereby enhancing
infiltration, herbage production, and seedling emergence.
The objective of this study was to document emergence
and establishment of winter annual forb and annual grass
19
species following short-duration grazing during the previous
year's flowering and seeding period. Emergence in ungrazed
exclosures was also recorded to test the hypothesis of
increased emergence with short-duration grazing trampling.
Materials and Methods
Research was conducted in a tobosagrass [Hilaria mutica
(Buckl.) Benth.]/alkali sacaton fSporobolus airoides (Torr.)
Torr.]/honey mesquite (Prosopis glandulosa var. glandulosa
Torr.) grassland in the Texas Rolling Plains (101° 11' W.,
32° 58' N.) (Gould 1969, Britton and Steuter 1983).
Regional climate is semiarid, with most of the 490 mm of
average annual precipitation falling from May to October.
Average precipitation during the fall-winter (September-
February) period of peak seedling emergence is 170 mm (NOAA
1985). Study site soils were nearly level Stamford clays
(fine, montmorillonitic, thermic Typic Chromusterts)
intermixed with small areas of Vernon clay loams (fine,
mixed, thermic Typic Ustochrepts). Stamford soils contain
predominantly montmorillonitic clays with high shrink-swell
potential (Richardson et al. 1965).
The site was moderately and continuously grazed by
domestic livestock prior to 1984. It was burned in February
1983 and sprayed with triclopyr {[(3,5,6-trichloro-2-pyri-
dinyl)oxy]acetic acid} in July 1983 for honey mesquite
20
control. A six-pasture short-duration grazing system was
initiated in 1984. Since then, pastures have been grazed by
livestock seasonally from mid-April to mid-July each year.
Animals were sequentially rotated from pasture to pasture
during the grazing season; adjustments in length of grazing
and rest periods were based on forage growth and availabil
ity (Savory and Parsons 1980, Savory 1983). Study plots
were located in one 14-ha pasture of the six-pasture system.
The study pasture was grazed by 60 and 42 yearling Hereford/
Angus crossbred steers for three periods in 1985 and 1986,
respectively. Stocking rates were 2.0 (1985) and 1.5 times
(1986) recommended for moderate, yearlong-continuous
grazing. In both years, the initial two grazing periods
were seven days, followed by rest periods of 35 and 21 days
in 1985 and 33 and 30 days in 1986. A final grazing period
of three days in 1985 and two days in 1986 occurred prior to
removal of all animals.
A randomized,- complete block design with eight blocks
was used. Thirty-two, O.Ol-m" plots were permanently marked
in each block, half in randomly-located ungrazed wire-mesh
exclosures (Figure 1.1). Each of four exclosures per block
contained four ungrazed plots; four groups of four grazed
plots were located nearby. Grazed plots were located at
least 3 meters from exclosures and were marked belowground
to avoid increased trampling by animals attracted to
21
exclosure fences or aboveground plot markers. A metal
detector was used to locate plots on sampling dates (Weigel
and Britton 1986). Blocks were relocated and new plots
established prior to the second season's grazing. Plots
were located in a 2-ha area about 550 m from the single
watering point of the 800-m long triangular pasture.
Beginning with the first post-grazing emergence in
October 1985, seedling frequency of all annual species was
recorded bimonthly through February 1987, when the onset of
a third season of grazing forced termination. Sampling was
not conducted during summer when the previous season's
plants had senesced and the next season's plants had not yet
germinated. Sample dates were classified as either Season 1
(1985-1986) or Season 2 (1986-1987) based on phenology of
species studied. Four and three sample dates comprised
Seasons 1 and 2, respectively.
Species recorded in at least 5% of plots for any
date-treatment combination were analyzed for treatment
response (Gauch 1982). Data were summarized in a 2 X 4
(Season 1) or 2 X 3 (Season 2) contingency table and
analyzed with a log-linear model that included treatment,
date, and a response variable (frequency) (Bishop et al.
1975) .
22
Results and Discn.s.sion
Ten species of winter annual forbs and two species of
annual grass were analyzed (Table 2.1). Six additional
species of annual forbs were encountered but not analyzed
because of low frequencies for each date-treatment combina
tion ,
Above normal fall precipitation in both seasons created
apparently excellent germination conditions both years
(Figure 2.1). However, frequencies of five of the six most
common forbs (rabbit's tobacco, common broomweed, woolly
plantain, red-seeded plantain, and bitterweed) and the most
common annual grass (little barley) were substantially
higher in Season 1 regardless of treatment (Table 2.2).
Lower frequency of these species in Season 2 may have been
related to very low Season 1 winter precipitation and very
high Season 2 fall precipitation. Many Season 1 seedlings
died before flowering or seeding, so fewer seeds were
available for germination the following fall. Beatley
(1974) attributed late-winter mortality of Mojave Desert
annuals to decreased soil moisture during this critical
growth period, although some mortality occurred even in
years with adequate moisture. Several researchers have
demonstrated density-dependent thinning in desert annuals
(see Fowler 1986 for a review). Season 2 fall precipita
tion occurred early in that period, and was nearly twice
23
CO 0) CO CO ^ u cn -d G fd
CO
x> u o
^H
r-i td p G G .•d
LM
o CO 0) g fd G
(D -d o o -d G (d
« b
G O g g o o ^
o - H VM - H .
