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INFLUENCE OF HEIGHT AND FREQUENCY OF CUTTING UPON THE GROWTH OF SMOOTH BROME GRASS, ORCHARD GRASS, AND KENTUCKY BLUEGRASS

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D OC TOR A L DISSERTATION SERIES
TITLE
Influence Of Hticfih AnJ Frequchrjs O f Cutting
Upon
T h t G ro w th Of
C r*«
A J.
author
Smoolh B fo m g frlrifff Oirch&rd ___
K m tucfy B
l u e ---------------
C lw te s V c d k V lo d g ie n
u n iv e rsity
Micloicjah
DATE
M L
Sf&fe C o lle g e
PUBLICATION NO M
DEGREE
m in i m im
1
I
UNIVERSITY MICROFILMS
ANN
ARBOR
-
MICHIGAN
Ut
INFLUENCE OF HEIGHT AND FREQUENCY OF CUTTING UPON
THE GROWTH OF SMOOTH 3ROME GRASS,
ORCHARD GRASS Al© KENTUCKY BLUEGRASS
A THESIS
S u b m itte d to t h e F a c u lty o f M ichigan S t a t e C o lle g e
i n P a r t i a l F u lf ilm e n t f o r th e D egree
o f D o c to r o f P h ilo so p h y
i n Farm C rops
C h a r le s W orth H odgson
E a s t L a n s in g , M ich ig an
TABLE OF COOTENTS
Page
G re e n h o u se S t u d i e s . . . . .
...................................................
M a t e r i a l s a n d M e th o d s .. . . .
F o ra g e Y i e l d s
1
.........................................................
..........................................................................
Y ie ld s o f R o o ts a n d R h iz o m e s
...........................................
C h em ical L a t a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
8
F i e l d S t u d i e s .........................................................................
D is c u s s io n .
..............................................................
Summary
............................................................................
L i t e r a t u r e C i t e d . .....................................................................
14
INFLUENCE OF HEIGHT AND FREQUENCY OF CUTTING UPON
THE GROWTH OF SMOOTH BROME GRASS,
ORCHARD GRASS AND KENTUCKY BLUEGRASS.
In re c e n t y e ars th e r e h a s b e e n a n in c re a s e d i n t e r e s t in g ra s s c u l­
t u r e an d i n th e management o f p a s t u r e g r a s s e s .
S tu d i e s o f th e re s p o n s e
o f many s p e c ie s of fo r a g e p l a n t s t o v a r i o u s c u t t i n g t r e a t m e n t s have
r e v e a le d t h a t s h o r t and f r e o u e n t l y r e p e a t e d d e f o l i a t i o n s r e s u l t i n d e ­
c r e a s e d y i e l d s of fo ra g e a n u i n d e c r e a s e d r o o t g ro w th *
G ordon an d Sampson ( 3 ) ,
1{ L e u k e l an d C olem an ( 5 ) , and L e u k e l an d
B a r n e t t e (6 ) g iv e r a t h e r e x t e n s i v e r e v ie w s o f th e l i t e r a t u r e p e r t a i n i n g
t o t h e e f f e c t s o f c u t t i n g a n d o t h e r t r e a t m e n t s u p o n th e p r o d u c tio n o f
to p g ro w th and r o o t r e s e r v e s b y f o r a g e p l a n t s .
The p r e s e n t p a p er d e a l s w i t h t h e i n f l u e n c e o f h e i g h t a n d fr e q u e n c y
o f c u t t i n g upon th e g ro w th o f sm o o th brom e g r a s s ( Bromus i n e r m i s ) , o r ­
c h a r d g r a s s ( D a c ty lis glom e r a t a ) , a n d K entucky b l u e g r a s s ( Poa p r a t e n s i s ) .
C h em ical a n a ly s e s were m ade o f some o f t h e c l i p p e d h e r b a g e .
One p h a se
o f t h e e x p e rim e n t was c o n d u c te d i n t h e g re e n h o u se an d a se c o n d p h a se
w as c a r r i e d on i n th e f i e l d *
GREENHOUSE STUDIES
M a t e r i a l s a n d M ethods
I n November, 1937, s e g m e n ts o f sm ooth brome g r a s s and o rc h a r d g r a s s
w ere c o l l e c t e d from th e f i e l d
l/
n u r s e r y a t M ic h ig a n S t a t e C o lle g e , E a s t
F ig u r e s i n p a r e n t h e s i s r e f e r t o L i t e r a t u r e C i t e d , P* 18*
L a n s in g , an d s e t o u t i n q u a r t z san d i n t e n - i n c h c l a y p o t s i n t h e g r e e n ­
house.
