Restoring native species to crested wheatgrass dominated rangelands
by Janel Denice Johnson
A thesis submitted in partial fulfillment of the requirements for the degree Of Master of Science In
Range Science
Montana State University
© Copyright by Janel Denice Johnson (2004)
Abstract:
In the 1980's, there were an estimated 7 to 12 million ha of crested wheatgrass (Agropyron cristatum
(L.) Gaertn.) in North America. Dense stands of crested wheatgrass lack species diversity, which
negatively affects populations of wild mammals, birds, and reptiles. There is new interest among land
managers in replacing stands of crested wheatgrass with native species for wildlife habitat, using
minimal disturbance techniques such as herbicide and no-till seeding.
The objectives of this project were to (1) evaluate the effects of glyphosate on crested wheatgrass and
other species and (2) test seedling establishment of native grass and forb seed mixes planted in
glyphosate treated crested wheatgrass sod with a no-till drill.
Field trials were conducted with two herbicide application treatments and five planting treatments in
2002 and 2003 at five sites in central and eastern Montana. Crested wheatgrass biomass and seedling
biomass index were collected in 2002 and crested wheatgrass, seeded species, and non-target species
biomass were collected in 2003.
Results from the field trials indicate that applying glyphosate in the spring was effective at reducing the
biomass of crested wheatgrass for two seasons and shifting the dominance in the stands toward native
or weedy species, depending on the plant and seedbank composition. Application of glyphosate
increased diversity at sites with low initial diversity but not at sites with high initial diversity.
Seeding was generally not successful, due primarily to lack of moisture and nitrogen. Switchgrass
(Panicum mrgatum L.) and slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners) were
the most successful seeded species. Other native bunch grasses and forbs did not establish well.
Because of the high cost of native seed and no-till drilling, this treatment is not recommended unless
there is sufficient moisture and nutrients in the soil at the time of planting to support seedling growth. RESTORING NATIVE SPECIES TO CRESTED
WHEATGRASS DOMINATED RANGELANDS
by
J a n e l D enice J o h n s o n
A th e s is su b m itte d in p a rtia l fulfillm ent
of th e re q u ire m e n ts for th e degree
Of
M aster of Science
In
Range Science
MONTANA STATE UNIVERSITY
B ozem an, M o n ta n a
F eb ru ary , 2004
N 21?
-UY)?
APPROVAL
Of a th e sis su b m itte d by
J a n e l D enice J o h n s o n
T his th e s is h a s been rea d by each m em b er of th e th esis
com m ittee a n d h a s b een found to be satisfacto ry reg a rd in g co n ten t,
E n g lish u sa g e, form at, c itatio n s, bibliographic style, a n d consistency,
a n d is rea d y for su b m issio n to th e College of G ra d u a te S tu d ies.
<3 -I I-O1/
Dr. Bok Sowell
Date
(Signature)
A pproved for th e D epartm ent_of A nim al a n d R ange Sciences
Dr. Mike T ess
(Signature)
\
Date
A pproved for th e College of G ra d u a te S tu d ie s
Dr. B ruce McLe
(Signature)
Date
Ill
STATEMENT OF PERMISSION TO USE
In p re se n tin g th is th e s is in p a rtia l fulfillm ent of th e req u ire m e n ts
for a m a s te r’s degree a t M o n tan a S ta te U niversity, I agree th a t th e
L ib raiy sh a ll m ak e it available to b o rrow ers u n d e r ru le s of th e Library.
S ig n a tu re
D ate
2-~ i
iv
ACKNOWLEDGEMENTS
F irst I w ould like to th a n k th e B u re a u of L and M anagem ent
offices in M o n ta n a for providing th e fu n d in g a n d la n d for th is project. I
w ould also like to th a n k T odd Yeager a n d A dam C a rr a t th e Miles City
Field Office, a n d F red R oberts a t th e Lew istow n office for helping u s in
th e field a n d providing u s w ith info rm atio n a n d tools.
T h a n k s to P au l H elland a t th e P rairie C o u n ty W eed D istrict for
sp ray in g all of m y p lo ts in Terry, a n d Al Lenz, W ade W arneke, Harley,
a n d J im W ood w ho h elp ed m e p la n t all of th o se seeds.
I w ould like to th a n k D rs. Sowell a n d M arlow for serving on m y
co m m ittee a n d
a special th a n k y o u to Dr. C a sh
for all of th e
c o n stru c tiv e c o m m en ts d u rin g th e th e s is revision p ro cess.
T h a n k s to M ary a n d Sheila, w ho alw ays m ad e s u re m y crew a n d I
got p aid , a n d to Dave a n d th e people a t E n te rp rise for n o t getting m ad
w h en I got th a t tru c k s tu c k in th e field. T h a n k y o u Kim for p u ttin g u p
w ith m y re q u e s ts for tru c k s a n d trailers.
L ast I w ould like to th a n k A u tu m n , A rian n e, C h risty , S tephanie,
Gary, a n d P a tric k for sp en d in g m a n y h o u rs c u ttin g p la n ts w ith scissors.
TABLE OF CONTENTS
1. INTRODUCTION...................................................................................................... I
2. REVIEW OF LITERATURE....................................................................................2
C rested W h ea tg ra ss S u p p re s s io n ......................................................................2
G ra z in g .......... ...........................
2
F ire ......................................................................
3
M e c h a n ic a l..........................................................................................................3
H e rb ic id e ..........................................
4
Native G ra ss E s ta b lis h m e n t.......................
8
B ro a d c a stin g ....................................................................................................... 8
D rillin g ................................................................................................................. 9
T im in g ..................................................................
10
S pecies S e le c tio n ............................................................................................ 11
F e rtiliz e r.........................................................................
13
N on-T arget S p e c ie s..................................................................
13
S u m m a r y .................................................................................................................14
O b jectiv es.................................................................................................................15
3. METHODS AND MATERIALS........................................................................... 16
S ite s ................................................................................................
16
E x p erim en tal D esig n ....................................................................................... 19 .
S p ray t r e a tm e n ts ............................................................................................21
P lan tin g t r e a tm e n ts ...................................................................................... 22
S a m p lin g .........................................
24
C re sted W h ea tg ra ss B iom ass 2 0 0 2 ......................................................... 24
Seedling B io m ass Index 2 0 0 2 ................................................
25
A ll-Species B iom ass 2 0 0 3 ...............
26
D iversity I n d e x ..................................................................................
27
S ta tistic a l A n aly ses..............................................................
27
2 0 0 2 .................................................................................................................. 27
2 0 0 3 ..................................................................................................................28
4. RESULTS AND D ISC U SSIO N ........................................................................... 31
W eath er a n d S o il.................................................................................................. 31
C rested W h e a tg ra s s ............................................................................................. 34
Seeded S p e c ie s ................................................................
37
N o n -targ et S p e c ie s................................................................................................43
D iversity I n d e x .............................................................................
49
vi
C o n c lu sio n s........................................................................................................... 51
Im p lic a tio n s................................ :..........................................................................53
LITERATURE C IT ED .......................................................................................... 54
V ll
LIST OF TABLES
T able
Page
1.
C o m p ariso n
of c re ste d w h e a tg ra ss su p p re ss io n
te c h n iq u e s ........................................................................................................ 7
2.
T re a tm e n t d a te s for glyphosate a p p licatio n (1.1 kg a.i.
ha"1) a n d p la n tin g seed m ixes a t five sites in e a s te rn
a n d c e n tra l M o n ta n a .................................................................................... 21
3.
C om position of w arm se a so n a n d cool se a so n seed
m ixes no-till seed ed into g lyphosate sp ray ed c re ste d
w h e a tg ra s s sod a t five sites in e a s te rn M o n ta n a ................................ 23
4.
S am p ling d a te s a t five sites in e a s te rn a n d c e n tra l
M o n ta n a ............................................................................................................ 25
5.
A n n u a l P recip itatio n (mm) a t five sites in e a s te rn a n d
c e n tra l M o n tan a, 2001 to 2 0 0 3 ............................................................... 31
6.
Soil p ro p e rtie s a t five sites in c e n tra l a n d e a s te rn
M o n ta n a ............................................................................................................ 33
7.
2 0 0 2 c re ste d w h e a tg ra ss b io m a ss after sp rin g
ap p lica tio n of glyphosate a n d p la n tin g w ith native seed
m ixes a t five sites in e a ste rn a n d c e n tra l M o n ta n a ............................. 34
8.
2003
crested w h e atg rass b io m ass after sp rin g
ap p lication of glyphosate in 2002 (IX) or 2002 a n d 2003
(2X) a n d seeding w ith native seed m ixes a t five sites in
e a ste rn a n d c en tral M o n tan a......................................................................35
9.
2 0 0 2 b io m a ss index of p lan ted -see d lin g s in p lo ts
tre a te d w ith glyphosate a n d seed ed w ith native sp ecies
a t five sites in e a s te rn a n d c e n tra l M o n ta n a ........................................ 37
10. 2 0 0 3
p lan ted -see d lin g s
b io m a ss
after
sp rin g
a p p lica tio n of g lyphosate in 2002 (IX) or 2 0 0 2 a n d
2 0 0 3 (2X) a n d seeding w ith native species a t five sites
in e a s te rn a n d c e n tra l M o n ta n a ................................................................38
viii
LIST OF TABLES - CONTINUED
T able
Page
11. C om position of p la n te d sp ecies seedlings in all
tre a tm e n ts a t th e K eltner site in e a s te rn M o n tan a,
A u g u st 2 0 0 3 .................................................................................................. 40
12. 2 0 0 3
n o n -ta rg e t species b io m a ss after sp rin g
ap p lica tio n of g lyphosate in 2 0 0 2 (IX) or 2002 a n d
2 0 0 3 (2X) a n d seeding w ith native seed m ixes a t five
sites in E a s te rn a n d C en tral M o n ta n a ..................................................44
13. 2 0 0 3 B io m ass of n o n -ta rg e t sp ecies by fu n ctio n al
g ro u p following sp rin g a p p licatio n of g lyphosate in
2 0 0 2 (IX) or 2 0 0 2 a n d 2003 (2X) a t C h ristin a ,
M o n ta n a ...........................................................................................................45
14. 2 0 0 3 B io m ass of n o n -ta rg e t sp ecies by fu n ctio n al
g ro u p following sp rin g a p p licatio n of g lyphosate in
2 0 0 2 (IX) or 2002 a n d 2003 (2X) a t J e n s , M o n ta n a ........................46
15. 2 0 0 3 B io m ass of n o n -ta rg e t sp ecies by fu n ctio n al
g ro u p following sp rin g a p p licatio n of g lyphosate in
2 0 0 2 (IX) or 2 0 0 2 a n d 2003 (2X) a t K eltner, M o n ta n a .................. 46
16. 2 0 0 3 B iom ass of n o n -ta rg e t sp ecies by fu n ctio n al
g ro u p following sp rin g a p p licatio n of glyphosate in
2 0 0 2 (IX) or 2 0 0 2 a n d 2003 (2X) a t Loma, M o n ta n a .................... 47
17. 2 0 0 3 B io m ass of n o n -ta rg e t sp ecies by fu n ctio n al
g ro u p following sp rin g a p p licatio n of g lyphosate in
2 0 0 2 (IX) or 2 0 0 2 a n d 2003 (2X) a t W hitney, M o n ta n a ................. 47
18. D iversity Index afte r sp rin g a p p licatio n of g lyphosate in
2 0 0 2 (IX) or 2 0 0 2 a n d 2003 (2X) a n d seeding w ith
n ativ e seed m ixes a t five sites in E a s te rn a n d C e n tra l
M o n ta n a ...........................................................................................................50
LIST OF FIGURES
F igure
Page
1. M ap of stu d y site s in M o n ta n a .............. ..................................................... 16
2. Site L ayout for ex p erim en tal p lo ts ............................................................... 20
3. S am p ling a re a lay o u t for a) d e n sity a n d seedling c o u n ts
(2002), b) c re ste d w h e a tg ra ss b io m a ss (2002), a n d c)
sp lit-p lo t b io m a ss (2003)............................................................................. 24
4. P recip itatio n in tre a tm e n t y e a r (2001-2002) a n d 5 0 -y ea r
average for five site s in e a ste rn a n d c e n tra l M o n ta n a .......................32
X
ABSTRACT
In th e 1980's, th e re w ere a n e stim a te d 7 to 12 m illion h a of
c re ste d w h e a tg ra ss {Agropyron cristatum (L.) G aertn.) in N orth Am erica.
D en se s ta n d s of c re ste d w h e a tg ra ss lack species diversity, w hich
negatively affects p o p u la tio n s of wild m am m als, b ird s, a n d reptiles.
T here is new in te re s t am ong la n d m a n a g e rs in rep la cin g sta n d s of
c re ste d w h e a tg ra s s w ith native sp ecies for wildlife h a b ita t, u sin g
m in im al d is tu rb a n c e te c h n iq u e s s u c h a s herbicide a n d no-till seeding.
T he objectives of th is p roject w ere to (I) e v alu ate th e effects of
g ly p h o sate on c re ste d w h e a tg ra ss a n d o th e r sp ecies a n d (2) te s t
seedling e sta b lis h m e n t of native g ra ss a n d forb seed m ixes p lan ted in
g ly p h o sate tre a te d c re ste d w h e a tg ra ss sod w ith a no-till drill.
Field tria ls w ere c o n d u cted w ith two h erb icid e application
tre a tm e n ts a n d five p la n tin g tre a tm e n ts in 2002 a n d 2 0 0 3 a t five sites
in c e n tra l a n d e a s te rn M ontana. C rested w h e a tg ra ss b io m ass a n d
seedling b io m a ss in d ex w ere collected in 2002 a n d c re ste d w h eatg rass,
seed ed species, a n d n o n -ta rg e t species b io m a ss w ere collected in 2003.
R e su lts from th e field tria ls in d icate th a t applying glyphosate in
th e sp rin g w as effective a t red u cin g th e b io m a ss of c re ste d w h e atg rass
for two se a s o n s a n d shifting th e d o m in an ce in th e s ta n d s tow ard native
or w eedy species, d ep en d in g on th e p la n t a n d se e d b a n k com position.
A pplication of g lyphosate in cre ased diversity a t site s w ith low initial
diversity b u t n o t a t sites w ith high in itial diversity.
S eeding w as generally n o t su c ce ssfu l, d u e p rim arily to lack of
m o istu re a n d n itrogen. S w itch g rass (Panicum virgatum L.) a n d slen d er
w h e a tg ra s s (Elymus trachycaulus (Link) Gould ex Shinners) w ere th e m o st
su c c e ssfu l seed ed species. O th er native b u n c h g ra s s e s a n d forbs did
n o t e sta b lis h well. B ecau se of th e h ig h c o st of n ativ e seed a n d no-till
drilling, th is tre a tm e n t is n o t reco m m en d ed u n le s s th e re is sufficient
m o istu re a n d n u trie n ts in th e soil a t th e tim e of p la n tin g to su p p o rt
seedling grow th.
I
INTRODUCTION
C re sted w h e a tg ra ss {Agropyron desertorum (Fisch.) Schult. & A.
cristatum (L.) G aertn.) w as in tro d u c e d to N orth A m erica from Asia in th e
1 8 9 0 ’s. D u rin g th e d ro u g h t a n d d e p re ssio n of th e 1 9 3 0 ’s, m illions of
h e c ta re s of form er cro p la n d w ere seed ed to c re ste d w h e a tg ra ss to
stabilize loose soil (Rogler a n d Lorenz 1983).