t! " G 00 (D cn
- H ^ O 1
C/5 lO 00 (T\
• rH t-i
• •. CN X )
CD 0) -H
-H X5 i3 P fd 4->
E H CO
CD g fd 2
CD -d o o
<D g Id
2 G o 5 O O
CD g fd 2
O - H ^H •ri 4-) G CD
- H O CO
Ixl
%
u
Pc: Q <C X
< a, h i
cu
K pc: ^ cu
Oi Ul D w
Q O >H
rc
cu Ul Ul <
o u w hq
u EH pc: pq
PC cu M h:i
o o o fd
JO o - p
CO
4-> - H XJ x> td SH
CO
X>
O
td
td c SH
CD
X fd >
- d CD CD
g O O u x>
G O g g O
u
CO u CD G G
- H
CJ Q
CO CD
- d -H O
P CJ c p u fd s-<
- d
a p
rH fd
.G O l CD U O
.G P C fd X
G - H fd 4-) G fd
r-i Qi
O O
cr o fd
o o td 4J G fd
•-i cu
G - H fd 4-) G fd
rH
73 CD
73 CD CD CO I
-d CD U
CD G U Q
td
u - H C o G fd 4-) fd Q
td g s CD P CO 0 -d 0 x:
1 u
O
fd p G fd
rH CU
CD Cn u P a CO
a CO
fd - H
X u o
J^
Q, P
-d CD CD
u CD 4-) 4-) - H
X
CJ CH
fd p fd SH
O - d o
CO > l X o c CD g > i X
CO
P rH td Cn td u
4-) CO
CO
CO
p rH td O td SH
4-) CO
Ti O
a CD
- d 73 fd
r-i JO
CO
G O
73 SH O
CO 4-1 td
> 1 td
<3
- H c O
d SH
O U
fdl
CD SH
a; p d ' CO CD
(D CD
td r-i - H m
CO td X CD iri
> i td U <3
P C fd X CD 4-1
g P
- H - d o SH
W
X Id
rH 4H
O - d td CD
g
td g
C O
4->
u O 2
CD CO C CD P
fd
Q ,
a p CO
(D CO CO (d SH CJ
D CU O K
O O D >
> i
CD r-i U fd X
CD rH 4-) 4-> - H rH
CD P U CO 0
4H
CO ^ CD CD ^ 1 X
- H CO
4J 4-> P 2
X 73 > i
4-> rH td
Sl p
rH r-i •ri CO p O
td SH
O <-i 4 H
O P
k u o
^ p CD
73 SH
O E
fd - H P
t—i
P >
o :--cn
G O 4-) CO G
O
- d G fd
(D SH ^1 O
CJ
CO
O
o L(H
(D SH
P P fd
rH U G (D g O
24 so
n 1
son
2
CO CO o at CO CO
n Rq
c c
i
3 o ) 00 1- +
o to
+
o o ' t CM
+ +
1 c
i
3 o o o o CM ^ (O oo
1 1 1 1
-100
4/1
- 6
/30
1/1
-3
/31
10/1
- 1
2/3
1
7/1
-9/3
0
flow
erin
g &
see
ding
w
inte
r em
erge
nce
& g
row
th
fall
emer
genc
e pr
e - e
mer
genc
e
(120
.4)
(46.
3)
(101
.2)
(74.
8)
y led
, 1
a
xis
th
ese
s
on
b
stu
d
tica
are
n
.tati
.i
es
ver
in
p
(mm
)
i p
recip
i lu
al
spec
L z
ero
on
Fig
ure
s a
mo
un
ts
n fr
om
a
ve
rag
e 1
sta
ge o
f a
nr
1
lin
e
thro
ug
h
ec
ipit
ati
on
. p
rec
ipit
ati
on
Fig
ure
2
.1.
De
via
tio
qu
art
erl
y
ph
en
olo
gic
a
19
85
-19
87
. H
ori
zo
nta
re
pre
se
nts
a
ve
rag
e
pr
are
a
ve
rag
e
qu
art
erl
y
(%) aOejaAB luoj^ uojiejAap
25
Table 2.2, Percent frequency of annual forb and grass species by season and treatment, 1985-1987,
Species-^
Forbs:
E W E
XADR
PLPA
PLRH
EUSP
HYOD
ASSP
LEGO^
ERTE
LIPR
Grasses:
HOPU
VUOC
Season
ungrazed
93.5
49.6^
52.7
36.1
25.0
11.7'
4.3
3.9
2.3
3.1
31.2-
1.4
.4
*:•
ll
grazed
91.6
55.7
49.0
36.5
28.3
6.8
4.9
3.1
3.3
1.8
34.6
2.3
Season
ungrazed
69.3
35.2
25.8
27.9
33.9
3.6
7 .8
6.5
2,1***
0,1***
11.7
2.3
22
grazed
70.3
38.8
25,3
24.2
28.4
3.4
6.5
5,5
7.3
4.7
12.5
1.6
^n = 4 sample dates (10/27/85, 11/29/85, 2/4/86, 4/5/86)
^n = 3 sample dates (10/14/86, 12/16/86, 2/4/87) .
^Species codes listed in Table 2.1,
^Different than frequency in grazed areas at P<0.05 (*), P<0.01 (**), and P<0.001 (***).
^Significant (P<0.05) 3-way interaction in Season 1,
26
average (Figure 2.1), This stimulated vigorous growth of
perennial grass dominants, which may have reduced germina
tion and survival of annuals by preemptive use of soil
moisture (Friedman et al. 1977).