E i g h t s e g m e n ts w ere p l a c e d i n e a c h o r c h a r d g r a s s p o t ; and 16
s e g m e n ts , w i t h 2 a t e a c h p l a o e , w e re p la c e d i n e a c h o f t h e brom e g r a s s
p o ts .
A l l p l a n t s w e re r e g u l a r l y w a te r e d an d g iv e n a n u t r i e n t s o l u t i o n
c o n t a i n i n g KH2PO4 , C a(1103)2 an d MgSO^.
No a r t i f i c i a l l i g h t w as u s e d .
The te m p e r a t u r e ra n g e d fro m 6 0 ° t o 8 0 ° F . d u r in g t h e w i n t e r m o n th s an d
som etim es w e n t a s h ig h a s 1 00° F . d u r in g t h e f o ll o w i n g sum m er.
p l a n t s b e g a n to h e a d o u t i n J a n u a r y , 1 9 3 9 .
The
B ec a u se o f i r r e g u l a r l i g h t
c o n d i t i o n s i n t h e g r e e n h o u s e , t h e r e was c o n s i d e r a b l e l a c k o f u n i f o r m i t y
among t h e p l a n t s l o c a t e d i n d i f f e r e n t p a r t s o f t h e g r e e n h o u s e .
No n u t r i e n t s o l u t i o n w as g iv e n t h e p l a n t s from th e f i r s t w eek i n
M arch u n t i l t h e b e g in n in g o f t h e c u t t i n g p e r i o d i n o r d e r t o g iv e th e
p l a n t s a n o p p o r t u n i t y to s t o r e up some c a r b o h y d r a te r e s e r v e s .
w as s u p p lie d a s b e f o r e .
T fater
A f t e r t h e f i r s t e m ittin g , a l l p l a n t s r e c e i v e d
n u t r i e n t s o l u t i o n once o r tw ic e p e r w e ek , d e p e n d in g u p o n t h e w e a th e r —
tw ic e d u r in g th e b e s t g ro w in g w e a th e r .
C u ttin g began on A p ril 1 3, 1 9 3 8 .
th e l a t e bloom s ta g e a t t h i s t i m e .
Some o f t h e p l a n t s w e re s t i l l i n
The p l a n t s o f e a c h s p e c i e s w ere
a r r a n g e d i n s e t s o f f o u r c u l t u r e s e a c h , c a r e b e in g t a k e n t h a t th e s e t s
w ould b e c o m p a ra b le w ith e a c h o t h e r w i t h i n a g iv e n s p e c i e s .
Four c u l­
t u r e s w e re w ashed f r e e o f s a n d , t h e r o o t s s e p a r a t e d fro m t h e t o p s , an d
g r e e n an d d ry w e ig h ts ta k e n f o r e a c h .
T h ese w e re d e s ig n a te d a s " i n i t i a l
checks".
Eaoh o f th e f o ll o w i n g c u t t i n g t r e a t m e n t s w as r e p l i c a t e d f o u r tim e s
i n each s p e c ie s :
H e ig h t o f C u t t i n g
a b o v e Sand
1 w eek
If
1
11
1
n
1
it
1
1 in c h
3 in c h e s
6
"
9
"
12
L e n g th o f I n t e r v a l B etw een C u t t i n g s
"
F in a l check
2 w eek s
H
2
w
2
II
2
n
2
:
:
:
:
:
4 w eek s
n
4
«■
4
n
4
n
4
8 w eek s
8
"
8
"
8
w
8
11
N ot c u t b u t w ash ed f r e e o f sa n d a t t h e c l o s e
o f t h e e x p e r im e n t*
The m eth o d o f c u t t i n g c o n s i s t e d o f r a i s i n g t h e ' l e a v e s a n d c u t t i n g
th em o f f , a lo n g -w ith t h e s te m s , a t t h e d e s i g n a t e d h e i g h t *
d r y w e ig h ts w e re
re c o rd e d fo r a l l p o rtio n s of to p s
re m o v e d .
w as a c c o m p lis h e d
b y f o r c e d a i r a t 6 0 ° t o 70° C* i n a n oven*
G re e n a n d
D ry in g
R e p re s e n ­
t a t i v e d r y s a m p le s w ere k e p t f o r f u t u r e c h e m ic a l a n a l y s e s *
On A u g u st 9 a n d 1 0 , 1 9 3 8 , a l l c u l t u r e s , i n c l u d i n g t h e f i n a l c h e c k s ,
w e re w a sh e d f r e e o f s a n d .