C rested w h e a tg ra ss h a s
rem a in e d p o p u la r b e c a u se it p ro d u c e s m ore forage th a n native g ra sse s
a n d is to le ra n t of d ro u g h t a n d grazing p re s s u re (Caldwell e t al. 1981). In
th e 1 9 8 0 ’s, th e re w ere a n e stim a te d 7 to 12 m illion h a of cre ste d
w h e a tg ra s s in N orth A m erica (Rogler a n d Lorenz 1983, H olechek 1981).
D espite its u se fu ln e ss , large p la n tin g s of c re ste d w h e a tg ra ss have
som e negative ecological im p acts. D ense s ta n d s exclude native g rasse s,
forbs, a n d s h ru b s th a t a d d species diversity to g ra s s la n d h a b ita ts.
A
lac k of diversity negatively affects p o p u la tio n s of n ativ e m am m als, b ird s,
a n d rep tile s (Reynolds a n d T ro st 1980). Wildlife m a n a g e rs recognize th e
n e ed to re in tro d u c e native p la n ts a n d in cre ase d iversity to provide
h a b ita t for native m a m m a ls a n d birds.
2
REVIEW OF LITERATURE
T h ere is new in te re s t in rep lacin g s ta n d s of c re ste d w h e atg rass
w ith n ativ e sp ecies u s in g m inim al d istu rb a n c e te c h n iq u e s. The p u rp o se
of th is c h a p te r is to review th e lite ra tu re c o n cern in g th e su p p re ssio n of
c re ste d w h e a tg ra s s a n d e s ta b lis h m e n t native g ra sse s a n d forbs.
C rested W h ea tg ra ss S u p p re ssio n
R esident vegetation com petes strongly with seedlings for nu trien ts an d
w ater, so it m u st be reduced or elim inated w hen planting native grasses.
M ost seedings fail w hen surrounding vegetation is no t su p p ressed (Bakker et
al. 1997, Wilson a n d Gerry 1995, Peat a n d Bowes 1995).
Many recent
experim ents to replace crested w heatgrass a n d other p a stu re grasses w ith
native species were conducted in so u th ern S askatchew an a n d M anitoba,
w here soils a n d clim ate are sim ilar to central a n d eastern M ontana.
G razing
G razing by c attle or sh eep is n o t effective for rem oving c re ste d
w h e a tg ra s s from a seeded area.
A lthough heavy grazing re d u c e s
p ro d u c tio n (A ustin e t al. 1983), s ta n d s recover q uickly w h en rem oved
from g razing p re s s u re , doubling yields two y e a rs a fte r grazing ceased
(Hull a n d Klomp 1966).
Tw enty to forty y e a r old p a s tu re s grazed
3
a n n u a lly h a d h igh d e n sitie s of c re ste d w h e a tg ra ss w ith m in o r in v asio n s
of n ativ e sp ecies (Loom an a n d H einrichs 1973).
Fire
In th e S a n d h ills of so u th e rn S a sk a tc h e w a n , b u rn in g in th e fall to
re ju v e n ate p a s tu re s re d u c e d th e yield of c re ste d w h e a tg ra s s in th e first
se a so n following tre a tm e n t b u t p ro d u c tio n in following y e a rs equaled or
exceeded th e co n tro l by u p to 170 kg h a -1 (Lodge 1960). S pring b u rn in g
re d u c e d th e yield of c re ste d w h e a tg ra ss p a s tu re s for two y e a rs by 450 to
1 100 kg h a -1 b u t did n o t a lte r th e sp ecies com position of th e sta n d .
Romo e t al. (1994) com bined fall or sp rin g b u rn in g w ith herbicide
tre a tm e n t w hile te stin g m e th o d s to s u p p re s s c re ste d w h e atg rass.
The
re s u lts w ere n o t different from u n b u rn e d herbicide tre a tm e n ts (P>0.05).
M echanical
Two ty p es of m ec h an ica l tre a tm e n ts com m only u s e d on cre ste d
w h e a tg ra ss s ta n d s a re scarification a n d rototilling or double disking.
T he effect on c re ste d w h e a tg ra ss d e p e n d s on th e a m o u n t of d istu rb a n c e
c a u se d by th e tre a tm e n t. S carification, or ripping, only p artially d istu rb s
th e s ta n d a n d in c re a s e s p ro d u ctio n by 15 to 45% for five y ears after
tre a tm e n t (Peat a n d Bowes 1995, Lorenz a n d Rogler 1962). Rototilling or
d isk in g re d u c e s th e cover of c re ste d w h e a tg ra ss by 72 to 87% (B akker et
al. 1997, W ilson a n d G erry 1995) a n d provides a b e tte r se ed b e d for g ra ss
4
seed in g s th a n no tillage.
No-till d ry lan d seedings of s a n d b lu este m
{Andropogon gerardii var. paucipilus (Nash) Fern.), sw itc h g rass {Panicum
virgatum L.), in te rm e d ia te w h e a tg ra ss (Thinopymm intermedium (Host)
B arkw . 8s D. R. Dewey), a n d sm o o th brom e (Bromus inermis L eyssJ into
crop re s id u e s p ro d u ce d only I to 5 seedlings n r 2 a t th e end of th e
grow ing se aso n . Seed of th e sam e sp ecies drilled in to tilled g ro u n d a t th e
sam e tim e p ro d u ce d 14 to 25 seedlings n r 2 (King e t al. 1989).
T he
d ra w b a c k s
of tillage
and
scarification
are:
th e
su rface
su sce p tib le to w ind a n d w a ter erosion u n til th e seed ed g ra sse s develop,
d isru p tio n of th e soil s tru c tu re affects soil m o istu re a n d n u trie n t cycling,
a n d d is tu rb a n c e of th e soil b rin g s se ed s of u n d e sira b le species to th e
su rface (B aker e t al. 1996). Tillage also d am ag es d esirab le, native p la n ts
th a t m ay be p re s e n t in th e sta n d .
P a rtia l m ec h an ica l d istu rb a n c e of sta n d s , s u c h a s ripping, only
stim u la te s th e grow th of cre ste d w h e a tg ra ss a n d is n o t a n a p p ro p riate
tool for su p p re ssio n .
Tilling is a good tool for a re a s w ith low erosion
p o ten tial, a n d few d esirab le species, b u t is n o t su ita b le for a re a s w here
ero sio n a n d p reserv a tio n of native p la n ts in th e s ta n d a re concerns.
H erbicide
Herbicides are a low disturbance m ethod to control crested w heatgrass
for one or m ore growing seasons. In M anitoba, Gobin (1994) u se d mowing,
5
Gramoxone® (paraquat), Lontril® (clopyralid), Poast® (sethoxydim), a n d
R oundup® (glyphosate) to control tim othy {Phleutn pratense L.) an d sm ooth
brom e prior to seeding w ith tall w heatgrass (Thinopyrum ponticum (Podp.)
Barkw. & D. R. Dewey), sw itchgrass, green needlegrass {Nassella viridula
(Trim) Barkworth), a n d thickspike w heatgrass {Elymus lanceolatus (Scribner
& J.G . Smith) Gould).
Plots treated w ith glyphosate, a non-selective
herbicide, h a d 1300 to 1700 kg h a -1 less dry m atter accum ulation th a n
control plots a n d 300 to 700 kg h a -1 less th a n other herbicide treated plots a t
86 or 95 days after treatm ent. Seedlings in glyphosate treated plots did no t
have the greatest seedling densities a t 100 days after seeding b u t did have
th e greatest seedling developm ent (Harm Stage), exceeding other herbicide
treated plots by 0.5 to 5.9 H aun stages by 100 days after seeding. H aun
stage a t th e end of the growing season w as correlated w ith in-season
(R=0.733) a n d over-winter (R=0.909) survival rate of seedlings.
Glyphosate
treated plots h a d the greatest in-season survival rates, 88 an d 97%, an d
over-winter survival rates, 43 an d 85%, of an y suppression treatm ent. Gobin
(1994)
concluded
th a t
glyphosate
application
resulted
in
the
least
com petition from resident vegetation a n d w as the b e st choice of the four
herbicides for controlling resident vegetation w hen seeding desired species.
O th e r
re s e a rc h e rs
applied
glyphosate
to
co n tro l
cre ste d
w h e a tg ra ss. In S a sk a tc h e w a n , applying glyphosate in th e sp rin g red u c ed
c re ste d w h e a tg ra s s cover in m o st tre a tm e n t plo ts by 20 to 70% (B akker
6
e t al. 1997).
Com bining glyphosate application w ith rototilling did no t
decrease crested w heatgrass cover in the valley plots (cover = 14% spray
only, 12% spray + rototill), b u t decreased crested w heatgrass cover in upland
plots (cover = 31% spray only, 15% spray + rototill). Veiy low rainfall a t the
u p lan d site m ay have caused differences betw een sites.
In pastu re
im provem ent trials, applying glyphosate in the spring a t 1.1 kg ha-1 with
m inim al disturbance of crested w heatgrass fields yielded 400 kg h a -1 less
crested w heatgrass th a n control plots (Peat an d Bowes 1995).
This
treatm en t also h a d the greatest yield of seeded alfalfa [Medicago sativa L.)
(760 kg ha-1) com pared to partially disturbed (520 kg h a 1) a n d fertilized (290
kg h a 1) treatm ents.
These studies show th a t applying glyphosate alone
controls crested w heatgrass adequately while allowing seeded species to
establish.
Timing of application is a n im portant factor w hen u sin g glyphosate.
Peat a n d Bowes (1995) conducted trials to te st the effectiveness of glyphosate
applied a t different growth stages. Their d a ta show th a t applying glyphosate
after crested w heatgrass is greater th a n 15 cm tall is m u ch less effective th a n
applying a t 8 to 15 cm height (Table I). Seeded alfalfa yields were 17 tim es
higher in early vs. late-treated plots.
They concluded th a t glyphosate
application followed by sod-seeding in early spring w as a good m ethod for
establishing desired species in old crested w heatgrass stan d s.
7
T able I. C o m p ariso n of c re ste d w h e a tg ra ss (CWG) su p p re ss io n
te c h n iq u e s.
T reatm ent (Citation)
Spring B u m (Lodge, 1960)
Fall B u m (Lodge, 1960)
Scarification 10 cm shovels (Peat a n d Bowes, 1995)
Scarification 8 cm shovels (Lorenz a n d Rogler, 1962).
Rototilling (Bakker et al., 1997)
Gram oxone (Paraquat) (Gobin, 1994)
Poast (Sethoxydim) (Gobin, 1994)
G lyphosate
Glyphosate
Glyphosate
G lyphosate
G lyphosate
(Gobin, 1994)
(Spring) (Bakker et al., 1997)
(Spring) (Wilson an d Gerry, 1995)
(CWG headed) (Peat an d Bowes, 1995)
(CWG 8 to 15 cm) (Peat a n d Bowes, 1995)
Percent yield of
crested w heatgrass
com pared to control
45
52
144
115
28
41
65
23
74 to 30
20 '
77
I
C re sted w h e a tg ra ss begins to grow earlier in th e sp rin g th a n m o st
n ativ e sp ecies (Caldwell e t al. 1981), so m ixed s ta n d s c a n be tre a te d w ith
a sh o rt-a c tin g , non-selective herbicide, s u c h a s glyp h o sate, w hen cre ste d
w h e a tg ra s s is grow ing a n d native sp ecies a re still d o rm a n t. Romo et al.
(1994) tre a te d a n old c re ste d w h e a tg ra ss s ta n d a t th e th re e to five-leaf
stag e o r a t ad v an c ed b oot stage by w ick a p p licatio n of glyphosate a t a
h e ig h t th a t w ould only c o n ta c t th e c re ste d w h e a tg ra ss. T h is red u ced th e
relative b a s a l cover of c re ste d w h e a tg ra s s from 78% , in control, to 35 or
55% , respectively, of to ta l b a sa l cover a n d in cre ased th e relative cover of
n ativ e sp ecies correspondingly.
In m ixed s ta n d s of c re ste d w h e a tg ra ss
8
a n d n ativ e sp ecies it m ay n o t be n e c e ssa ry to p la n t native species if
g ly p h o sate is applied only to c re ste d w h e a tg ra ss a n d native species are
d o rm a n t or n o t tre a te d .
Herbicides provide a window of reduced com petition for planted
species; crested w heatgrass is reduced, b u t no t elim inated, by a single
herbicide application. Glyphosate is a very good tool for suppressing crested
w heatgrass b u t it does no t completely eradicate crested w heatgrass from
well-established stands.
Native G ra ss E sta b lish m e n t
After th e c re ste d w h e a tg ra ss su p p re ssio n , o th e r sp ecies m u s t be
e sta b lis h e d to com pete w ith w eeds a n d a n y surviving c re ste d w h e atg rass
p la n ts o r seedlings.
D esired species u s u a lly m u s t be p la n te d a s seed
so u rc e s a re often lacking.
E stim a te s for seedling d e n sitie s needed to
e sta b lis h a su c c e ssfu l s ta n d ran g e from 40 to 80 seed lin g s n r 2 a t th e en d
of th e first seaso n ; m o st agree th a t 25 seedlings n r 2 is th e m in im u m
d e n sity n e ed for m arg in al s ta n d s (King e t al. 1989, M organ et al. 1995,
W ark e t al. 1995).
The m o st im p o rta n t facto rs to co n sid er are th e
m eth o d of p lan tin g , seed m ix, a n d tim e of seeding.
B ro a d ca stin g
B ro a d c a stin g se ed s is m ore risk y th a n drilling a n d often req u ire s
m ore seed to e sta b lis h new sta n d s.
D ep red atio n by b ird s a n d ro d en ts,
9
poor
soil-seed
c o n ta ct,
and
flu c tu a tin g
m o istu re
and
c o n trib u te to low g e rm in atio n a n d seedling survival ra te s.
te m p e ra tu re
Six w eeks
afte r seeding, ro d e n ts a n d b ird s c o n su m e d 98% of b ro a d c a s t w h e atg rass
seed m ix in u n p ro te c te d a re a s (Nelson e t al. 1970).
W ater p o ten tial a t
th e su rfa ce flu c tu a te d m ore a n d re a c h e d m u c h lower levels (-0.01 to -80
MPa) th a n a t 2 cm below th e soil su rfa ce (-0.01 to -7 .2 MPa) (Nelson e t
al. 1970). O n tilled seed b ed s, b ro a d c a s t se ed s c a n be ra k e d a n d p ack ed
dow n to red u c e th e se p roblem s b u t existing vegetatio n m ak es th is
u n feasib le. B a k k er e t al. (1997) achieved s ta n d s of 145 seedlings n r 2 by
b ro a d c a stin g b lu e g ra m a (Bouteloua gracilis (H.B.K.) Lag. ex Steud.) seed
into rototilled a n d herb icid e tre a te d p lo ts a t a n u p la n d site. Valley plo ts
of th e
sa m e tre a tm e n t h a d only 35
seedlings n r 2 a n d u n tre a te d
b ro a d c a s t seed ed p lo ts h a d less th a n 25 seedlings n r 2.
S m all se ed s s u c h a s blu e g ra m a m ay experience le sse r p red atio n
ra te s th a n larg er seed ed species. If th e seed is expensive, b ro ad c astin g is
likely n o t c o st effective d u e to th e h ig h er seed in g ra te needed to
c o m p e n sa te for p re d a tio n a n d lower g e rm in atio n ra te s.