Five of ten winter annual forb and both annual grass
species showed no difference between treatments in both
seasons (Table 2.2) . In Season 1, frequency of common
broomweed was greater in grazed plots, while frequency of
bitterweed was higher in ungrazed exclosures. A 3-way
interaction (P<0.05) for Gordon's bladderpod indicated that
frequency varied by date and treatment.
Gordon (1982) found significant negative correlations
between broomweed emergence and biomass of standing dead
herbaceous material and litter, indicating that lower
broomweed emergence could be expected in ungrazed areas.
Season 1 results in this study support this conclusion.
The response of bitterweed was not expected. Bitterweed is
a poisonous, unpalatable species, considered an "increaser"
by range managers, yet it occurred more frequently in
ungrazed plots. No differences by treatment for broomweed
or bitterweed emergence were found in Season 2.
Texas filaree and meadow flax emerged more frequently
in grazed plots than in ungrazed plots in Season 2. Filaree
apparently preferred bare areas, which were less common in
ungrazed exclosures. Baker (1974) considered the genus
27
Erpcjiiym, with its prostrate vegetative rosette and seed
morphology conducive to animal dispersal, to be well-adapted
to animal trampling. Greater presence of meadow flax in
grazed plots was not readily explainable.
Conclusions
Precipitation at critical life history stages is the
primary factor controlling germination and survival of
winter annual forbs and annual grasses. Large fluctuations
in annual populations between years are common (Beatley
1967, 1974) . Livestock trampling at the stocking rates used
in this study provided no consistent beneficial or harmful
impact to any of the annual species studied. The short-term
nature of the study is emphasized; impacts on annual species
over longer periods of short-duration grazing are needed.
LITERATURE CITED
Anscombe, F.J., and J.W. Tukey. 1963. The examination and analysis of residuals. Technometrics 5:141-160.
Baker, H.G. 1974. The evolution of weeds. Ann. Rev. Ecol. Syst. 5:1-24.
Balph, D.F., and J.C. Malachek. 1985. Cattle trampling of crested wheatgrass under short-duration grazing trampling. J. Range Manage. 38:226-227.
Bazzaz, F.A. 1979. The physiological ecology of plant succession. Ann. Rev. Ecol, Syst. 10:351-371.
Beatley, J.C. 1967. Survival of winter annuals in the northern Mojave Desert. Ecology 48:745-750.
Beatley, J.C. 1974. Phenological events and their environmental triggers in Mojave Desert ecosystems. Ecol. 55:856-863.
Belsky, A.J. 1986. Revegetation of artificial disturbances in grasslands of the Serengeti National Park, Tanzania. I. Colonization of grazed and ungrazed plots. J. Ecol. 74:419-437,
Bewley, J,D., and M. Black. 1985. Seeds: physiology of development and germination. Plenum Press, New York,
Bishop, Y.M., S.E. Fienberg, and P.W. Holland. 1975. Discrete multivariate analysis: theory and practice, MIT Press, Cambridge, Mass.
Blackburn, W.H. 1984. Impacts of grazing intensity and specialized grazing systems on watershed characteristics and responses, p. 927-983. In: Developing strategies for rangeland managemient. National Research Council/National Academy of Sciences, Westview Press, Boulder, CO.
Blackburn, W.H., R.W. Knight, andM.K. Wood. 1982. Impacts of grazing on watersheds: a state of knowledge, Texas Agr. Exp. Sta. Rep. MP-14 96.
Britton, CM., and A.A. Steuter. 1983. Production and nutritional attributes of tobosagrass following burning. Southwest. Natur. 28:347-352.
28
29
Correll, D.S., and M.C. Johnston. 1970. Manual of the vascular plants of Texas. Texas Res. Found., Renner, TX.
Crawley, M.J. 1983. Herbivory - the dynamics of animal-plant interactions. Univ, Cal, Press, Los Angeles.
Dahl, B.E. 1986. The west Texas experience in short duration grazing, p. 103-116. In: J.A. Tiedeman (ed.). Short duration grazing: Proc. short duration grazing and current issues in grazing manage, shortcourse. Wash. State Univ., Pullman.
Eckert, R.E., Jr., F.F. Peterson, M.S. Meurisse, and J.L. Stephens. 1986. Effects of soil-surface morphology on emergence and survival of seedlings in big sagebrush communities. J, Range Manage. 39:414-420,
Fowler, N.L. 1986. The role of competition in plant communities in arid and semiarid regions. Ann. Rev. Ecol. Syst. 17:89-110.
Friedman, J., G. Orshan, and Y, Ziger-Cfir. 1977, Suppre-sion of annuals by Artemesia herba-alba in the Negev Desert of Israel, J. Ecol. 65:413-426.
Gamougoun, N.D., R.P. Smith, M.K. Wood, and R.D. Pieper. 1984, Soil, vegetation, and hydrologic responses to grazing management at Ft, Stanton, New Mexico. J. Range Manage. 37:538-541.
Gauch, H.G. 1982. Multivariate analysis in community ecology. Cambridge Univ. Press, New York.
Gifford, G.F., R.H-. Faust, and G.B. Coltharp. 1977. Measuring soil compaction on rangeland. J. Range Manage. 30:457-460.
Gordon, R.A. 1982. The ecology and control of common broomweed. Ph.D. Diss. Texas Tech Univ., Lubbock.
Gould, F.W. 1969. Texas plants: a checklist and ecological summary. Texas Agr. Exp. Sta. Rep. MP-585.
Graff, P.S. 1983. Trampling effect on seedling production and soil strength under short-duration and continuous grazing. M.S. Thesis. Texas Tech Univ., Lubbock.