The r o o t s w e re s e p a r a t e d fro m t h e t o p s , a n d
f r e s h a n d d r y w e i g h t s w e re d e te r m in e d f o r e a c h *
The rh iz o m e s o f t h e
brom e g r a s s w e re a l s o rem oved and w e ig h ed *
F o r a g e Y ie ld s
I n t h e c a s e o f t h e p l a n t s w h ic h w e re c u t once e v e r y w e ek , t h e s h o r t ­
e r th e p l a n t s w e re c u t th e g r e a t e r th e y i e l d o f f o r a g e a t t h e b e g in n in g
o f t h e c u t t i n g p e r io d #
As t h e c u t t i n g
th e p l a n t s vAiioh w e re c u t
w h ile t h e y i e l d s
t r e a t m e n t s c o n t i n u e d , h o w e v e r,
a t one in c h d e c r e a s e d i n f o r a g e p r o d u c t i o n ,
fro m t h e p l a n t s w h ic h w e re o u t
i n c r e a s e d f o r a tim e *
a t th e h ig h e r l e v e l s
By t h e en d o f t h e c u t t i n g p e r i o d t h e p l a n t s
w h ic h w e re c u t a t one in c h e v e r y w eek h a d a lm o s t c e a s e d t o p ro d u c e a n y
new growth*
B e fo re c u t t i n g w as b e g u n , a l l p l a n t s w e re r e l a t i v e l y low i n n i t r o ­
g e n a n d r e l a t i v e l y h ig h i n c a r b o h y d r a t e s .
t o a slo w r a t e o f v e g e t a t i v e g ro w th .
T h is o o n d i t i o n w as c o n d u c iv e
C lo se c u t t i n g and t h e a p p l i c a t i o n
o f n i t r o g e n ( s u p p l i e d i n t h e n u t r i e n t s o l u t i o n ) e a c h a c t e d t o re d u c e
th e p r o p o r t i o n o f c a r b o h y d r a t e s to n i t r o g e n i n t h e p l a n t s and th u s t o
s t i m u l a t e th e r a t e o f g ro w th , a t l e a s t f o r a t i m e .
The p l a n t s w h ich
w ere c u t f r e q u e n t l y a t one i n c h , h o w e v e r, so o n e x h a u s te d t h e i r r e s e r v e
s u p p ly o f c a r b o h y d r a te s a n d w ere u n a b le t o s u p p ly s u f f i c i e n t c a rb o h y ­
d r a t e s f o r a maximum r a t e o f g ro w th b e c a u s e o f l i m i t e d p h o to s y n t h e t i c
tis s u e .
As a r e s u l t t h e s e p l a n t s g r a d u a l l y d e c r e a s e d i n f o r a g e y i e l d s
an d w e re s lo w ly s t a r v i n g t o d e a t h .