D rilling
No-tillage drilling or so d-seeding is p o p u la r for ra n g e p lan tin g s a n d
several m a n u fa c tu re rs have developed drills for th is p u rp o se .
No-till
d rills place th e seed a t th e p ro p er d e p th a n d p ack in g w h eels e n su re good
soil-seed c o n ta c t (B aker e t al. 1996).
G obin (1994) so d-seeded tall
10
w h e a tg ra ss, n o rth e rn w h e a tg ra ss, green n eed leg ra ss, a n d sw itch g rass
into se ed b e d s tre a te d w ith 2.5 L h a -1 glyphosate.
B o th sites p ro d u ced
accep tab le s ta n d s of 60, 65, 32, a n d 130 seedlings n r 2 respectively.
B a k k er e t al. (1997), u sin g a no-till drill, e sta b lish e d m o derately d e n se
(90 a n d 4 5 seedlings n r 2 a t valley a n d u p la n d sites respectively) s ta n d s of
b lu e g ra m a seedlings in old c re ste d w h e a tg ra ss fields.
At th e ir valley
site, e sta b lis h m e n t w ith th e drill w a s th re e tim es g re a te r th a n w ith
b ro a d c astin g ; th o u g h th e opposite w a s tru e a t th e ir u p la n d site.
Low
survival r a te s of seed lin g s in th e se p lo ts m ay have b e e n d u e to very low
su m m e r rainfall.
Tim ing
S eeding too soon after applying glyphosate c a n re s u lt in low
e s ta b lis h m e n t ra te s; w aiting 12 to 14 d a y s betw een h e rb ic id e application
and
seed in g re d u c e s th e risk to seedlings w hile c a p tu rin g sp rin g
m o istu re (Welty e t al. 1983).
P lan tin g m ore th a n two w eeks after
h erb icid e a p p licatio n m ay re s u lt in re d u c e d e s ta b lis h m e n t d u e to
co m p etitio n from th e recovering re s id e n t vegetation (W addington a n d
S ch ellen b erg 1976).
Cool se a so n g ra s se s c an be se ed e d in th e fall or
sp rin g th o u g h re s u ltin g s ta n d s c a n vary widely d e p en d in g on th e
w e ath e r, location, a n d species.
Six w h e a tg ra ss sp ecies drilled into
chem ically p re p a re d se ed b ed s in O ctober or M arch p ro d u c e d acceptable
s ta n d s in J u ly b u t by N ovem ber, sp rin g seeded p lo ts h a d two to th re e
11
tim es m ore seedlings th a n fall seeded p lo ts (Nelson e t al. 1970).
In
S a sk a tc h e w a n , green n e ed leg ra ss a n d c re ste d w h e a tg ra s s h a d g reater
g e rm in atio n w h en p la n te d in th e fall a n d in te rm e d ia te w h e a tg ra ss a n d
R u ss ia n
w ildrye
[Psathyrostachys juncea (Fisch.) Nevski) in sp rin g
(Kilcher a n d L oom an
1983).
A m in im u m of 60 cm of m oist soil
(approxim ately 10 cm of precipitation) is reco m m en d ed for sp rin g seeding
(Holzworth e t al. 2003). If sp rin g m o istu re is insufficient, fall seeding is
highly recom m ended.
W arm se a so n g ra sse s a n d forbs c o n sisten tly p ro d u c e d acceptable
s ta n d s w h en p la n te d in spring.
Fall seeding is n o t recom m ended for
w arm se a so n g ra s se s (McWilliams 1973, Ries a n d H offm an 1996). D ue
to v ariab le p referen ces of different sp ecies in native g ra s s seed m ixes a n d
v ariab le co n d itio n s betw een sites, b o th fall a n d sp rin g p la n tin g tim es are
reco m m en d ed to d eterm in e th e b e s t p la n tin g tim e for a seed m ix a t a
c e rta in site.
S pecies Selection
A diverse c o m m u n ity of n ative p la n ts is n e c e ssa ry to fill n ich es a n d
com pete w ith surviving c re ste d w h e a tg ra ss p la n ts a n d seedlings. A m ix
of differen t grow th form s a n d m id- a n d la te -se ra i sp ecies is m o st effective
a t u s in g re s o u rc e s a n d com peting w ith u n d e sira b le sp ecies (Sheley e t al.
1996).
A diverse seed m ix is n eed ed to e sta b lish a diverse com m unity
12
a n d is m ore likely to c o n ta in som e sp ecies th a t will survive adverse
grow ing co nditions.
H olzw orth e t al. (2003) list 18 n ativ e g ra ss sp ecies a n d four native
forb sp ecies th a t a re su ita b le for p la n tin g in e a s te rn M ontana a n d
com m ercially available.
The USDA softw are VegSpec (2001) confirm s
th a t m a n y of th e s e a re su ita b le for p la n tin g in silty clay lo am s in th e 25
to 35 cm p rec ip ita tio n zone.
N ear Terry, M o n ta n a g reen need leg rass,
w e ste rn w h e a tg ra s s (Pascopyrum smithii (Rydb.) Love), a n d n eedle-andth re a d g ra s s (Stipa comata T rin . & R upr.) com peted b e s t w ith c re ste d
w h e a tg ra s s w h en p la n te d in a m ix tu re (McWilliams a n d vanCleve 1950).
In b o th p a s tu re s , green n e ed leg ra ss yielded 2.5 to 3 .5 tim es m ore
b io m a ss th a n c re ste d w h e a tg ra ss w h en p la n te d a t th e sa m e rate. G obin
(1994) p la n te d sw itc h g rass into glyp h o sate s u p p re ss e d sod, re su ltin g in
seedling d e n sitie s of 85 to 175 n r 2.
Of 41 native sp ecies p lan ted into
g ly p h o sate su p p re s s e d c re ste d w h e a tg ra ss sod, W ilson a n d G erry (1995)
fo u n d seedlings of only seven species. Big b lu e ste m (Andropogon gerardii
var. gerardii V itm an), sle n d er w h e a tg ra ss, yellow coneflow er (Ratibida
columnifera (Nutt.) W oot. a n d S tandi.), a n d p u rp le p ra irie clover (Dalea
purpurea Vent.) h a d th e g re a te st n u m b e r of seedlings (93, 27, 11, a n d 6
seed lin g s in 60 m 2, respectively).
W h ea tg ra sse s, n e ed leg ra sse s, a n d
sw itc h g rass a re th e m o st likely to e sta b lis h a n d co m p ete successfully
w ith c re ste d w h e a tg ra s s on silty ran g e site s in e a s te rn M ontana.
13
Fertilizer
N itrogen (N) fertilizer in c re a se d c re ste d w h e a tg ra s s yields or cover,
th u s in c re a sin g com petition w ith p la n te d species (Bowes 1997, G obin
1994; a n d P e a t a n d Bowes 1995).
In u n d is tu rb e d p lo ts, O g N
n r2
tre a tm e n ts averaged 6 seedlings of p la n te d species n r 2 w hile 5 a n d 15 g
n itro g en n r 2 tre a tm e n ts averaged I a n d 0 seedlings n r 2 respectively
(Wilson a n d G erry 1995). A dding fertilizer d u rin g th e p la n tin g y e ar m ay
be d e trim e n ta l to th e e s ta b lis h m e n t of seed ed species.
N on-T arget Species
B e ca u se g lyphosate is non-selective a n d d e ac tiv ate d by c o n ta c t
w ith soil, a n y n o n -ta rg e t species w hich a re actively grow ing a t th e tim e of
a p p lica tio n a re su b je c t to dam age, w hile species w hich a re n o t active a re
n o t affected.
U sing carefully tim ed ap p lica tio n s of glyphosate, th e
sp ecies co m position m ay be a ltere d w ith o u t th e n e ed for seeding
(S am p so n a n d M oser 1982).
N o n -targ et sp ecies c a n com pete w ith seedlings a s severely a s
c re ste d
w h e a tg ra s s
(B akker
1996).
Species
th a t
are
sim ilar
physiologically com pete m ore strongly for w ater a n d n u trie n ts th a n
d issim ila r sp ecies (R. S heley, P e rs. Com m . 2002).
N o n -targ et species
14
th a t a re p re s e n t in th e s ta n d m ay com pete w ith seedlings a s m u c h a s
u n s u p p re s s e d c re ste d w h e atg rass.
S u m m ary
No te c h n iq u e h a s proven to elim inate c re ste d w h e a tg ra ss in a
single
ap p licatio n .
As
w ith
m any
u n d e sira b le
species,
rep e ate d
tre a tm e n ts or c o m b in atio n s of tre a tm e n ts a re n e c e ssa ry to red u ce th e
p o p u la tio n level.
H erbicide a p p licatio n is th e m o st effective m ethod to
red u c e c re ste d w h e a tg ra ss b io m ass a n d allow e sta b lis h m e n t of o th e r
p la n t
species.
S pring
applied
h erb icid e
m ay
sh ift
th e
species
co m p o sition of th e s ta n d to w ard w arm se a so n species in a m ixed species
s ta n d .
T he b e s t tre a tm e n t a p p e a rs to be glyphosate ap p lied a t 1.1 kg
h a -1 in th e sp rin g w h en c re ste d w h e a tg ra ss is 8 to 15 cm tall.
For ch em ically -p rep ared se ed b ed s, no-till drilling h a s a g reater
su c c e ss ra te th a n b ro ad c astin g .
D rilling seed s 12 to 15 days after
h erb icid e a p p lica tio n avoids h a rm fu l effects of th e h erb icid e to seedlings
w hile u tilizing h igh sp rin g soil m o istu re . If sp rin g m o istu re is insufficient
(<60 cm m o ist soil) fall p lan tin g afte r a se aso n of ch em ical fallow is
reco m m en d ed for cool se a so n species.
Individual sp ecies perform ance
v aries b etw een site a n d y ear, so several species, w hich m im ic th e n a tu ra l
p la n t c o m m u n ity for th a t site, sh o u ld be in clu d ed in a se ed m ix for b e tte r
c h a n c e s of a su c c e ssfu l sta n d .
15
O bjectives
T he objectives of th is p roject w ere to (I) ev alu ate th e effects of
sp rin g -ap p lied g lyphosate on c re ste d w h e a tg ra ss, se ed e d native species,
and
o th er,
n a tu ra lly
o ccurring,
sp ecies
and
(2)
te s t
seedling
e s ta b lis h m e n t of v a rio u s native g ra s s a n d forb sp ecies p lan ted in
g ly p h o sate tre a te d c re ste d w h e a tg ra ss sod w ith a no-till drill. The n u ll
h y p o th e se s were: (I) c re ste d w h e a tg ra ss b io m a ss w ould n o t be altered by
ap plying g lyphosate in th e spring, (2) different seed m ixes w ould n o t
re s u lt in different seed ed species b io m a ss, a n d (3) n o n -ta rg e t species
b io m a ss w ould n o t be altere d by applying glyphosate in th e spring a n d
p la n tin g n ativ e species.
16
METHODS AND MATERIALS
E x p erim e n t site s w ere e sta b lish e d a t five lo catio n s in e a ste rn a n d
c e n tra l M o n ta n a (Figure I) to te s t tre a tm e n t effects on a variety of soil,
clim ate,
and
vegetation
types.
C onditions
at
th e s e
sites
a re
re p re se n ta tiv e of m a n y decades-old c re ste d w h e a tg ra ss fields th e B u re a u
of L and M an ag em en t (BLM) m an a g es in M ontana.
Lom a
K eltner
C h ristin a
Jens
☆ -ft
W hitney
F igure I. M ap of stu d y sites in M ontana.
S ites
All sites w ere c h o se n on BLM la n d th a t h a d b e e n p lan ted to
c re ste d w h e a tg ra s s in th e p a s t 70 y e ars.
F o u r of th e sites, C h ristin a,
J e n s , K eltner, a n d W hitney, w ere form er h o m e ste a d s, p lan ted w ith
c re ste d w h e a tg ra s s a n d re tu rn e d to th e BLM u n d e r th e B a n k h e a d -Jo n e s
L and U tilization Act d u rin g th e d ro u g h t of th e 1930s.
T hese four sites
w ere also p a r t of large grazing a llo tm e n ts p rior to a n d d u rin g th is stu d y .
17
The fifth site, Lom a, w as tra d e d to th e BLM a s p a rt of a la n d exchange in
1988 a n d p la n te d to c re ste d w h e a tg ra ss a t th a t tim e.
C h ristin a (47° 2 4 ’ N, 109° 17’ W; elev. 1125 m) is located 10 km
n o rth e a s t of C h ristin a , M o n tan a on a level te rra c e over Arnell Creek.
T his is p a rt of a large p a s tu re a n d is s u rro u n d e d by n ativ e vegetation.
The soil type is L innet clay loam , 2 to 8% slope (fine-m ontm orillonitic
U steric Argiboroll).
The c h a ra c te ristic vegetation for th is soil type is
w e ste rn a n d b lu e b u n c h
(Pseudoroegneria spicata (Pursh) S c rib n . 8s
Sm ith) w h e a tg ra sse s, green n eed leg ra ss, a n d Wyoming big sa g e b ru sh
(Artemisia tridentata ssp . wyomingensis (Nutt.) B eetle & Young ) (USDANRCS
1988).
b lu e g ra sse s
T he re s id e n t vegetation is c re ste d w h e a tg ra ss w ith
(Poa spp. L.), w e ste rn w h e a tg ra ss, ju n e g ra s s (Koeleria
macrantha (Ledeb.) J . A. S chultes), a n d a wide v ariety of o th er g ra sse s
and
forbs;
c lu b m o ss
(Selaginella
densa
R ydbJ
form s
a
d en se
g ro u n d co v er in places.
J e n s (46° 4 0 ’ N, 105° 15’ W; elev. 790 m) is lo cated 13 km so u th of
T eriy , M o n tan a, n e a r th e J e n s R a n ch on a flat te rra c e above th e Pow der
River b re a k s.
Plots a re approxim ately 100 m from d ry la n d grain fields.
T he soil type is D eg ran d loam 0 to 4% slope (fine-loam y over sandysk eletal, m ixed Aridic Argiboroll).
C h a ra c te ristic v eg etatio n for th is soil
type is w e ste rn a n d b lu e b u n c h w h e a tg ra sse s, green n eed leg rass, a n d
n e e d le -a n d -th re a d g ra s s (USDA-NRCS 1996). The re s id e n t vegetation is
18
d o m in a ted by c re ste d w h e a tg ra ss w ith n e e d le -a n d -th re a d g rass, sa n d
d ro p se ed
[Sporobolus cryptandrus (Torrey) A. Gray), red th reeaw n
(Aristida longiseta Steudel), blu e g ram a, J a p a n e s e
(Bromus
brom e
japonicus T h u n b .), a n d green sagew ort {Artemisia dracunculus L.).
K eltner (47° 0 0 ’ N, 105° 3 7 ’ W; elev. 855 m) is located 30 km
n o rth w e s t of Terry, n e a r th e K eltner R a n ch on a flat b e n c h over th e
H o m estead reservoir.
T his site is p a rt of a 5 ,5 0 0 h a p a s tu re a n d is
s u rro u n d e d by native p rairie. The soil type is S ubw ell-P eerless loam , 0
to 4% slope (loam y-skeletal, m ixed Typic H aploboroll).
C h arac te ristic
v eg etatio n for th is soil is w e ste rn a n d b lu e b u n c h w h e a tg ra sse s, green
n e ed leg ra ss, a n d n e e d le -a n d -th re a d g ra s s (USDA-NRCS 1996).