Grime, J.P. 1979. Plant strategies and vegetation processes. J. Wiley Pub., Inc., New York.
30
Hanks, R.J., and F.C. Thorp. 1956. Seedling emergence of wheat as related to soil moisture content, bulk density, oxygen diffusion rate, and crust strength. Soil Sci. Soc. Amer. Proc. 20:307-310.
Hanks, R,J., and F.C. Thorp. 1957. Seedling emergence of wheat, grain sorghum, and soybeans as influenced by soil crust strength and moisture content. Soil Sci. Soc. Amer. Proc. 21:357-359.
Harper, J.L. 1977. Population biology of plants. Academic Press, London.
Harper, J.L., J.T. Williams, and G.R. Sagar, 1965. The behavior of seeds in soil. I. The heterogeneity of soil surfaces and its role in determining the establishment of plants from seed. J. Ecol. 53:273-286,
Heitschmidt, R.K., J,R. Erasure, D.L. Price, and L.R. Rittenhouse. 1982. Short duration grazing at the Texas Experimental Ranch: weight gains of growing heifers. J. Range Manage. 35:375-379.
Hillel, D. 1982. Introduction to soil physics. Academic Press, New York.
Howell, L.N. 1978. Development of multi-camp grazing systems in the Southern Orange Free State, Republic of South Africa. J. Range Manage. 31:459-465,
Huston, M. 1979. A general hypothesis of diversity. Amer, Nat. 113:81-101.
Jensen, E.H., J.R. Frelich, and R.O. Gifford. 1972. Emergence force of forage seedlings. Agron. J. 64:635-639.
Larson, W.E., and R.R. Allmaras. 1971. Management factors and natural forces related to compaction, p. 367-427. In: K.K. Barnes et al. (eds.). Compaction of agricultural soils. Amer. Soc. Agr. Eng. Monogr. No. 1.
Lull, H.W. 1959. Soil compaction in forest and range lands. USDA Misc. Pub. 768.
McCalla, G.R., W.H. Blackburn, and L.B. Merrill. 1984a. Effects of livestock grazing on infiltration rates, Edwards Plateau of Texas. J. Range Manage. 37:265-269
31
McCalla, G.R., W.H. Blackburn, and L.B. Merrill. 1984b. Effects of livestock grazing on sediment production, Edwards Plateau of Texas. J. Range Manage. 37:291-194
National Oceanic and Atmospheric Administration. 1985. Climatological data annual summary - Texas 1984. Vol. 89, No. 13.
Newman, E.I. 1963. Factors controlling the germination date of winter annuals. J. Ecol. 51:625-638.
Norton, B.E., and Owens, M.K. 1986. Studies in short duration grazing on crested wheatgrass pastures in Utah, p. 83-90. In: J.A. Tiedeman (ed.). Short duration grazing: Proc. short duration grazing and current issues in grazing manage, shortcourse. Wash. State Univ., Pullman.
Orr, H.K. 1975. Recovery from soil compaction on bluegrass range in the Black Hills. Trans. Amer. Soc. Agr. Eng. 18:1076-1081.
Polley, H.W., and S.L. Collins. 1984. Relationships of vegetation and environment in buffalo wallows. Amer. Midi. Nat. 112:178-186.
Ralphs, M.H., M.M. Kothmann, and L.B. Merrill. 1984. Proper stocking for short duration grazing. Texas Agr, Exp. Sta. Rep. PR-4190.
Reynolds, H.G., and P.E. Packer. 1963. Effects of trampling on soil and vegetation. USDA Misc. Pub. 940
Richardson, W.E., D.G. Grice, and L.A. Putnam. 1965. Soil survey of Garza County, Texas. USDA Soil Cons. Serv.
Savory, A. 1983. The Savory Grazing Method or Holistic Resource Management. Rangelands 5:155-159.
Savory, A., and S. Parsons. 1980. The Savory Grazing Method. Rangelands 2:234-237.
Shapiro, S.S., and M.B. Wilk. 1965. An analysis of variance test for normality (complete samples). Biometrika 52:591-611.
Sheldon, J.C. 1974. The behaviour of seeds in soil. III. The influence of seed morphology and the behaviour of seedlings on the establishment of plants from surface-lying seeds. J. Ecol. 62:47-66.
32
Sims, P.L., J.S. Singh, andW.K. Lauenroth. 1978. The structure and function of ten western North American grasslands. I, Abiotic and vegetational characteristics, J, Ecol, 66:251-285,
Spedding, C.R.W. 1971, Grassland ecology, Oxford Univ, Press, London.
Steel, R,G,D., and J,H. Torrie. 1980, Principles and procedures of statistics. McGraw-Hill Book Co., Inc., New York.
Stephens, J.L, 1980. Seedling emergence on vesicular crusted surfaces as affected by artifical and natural cattle trampling. M.S. Thesis. Univ. Nevada-Reno.
Stephenson, G.R., and A. Veigel. 1987. Recovery of compacted soil on pastures used for winter cattle feeding. J. Range Manage. 40:4 6-48.
Tainton, N.M, 1985. Recent trends in grazing management philosophy in South Africa. J. Grassl. Soc. S. Afr. 2:4-6.
Taylor, H.M. 1971. Effects of soil strength on seedling emergence, root growth, and crop yield, p. XX-ZZ. In: K.K Barnes, et al. (eds,). Compaction of agricultural soils. Amer. Soc. Agr. Eng. Monogr. No, 1.