The p l a n t s w hich w ere c u t w e e k ly a t t h r e e in c h e s a l s o s u f f e r e d
from a d e f i c i e n c y o f c a r b o h y d r a t e s , b u t n o t so s e v e r e l y a s d id th o s e
c u t a t one in c h p e r w eek*
The p r o p o r t i o n o f c a r b o h y d r a t e s to n i t r o g e n i n t h e p l a n t s w hich
w e re c u t a t th e h ig h e r l e v e l s ( 6 , 9 , and 12 in c h e s ) w as t o o h ig h a t
t h e b e g in n in g o f t h e c u t t i n g p e r io d f o r maximum g ro w th ; b u t , a f t e r
t h e s e p l a n t s had h ad tim e t o a b s o r b and to a s s i m i l a t e m ore n i t r o g e n ,
t h e i r r a t e s o f g ro w th i n c r e a s e d an d w e re m a in ta in e d ab o v e t h a t o f t h e
p l a n t s w h ich w e re c u t a t one in c h p e r week*
The r e l a t i v e l y h ig h y i e l d s
p ro d u c e d d u r in g th e l a t t e r p a r t o f t h e c u t t i n g p e r i o d b y th e p l a n t s
w h ic h w ere c u t a t th e h i g h e r l e v e l s w o re made p o s s i b l e b e c a u s e th e s e
p l a n t s p o s s e s s e d enough p h o t o s y n t h e t i c a r e a w i t h w h ic h to m a n u fa c tu re
a n a d e q u a te s u p p ly o f c a r b o h y d r a t e s f o r grow th*
When th e p l a n t s w ere c u t once e v e r y two w e ek s and once e v e r y f o u r
-4 -
w e e k s, r e s p e c t i v e l y , t h e in f l u e n c e o f h e i g h t o f c u t t i n g u p o n th e r a t e
o f to p g ro w th fo llo w e d th e same g e n e r a l t r e n d a s i n t h e c a s e o f th o s e
w h ic h w ere c u t once e v e ry w eek , e x c e p t t h a t c l o s e c u t t i n g was n o t so
s e v e r e on t h e p l a n t s b e c a u s e t h e y h a d m ore tim e b e tw e e n c u t t i n g s i n
w h ic h t o p ro d u c e p h o to s y n th e t ic t i s s u e and t o m a n u fa c tu re c a r b o h y d r a t e s .
C lo se c u t t i n g onoe e v e ry e i g h t w eeks d id n o t a p p e a r t o r e d u c e th e
v ig o r o f th e p l a n t s .
The c l o s e r t h e p l a n t s w ere c u t , t h e more f o r a g e
th e y y i e l d e d above th e c u t t i n g l e v e l , b u t t h e l e s s g ro w th th e y made b e ­
low t h a t l e v e l *
The t o t a l y i e l d o f f o r a g e made ab o v e th e c u t t i n g l e v e l and a l s o
t h e sum o f t h a t p ro d u c e d above an d b e lo w th e c u t t i n g l e v e l a r e g iv e n i n
T a b le s 1 and 2 , r e s p e c t i v e l y .
TABLE 1 .
T o ta l Y ie ld o f F o ra g e i n Grams o f D ry W eight P ro d u o ed
Above t h e C u ttin g L e v e l D u rin g th e E n t i r e C u ttin g P e rio d *
(A v erag e o f f o u r c u l t u r e s )
S p e c ie s and
C u ttin g
H e ig h t
j
C ut E v ery
Week
C ut E v e ry
Two Weeks
:
.
.
C ut E v e ry
Four
Tfeeks
C ut E v e ry
E ig h t
Weeks
Brome G ra s s
1 in c h
3 in c h e s
6
"
9
"
12
"
1 0 .4 0
3 3 .2 6
3 9 .2 4
3 5 .6 1
1 8 .3 3
2 7 .8 4
4 4 .8 0
3 7 .4 0
2 8 .0 1
1 7 .6 9
4 6 .1 1
5 2 .1 3
4 3 .4 6
4 1 .6 9
1 3 .6 2
6 0 .5 3
5 8 .8 0
5 2 .3 0
2 2 .1 6
1 9 .3 2
O rc h ard G ra ss
1 in c h
3 in c h e s
6
"
9
"
12
"
1 4 .2 1
4 0 .6 3
4 9 .2 4
4 7 .7 7
2 9 .7 2
3 2 .3 9
4 7 .0 4
4 9 .6 0
5 5 .0 7
3 4 .1 8
6 1 .2 6
6 9 .3 7
5 5 .8 4
5 1 .1 1
3 0 .5 1
7 4 .2 3
6 9 .3 1
6 4 .6 5
4 8 .6 6
3 8 .5 1
>
4
i
T a b le 1 shows t h a t t h e g r e a t e s t p r o d u c ti o n ab o v e th e c u t t i n g l e v e l
■was made by t h o s e p l a n t s w h ic h w ere c u t a t one o r t h r e e in c h e s e v e r y
f o u r w eek s o r a t o n e , 3 , o r 6 in c h e s e v e r y e i g h t w e e k s , w h ile t h e
s m a l l e s t y e i l d w as p ro d u c e d b y t h e p l a n t s w h ic h w e re c u t a t one in c h
e v e ry w eek.