The
re s id e n t v egetation is c re ste d w h e a tg ra ss w ith n e e d le -a n d -th re a d g ra ss
a n d silver s a g e b ru s h [Artemisia cana ssp . cana P u rs h ).
L om a (47° 5 3 ’ N, 1 10° 3 2 ’ W; elev. 825 m) is located 3 k m
s o u th e a s t of Lom a, M o n ta n a on a level te rra c e overlooking th e M issouri
River. T h is site is app ro x im ately I k m dow nw ind of d ry la n d grain fields.
T he soil type is F o rtb e n to n - C hinook fine sa n d y loam , 0 to 6% slope
(fine-loam y, m ixed Aridic Haploboroll). C h a rac te ristic vegetation for th is
soil type is p rairie sa n d re e d [Calamovilfa longifolia (Hook.) Scribn.),
n e e d le -a n d -th re a d
g ra ss,
w e stern
w h e a tg ra ss
and
In d ian
riceg rass
(Achnatherum hymenoides (Roemer & J.A . S chultes) B arkw orth) (USDANRCS 2001).
T he re s id e n t vegetation is c re ste d w h e a tg ra s s a n d alfalfa
19
w ith a n n u a l w eeds s u c h a s c h e a tg ra ss {Bromus tectorum L.), k o ch ia
(Kochia scoparia (L.) S chrad.), ru s s ia n th istle (Salsola iberica Sennen),
a n d su n flow er [Helianthus annuus L.). The s ta n d a t th is site is m u c h
y o u n g e r th a n th e o th e r sites. It w as n o t grazed, b u t it w a s b u rn e d by th e
BLM in 1996 to rem ove a c c u m u la te d fuels.
W hitney (46° 4 4 ’ N, 105° 0 1 ’ W; elev. 780 m) is located 22 km
s o u th of Fallon, M o n tan a, in rolling hills betw een W hitney a n d O’Fallon
C reeks, ap p ro x im ately 200 m from d ry lan d grain fields. T he soil type is
Flowree silt loam , 0 to 6% slope (fine-silty, m ixed A ridic H aploboroll).
C h a ra c te ristic
vegetation
for
th is
soil
is
w e ste rn
and
b lu e b u n c h
w h e a tg ra sse s, green n eed leg rass, a n d n e e d le -a n d -th re a d g ra ss (USDANRCS 1996). T he re s id e n t vegetation is c re ste d w h e a tg ra s s w ith a large
c o m p o n e n t of m ixed blu e g ra m a a n d b u ffalograss (Buchloe dactyloides
(Nutt.)
Engelm .), w hich
covers app ro x im ately
50-60%
of th e
site,
b lu e g ra sse s, ju n e g ra s s , n e e d le -a n d -th re a d g rass, a n d a wide variety of
forbs.
E x p erim en tal D esign
T he in itial e x p erim en tal design a t all sites w a s a random ized
com plete block w ith five tre a tm e n ts a n d four rep lica tio n s (Figure 2). The
d im e n sio n s of e a c h p lo t w ere 36 m x 36 m , su rro u n d e d by a 2 m wide
buffer strip . Individual plo ts were ex p erim en tal u n its .
20
T he tre a tm e n ts were:
•
C ontrol,
•
S p rin g a p p licatio n of g lyphosate only,
•
S p rin g a p p licatio n of g lyphosate a n d p la n t w ith m ixed native
w a rm -se a so n a n d cool-season g ra sse s a n d forbs in spring 2002,
•
S pring a p p lica tio n of g lyphosate a n d p la n t w ith m ixed native
co o l-seaso n g ra sse s a n d forbs in sp rin g 2002,
•
S p rin g a p p licatio n of g lyphosate a n d p la n t w ith m ixed native
co o l-seaso n g ra s se s a n d forbs in fall 2002.
S p ray
T re a tm e n t
R eplication
IX
C ontrol
2X
IX
C ontrol
2X
IX
C ontrol
2X
IX
C ontrol
2X
F igure 2. Site lay o u t for ex p erim en tal plots. E ach 36 x 36 m plot (heavy
outline) w as a ssig n ed a p la n tin g tre a tm e n t a n d p lan ted in
2002. Plots w ere split into two 18 x 36 m sp ra y tre a tm e n t
p lots (d ash ed line), 2002 only (IX) a n d 2 0 0 2 a n d 2003 (2X).
E ach rep licatio n c o n ta in s all five p lan tin g tre a tm e n ts ,
ran d o m ly assig n ed .
21
S p ray tre a tm e n ts
All p lo ts except th e control w ere tre a te d w ith R o u n d u p Ultra®
(glyphosate) applied a t 1.1 kg active in g red ien t (a.i.) h a -1 in early sp rin g
2 0 0 2 w h en th e c re ste d w h e a tg ra ss w as 8 to 10 cm tall a n d m o st native
sp ecies h a d n o t y e t em erged. The g lyphosate w as ap p lied by sp ray tru c k
in 100 L of w a te r p e r acre. An in e rt b lu e dye w as u s e d to m a rk tre a te d
a re a s a n d no site received p rec ip ita tio n w ith in two d a y s a fte r trea tm e n t.
D ates of tre a tm e n t ra n g e d from April 30 to May 30 (Table 2). Tordon®
(picloram ) w as also applied to a sm all p a tc h of leafy sp u rg e (Euphorbia
esula L.) w ith in th e Lom a site in J u n e 2002.
T h is a re a w as excluded
from sam pling.
T able 2. T re a tm e n t d a te s for g lyphosate a p p licatio n (1.1 kg a.i. h a -1)
a n d p la n tin g seed m ixes a t five sites in e a s te rn a n d cen tral
M ontana.
G lyphosate
G lyphosate
A pplication
Location A pplication
Spring planting Fall p la n tin g
November 7, 2002 April 23, 2003
Christina May .30, 2002
June 15,2002
Jens
May 16, 2002
June 6, 2002
October 8, 2002
April 28, 2003
Keltner
May 17, 2002
June 7, 2002
October 8, 2002
April 28, 2003
Loma
April 30, 2002
May 14, 2002
October 22, 2002
Not Treated
Whitney
May 16, 2002
June 6, 2002
October 10, 2002
April 28, 2003
The n o n -co n tro l p lo ts a t C h ristin a , J e n s , K eltner, a n d W hitney
w ere e a c h sp lit in to two 18 x 36 m halv es a n d h erb icid e w as applied to
one h a lf a g ain in April 2003, u sin g th e sam e m e th o d a s in 2002, to
co n tro l a n y regrow th of c re ste d w h e a tg ra ss.
Following th is tre a tm e n t,
22
th e 18 x 36 m sp lit-p lo t w as u s e d a s th e ex p erim en tal u n it.
S plit-plot
d a ta is referred to a s tre a te d once (IX) for sp lit-p lo ts tre a te d only in 2 0 0 2
a n d tre a te d tw ice (2X) for sp lit-p lo ts tre a te d in 2 0 0 2 a n d 2003.
Lom a
w as n o t re tre a te d b e c a u se of th e very low kill ra te in th e first season.
P lan tin g tre a tm e n ts
T he sp rin g -p la n te d m ixes w ere p la n te d 14 to 21 d ay s after th e
in itial tre a tm e n t (Table 2), a t a d e p th of 2 cm , w ith a T ruax™ no-till drill
d esig n ed for native seed m ixes. The site s w ere fenced w ith b a rb e d wire to
exclude c attle following th e first p lan tin g .
The cool se a s o n seed m ix
c o n ta in e d 100% cool se a so n sp ecies a n d th e w a rm se a s o n seed m ix
c o n ta in e d 32% cool se a so n species a n d 68% w arm s e a s o n species by
n u m b e r of p u re live se ed s (Table 3).
g ra s se s
and
one
and
two
forbs.
Seed m ixes e a c h co n ta in e d eight
Selected
sp ecies
w ere
e ith er
c h a ra c te ristic v egetation for te ste d soil ty p es or fast-grow ing, a d ap tab le
sp ecies th a t co u ld com pete well w ith c re ste d w h e a tg ra s s in a variety of
clim ate co nditions.
T he large n u m b e r of species in clu d ed reflects
a d a p ta tio n to different soil a n d clim ate ty p es am ong sites.
T he
fall-p lan ted
cool
se aso n -m ix
w as
p la n te d
after
a ir
te m p e ra tu re s d ro p p ed below freezing d u rin g th e d ay b u t before th e
g ro u n d froze. P lan tin g d a te s ran g e d from O ctober 8 th ro u g h Novem ber 7
(Table 2).
23
T able 3. C om position of w arm se aso n a n d cool se aso n seed m ixes no-till
seed ed into g lyphosate tre a te d c re ste d w h e a tg ra s s sod a t five
sites in e a ste rn M ontana.
P ercen t by
Kg p u re live
Species
num ber 1
seed h a 1
Cool W arm Cool W arm
B luebunch w heatgrass cv. Secar
Pseudoroegneria spicata (Pursh) Scribn. & Smith.
17.1% 8.3%
1.93
1.23
Slender w heatgrass cv. Piyor E lym us
trachycaulus (Link) Gould ex S hinners
14.9% 14.7%
1.43
1 .6 6
Thickspike w heatgrass cv. C ritana E lym us
lanceolatus (Scribner 8 5 J.G . Smith) Gould
13.1% 5.9%
1.09
0 .6 8
W estern w heatgrass cv. R osana Pascopyrum
smithii (Rydb.) A. Love
12.4% 3.0%
1.33
0 .2 0
Prairie ju n eg ra ss Koeleria macrantha (Ledeb.) J.
A. Schultes 1
3.1%
—
0.25
—
Sandberg's bluegrass Poa se c u n d a J .S . Presl
2.7%
—
0.17
—
2
Indian ricegrass cv. Rimrock Achnatherum
hym enoides (Roemer & J.A. Schultes) Barkworth
23.2%
—
2.35
—
Green needlegrass cv. Lordom Nassella uiridula
(Trim) B arkw orth
12.3%
—
1.54
—
. %
—
0.15
Lewis' blue flax cv. A ppar Linum lewisii P u rs h .
1 2
—
Little bluestem cv. C am per Schizachyhum
scopahum (Michx.) N ash
—
17.7%
—
2 .0 0
Sideoats gram a cv. B utte Bouteloua
curtipendula (Michaux) Torrey
—
18.3%
—
1.19
Sw itchgrass cv. Forestberg Panicum virgatum L.
—
11.3%
—
1.05
Prairie sandreed Calamovilfa longifolia (Hook.)
S cribn . 2
—
13.2%
—
1.19
Purple prairie clover Dalea purpurea V ent . 2
W interfat Krascheninnikovia lanata (Pursh)
A.D.J. M eeuse 8 s Sm ith 2
—
7.1%
—
0 .3 8
—
0.5%
—
0 .2 8
T otal kg h a -1
10.23
1 P u re live seeds.
2 C om m on seed u se d .
All se ed s p u rc h a s e d from Circle S S eeds, T hree F orks, M ontana.
9 .8 6
24
S am pling
All vegetation sam p lin g w as c o n d u cted w ith 0.25 m 2 sam p lin g fram es
ran d o m ly located in a re a s a ssig n ed to eac h sam ple n u m b e r in each plot
(Figure 3) so th a t sam p lin g could be re p e ate d in possible fu tu re studies.
S am ple p a tte rn s w ere altere d in 2003 to reflect c h a n g e s in plot shape.
a
b
c
Figure 3. S am pling a re a layout for a) c re ste d w h e a tg ra ss b io m ass in
2 0 0 2
, b) seedling c o u n ts in
2 0 0 2
, a n d c) sp lit-p lo t biom ass
in2003.
C rested W h ea tg ra ss B iom ass 2002
In J u ly 2002, a t th e ap p ro x im ate tim e of p e ak sta n d in g crop (Table
4), c re ste d w h e a tg ra ss b io m ass sa m p le s w ere clipped a t gro u n d level a t
five lo catio n s p er plot (Figure 3a). S am p les were sto re d in brow n p a p e r
b ag s, oven dried a t 50°C for 48 h rs , a n d w eighed.
e ac h plot converted to g n r 2.
S am ple w eights for
25
Seedling B io m ass Index 2002
In O cto b er 2 0 0 2 , a t th e e n d of th e first grow ing se a s o n (Table 4), th e
seed lin g s w ere m e a su re d a n d c o u n te d u sin g ten sa m p le locations p e r
p lo t (Figure 3b).
To e n su re th a t a n eq u al a m o u n t of drill row w as
sam p led , th e sam p le fram e s w ere aligned w ith th e drill row s. E ach 50 x
50 cm fram e covered th re e drill row s, so 150 cm of row a re included in
e a c h sam ple.
In e a c h sam ple, seedlings w ere c o u n te d by species a n d
average p la n t h e ig h t w as e stim ate d for eac h species. S eedling d a ta w ere
la te r tra n sfo rm e d by m ultiplying average h e ig h t by n u m b e r of seedlings
to o b ta in a to ta l h e ig h t of eac h sp ecies p e r sam ple.
T h is provided a
ro u g h e stim a te of b io m a ss w ith o u t th e n eed for d e stru c tiv e sam pling a n d
is called th e “b io m a ss index”. The to ta l index for e a c h p lo t w as divided
by 2 .5 , so th e final u n its w ere cm (of p la n t height) n r 2.
T able 4. S am pling d a te s a t five sites in e a s te rn a n d c e n tra l M ontana.
Site
Peak Crop
End of Season
Final
Christina
July/August, 2002
October, 2002
August, 2003
Jens
July, 2002
October, 2002
August, 2003
Loma
July/August, 2002
October, 2002
August, 2003
Keltner
July, 2002
October, 2002
August, 2003
Whitney
July/August, 2002
October, 2002
August, 2003
26
A ll-Species B io m ass 2003
In A u g u st 2 0 0 3 , th e final b io m a ss a n d d e n sity sa m p le s w ere ta k e n
(Table 4). T en sa m p le s w ere clipped in e a c h plot, five in each sp ra y
tre a tm e n t, except co n tro l p lo ts a n d all p lo ts a t Loma. S am ple a re a s w ere
re a rra n g e d to acco m m o d ate th e sp lit plo t (Figure 3c) a n d th e sam e
p a tte rn .w as u s e d in control plots.
As w ith p rev io u s sam pling, th e
sam p le fram e s w ere aligned in p la n te d p lo ts to in clu d e 150 cm of drill
row. T he p la n ts w ere c o u n te d , th e n clipped a n d sto re d in brow n p a p e r
b a g s by species. All sa m p le s w ere oven dried for a m in im u m of 48 h rs a t
50° C a n d w eighed.
C rested w h e a tg ra s s sam p les w ere to talled for e a c h plot a n d
co n v erted to g n r 2. T he to ta l of seed ed species b io m a ss sa m p le s for eac h
p lo t w as converted to g n r 2. N on-target b io m a ss sa m p le s w ere converted
to g n r 2 a n d g ro u p ed by th e following fu n ctio n al g ro u p s (modified from
T ilm an e t al. 1997): native a n n u a l g ra sse s, native cool se a so n p e re n n ial
g ra sse s, native w arm se a so n p e re n n ia l g rasse s, n ativ e a n n u a l forbs,
n ativ e p e re n n ia l forbs, native s h ru b s , cacti, clu b m o ss, in tro d u c e d a n n u a l
g ra sse s, in tro d u c e d p e re n n ia l cool se a s o n g rasse s, in tro d u c e d a n n u a l
forbs, a n d in tro d u c e d p e re n n ial forbs.
Soil sa m p le s w ere also o b tain ed from e ac h site in A u g u st 2003.