Taylor, H.M., J.J. Parker, and G.M. Roberson. 1966. Soil strength and seedling emergence relations. II. A generalized relation for Gramineae. Agron. J. 58:393-395.
Thurow, T.L., W.H. Blackburn, and C A . Taylor. 1986. Hydrologic characteristics of vegetation types as affected by livestock grazing systems, Edwards Plateau, Texas. J. Range Manage. 39:505-50 9.
van Haveren, B.P. 1983. Soil bulk density as influenced by grazing intensity and soil type on a shortgrass prairie site. J. Range Manage. 36:586-588.
Walter, J. 1984 . Rangeland revolutionary: an interview with Allen Savory. J. Soil and Water Cons, 39:235-240.
Warren, S.D., W.H. Blackburn, and C A . Taylor, Jr. 1986a. Effects of season and stage of rotation cycle on hydrologic condition of rangeland under intensive rotation grazing. J. Range Manage. 39:486-491.
Warren, S.D., W.H. Blackburn, a n d C A . Taylor, Jr. 1986b. Soil hydrologic response to number of pastures and stocking density under intensive rotation grazing. J. Range Manage. 39:500-504.
Warren, S.D,, M,B. Nevill, W.H. Blackburn, andN.E. Garza. 1986c. Soil response to trampling under intensive rotation grazing. Soil Sci. Soc. Amer. J. 50:1336-1341.
Warren, S.D., T.L. Thurow, W.H. Blackburn, and N.E. Garza. 1986d. The influence of livestock trampling under intensive rotation grazing on soil hydrologic characteristics. J. Range Manage. 39:491-495.
Weigel, J.R., and C M . Britton. 1986. Use of a metal detector to locate permanent plots. J. Range Manage, 39:565,
Weltz, M., and M.K. Wood. 1986. Short duration grazing in central New Mexico: effects on infiltration rates, J. Range Manage, 39:365-368.
Wester, D,B,, B,E. Dahl, and P.F. Cotter, 1986. Effects of pattern and amount of simulated rainfall on seedling dynamics of weeping lovegrass and kleingrass. Agron. J, 78:851-855,
Wood, M,K., R,E. Eckert, Jr., W.H. Blackburn, and F.F. Peterson. 1982. Influence of crusting soil surfaces on emergence and establishment of crested wheatgrass, squirreltail, Thurber needlegrass, and fourwing saltbush. J, Range Manage. 35:282-287,
APPENDIX A
SOIL PROFILE DESCRIPTIONS
34
35
Soil Series: Stamford
General Description: Soils formed from clayey, micaceous
Triassic redbed material on gently sloping alluvial flats.
This series consists of deep, very slowly permeable but
v;ell-drained soils with high shrink-swell potential. Gilgai
microrelief and dry-season cracks up to 50 cm deep are
present,
Pedon Al: Typical pedon from short duration grazing cell 1,
pasture 2 .
Al—0 to 15 cm; dark reddish brown (2.5YR 3/4) clay; dark
reddish brown (2.5YR 2.5/4) moist; weak platy in upper 2 cm,
otherwise weak subangular blocky structure; firm; strong
effervescence; common medium roots; gradual, smooth
boundary.
A2--15 to 50 cm; dark reddish brown (2.5YR 3/4) clay; dark
reddish brown (2.5YR 2.5/4) moist; moderate subangular
blocky structure; very firm; strong effervescence; common
medium roots; gradual smooth boundary.
Bw—50 to 78 cm; reddish brown (2.5YR 4/4) clay; dark
reddish brown (2.5YR 3/4) moist; moderate subangular and
angular blocky structure; very firm; common medium
slickensides, some intersecting; discontinuous areas of
common calcium carbonate concretions; strong effervescence;
common fine roots; clear, wavy boundary.
36
Bk—78 to 98 cm; reddish brown (2,5YR 4/4) clay; aark
reddish brown (2.5YR 3/4) moist; weak subangular blocky
structure; very hard; violent effervescence; few fine roots;
clear, wavy boundary,
BC—98 to 116 cm; reddish brown (2,5YR 4/4) clay; dark
reddish brown (2.5YR 3/4) moist; weak subangular blocky
structure; very hard; violent effervescence; very few fine
roots; gradual, smooth boundary.
Cr—116+ cm; red (2.5YR 4/6) loam; reddish brown (2.5YR 4/4)
moist; massive; hard; strong effervescence.
Pedon All: Shallower pedon near well-defined drainage in
short duration grazing cell 1, pasture 2.
A — 0 to 13 cm; dark reddish brown (2.5YR 3/4) clay; dark
reddish brown (2.5YR 2.5/4) moist; weak platy in upper 2 cm,
otherwise granular and weak subangular blocky structure;
friable; strong effervescence; many fine and medium roots;
clear, smooth boundary.
Bwl—13 to 34 cm; reddish brown (2,5YR 4/4) clay; dark
reddish brown (2.5YR 2.5/4) moist; weak prismatic breaking
to moderate subangular blocky structure; firm; strong
effervescence; common fine and medium roots; gradual, smiooth
boundary.
Bw2--34 to 61 cm; reddish brown (2.5YR 5/4) clay; dark
reddish brown (2.5YR 3/4) moist; weak prismatic breaking to
37
angular and subangular blocky structure; firm; weak
slickenside development; strong effervescence; few fine
roots; gradual, wavy boundary.