I n th e c a s e o f th e p l a n t s v h ic h w e re c u t a t 12 i n c h e s ,
o n ly a r e l a t i v e l y
s m a ll p r o p o r t i o n o f t h e t o t a l f o r a g e p ro d u c e d e x te n ­
ded a b o v e th e c u t t i n g l e v e l .
TABLE 2 .
T o ta l Y ie ld o f F o ra g e i n Grams o f D ry W eight P ro d u c e d
B o th Above a n d Below th e C u t t i n g L e v e l .
(A v erag e o f f o u r c u l t u r e s . )
S p e c ie s an d
C u ttin g
H e ig h t
Brome G ra ss
ifni-fcial C heck
1 in c h
3 in c h e s
6
"
9
"
12
"
F i n a l C heck
O rc h a rd G ra s s
I n i t i a l C heck
1 in c h
3 in c h e s
6
"
9
"
12
"
F i n a l C heck
C u t E v e iy . Cut E v e ry
’Week
. Two Weeks
C u t E v e ry
Four
Weeks
C u t E v e ry
E ig h t
Weeks
7 7 .1 1
8 5 .6 1
8 5 .4 4
9 5 .9 2
7 5 .1 5
9 7 .7 6
9 1 .9 5
1 0 1 .1 5
7 8 .8 6
9 1 .0 7
C heck
3 2 .9 0
3 9 .5 7
6 7 .1 4
8 9 .2 4
9 0 .0 9
7 2 .1 3
:
:
:
:
:
5 6 .7 8
7 7 .7 5
8 8 .0 8
9 2 .1 6
8 1 .9 2
7 2 .3 8
4 9 .4 0
5 0 .0 1
7 7 .8 7
9 6 .6 7
1 2 2 .4 5
1 1 9 .2 0
The t o t a l y i e l d
:
:
:
:
:
6 7 .3 9
9 2 .3 7
1 1 1 .8 8
1 2 1 .1 2
1 1 6 .7 3
1 0 3 .0 1
1 3 6 .0 5
1 1 9 .7 4
1 0 1 .1 1
1 2 5 .5 4
1 1 9 .2 8
1 3 0 .2 9
1 3 7 .2 8
1 2 2 .3 9
1 3 0 .5 4
9 9 .5 0
(T a b le 2) p ro d u c e d b y t h e p l a n t s w h ic h w ere c u t a t
one in c h a n d , to a o e r t a i n e x t e n t , th o s e w h ic h w e re c u t a t 3 in c h e s i n ­
c r e a s e d a s th e i n t e r v a l o f tim e b e tw e e n c u t t i n g s w as le n g t h e n e d .
S e v e ra l of th e c u ttin g tre a tm e n ts r e s u lte d i n g r e a te r t o t a l y ie l d s th a n
was made b y t h e f i n a l c h e c k , i n d i c a t i n g a s t i m u l a t i n g e f f e c t o f c u t t i n g
upon p la n t growth*
Y ie ld s o f R o o ts an d R hizom es
The d r y w e ig h ts o f t h e r o o t s p ro d u c e d b y t h e v a r i o u s l y t r e a t e d
p l a n t s a r e sum m arized i n T a b le 3*
TABLE 3 .
T h ese d a t a show t h a t t h e p l a n t s
D ry W eig h t o f R o o ts i n G ram s.
(A v erag e o f f o u r c u l t u r e s . )
Brome G ra s s
O rc h a rd G ra ss
2 2 .6 3
1 8 .3 0
2 .4 1
1 3 .0 7
2 3 .0 0
3 1 .0 0
2 2 .1 7
7 .3 3
1 5 .1 7
2 1 .6 7
3 6 .8 3
3 4 .8 3
6 .7 7
1 4 .4 7
3 4 .5 0
4 2 .3 3
3 7 .0 0
1 4 .3 3
1 7 .1 7
2 9 .0 0
3 6 .0 0
3 3 .6 7
1 in c h e v e r y 4 w k s.
3 in c h e s e v e r y 4 w k s.
1 3 .5 0
1 9 .6 7
2 8 .6 0
3 7 .3 3
3 6 .3 3
1 6 .9 0
2 9 .6 3
2 7 .3 3
3 2 .8 3
3 5 .6 7
1 in c h e v e r y 8 w k s.