T en 15 cm deep cores w ere d u g a t ra n d o m sp o ts in e a c h field a n d th e n
m ixed
and
analy zed
for tex tu re,
n itra te
(NOs-N);, p h o sp h o ru s
(P),
27
p o ta s s iu m
(K), organic
m a tte r
(OM), a n d
pH
a t th e
Soil T esting
L ab o rato ry a t M o n ta n a S ta te U niversity.
For all p la n t a n d soil sam p les th e following a re a s w ere avoided:
se aso n ally w et a re a s , a n t hills, a n im a l bu rro w s, c a ttle tra il ru ts , a n d
a re a s n o t tre a te d acco rd in g to protocol (u n sp ra y ed or u n p lan ted ).
D iversity Index
D iversity in d ices w ere c a lcu late d for each sp lit-p lo t a n d control
u s in g th e S im p so n Index.
T his in d ex w as u s e d b e c a u se it is m ore
sen sitiv e to th e m o st d o m in a n t species, s u c h a s c re ste d w h e a tg ra ss, th a n
th e S h an n o n -W ie n er Index (B arbour e t al. 1999). T he fo rm u la u se d for
th e S im p so n Index w as C = B(p ; ) 2 W here p; is th e p ro p o rtio n of e ac h
sp ecies b a se d on b io m a ss a n d C is d o m in an ce. To e x p re ss th e re s u lt a s
diversity in s te a d of d o m in an ce, it w as tra n sfo rm e d to D = I - C w here D
is diversity, w ith I being th e m o st diverse a n d O being th e least. All d a ta
is p re s e n te d a s D.
S ta tistica l A nalyses
2002
For sam p lin g in th e first year, th e e x p erim en tal u n it w as each 36 x
36 m plot.
All sites co n ta in e d 20 seed in g tre a tm e n t p lo ts each in a
28
ran d o m ized com plete block of five tre a tm e n ts a n d fo u r rep licatio n s. The
to ta l n u m b e r of plo ts a c ro ss all sites w as
1 0 0
.
Site by tre a tm e n t in te ra c tio n s for c re ste d w h e a tg ra s s biom ass a n d
seed ed sp ecies b io m a ss in d ex w ere te s te d w ith tw o-w ay ANOVA a n d
fo u n d to be significant (P>0.10). B e ca u se of th e in te ra c tio n s, d a ta are
p re s e n te d by site for all variables.
W ithin e ac h site th e following m odel
w as u s e d for c re ste d w h e a tg ra ss b io m a ss a n d seedling b io m a ss index: Y
= g en eral m e a n + p la n tin g tre a tm e n t + rep licatio n + re sid u a l error.
R esid u al e rro r (12 d.f.) w as u s e d a s th e te stin g term . M ean se p a ra tio n s
w ere te s te d u s in g th e S tudent-N ew m an-K euls te s t a t P=O. 10 w h en
tre a tm e n t differences w ere in d ic ate d by ANOVA.
2003
E x p erim en tal u n it for sp lit p lo ts w as each 18 x 36 m split-plot.
C ontrol p lo ts a t all sites a n d all plo ts a t Lom a w ere n o t sp lit a n d eac h 36
x 36 m p lo t is th e ex p erim en tal u n it. T he to ta l n u m b e r of ex perim ental
u n its a t e a c h site in 2 0 0 3 w as 36 (32 tre a te d sp lit-p lo ts a n d 4 control
plots), ex cep t a t Lom a w here th e n u m b e r w as 20.
T otal n u m b e r of
ex p erim e n tal u n its a c ro ss all sites w as 164.
T he following m odel w as u s e d for c re ste d w h e a tg ra ss, seeded
sp ecies, n o n -ta rg e t b io m ass, a n d diversity index d a ta w ith in site: Y =
g en eral m e a n + p la n tin g tre a tm e n t + sp ra y tre a tm e n t + sp ra y x p lan tin g
tre a tm e n t in te ra c tio n + rep licatio n + w hole-plot e rro r + split-plot error.
29
S p lit-p lo t e rro r (11 d.f.) w as th e te stin g te rm for sp ra y tre a tm e n t
differences a n d w hole-plot e rro r
differences.
(12
d.f.) is th e te stin g te rm for p lan tin g
T he d a ta w ere n o t n orm ally d istrib u te d so th e y were ra n k -
tra n sfo rm e d
p rio r to a n aly sis
(Abbott a n d
R o u n d y 2003).
W hen
tre a tm e n t differences w ere in d ic ate d by ANOVA, m e a n se p a ra tio n s w ere
te s te d pairw ise w ith D u n n ’s te st.
L east sq u a re m e a n s a re p rese n te d in
ta b le s for clarity.
For n o n -ta rg e t d a ta , fu n ctio n al g ro u p s th a t c o n ta in e d only a sm all
n u m b e r (N<6 ) of non-zero d a ta w ith in e a c h site d e sig n a te d a s trace (T)
a m o u n ts.
T race a m o u n ts w ere in clu d ed in to ta ls a n d averages w ithin
site b u t w ere n o t analyzed individually.
D a ta a re p re s e n te d by site for all v ariab les b e c a u se site by
tre a tm e n t in te ra c tio n s for all 2003 b io m a ss d a ta w ere te s te d w ith twow ay ANOVA on ra n k -tra n sfo rm e d d a ta a n d fo u n d to be significant
(P<0.10).
C ontrol p lo ts w ere excluded from te s ts for sp ra y tre a tm e n t
in te ra c tio n s b e c a u se th ey w ere n o t split.
S pray tre a tm e n t by p lan tin g
tre a tm e n t in te ra c tio n s, w ithin site, a re n o ted in d a ta tab les.
For all
b io m a ss d a ta , averages a cro ss p la n tin g tre a tm e n ts w ith in site a n d
av erag es a c ro ss site s w ith in sp ra y a n d p lan tin g tre a tm e n t are provided
for review b u t w ere n o t te s te d d u e to in te ra c tio n s (P<0.10).
30
A P-value of 0 .1 0 w as c h o se n to c o m p e n sa te for th e large
variab ility w ith in a n d betw een sites. A nalyses w ere c o n d u cted w ith
Sigm aS tat© 3.0 for W indow s (2003) softw are from SPSS Inc.
31
RESULTS AND DISCUSSION
W eath er a n d Soil
N ational W eath er Service rec o rd s in d ic ate d v a ria tio n in th e a m o u n t
of p rec ip ita tio n a t e a c h site d u rin g th e tre a tm e n t y e a r
(2 0 0 1
to
2 0 0 2
),
from 1 1% m ore to 19% less th a n th e 50 y e a r average (Table 5).
T able 5. A n n u a l p rec ip ita tio n (mm) a t five sites in e a s te rn a n d cen tral
M o n tan a, Oct. 2001 th ro u g h Sept. 2002 a n d Oct. 2002
_________ th ro u g h May 2003._________________________________________
2 0 0 1 50 -y ear
P ercen t
5 0 -y ea r
P ercent
2 0 0 2 2 0 0 2
Average D ifference
2003
Average Difference
423
11
C h ristin a
380
194.
195
-I
267
Jen s
295
-2
152
117
30
289
K eltner
354
-19
169
163
4
288
-27
Lom a
118
163
322
-1 1
287
W hitney
314
-9
162
150
8
T he reco m m en d ed soil m o istu re c o n te n t for seed in g in e a ste rn
M o n ta n a is 60 cm of m o ist soil (Holzworth e t al. 2003), w hich is
eq u iv alen t to a b o u t 10 cm of p rec ip ita tio n from O cto b er to th e d ate of
p la n tin g for loam y soils. From O ctober to April, th e s tu d y sites received
35 to 75% of th e reco m m en d ed p rec ip ita tio n (Figure 4). T his lack of soil
m o istu re com bined w ith a late sp rin g d ro u g h t of 25 to 50 % below
average p rec ip ita tio n p ro b ab ly c a u se d th e low seedling e sta b lish m e n t
ra te s a t all sites.
32
Christina
50-year average
e 60
2001-2002 Precipitation
100 -I Jens
100 -I Keltner
E 60
100
80
E 60
J
Loma
100 Whitney
F igure 4. P recip itatio n in seeding y e a r (2001-2002) a n d 5 0 -y ear average
for five sites in e a ste rn a n d c e n tra l M ontana.
33
M uch of th e 2 0 0 2 p rec ip ita tio n fell in late su m m er; C h ristin a , J e n s , a n d
K eltner all received a b o u t twice th e n o rm al p rec ip ita tio n in A u g u st
(Figure 4). All site s received 2 to 60 p e rc e n t above average precip itatio n
in M arch a n d April 2 0 0 3 , co m p e n sa tin g so m ew h at for a d ry w inter.
Soil te x tu re s ra n g e d from sa n d y to clay loam s (Table
m a tc h e d d e sc rip tio n s from soil surveys.
6
) a n d closely
H igh levels of organic m a tte r
w ere fo u n d a t C h ristin a a n d W hitney, w hich have a n a b u n d a n c e of
shallow rooted, sod-form ing species s u c h a s b u ffalo g rass a n d clubm oss.
B u ffalo g rass a n d b lu e g ra m a te n d to have h ig h er soil org an ic m a tte r th a n
b u n c h g ra s s e s to 15 cm d e p th on p rairie soils (M cHenry a n d Newell
1947).
Table
. Soil p ro p e rtie s a t five sites in c e n tra l a n d
S a n d Silt Clay NO3-N
P
ppm
ppm
%
%
%
37
31
1 .6
1 1 .1
C h ristin a
32
Jen s
54
33
13
0 .8
4.2
K eltner
48
37
15
6.5
6.5
77
11
1 1 .1
Lom a
12
2 .2
W hitney
53
25
1 2 .6
3.2
22
6
e a s te rn M ontana.
OM
K
ppm
pH
%
538
4.17
6.8
204
7.3
1.35
7.9
2.02
232
8.4
0.90
298
344
6 .1
5.22
P h o s p h o ru s a n d K levels w ere a d e q u a te to low a t all sites (Table
6
).
N itrate levels w ere very low a t C h ristin a , J e n s , Lom a, a n d W hitney, a n d
low a t K eltner (Ja co b sen et al. 2003), w hich p ro b ab ly re d u c e d seedling
grow th a n d e sta b lish m e n t.
M oisture a n d n itro g en w ere probably th e
m o st lim iting fac to rs for p la n t grow th a t all of o u r stu d y sites.
34
C rested W h eatg rass
C re sted w h e a tg ra s s b io m a ss a t all sites, except Lom a, w as red u c ed
30 to 100 % by applying glyphosate in 2 0 0 2 (Table 7).
Table 7. 2 0 0 2 c re ste d w h e a tg ra ss b io m a ss after sp rin g a p p licatio n of
g lyphosate a n d p la n tin g w ith native seed m ixes a t five sites in
e a s te rn a n d c e n tra l M ontana.
Site
C h ristin a J e n s K eltner Lom a W hitney All S ites
- LS M eans, g n r 2
C ontrol
15.4 b 1 8 . 1 b
2 4 .6 b
38.3 b
9 .5 b
1 2 .8
S p ray Only
0 .0 a
2 0 .5 ab 37.9 b
9.0
0 .8 a
5.0 a
W arm se a so n
0 .0 a
0 .0 a
14.7 a
24.5 a
4 .2 a
5.2
m ix
Cool se a s o n m ix
5.0 a
6 .0
0 .0 a
15.1 a
27.5 ab
2.8 a
/ S p rin g p la n te d
Cool se a s o n m ix
4.1 a
7.8
0 .0 a
0 .0 a
18.1 ab 34.3 ab
/ Fall p la n te d
Average 2
0 .0
17.1
31.1
4 .6
7.0
0.9
1 T re a tm e n t differences te s te d u sin g one-w ay ANOVA a n d S tu d e n tN ew m an-K euls m e a n sep ara tio n . M eans sh a rin g a com m on letter
w ith in site a re n o t different (P<0.10).
2 D oes n o t in clu d e control.
After one y e a r of regrow th, in IX split-plots, c re ste d w h e atg rass
b io m a ss w a s still re d u c e d 48 to 94% v e rsu s th e control, a t all sites
except Lom a (Table
8
, IX d a ta ). T hese re s u lts a re c o n siste n t w ith
p rev io u s re s e a rc h u sin g glyphosate in th e spring.
Gobin (1994) found a
77% average reduction in crested w heatgrass yields; B a k k e r et al. (1997)
h a d a 2 6 to 70 % re d u c tio n in c re ste d w h e a tg ra ss cover. P e a t a n d Bowes
(1995), by applying glyphosate w h en c re ste d w h e a tg ra ss w a s
8
to 15 cm
Table 8 . 2003 crested w h e atg rass biom ass after spring application of glyphosate in 2002 (IX) or 2002
a n d 2003 (2X) a n d seeding w ith native seed m ixes a t five sites in e a ste rn a n d cen tral M ontana.
Site
C h ristin a
C ontrol
S pray Only
Jens
K eltner
Lom a
0 .0
a
1 .6
a
0.4 a
4 7.4 b
20.4 ab
Cool se aso n
m ix / S pring
p lan ted
0 .0
a
3 1.3 a
13.8 a
22.9 b
1 .9 a
0.3 a
1 0
0 .0
Average
2 .1
0 .0
2
1 0 2 .1
a 4 3 .1 ab
105.8 a
1 9 .0 a
2 .1
a
39.8
13.2
0 .1
a
35.9
7.0
Co
Oi
Cool se aso n
m ix/ Fall
p lan ted
1
All Sites
------------------------------------------------- LS m e a n s, g n r 2 — --------- --------------------------------------33.8 b 1
65.3 b
116.3 c
91.7 a
7 8.0 b
91.7
IX
IX
IX
2X
IX
IX
2X
2X
2X
IX
2X
0 .6 a
8 0.5 be 7.0 a
98.6 a
2 .1 a
0 .0 a
9 .0 a
7.4 a
0 .0 a
39.5
3.0
W arm seaso n
4.8 a
mix
2
1
W hitney
. a
a
18.5 a
0 .6
15.1
3.8
a
8 9.8 be
2 .2
60.2
7.9
a
78.3 a 3 0 .8 ab
96.2
25.1
0 .0
0.5
a
43.7
6.7
39.7
7.5
T rea tm en t differences te ste d u sin g K ruskal-W allis ANOVA on ra n k s a n d D u n n ’s pairw ise m ean
sep aratio n . M eans sh a rin g a com m on letter w ithin site are n o t different (P<0.10).
Does n o t include control.
36
tall, achieved a 99% re d u c tio n in c re ste d w h e a tg ra ss ste m d en sities in
th e first year.
A pplying glyp h o sate in b o th 2 0 0 2 a n d 2003 (2X) a t K eltner a n d
W hitney re d u c e d th e b io m a ss of c re ste d w h e a tg ra ss, 87 a n d 98%
respectively, v e rs u s applying only in 2 0 0 2 (IX) (Table
8
, P<0.10). C rested
w h e a tg ra s s b io m a ss a t Lom a afte r one y e a r w a s n o t red u ced by
g ly p h o sate a p p licatio n (Table
8
, P=O.83). G lyphosate m u s t be applied to
g reen leaf tis s u e to be effective a n d th e large a m o u n t of sta n d in g d ead
m a te ria l a t Lom a p ro b ab ly lim ited th e a m o u n t of g ly p h o sate co n tactin g
th e y o u n g sh o o ts (M onsanto 1996). G razing, m owing, o r b u rn in g p rio r to
a p p licatio n m ig h t have in cre ased th e effectiveness of glyphosate a t th is
site.