Bk—61 to 83+ cm; red (2.5YR 4/6) clay loam; reddish brown
(2.SYR 4/4) moist; weak subangular blocky structure; very
hard; violent effervescence; very few fine roots.
Series: Vernon
General Description: Soils formed from clayey Triassic
redbed material on footslopes, convex ridges, and along
shallow drainageways. This series consists of moderately
deep, very slowly permeable but well-drained soils underlain
by partially weathered redbed shale.
Pedon BI: Typical pedon from short duration grazing cell 1,
pasture 2.
A — 0 to 9 cm; reddish brown (2.5YR 4/4) clay loam; dark
reddish brown (2.5YR 3/4) moist; weak subangular blocky
structure; friable; violent effervescence; common fine and
medium roots; clear, smooth boundary.
Bw—9 to 27 cm; reddish brown (2.5YR 5/4) clay; reddish
brown (2.5YR 4/4) moist; moderate subangular blocky and weak
prismatic structure; very firm; violent effervescence;
common fine roots; clear, irregular boundary.
38
Bk--27 to 48 cm; red (2.5YR 5/6) clay; red (2.5YR 4/6)
moist; discontinuous areas of common pink (5YR 7/4) calcium
carbonate concretions, light reddish brown (5YR 6/4) moist;
inherited shale parting; very hard; violent effervescence;
few fine roots; clear, wavy boundary.
Cr—48 to 68+; light red (2.5YR 6/6) shale; red (2.5 YR 5/6)
moist; massive; light effervescence; very few fine roots.
APPENDIX B
SOIL TEXTURE DATA
39
40
Table B.l, Soil texture data for study site soils.
Pedon
Al -
All -
BI -
Stamford
Stamford
Vernon
Horizon
Al
A2
Bw
Bk
BC
Cr
A
Bwl
Bw2
Bk
Bk
A
Bw
Bk
Cr
(lower)
Sand
15.7
13.0
13.1
20.5
16.6
60.0
29.7
22.9
15.4
33,2
23,3
33.6
11.4
13.7
25.1
Percent Silt
35.6
34.5
38.9
44 .0
37.2
24 .1
38.3
37.1
39.4
34 .0
53.5
45.5
42.9
55.0
50.2
Clay
48.7
52.6
48.1
35.6
46.2
24.9
32.0
40.0
45.2
32.8
23.2
20.9
45.7
31.4
24.6
APPENDIX C
BASAL COVER OF PERENNIAL GRASS SPECIES
41
42
Table C.l. Percent basal cover of bare ground, mulch, and perennial grass by study block, 5 August 1986.
Block^ Class or species
BARE MULCH HIMU SPAI SCPA BUDA SPPY
1
2
3
4
5
6
7
8
63.2
60.0
72.8
49.2
69.8
43.8
36.6
50.4
28,8
31,2
20.2
40.0
20.8
43.4
53.0
39.4
5,4
3.4
2.2
1.4
1.4
8.8
8.8
4.2
2 . 6
5 . 2
1 , 4
9 . 4
0 . 0
0 , 2
0 , 0
0 . 0
6,6
4,0
1.0
5.6
0.4
0.0
0,0
0.0
0.0
0.0
3,2
0.0
0,0
0.0
0.6
0.4
0.0
0.0
0.2
0.0
1.0
0.0
0.0
0.0
X 55.7 34 .6 4.4 4.5 0.1 0.5 0.2
In = conducted in grazed areas
500 ten-point-frame sample points per block; sampling
^BARE = bare ground, MULCH = mulch, HIMU = Hilaria mutica^
SPAI = .sporoboius a i r o i d e s , SCPA = Schedonnacdus panicu-latus, BUDA = Bnchloe dactyloides. SPPY = SporoboluS 2.y£-amidatus.
APPENDIX D
PRECIPITATION, TRAMPLING TRANSECT, AND KLEINGRASS
EMERGENCE DATA, AND KLEINGRASS ANALYSIS OF
VARIANCE TABLES
43
44
Table D.l. Kleingrass seeding and emergence dates and precipitation by day. Spring 1985 and 1986.
Sorina 1qfiS
Date
21 April
28 April
28 April
0 6 May
08 May
13 May
16 May
17 May
21 May
22 May
25 May
05 June
0 6 June
11 June
ppt (mm)
9.1
seeding
30.5
10.4
11.2
5,1
17,5
2.0
10.2
8.9
emergence
42,2
16,3
15,0
Sprina 1986
Date
27
02
06
19
24
25
25
26
27
30
01
03
05
06
17
19
March
April
April
April
April
April
May
May
May
May
June
June
June
June
June
June
ppt (mm)
seeding
16.5
7.6
56.6
4.1
emergence
9,6
10,7
27.4
35.6
33.5
11.9
4,8
emergence
23.9
38.9
45
Table D,2, Trampling intensity in grazing cycles before kleingrass emergence dates, 1985 and 1986.
Sample Date: 14 May 1985 23 April 1986 31 May 1986
Emergence Date: 25 May 1985 25 April 1986 06 June 1986
% Hoofprints / 10.0 m
42.5
24.1
16.4
16.9
12.0
3.1
11.3
10.3
27,4
17,6
7.1
18.2
29.3
9.4
31.6
14.0
X = 18.2 X =
S.E. = 2.6 S.E, = 1,8 S.E. = 1.6
2 6 , 6
9 , 8
6 , 9
1 1 , 6
1 1 . 3
4 . 3
2 3 . 4
1 3 . 5
7 . 0
1 9 . 7
3 . 0
8 . 2
1 0 . 2
3 . 4
5 . 2
1 6 . 7
1 1 . 3
6 . 0
1 6 . 0
1 3 . 0
1 0 . 0
2 2 . 0
2 8 . 5
4 . 0
1 3 . 5
1 6 . 0
7 . 5
9 . 5
14 .0
1 5 . 5
1 0 . 5
17 . 0
2 3 . 0
X = 14 . 1
46
T a b l e D . 3 . K l e i n g r a s s emergence d a t a fo r 25 May 1985.