3 in c h e s e v e r y 8 w k s.
3 3 .5 0
3 5 .8 3
3 0 .6 0
3 7 .7 8
4 0 .7 0
3 5 .5 0
2 7 .8 3
3 4 .3 3
4 3 ,8 3
4 0 .3 3
3 6 .1 3
2 8 .3 3
C u t t i n g T re a tm e n t
I n i t i a l C heck
1 in c h p e r w eek
3 in c h e s p e r w eek
£»
g
tt
It
ft
ft
tf
It
12
n
«
11
1 in c h e v e r y 2 wks*
3 in c h e s e v e r y 2 w k s.
g
g
j2
g
g
tt
••
w
tt
II
w
tt
It
»
it
II
It
ii
ii
II
it
It
n
it
tt
II
it
II
11
g
g
it
II
tt
It
tt
It
n
II
12
"
"
11
"
F i n a l C heck
w h ic h w e re o u t a t o n e , 3 , o r 6 in c h e s e v e r y w eek ; one o r 3 in c h e s e v e r y
tw o w e e k s; and one in c h (a n d 3 in c h e s i n brom e g r a s s ) e v e r y f o u r w eek s
s u s t a i n e d some r o o t i n j u r y a s a r e s u l t o f t h e t o p - c u t t i n g t r e a t m e n t
t h a t th e y r e c e i v e d .
As h a s b e e n i n d i c a t e d p r e v i o u s l y i n t h i s r e p o r t ,
-7 -
f r e q u e n t c l o s e c u t t i n g p r e v e n te d t h e p l a n t s fro m m a n u f a c tu r in g enough
c a r b o h y d r a te s f o r t h e i r g ro w th n e e d s .
T h is r e s u l t e d i n a d e p l e t i o n o f
t h e i r r o o t r e s e r v e s , a slo w r a t e
o f r o o t g ro w th , a n d , i n e x tre m e
d e a th and d i s i n t e g r a t i o n o f some
o f th e e x is tin g r o o ts .
cases,
The low y i e l d o f r o o t s p ro d u c e d b y th e brome g r a s s p l a n t s w hich
w ere c\at a t 12 in c h e s e v e r y w eek i s v e r y d i f f i c u l t t o e x p l a i n .
I t i s i n t e r e s t i n g to n o te t h a t , a lth o u g h o r c h a r d g r a s s o u ty i e ld e d
brome g r a s s i n f o r a g e , many o f th e c u t t i n g t r e a t m e n t s r e s u l t e d i n a
lo w e r p r o d u c tio n o f r o o t s by o rc h a r d g r a s s t h a n b y t h e c o r r e s p o n d in g
brome g r a s s c u l t u r e s .
T a b le 4 g iv e s th e p r o d u c tio n o f brom e g r a s s r h iz o m e s .
A lth o u g h
t h e a v e r a g e d ry w e ig h t o f rh iz o m e s p e r c u l t u r e w as c o n s i d e r a b l y g r e a t e r
f o llo w in g some t r e a t m e n t s t h a n f o llo w in g o t h e r s , w hen a l l f o u r c u l t u r e s
o f e a c h tr e a tm e n t a r e c o n s id e r e d , f r e a u e n t c u t t i n g r e s u l t e d i n a low
p r o d u c tio n o f rh iz o m e s , w h ile l e s s s e v e r e c u t t i n g h ad no c o n s i s t e n t i n ­
f lu e n c e u p o n t h e y i e l d o f r h iz o m e s .
C hem ical D ata
I n o b ta in in g sa m p le s o f t h e c l i p p i n g s f o r c h e m ic a l a n a l y s e s , com­
p o s i t e sam p les w ere p re p a re d a s f o l l o w s :
a l l o f th e sam p les o f fo r a g e
w h ic h h a d b e e n rem oved d u rin g th e f i r s t m onth from t h e brom e g r a s s
p l a n t s c u t a t one in c h w ere p la c e d i n a s i n g l e c o n t a i n e r .
T hose r e ­
moved d u r in g t h e s e c o n d m onth w ere p la c e d i n a seco n d c o n t a i n e r , and
so on f o r t h e t h i r d and f o u r t h m o n th s, r e s p e c t i v e l y .