W hen applied to
8
to 15 cm tall c re ste d w h e a tg ra ss, a single
a p p licatio n of g lyphosate w as a good tool for re d u c in g th e b io m ass of
c re ste d w h e a tg ra s s for two growing se aso n s; applying in consecutive
y e a rs re d u c e d th e b io m a ss fu rth e r.
R educing th e b io m a ss of cre ste d
w h e a tg ra s s allow ed o th e r p la n ts to in c re a se in b io m a ss, changing th e
d o m in a n t sp ecies in th e c o m m u n ity over th e perio d of th e study.
37
S eeded Species
M ortality ra te s am o n g th e cool se a so n seedlings w ere visually
e stim a te d to be 5 to 100%, w ith g re a t variability w ith in sites. D esiccated
seed lin g s w ere freq u en tly fo u n d in th e drill row s th a t h a d germ in ated
a n d grow n for several w eeks before dying.
May p rec ip ita tio n Was 25 to
50% below average a t all sites (Figure 4) a n d p ro b ab ly c a u se d th e low
cool se a s o n e sta b lis h m e n t ra te s (Ries a n d H ofm ann 1996).
K eltner w a s th e only site w ith different seedling s ta n d s a t th e en d
of th e first grow ing se aso n , w ith a m u c h larger b io m a ss in d ex for w arm
se a so n seedlings (Table 9). B iom ass in d ex (total seedling height) a t th e
e n d of th e first grow ing se aso n co rre sp o n d e d ro u g h ly w ith seedling
b io m a ss in th e following se a so n (Tables 9 a n d 10).
Table 9. 2 0 0 2 b io m a ss in d ex 1 of p lan ted -see d lin g s in p lo ts tre a te d w ith
glyp h o sate a n d seeded w ith native species a t five sites in
e a s te rn a n d c e n tra l M ontana.
Keltner Loma W hitney All Sites
Site
C hristina J e n s 3
LS m e a n s, cm n r -2 ______
Warm season mix2
2 .4 a
33.3
0.5 a 2
26.3 a 135.5 b 1 .7 a
Cool season m ix/
1 0 .1
4 4 .0 a 2 . 0 a
1 .0 a
0 .0 a
3.6 a
Spring planted
1.7
21.7
Average
0 .2
14.9
1.9
8 9 .7
1 O b ta in e d by m u ltiplying average h e ig h t by to tal n u m b e r of seedlings.
2 T re a tm e n t differences te ste d u sin g one-w ay ANOVA a n d S tu d e n tN ew m an-K euls m e a n se p ara tio n . M eans sh a rin g a com m on letter
w ith in site a re n o t different (P<0.10).
3 All sa m p le s a t J e n s c o n sisted of u n id en tifiab le seedlings.
Table 10. 2003 p lan ted -see d lin g s b io m a ss after sp rin g a p p licatio n of glyphosate in 2 0 0 2 (IX) or 2002
a n d 2 0 03 (2X) a n d seeding w ith native species a t five sites in e a ste rn a n d c e n tra l M ontana.
Site
C h ristin a
Jens
K eltner 21
Loma
W hitney
All Sites
IX
IX
IX
2X
2X
2X
IX
IX
2X
IX
2X
J -/O I llL z c L liO j ^
W arm se aso n
0 .1 a1
9.0 a 0 . 0 a
0 .0 a
64.2 b 158.8 c
2.3 a
3 .0 a 8 . 6 a 13.9 35.9
m ix
Cool se aso n
m ix / S pring
p lan ted
Cool se aso n
m ix / Fall
p lan ted
Average
1
2
a
0 .0
a
0 .0
a
0 .0
a
1.9 a
0 .0
a
0 .0
a
0 .0
a
0.5
2.2
0 .0
0 .0
0 .0
2 4 .0 a
1 6 .1 a
0 .0
a
0 .0
a
0 .0
a
4.8
3.2
a
2.7 a
0 .1
a
0 .0
a
0 .0
a
0.5
0.5
6.4
13.1
0 .6
2 9 .6
59.2
0.8
1 .0
2.9
T re a tm e n t differences te ste d u s in g K ruskal-W allis ANOVA on ra n k s a n d D u n n ’s pairw ise m ean
se p ara tio n . M eans sh a rin g a com m on le tte r w ith in site a re n o t different (P<0.10).
S p ray x p la n tin g tre a tm e n t in te ra c tio n (P<0.01).
39
By A u g u st 2 0 0 3 , J e n s h a d p ro d u ce d no p la n te d seedlings a n d
Loma, C h ristin a , a n d W hitney e a c h p ro d u ce d a sm all b io m ass of
seed lin g s b u t th e b io m a ss w as n o t different betw een tre a tm e n ts (Table
10, P>0.10).
T he only site th a t h a d a large b io m a ss of p la n te d seedlings in 2003
w as K eltner, w here th e re w as a larg er b io m a ss of w arm se a so n seedlings
th a n cool se a s o n seedlings a c ro ss sp ra y tre a tm e n ts (Table 10, P<0.10).
T he d o m in a n ce of w arm se a so n seedlings in th e p la n tin g s is m ost likely
d u e to th e p rec ip ita tio n p a tte rn d u rin g th e tre a tm e n t y ear, w hich w as
126% above average d u rin g A u g u st a n d favored th e grow th of w arm
se a so n species. A pplying glyphosate tw ice (2X) in c re a se d th e biom ass of
w arm se a s o n seedlings (Table 10, P=0.006) v e rs u s applying once (IX).
G lyphosate d am ag e w as visible on cool-season seedlings in th e 2X plots
b u t th e re w ere no differences betw een sp ra y tre a tm e n ts site (P=0.67).
Native p rairie re sto ra tio n h a n d b o o k s reco m m en d >40 seedlings n r 2
in th e first y e a r for su c ce ssfu l s ta n d s a n d 25 seedlings n r 2 for m arginal
s ta n d s (King e t al. 1989, W ark et al. 1995). The average seedling d e n sity
a t C h ristin a , J e n s , Lom a a n d W hitney w as less th a n I n r 2, well below
th e reco m m en d ed d en sities. The g re a te s t seedling d e n sity in o u r stu d y
w as in th e w arm se a so n 2X p la n te d p lo ts a t K eltner a n d averaged 25
seed lin g s n r 2, th e m in im u m
reco m m en d ed d e n sity for a m arginal
seedling s ta n d . L a u n c h b a u g h a n d B e m e n t (1966) rec o m m e n d 11 p la n ts
40
rrr 2 for a su c c e ssfu l a d u lt sta n d , w hich w arm se a so n s ta n d s a t K eltner
exceeded. A lthough th e seedling s ta n d s a t K eltner initially failed to m ee t
reco m m en d ed seedling d e n sities for su c c e ssfu l s ta n d s , survival ra te w as
likely h ig h e n o u g h to re s u lt in a su c c e ssfu l a d u lt sta n d .
T ab le! I. C om position of p la n te d sp ecies seedlings a c ro ss all p lan ted
tre a tm e n ts a t th e K eltner site in e a ste rn M o n tan a, A ugust
2003.
S pecies
B iom ass P ercentage
T otal
Average b io m ass
n
u
m
b
e
r
p e r p la n t
by
b
io
m
a
ss
(g)
(R)
4
1.5
In d ia n rice g rass
5.8 1
0.3
I
1.9
0 .1
G reen n e ed le g ra ss
1.9
2.3
S len d er w h e a tg ra ss
187.9
9.2
83
27
1.9
Little b lu e stem
52.0
2.5
5
2.5
12.3
0 .6
S id eo ats g ra m a
9.4
155
1463.9
7 1 .5
S w itch g rass
13.1
2 6 1 .6
1 2 .8
2 0
B lue flax
1.4
2.5
38
P u rp le p rairie clover
51.5
1.3
9
11.7
0 .6
U nk n o w n
4.0
542
2 1 4 8 .7
Total
1 T otal sam p lin g a re a for p la n te d p lo ts = 30 m 2.
W arm se a s o n seedlings co m p rised appro x im ately 77% of seedling
b io m a ss a n d 65% of seedling n u m b e rs a t K eltner (Table 11). S w itchgrass
p ro d u ce d th e la rg e st n u m b e r a n d b io m a ss of seedlings a lth o u g h it w as
only 3.5% of th e to ta l se e d s p lan ted . At all sites, sw itc h g ra ss com prised
th e la rg e st p ro p o rtio n of th e seedling b io m a ss a n d n u m b e rs .
S len d er
w h e a tg ra s s p ro d u c e d th e larg e st n u m b e r of cool se a s o n seedlings.
S w itc h g rass a n d sle n d e r w h e a tg ra ss w ere also th e le a s t expensive se ed s
41
p u rc h a s e d for th is p ro ject a t $5 a n d $3 p e r kg of p u re live seed.
seed lin g s
w ere
observed
for:
b lu e b u n c h
w h e a tg ra ss,
1
No
thick sp ik e
w h e a tg ra ss, S a n d b e rg b lu eg ra ss, p rairie ju n e g ra s s , p ra irie sa n d ree d , or
w in terfat. S w itc h g rass, little b lu este m , p u rp le p rairie clover, a n d sle n d er
w h e a tg ra s s w ere th e m o st su c ce ssfu l sp ecies p la n te d in th is project.
Low n itra te in th e soil m ay hav e h a d a n im p a c t on seedling
e sta b lish m e n t. The soil a t K eltner c o n ta in e d 2 to
a s soil a t o th e r sites (Table
b io m a ss (Table
6
8
tim e s a s m u c h n itra te
) a n d K eltner h a d th e larg e st seedling
10), com posed p rim arily of sw itc h g ra ss (Table 11).
S a n d e rso n a n d Reed (2000) a n d H a rtn e tt (1993) su g g e st th a t available
NO 3 -N levels do n o t affect sw itc h g rass grow th b u t b o th stu d ie s applied
NO 3 -N levels m u c h h ig h er th a n th o se fo u n d on o u r s tu d y sites (4 to 20
tim es h ig h er th a n a t Keltner).
E xtrem ely low NO 3 -N levels likely h a d a
negative im p a c t on sw itc h g rass seedling grow th a n d e sta b lish m e n t.
At C h ristin a , J e n s , a n d W hitney, lim ited m o istu re a n d n itra te , a n d
co m p etitio n from n o n -ta rg e t species likely c a u se d th e low seedling
e sta b lis h m e n t ra te .
G reen h o u se s tu d ie s show th a t g ra s s ro o ts com pete
stro n g ly for w a te r a n d n itro g en even w h en b o th a re in a d e q u a te su p p ly
(H augland a n d Froud-W illiam s 1999). Seedling ro o ts, bein g sm aller, are
a t a com petitive d isa d v an tag e a g a in st th e ro o ts of e sta b lish e d p la n ts
(B akker 1996).
T he ro o ts of seedlings a t C h ristin a a n d W hitney w ere
likely co m peting w ith native m at-form ing species s u c h a s buffalograss
42
a n d clu b m o ss. Seedlings a t Lom a w ere com peting w ith th e u n co n tro lled
c re ste d w h e a tg ra s s sod. S eedlings a t J e n s e n c o u n te re d b o th com petition
from w eeds a n d c o n su m p tio n by g ra ssh o p p e rs, w h ic h c an have a
s u b s ta n tia l im p a c t on native g ra ss p o p u la tio n s (Q uinn e t al. 1993).
T he
c o m b in atio n
of
lim ited
w a te r
and
n itra te
reso u rces,
co m p etition w ith e sta b lish e d p la n ts, a n d dam age by g ra ssh o p p e rs likely
c a u se d th e poor seedling crop.
Rem oval of species o th e r th a n cre ste d
w h e a tg ra ss, s u c h a s w eeds a n d m at-fo rm in g p la n ts, m ay be n e ce ssa ry
for e sta b lish in g seed ed species.
T he ex p en se of no-till drilling, a b o u t $ 2 5 0 h a -1, w a s m u c h g rea ter
th a n th e ex p en se of g lyphosate ap p licatio n , a b o u t $ 8 0 h a -1. M any of th e
n ativ e se e d s p u rc h a s e d c o st m ore th a n $10 kg"1 a n d th e average co st for
b o th seed m ixes w as approxim ately $95 h a 1, th o u g h a m o re conservative
seed m ix m ay c o st m u c h less.
A dditionally, o p e ra tin g th e drill a n d
tra c to r c o st ro u g h ly $ 1 5 5 h a -1. C onsidering th e large ex p en se a n d low
su c c e ss ra te of th e seed in g s on o u r project, no-till drilling w as n o t c o st
effective. In c re ste d w h e a tg ra ss s ta n d s th a t c o n ta in d e sire d species, th e
large c o st seed in g m ay be avoidable w ith th e c arefu l application of
g ly p h o sate tim ed to red u c e only th e c re ste d w h e a tg ra s s a n d encourage
grow th of d e sired species. In a re a s w ith large p o p u la tio n s of u n d e sira b le
sp ecies, co n v en tio n al tillage a n d p la n tin g into stu b b le m ay be m ore
su c c e ssfu l th a n no-till drilling (Holzworth el al. 2003).
43
N on-target Species
G ly phosate a p p licatio n te n d e d to
shift d o m in a n ce in cre ste d
w h e a tg ra s s s ta n d s to w ard w arm se a so n native g ra s se s o r w eedy species,
d e p en d in g on th e in itial com position of th e sta n d . T he to ta l b io m ass of
n o n -ta rg e t sp ecies w as n o t altere d by a n y tre a tm e n t a t Loma a n d
W hitney (Table 12, P > 0 .10), b u t th e species co m position w as altered.
G ly p h o sate a p p lica tio n a t C h ristin a , J e n s , a n d K eltner in cre ased n o n ­
ta rg e t b io m a ss in one or m ore tre a tm e n ts .
All tre a tm e n ts in th e IX sp lit-p lo ts p ro d u ce d m ore to ta l n o n -ta rg e t
b io m a ss th a n th e co n tro l a n d th e 2X sp lit-p lo ts a t C h ris tin a (Table 12,
P<0.10).
T reatin g one y e a r (IX) in c re a se d th e b io m a ss of native cool
se a so n p e re n n ia l g ra s se s a n d forbs in th e following y ear, b u t tre a tin g
co n secu tiv e y e a rs (2X) d am ag ed th e m (P<0.10). T rea tin g consecutive
y e a rs
also
re d u c e d
th e
b io m ass
of in tro d u c ed
p e re n n ia l g rasse s,
p rim arily K entucky b lu e g ra ss (Table 13).
The b io m a ss of a n n u a l p la n ts a t J e n s in c re a se d in th e glyphosate
tre a te d
p lo ts
(Table
14,
P<0.10).
T hese
w eedy
a n n u a ls
co n sisted
p rim arily of sp ecies th a t are com m only fo u n d in th e n e a rb y w h eat fields;
a n n u a l b ro m es a n d forbs. S a m p so n a n d M oser (1982) re p o rte d a n n u a l
Table 12. 2 003 n o n -ta rg e t species b io m a ss afte r spring a p p licatio n of glyphosate in 2002 (IX) or 2002
a n d 2 0 03 (2X) a n d seeding w ith native seed m ixes a t five sites in E a ste rn a n d C en tral M ontana.