Block.
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
5 5 5 5
6 6 6 6
7 7 7 7
8 8 8 8
Quadrant
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
Treatment
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
No
1
6 5 14 7
4 4 7 10
11 9 5 9
2 7 1 7
3 7 2 9
10 6
11 28
3 1 0 7
3 4 3 1
. see plot
2
11 9 8 4
6 1 7
20
13 8 7 6
5 4
11 5
19 5
12 9
9 6 8
13
3 3 3 5
3 0 0 3
dlings number
3
12 4 6
10
5 3 8 9
4 13 18 2
6 6 4
13
6 13 9 9
6 14 9
25
0 0 4 3
1 5 1 1
in
4
3 24 8 7
11 2 6 1
17 8
11 8
5 10 2
20
5 2 5 10
26 11 7 14
0 9 2 4
0 2 6 4
Ave^
8.0 10.5 9.0 7.0
6.5 2.5 7,0 10.0
11.2 9.5
10.2 6.2
4.5 6.7 4.5
11.2
8.2 6.7 7.0 9.2
12.7 9,2 8.7
20.0
1.5 3.2 2.2 4.7
1.7 2.7 2.5 2.2
0 = ungrazed, 1 = grazed.
Average of four p l o t s in row,
47
Table D.4 . K le ing ra s s emergence data for 25 Apr i l 1986
Block
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
5 5 5 5
6 6 6 6
7 7 7 7
8 8 8 8
Quadrant
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
Treatment
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
No. p
1
1 1
14 6
11 0 3 5
0 0 0 0
2 1 7 6
7 14 22 14
4 0 6 3
13 1
15 24
1 6 9 8
seedlings lot
2
1 8
31 6
17 2 5 3
2 0 0 0
7 5 4 0
28 17 11 7
6 24 10 6
41 17 30 29
8 17 18 40
number
3
4 0
44 8
12 0 9
14
0 1 0 0
9 2 3 4
22 12 18 6
13 8 5
18
30 5
24 35
12 8
18 21
in
4
7 3
24 13
8 2 0
20
0 17 0 0
1 JL
5 1
12 23 24 13
14 4 5 5
7 0
15 14
3 1 3 11
Ave^
3.2 3.0
28.2 8.2
12.0 1.0 4.2
10.5
0.5 4.5 0.0 0.0
4.7 2.5 4.7 2.7
17.2 16.5 18.7 10.0
9.2 9.0 6.5 8.0
22.7 5.7
21.0 25.5
6.0 8.0
12.0 20.0
• 0 = ungrazed, 1 = grazed.
Average of four p l o t s in row.
48
Table
Block
1
1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
5 5 5 5
6 6 6 6
7 7 7 7
8 8 8 8
D.5. Kleingrass
Quadrant
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
1 1 2 2
emergence
Treatment
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
0 1 0 1
data
No
1
3 15 8 3
6 0
13 13
2 6 3 6
25 9
17 10
9 2 5
17
20 14 5 4
15 16 11 9
13 15 4
17
for 1
. see plot
2
15 4
16 2
15 10 3 5
17 5 4 5
21 11 16 10
16 19 5 5
10 27 14 3
18 15 17 16
16 13 12 16
5 June
dlings number
3
11 3
11 3
15 5 11 11
2 6
12 12
14 8
26 13
18 7 13 5
20 18 13 10
15 18 17 12
26 8
11 7
1986.
in
4
11 5 1 2
19 3
20 8
7 20 4 7
30 13 17 15
14 7
16 29
16 6 7 3
7 21 7
29
9 17 7 3
2 Ave^
10.0 6.7 9.0 2.5
13.7 4.5
11.7 9.2
7.0 9.2 5.7 7.5
22.5 10.2 19.0 12.0
14.2 8.7 9.7
14.0
16.5 16.2 9.7 5.0
13.7 17.5 13.0 16.5
16.0 13.2 8.5 10.7
0 = ungrazed, 1 = grazed.
Average of four plots in row,
/ 9
Table D.6. Analysis of variance tables for kleingrass emergence data, 1985 and 1986.
Date; 25 May iqRS
Source Degrees Sum of of Variation of Freedom Squares F Prob > F
Blocks 7
Treatments 1 8.2519 1.43 0.2707
Blk X Trt (Exp. Error) 7 40.3887
Sampling Error 16
Total 31
Date; 25 April 1986
Source Degrees Sum of of Variation of Freedom Squares E Pirob > F
Blocks 7
Treatments
Blk X Trt (Exp.
Sampling Error
Total
1
Error) 7
16
31
40.5000
163.1875
1,74 0,2290
Date: 06 June 1986
Source Degrees Sum of of Variation of Freedom Squares E Frob > F
Blocks 7
Treatments 1 41.0645 2.15 0.1860
Blk X Trt (Exp, Error) 7 133.7012
Sampling Error 16
Total II
APPENDIX E
ANALYSIS OF VARIANCE TABLES FOR SOIL
STRENGTH DATA
50
51
Table E.l, Generalized analysis of variance table for soil strength data, 1985 and 1986.