Site__________ C h ristin a __________ J e n s __________ K eltner______ Loma_____ W hitney_______ All Sites
----------------------------------------------------------LS m e a n s, g n r 2 ---- --------------------------------------------6 1 .4 a 1
9.0 a
6.4 a
C ontrol
10.7 a
69.0 a
29.5
IX
2X
IX
2X
IX
2X
IX
IX
2X
IX
2X
Spray
188.3 c 1 1 1.5 ab 94.9 b 8 7 .5 b 166.8 b 59.4 a 2 9 .6 a 123.2 a 1 1 7 .8 a 102.1 76.1
Only
W arm
se aso n
140.3 b
56.0 a 79.5 b 54.9 ab 35.5 a 37.2 a 13.8 a 116.5 a 109.8 a
62.2 51.8
m ix
Cool
seaso n
m ix /
164.7 b
6 3 .1 a 43.9 ab 47.1 ab 52.5 a 2 1 .4 a 30.1 a 103.2 a
6 5 .7 a
70.3 38.4
S pring
p lan ted
Cool
seaso n
m ix /
125.2 b
8 1 .9 a 54.0 ab 56.5 ab 36.3 a 4 8 .5 a 29.7 a 104.2 a
9 7 .7 a
59.4 58.8
Fall
p lan ted
78.1
68.1
61.5
Average 2 154.6
72.8
4 1 .6
25.8
111.8
9 7 .8
73.5 56.3
1 T re a tm e n t differences te ste d u sin g K ruskal-W allis ANOVA on ra n k s a n d D u n n ’s pairw ise m ean
sep ara tio n . M eans sh a rin g a com m on letter w ithin site are n o t different (P<0.10).
2 Does n o t include control.
45
weed in v asion, p rim arily a n n u a ls brom es, on g lyphosate tre a te d p lots in
N eb rask a. The sam e situ a tio n o c cu rred a t Lom a th o u g h th e effect w as
m u c h less noticeable b e c a u se of th e large b io m a ss of c re ste d w h e atg rass
co m p etin g w ith th e w eeds (Table 16). W eed grow th a t W hitney w as likely
s u p p re ss e d by com petition from th e d o m in a n t p e re n n ial, buffalograss
(Table 17). In a re a s w here th e re is a h igh p o ten tial for w eed invasion,
co n v en tio n al tilling a n d /o r non-selective herbicide m ay provide b e tte r
grow ing c o n d itio n s for seedlings (D. C ash , P e rs. Com m . 2003)
Table 13. 2003 B iom ass of n o n -ta rg e t sp ecies by fu n ctio n al group
following sp rin g a p p licatio n of glyphosate in 2 0 0 2 (IX) or
__________ 2002 a n d 2003 (2X) a t C h ristin a , M ontana.
Native Species
In tro d u c e d Species
1X2
C ontrol
2X
C ontrol IX
2X
LS M eans, g n r 2 Cool S easo n
18.4 a 1
4 9 .4 b 11.1 a
7.9 y
0.5 z
5 .8 y
P eren n ial G ra sse s
W arm S easo n
0.2 a
8.0 b 10.2 b
P eren n ial G ra sse s
T3
A n n u al F orbs
0.0 a
1.2 a
0.4 a
0.0
0.0
P eren n ial F orbs
3 4 .5 a
9 7 .7 b 57.4 a
0.0
T
T
S h ru b s
0.3 a
0.4 a
0.5 a
T otal 4
53.4
156.7
7 9 .6
8.0
5.8
0.5
—
—
1Treatment differences tested using Kruskal-Wallis ANOVA on Ranks, and Dunn’s
pairwise. Means sharing a common letter within functional group are not different
(P<0.10).
2 Average of four planting treatments.
3 T=Trace. More than 75% of samples did not contain plants in this group.
4 Clubmoss cover was 44.8, 28.8, and 36.0 % in Control, IX, and 2X respectively.
46
Table 14. 2 0 0 3 B iom ass of n o n -ta rg e t species by fu n ctio n al group
following sp rin g a p p licatio n of g lyphosate in 2 0 0 2 (IX) or
__________ 2002 a n d 2 0 0 3 (2X) a t J e n s , M ontana.____________________
Native S pecies
In tro d u c e d Species
C ontrol
IX 2
2X
C ontrol
IX
2X
LS M eans, g n r 2
A n n u al G ra sse s
0.0 a 1 5.0 b
0.3 a
0.5 z
12.5 y 10.0 y
Cool S easo n
0.4 a
—
—
1 .8 a
0.5 a
P eren n ial G ra sse s
W arm S easo n
—
—
—
4 .1 a 17.4 a
29.9 b
P eren n ial G ra sse s
A n n u al F o rb s
0.0 a 17.6 b
6.2 a
0.0 z
3 .9 z
9 .2 y
T3
P eren n ial F orbs
1 .7 a
8.2 a
1 .9 a
0.0
T
C acti
1.5 a
1 .8 a
3.6 a
Total
7.7
51.8
4 2 .4
0.5
16.6
19.2
—
—
—
—
•Treatment differences tested using Kruskal-Wallis ANOVA on Ranks, and Dunn’s
pairwise. Means sharing a common letter within functional group are not different
(P<0.10).
2 Average of four planting treatments. No difference between planting treatments
(P<0.10)
3 T=Trace. More than 75% of samples did not contain plants in this group.
Table 15. 2 0 0 3 B iom ass of n o n -ta rg e t sp ecies by fu n ctio n al group
following sp rin g a p p licatio n of glyphosate in 2 0 0 2 (IX) or
__________ 2002 a n d 2 0 0 3 (2X) a t K eltner, M ontana.___________________
Native S pecies
In tro d u c e d Species
IX 2
C ontrol
IX
2X
C ontrol
2X
Iv O
A n n u al G ra sse s
Cool S easo n
P eren n ial G ra sse s
W arm S easo n
P eren n ial G ra sse s
A n n u al F orbs
P eren n ial F orbs
S h ru b s
C acti
T otal
IV lC c lllo ,
0.0
T3
T
3.4 a 1
2.6 a
1 .7 a
0.0 a
10.2 a
18.3 a
0.0 a
2 .6 a
0.0 a
T
6.0
0.1 a
4 8 .7 b
2.6 a
T
64.4
0.7 a
9.9 a
4 .6 a
T
35.3
g
111
0.1
0.0
0.0
T
T
T
—
0 .6 z
T
—
—
0.8
—
—
0.4 z
0.0
0.0 z
T
—
—
—
0.4
—
0.0
•Treatment differences tested using Kruskal-Wallis ANOVA on Ranks, and Dunn’s
pairwise. Means sharing a common letter within functional group are not different
(P<0.10).
2 Average of four planting treatments. Planting x spray treatment interaction, P<0.001.
3 T=Trace. More than 75% of samples did not contain plants in this group.
47
Table 16. 2003 B iom ass of n o n -ta rg e t species by fu n ctio n al group
following sp rin g a p p licatio n of glyphosate in 2002 (IX) or 2002
___________a n d 2003 (2X) a t Loma, M ontana.____________________________
Native Species
In tro d u ce d Species
C ontrol
IX 2
C ontrol
IX
LS M eans, g n r 2
T3
Cool S e a so n P eren n ial G ra sses
T
T
T
A n n u al F orbs
T
T
0.0 z
0.4 z
P eren n ial F orbs
0 .7 a 1
0.4 a
2.2 z
9 .0 z
S h ru b s
T
T
Total
0.8
0.6
2.2
9.5
—
—
•Treatment differences tested using Kruskal-Wallis ANOVA on Ranks, and Dunn’s
pairwise. Means sharing a common letter within functional group are not different
(P<0.10).
2 Average of four planting treatments. No difference between planting treatments
(P<0.10)
3 T=Trace. More than 75% of samples did not contain plants in this group.
Table 17. 2 0 0 3 B iom ass of n o n -ta rg e t species by fu n ctio n al group
following sp rin g app licatio n of glyphosate in 2 0 0 2 (IX) or 2002
__________ a n d 2003 (2X) a t W hitney, M ontana._________________________
Native S pecies
In tro d u c e d Species
C ontrol
IX 2
C ontrol
IX
2X
2X
LS M eans, g n r 2 T3
A n n u al G ra sse s
0
T
I .Oz
1.5 z 2.7 z
Cool S ea so n
—
—
12.2 b 1
9.3 b
2.6 a
P eren n ial G ra sse s
W arm S easo n
—
—
3 2 .5 a
8 5 .7 b
6 9 .5 b
P eren n ial G ra sse s
A n n u al F orbs
T
T
T
3.0 a
7.5 a
2.8 a
0.0 z
0.1 z 0.7 z
P eren n ial F orbs
1.0 a
1 .5 a
2.7 b
77.7
1.7
3.5
Total
48.7
104.0
1.1
—
—
•Treatment differences tested using Kruskal-Wallis ANOVA on Ranks, and Dunn’s
pairwise. Means sharing a common letter within functional group are not different
(P<0.10).
2 Average of four planting treatments. No difference between planting treatments
(PO. 10)
3 T=Trace. More than 75% of samples did not contain plants in this group.
48
T he 2 0 0 3 glyp h o sate a p p licatio n (2X) a t all site s o c cu rred slightly
la te r in th e grow ing se a so n th a n th e 2 0 0 2 a p p lica tio n (IX). Native cool
se a so n sp ecies h a d alre ad y b ro k en d o rm an c y in 2 0 0 3 w h en glyphosate
w as ap p lied a n d m a n y w ere d am ag ed a t C h ristin a , K eltner, a n d J e n s
(Tables 13, 14, a n d 15).
T he IX tre a tm e n t of th e spray -o n ly tre a tm e n t a t K eltner h a d m ore
to ta l b io m a ss of n o n -ta rg e t species th a n all o th e r tre a tm e n ts (Table 12,
P<0.10), m o st of w hich w as p e re n n ia l forb b io m ass.
b io m a ss of p e re n n ia l forbs in th e
The very h igh
IX spray-only tre a tm e n t c a n be
a ttrib u te d to very large fringed sagew ort p la n ts, w h ich w eighed m ore
th a n I kg each , th a t o c cu rred in th e sam p le a re a s. F rin g ed sagew ort in
th e N o rth ern P lain s often in c re a se s in b io m ass a fte r d istu rb a n c e (Bai
a n d Rom o 1996). A pplying glyphosate one y e ar (IX), b u t n o t consecutive
y e a rs (2X), in c re a se d th e b io m a ss of native p e re n n ia l forbs a t K eltner
(Table 15, P=0.065). M ost of th e p e re n n ia l forb b io m a ss in th e IX plo ts
w as co m posed of cool se a so n species, m an y of w hich w ere dam aged by
th e 2 0 0 3 g lyphosate application.
A pplying g lyphosate in 2002 (IX) in cre ased th e b io m a ss of native
w arm se a s o n g ra s se s a t C h ristin a , J e n s , K eltner, a n d W hitney (Tables
13, 14, 15, & 17, P<0.10). Applying glyphosate tw o y e a rs in creased
b io m a ss of w arm se a so n species over applying one y e a r a t C h ristin a,
49
J e n s , a n d K eltner; th is ag rees w ith th e d a ta from w a rm se aso n seeded
sp ecies a t K eltner (Table 10).
The c o m b in atio n of in cre ased w a rm ' se a so n p e re n n ia l g rasses,
d e c re a se d cool se a so n p e re n n ial g ra sse s, a n d in c re a se d a n n u a ls w eeds
ag rees w ith re s u lts from sp rin g ap p lied glyphosate tria ls in N eb rask a
(S am p so n a n d M oser 1982).
Applying glyphosate in early spring sh ifts
sp ecies co m p o sitio n s by in cre asin g th e b io m a ss of w a rm se aso n species
a n d d e crea sin g th e b io m a ss of cool se a s o n species.
S ta n d s th a t a re d o m in ated by c re ste d w h e a tg ra s s a n d co n ta in
n ativ e sp ecies c a n be sh ifted tow ard m ore native sp ecies a n d less cre ste d
w h e a tg ra s s by th e p ro p e r a p p licatio n of glyphosate. To achieve th e b e s t
re s u lts , g lyp h o sate a p p licatio n m u s t be done while c re ste d w h e atg rass is
rap id ly grow ing b u t d esired species a re still d o rm an t.
T he com petitive
ad v an tag e g ained by th e d esired sp ecies in th e tre a tm e n t y e ar c arries
over in to th e following y e a r a n d p o ten tially m an y y e ars. S ta n d s th a t are
p ro n e to w eed in festa tio n are n o t reco m m en d ed for th is tre a tm e n t a n d
m ay re q u ire different h erb icid es or co n v en tio n al tillage tre a tm e n ts .
D iversity Index
S pecies diversity c a n be in c re a se d by applying glyp h o sate to sites
w ith low diversity. At K eltner a n d J e n s , diversity in th e co n tro l plots w as
low (D<0.20) b u t in c re a se d in all tre a tm e n t plots (Table 18, P < 0 .10). At
T able 18. 2003 D iversity in d ex a fte r sp rin g a p p lica tio n of glyphosate in 2002 (IX) or 2002 a n d 2003
(2X) a n d seeding w ith native seed m ixes a t five site s in E a s te rn a n d C en tra l M ontana.
Site
C ontrol
C h ristin a
0 .6 7 a 2
IX
2X
0.77 a
0 .6 4 a
S p ra y Only
W arm
0.66 a
se a so n m ix
Cool se a so n
m ix / S p rin g 0.69 a
p la n te d
Cool se a so n
m ix / Fall
p la n te d
0.71 a
K eltner
Loma
W hitney
All Sites
-------LS m ea n s, D 1 ---------0.20 a
0.09 a
0.12 a
0 .6 6 a
0.35
IX
IX
2X
2X
IX
IX
2X
IX
2X
0.73 b 0.64 b
0 .4 3 b 0.65 b 0.18 a
0.59 a
0 .5 8 a 0.54 0.63
Jens
0.61 a
0.73 b
0.65 b
0 .7 0 b
0.44 b
0.20 a
0.7 4 a
0.53 a 0.61
0 .7 8 a
0 .5 5 b
0.60 b
0 .7 2 b
0.62 b
0.11 a
0 .6 5 a
0.60 a 0.54 0.65
0.69 a
0 .7 7 b
0.60 b
0 .4 8 b
0.60 b
0.32 a
0.61 a
0.63 a 0.58 0.63
0.56
0.71
0.63
0 .5 8
Average 3
0.69
0.58
0.20
0.65
0.68
0.59
0.62 0.57
1 D = I-C . C is S im p so n ’s in d ex calcu late d from b io m ass. L east diverse eq u als zero, m o st eq u als one.
2 T re a tm e n t differences te s te d u s in g K ruskal-W allis ANOVA on ra n k s a n d D u n n ’s pairw ise m ean
se p ara tio n . M eans sh a rin g a com m on le tte r w ith in site are n o t different (P<0.10).
3 D oes n o t include control.
51
K eltner, m u c h of th e in cre ase in diversity w as d u e to p la n te d species a n d
native forbs. At J e n s , m o st of th e in c re a se w as d u e to a n n u a l w eeds a n d
w arm se a s o n g ra sse s. R eduction of c re ste d w h e a tg ra ss on sites w here it
d o m in a ted open ed a re a s for existing p la n ts to e x p an d a n d new p la n ts to
grow.
At Lom a, w here glyphosate a p p licatio n w as n o t effective a t
s u p p re ss in g c re ste d w h e a tg ra ss, diversity w as low in co n tro l plots a n d
tre a tm e n t plots. At C h ristin a a n d W hitney, diversity in co n tro l plots w as
h ig h (D>0.65) a n d did n o t in cre ase in a n y tre a tm e n t p lots. At sites w here
d iversity w a s h igh in u n tre a te d a re a s , diversity w as n o t in c re a se d by a n y
tre a tm e n t.
T he in p u t req u ire d to acco m p lish th e sam e in c re a se in diversity
b eco m es m u c h larg er a s diversity in c re a se s, so th e sa m e effort expended
on co m m u n ities of different initial diversity will have different resu lts. At
sites w h ere diversity w as initially low, a n d g lyphosate w a s effective a t
re d u c in g c re ste d w h e a tg ra ss b io m ass, diversity w a s in c re a se d by all
tre a tm e n ts , b u t th e re w a s little difference a t sites w h ic h w ere initially
m ore diverse.
D eterm ining w h e th e r th e s e c h a n g e s in diversity w ere
tem p o ra ry or la stin g will req u ire fu tu re observation.
C o n clu sio n s
A pplying g lyphosate w as effective a t re d u c in g th e b io m ass of
c re ste d w h e a tg ra s s a n d in cre asin g th e b io m a ss of n ativ e species if
52
ap p lied a t th e c o rre ct stag e of grow th. A pplication sh o u ld be done before
d esirab le
sp ecies em erge for m o st effective tre a tm e n t.
A dditional
g ly p h o sate a p p lica tio n one y e a r afte r p la n tin g in c re a se d th e b io m ass of
w arm se a s o n p la n te d species, b u t d a m ag ed cool se a s o n p la n te d species.
G ly p h o sate a p p lica tio n shifted th e d o m in an ce in th e s ta n d s tow ard
n ativ e sp ecies or w eedy species, d e p en d in g on th e p la n t a n d se e d b a n k
com position, by releasin g th o se sp ecies from co m p etitio n w ith th e
c re ste d w h e a tg ra ss.
G lyphosate a p p lica tio n also in c re a s e d th e species
diversity on sites w ith low in itial diversity.
The r e s u lt of glyphosate
a p p lica tio n is highly d e p e n d e n t on th e in itial com p o sitio n of th e s ta n d
a n d th e tim ing of ap p licatio n .
T hese a re a s sh o u ld be m on ito red in th e
fu tu re to d e te rm in e th e long-term effects of g lyphosate application on
c re ste d w h e a tg ra s s a n d o th e r species.
No-till seeding w as generally n o t su c ce ssfu l a n d lim iting factors
w ere likely lac k of m o istu re a n d n itrogen.
B ecau se of th e high co st of
n ativ e seed a n d no-till drilling, th is tre a tm e n t is n o t recom m ended
u n le s s th e re is sufficient m o istu re (>60 cm m o ist soil) a n d n u trie n ts in
th e soil a t th e tim e of seeding to s u p p o rt seedling grow th.
S w itchgrass
a n d sle n d e r w h e a tg ra ss w ere th e m o st su c ce ssfu l se ed e d species, m ak in g
th e m good choices for p la n tin g p ro jects w here native sp ecies are desired.
53
Im plications
A pplying g lyphosate is a n effective tool for re d u c in g th e biom ass of
c re ste d w h e a tg ra ss, b u t it c a n in c re a se w eedy species if so u rc es of w eed
seed s, s u c h a s cu ltiv ated fields, a re n earb y . Applying g lyphosate in a re a s
occu p ied by m ixed s ta n d s of native p la n ts a n d c re ste d w h e a tg ra ss c a n
sh ift th e d o m in an ce to w ard th e native g ra sse s a n d forbs, a n d in crease
sp ecies diversity, w ith o u t th e a d d itio n al expense a n d effort of seeding, if
th e h erb icid e is applied only to c re ste d w h e a tg ra ss a n d n o t native
species. S eeding c a n be avoided w h en native species co m p rise a portion
of th e s ta n d , w eed so u rc e s are n o t n e a r by, a n d g lyphosate is applied to
rap id ly grow ing c re ste d w h e a tg ra ss w hile native sp ecies a re d o rm an t.
54
LITERATURE CITED
A bbott, L.B., a n d B.A. R o u n d y . 2003. A vailable w a te r in flu en ces field
g e rm in atio n a n d re c ru itm e n t of seed ed g rasse s. J . R ange M anage.
5 6 :5 6 -6 4 .
A u stin , D. D., P. J . U rn e ss, a n d L. C. Fierro. 1983. S p rin g livestock
grazing affects c re ste d w h e a tg ra ss regrow th a n d w in ter u s e by m ule
deer. J . R ange M anage. 36:5 8 9 -5 9 3 .
B ai, T., a n d J.T . Romo. 1996. Fringed s a g e b ru s h re s p o n se to sw ard
d istu rb a n c e s : seedling d y n am ics a n d p la n t grow th. J . R ange M anage.
4 9 :2 2 8 -2 3 3
B ak er, C .J., K.E. S ax to n a n d W.R. R itchie. 1996. No-tillage seeding :
science a n d p ractice. CAB In te rn a tio n a l, W allingford, Oxford, UK.
B ak k er, J.D . 1996. C om petition a n d th e e s ta b lis h m e n t of native g ra sse s
in c re ste d w h e a tg ra ss fields. M a ste rs th e s is , Univ. of R egina, 70pp.
B ak k er, J.D ., J . C h ristia n , S.D. W ilson a n d J . W addington. 1997.
S eeding b lu e g ra m a in old c re ste d w h e a tg ra ss fields in so u th w e ste rn
S a sk a tc h e w a n . J . R ange M anage. 50:1 5 6 -1 5 9 .
B a rb o u r, M.G., J.H . B u rk , W.D. P itts, F.S. Gilliam , M.W. Schw artz.
1999. T errestria l P la n t Ecology - 3rd ed. B enjam in / C um m ings,
M enlo P ark, CA. p p 191-193.
Bowes, G. 1997. Sod seeding forage to im prove p a stu re : S u m m ary of
p ro g ress to 1994. A griculture a n d Agri-Food C a n a d a , S a sk a to o n
R ese arch C enter.
h ttp : / / re s 2 .a g r.c a /s a s k a to o n /b ru s h _ m g m t/s o d s e e d 9 4 .h tm l
Caldwell, M.M., J.H . R ich ard s, D. A. J o h n s o n , R. S. Nowak, a n d R. S.
D zu rec. 1981. C oping w ith herbivory: p h o to sy n th e tic cap acity a n d
re so u rc e allocation in two sem iarid A gfopyron b u n c h g ra ss e s .
O ecologia 5 0:14-24.
G obin, S.M. 1994. E v alu atio n of g ra ss e sta b lish m e n t, developm ent, a n d
su rv iv al u n d e r so d -seed in g co n d itio n s in th e dry, s u b -h u m id p rairies.
M a ste rs T hesis, Univ. of M anitoba 195pp.
55
H a rtn e tt, D.C. 1993. R egulation of clonal grow th a n d d y n am ics of
Panicum virgatum (Poaceae) in ta llg ra ss prairie: Effects of neighbor
rem oval a n d n u trie n t additio n. Amer. J . Bot. 8 0 :1 1 14-1120.
H a u g lan d E. a n d R .J. Froud-W illiam s. 1999. Im proving g rassla n d s: th e
in flu en ce of soil m o istu re a n d n itro g en fertilization on th e
e sta b lis h m e n t of seedlings. J . A pp. Ecol. 3 6 :2 6 3 -2 7 0 .
H olechek, J . L. 1981. C rested w h e a tg ra ss. R ang elan d s. 3:237-250.
H olzw orth, L., J . Mosley, D. C ash, D. Koch, a n d K.C ran e. 2000.
D ry lan d p a s tu re s in M o n tan a a n d W yoming: S pecies a n d cultivars,
seed in g te c h n iq u e s, a n d grazing m an a g em en t. Ext. Bull. 19. Mont.
St. U niv. Ext. Ser., B ozem an, MT.
Hull, A. C., J r ., a n d G. J . K lom p. 1966. Longevity of c re ste d w h e atg rass
in th e sa g e b ru s h -g ra s s type of so u th e rn Idaho. J . R ange M anage.
19:5-11.
J a c o b s e n , J ., G. J a c k s o n , a n d C. Jo n e s. 2003. F ertilizer guidelines for
M o n ta n a crops. Ext. Bull. 161. M ont. St. U niv. Ext. S er., Bozem an,
MT.
Kilcher, M.R. a n d Loom an, J . 1983. C om parative p e rfo rm an ce of som e
n ativ e a n d in tro d u c e d g ra sse s in so u th e rn S a sk a tc h e w a n , C anada. J .
R ange. M anage. 3 6 :6 5 4 -6 5 7 .
King, M.A., S.S. W aller, L.E. M oser, a n d J.L . S tu b b e n d ie ck . 1989.
S eed b ed effects on g ra s s e sta b lis h m e n t on a b a n d o n e d N eb rask a
S a n d h ills cro p lan d . J . R ange M anage. 4 2 :1 8 3 -1 8 6 .
L a u n c h b a u g h , J.L ., R.E. B em ent. 1966. A s ta n d e s ta b lis h m e n t survey of
g ra ss p la n tin g s in th e G reat P lains. G re a t P lains A gricu ltu ral C ouncil
P ub. no. 23. U niv. of Neb. Ag. Exp. S ta., Lincoln, NB.
Lodge, R.W. 1960. E ffects of b u rn in g , cultiv atin g a n d m ow ing on the
yield a n d c o n su m p tio n of c re ste d w h e a tg ra ss. J . R ange M anage.
1 3:318-321.
L oom an, R.E. a n d D.H. H einrichs. 1973. S tability of c re ste d w h e atg rass
p a s tu r e s u n d e r long-term p a s tu re u se . C an. J . P la n t Sci. 53:501- 506.
56
Lorenz, R .J. a n d G A . Rogler. 1962. A co m p a riso n of m e th o d s of
ren o v a tin g old s ta n d s of c re ste d w h e a tg ra ss. J . R ange M anage.
15:215- 219.
M cH em y J . R., a n d L.C. Newell. 1947. Influence of som e p e ren n ial
g ra s se s on th e organic m a tte r c o n te n t a n d s tru c tu re of e a ste rn
N e b ra sk a fine te x tu re d soils. J . Am. Soc. A gron. 3 9 :9 8 1 -9 8 4 .
M cW illiams, J.L . 1973. Effects of som e c u ltu ra l p ra c tic e s o n g rass
p ro d u c tio n a t M an d an , N orth D akota. Tech. Bui. No. 1097. USDA,
W ash in g to n , DC.
M cW illiams, J.L . a n d P.E. vanCleve. 1960. A c o m p a riso n of crested
w h e a tg ra s s a n d native g ra ss m ix tu re s seeded on ra n g e la n d in e a ste rn
M o n tana. J . R ange M anage. 13:91-94.
M o n san to C om pany. 1996. C R P-to-crops conversion: A guide for
grow ers in th e N o rth ern Plains.
M organ, J .P ., D.R. C ollicutt a n d J.D . T hom pson. 1995. R estoring
C a n a d a 's n ativ e prairies: A p ra c tic a l m a n u a l. P rairie H a b ita ts, Argyle,
M anitoba.
N elson, J . R., A. M. W ilson, a n d C. J . Goebel. 1970. F a c to rs influencing
b ro a d c a s t seed in g in b u n c h g ra s s ran g e. J . Range M anage. 23:163170.
P eat, H.C. a n d G.G. Bowes. 1995. D irect seeding into c re ste d
w h e a tg ra ss: final rep o rt. S a sk a tc h e w a n A griculture a n d Food.
Q u in n , M.A., P.S. J o h n s o n , C.H. B utterfield, D .D .W algenbach. 1993.
Effect of g ra s sh o p p e r (O rthoptera: Acrididae) d e n sity a n d p la n t
co m p o sition on grow th a n d d e stru c tio n of g rasse s. E n v . E n to . 22:9931002.
R eynolds, T. D., a n d C. H. T rost. 1980. The re sp o n se of native
v e rte b ra te p o p u la tio n s to c re ste d w h e a tg ra ss p la n tin g a n d grazing
sh eep . J . R ange M anage. 3:1 2 2 -1 2 5 .
Ries , R.E. a n d L. H ofm ann. 1996. P eren n ia l g ra ss e sta b lis h m e n t in
re la tio n sh ip to seed in g d a te s in th e n o rth e rn g re a t p la in s. J . Range
M anage. 4 9 :5 0 4 -5 0 8 .
57
R ogler, G. A. a n d R. J . Lorenz. 1983. C rested w h e a tg ra s s - early h isto ry
in th e U nited S ta te s. J . R ange M anage. 36:91-93.
Romo, J.T ., P.L. Grilz a n d L. D elanoy. 1994. Selective co n tro l of crested
w h e a tg ra s s (Agropyron cristatum [L.] G a e rtn . a n d A. deseriorum
Fisch.) in th e n o rth e rn G reat P lains. Nat. A reas J . 14:308-309.
S am p so n , J.F . a n d L.E. M oser. 1982. S od-seeding p e re n n ia l g rasse s
into e a s te rn N e b rask a p a s tu re s . A gron. J . 7 4 :1 0 5 5 -1 0 6 0 .
S a n d e rso n , M.A. a n d R.L. Reed. 2000. S w iteh g rass grow th a n d
developm ent: w ater, nitrogen, a n d p la n t d e n sity effects. J . Range
M anage. 53:2 2 1 -2 2 7 .
S heley, R. L., T. J . Svejcar, B. D. Maxwell. 1996. A th eo re tic al
fram ew ork for developing su c e ssio n a l w eed m a n a g e m e n t strateg ies on
ran g e la n d . W eed Tech. 10:766-773.
T ilm an , D., J . K nops, D. W edin, P. Reich, M. Ritchie, E. S ie m a n n . 1997.
T he Influence of F u n c tio n a l D iversity a n d C om position on E cosystem
P ro cesses. Science. 2 7 7 :1 3 0 0 -1 3 0 2 .
USDA. 2 001. VegSpec Software.
h ttp : //iro n w o o d .itc .n rc s.u sd a .g o v /N e td y n a m ic s/V e g s p e c /p a g e s/H o m
eV egspec.htm
USDA-NRCS. 1988. Soil survey of F e rg u s county, M o n tan a. B ozem an,
MT.
USDA-NRCS. 1996. Soil survey of Prairie county, M o n tan a. B ozem an,
MT.
USDA-NRCS. 2001. Soil survey of C h o te a u county, M o n tan a. B ozem an,
MT.
W ad d in g to n , J . a n d M. P. Schellenberg. 1976. No-till seed in g alfalfa in
y o u r old c re ste d w h e a tg ra ss field. R ese arch N ew sletter: Sem i-arid
P rairie A gricu ltu ral R esearch C enter.
h ttp : / /r e s 2 .a g r .c a / sw iftc u rre n t/n e w s-n o u v e lle s/9 6 0 3 0 1 .h tm
W ark, D. B., W.R. Poole, R.G. A rnott, L.R. M oats, a n d L. W etter. 1995.
R evegetating w ith native g rasse s. D u c k s U nlim ited C a n ad a ,
Stonew all, M anitoba.
58
W elty, L.E., P.F. H ensleigh, a n d V.R. S tew art. 1983. M ethods for sodseed in g of sm all-seed ed legum es a n d g rasse s. Ext. B ull. 752. Mont.
St. U niv. Ext. Ser., B ozem an, MT.
W ilson, S.D ., a n d A.G. G e riy . 1995. S trateg ies for m ix e d -g rass prairie
resto ra tio n : h erbicide, tilling, a n d n itro g e n m a n ip u la tio n . Rest. Ecol.
3: 2 9 0 -2 9 8 .