Source Degrees
of Variance of Freedom
Blocks 7
Treatments 1
Blk X Trt (Exp. Error) 7
Sampling Error 48
Total 63
52
Table E,2. Analysis of variance table for soil strength data by date, 1933 and 1986.
Sum of Squares
Date Treatment B X T F Prob > F
5-06-85 0.2650 0,1330 13.95 0.0073
6-09-85^ 0.003800 0.000164 162.20 0.0001
6-18-85^ 0.176129 0,005550 222.14 0.0001
7-08-85^ 2,2762 0.1991 80.01 0,0001
3-20-86 0.001279 0.011479 0.78 0.4064
4-13-86 0.000067 0.063866 0.01 0.9341
4-23-86 0.2723 0.0232 82.33 0.0001
5-14-86 0.4264 0.0410 72.82 0.0001
5-25-86 0.3338 0.0152 153.37 0.0001
5-31-86 0.0013 0.0047 1.96 0.2041
7-16-86 1.2905 0.0814 110.96 0.0001
Analysis on power-transformed data.
wqwpip
APPENDIX F
FREQUENCY DATA FOR ANNUAL FORB AND
GRASS SPECIES
53
54
Table F.l. Frequency data for rabbit's tobacco, common broomweed, and woolly plantain, 1985-1987.
Frequency (No. plots with plants)
Season 1 Season 2
Species Date Ungrazed Grazed Ungrazed Grazed
E W E
XADR
PLPA
1
CN
00
4
Total plots
% frequency
1
2
3
4
Total plots
% frequency
1
2
3
4
Total plots
% frequency
12 8
12 5
12 3
103
4 7 9
93.5
62
73
71
48
2 5 4
49.6
63
68
72
67
2 7 0
52.7
12 7
12 7
115
100
4 6 9
91.6
74
91
67
53
2 8 5
55.7
66
68
62
55
2 5 1
49.0
86
96
84
2 6 6
69.3
44
45
46
13 5
35.2
31
35
33
99
25.8
93
91
86
2 70
70.3
52
52
45
14 9
38.8
24
35
38
97
25.3
n = 128 total possible plots/date-treatment combination.
55
^^^•^^•5'^' ^^equency data for red-seeded plantain, spurge, and bitterweed, 1985-1987.
Species Date
r-i
2 PLRH
3
4
Total plots
% frequency
1
2 EUSP
3
4
Total plots
% frequency
1
2 HYOD
3
4
Total plots
% frequency
Frequ
Seas
Ungrazed
84
42
34
25
18 5
36.1
53
44
24
7
12 8
25.0
21
15
16
8
60
11.7
ency (No.
on 1
Grazed
95
33
30
29
187
36.5
61
50
23
11
14 5
28.3
11
8
6
10
35
6.8
plots with plants)
Season 2
Ungrazed
41
36
30
10 7
27,9
28
53
49
13 0
33,9
4
4
6
14
3.6
Grazed
32
34
27
93
24 .2
23
43
43
10 9
28.4
4
6
3
13
3.4
n = 128 total possible plots/date-treatment combination
56
Table F.3. Frequency data for Astragalus, Gordon's bladderpod, and Texas filaree, 1985-1987.
Species Date
1
2 ASSP
3
4
Total plots
% frequency
1
2 LEGO
3
4
Total plots
% frequency
1
2 ERTE
3
4
Total plots
% frequency
Ung
Frequ ency (No.
Season 1
razed
5
4
4
9
22
4.3
7
5
3
5
20
3.9
4
5
2
1
12
2.3
Grazed
7
7
5
6
25
4.9
5
3
8
0
16
3.1
5
3
4
5
1 7
3.3
plot
Ung
s with plants)
Season 2
razed
15
9
6
30
7.8
9
7
9
25
6.5
4
2
2
8
2.1
Grazed
12
6
7
25
6.5
9
6
6
21
5.5
13
7
8
28
7.3
n = 128 total possible plots/date-treatment combination
57
Table F.4. Frequency data for meadow flax, little barley, and six-weeks fescue, 1985-1987.
Frequency (No. plots with plants)
Season 1 Season 2
Species Date Ungrazed Grazed Ungrazed Grazed
LIPR
HOPU
PLPA
1
2
3
4
Total plots
% frequency
1
2
3
4
Total plots
% frequency
1
2
3
4
Total plots
% frequency
4
4
3
5
16
3.1
49
57
52
2
160
31.2
63
68
72
67
2 70
52.7
3
1
2
3
9
1.8
55
61
60
1
17 7
34.6
66
68
62
55
2 5 1
49.0
0
1
0
1
0,1
3
19
23
45
11,7
31
35
33
99
25.8
2
9
7
18
4,7
6
23
19
48
12,5
24
35
38
97
25.3
n = 128 total possible plots/date-treatment combination.
PERMISSION TO COPY
In presenting this thesis in partial fulfillment of the
requirements for a master's degree at Texas Tech University, I agree
that the Library and my major department shall make it freely avail
able for research purposes. Permission to copy this thesis for
scholarly purposes may be granted by the Director of the Library or
my major professor. It is understood that any copying or publication
of this thesis for financial gain shall not be allowed without my
further written permission and that any user may be liable for copy
right infringement.
Disagree (Permission not granted) Agree (Permission granted)
Student's signature signature /
Date (\MJM. I . m i
Dat3 ^