The same p ro c e d u re
was f o llo w e d w ith e a c h o f th e o t h e r c u t t i n g t r e a t m e n t s i n brom e g r a s s ,
an d a l s o w ith e a c h o f th e c u t t i n g tr e a tm e n ts i n o rc h a rd g r a s s .
The d r y ,
c o m p o site sam p les w ere f i n e l y g ro u n d and k e p t I n s to p p e r e d b o t t l e s
-8 -
u n t i l a n a ly z e d
TABLE 4*
D ry W eig h t o f Brome G ra s s R hizom es P e r C u l t u r e
(W eig h t i n Grams)
C u l tu r e Number
C u t t i n g T re a tm e n t
A v e rag e
1
2
3
1 .3 4
0 .1 3
0 .5 4
2 .6 0
1 .1 5
1 .0 0
6 .5 0
-----1 .8 0
0 .9 6
1 .5 0
-----5 .0 0
0 .5 4
__ _
-----3 .0 0
1 .2 4
1 0 .0 0
0 .6 4
0 .1 1
1 .2 0
1 5 .5 0
3 .5 0
0 .4 0
0 .6 5
2 .7 0
5 .4 4
3 .9 6
___ _
0 .6 0
2 .0 0
4 .0 0
0 .9 8
0 .7 7
0 .6 5
0 .4 4
6 .3 0
5 .0 0
0 .8 7
2 .8 0
1 .1 1
8 .7 0
1 3 .0 0
0 .5 7
1 .7 6
3 .3 5
5 .1 3
4 .9 8
1 in c h e v e r y 4 w eeks
» »
3 in c h e s tt
n
tt
6
"
"
tt
tt
9
"
"
tt
tt
12
"
"
0 .2 7
0 .9 1
3 .6 0
1 .5 0
6 .5 0
4 20
6 .8 0
2 .8 0
3 .5 0
5 .5 0
0 .7 1
2 .0 0
4 .4 0
1 .3 4
4 .0 0
4 .0 0
5 .8 0
6 .1 0
4 .8 0
9 .0 0
2 .3 0
3 .8 8
4 .2 3
4 .7 9
6 .2 5
1 in c h e v e r y 8 w eeks
3 in c h e s " tt tt
0 .1 7
1 .0 0
1 .2 0
0 .4 0
0 .0 6
3 .3 0
1 .6 4
1 .1 4
2 .5 0
3 .8 0
0 .1 2
1 .3 2
1 .7 0
1 .0 0
4 .4 0
0 .7 2
1 5 .0 0
7 .0 0
8 .0 0
2 .1 1
1 .0 4
4 .7 4
2 .7 6
2 .9 8
3 .5 0
1 .7 0
2 .4 0
4 .4 0
3 .0 0
I n i t i a l C heck
1 in c h p e r w eek
3 in c h e s p e r w eek
6 in c h e s p e r w eek
tt
9
»
"
n
12
"
”
1 in c h e v e ry 2 w eeks
tt Tt
t/
11
V
6
tt
tt tt ft
9
12
6
9
12
"
"
"
"
n
11
"
It
It
tt
tt
ti
tt
tt
"
"
tt
tt
tt
tt
F i n a l C heck
■z o n
4 .0 0
7 .8 0
0 .9 2
4
A l a r g e num ber o f t h e f o r a g e s a m p le s w ere a n a ly z e d f o r c ru d e p r o ­
t e i n , p h o s p h o r u s , a n d c a lc iu m ; a n d s e v e r a l w e re a n a ly z e d f o r f r e e r e d u c i n g s u g a r s , t o t a l s o l u b l e s u g a r s , s o l u b l e s t a r c h e s an d d e x t r i n s , and
in s o lu b le s ta r c h .
Some o f t h e s e d a t a a r e p r e s e n t e d i n T a b le 5 .
The i n i t i a l c h e c k s
w e re r e l a t i v e l y lo w i n c ru d e p r o t e i n an d r e l a t i v e l y h ig h i n s o lu b le
c a r b o h y d r a t e s , a s a r e s u l t o f h a v in g r e c e iv e d no n u t r i e n t s o l u t i o n f o r
s e v e r a l w eeks j u s t p re o e d in g th e s t a r t of t h e c u t t i n g p e r i o d .
TABLE 5 .
P e rc e n ta g e o f C rude P r o t e i n , T o t a l S o lu b le S u g a rs , and.
D e x tr in s and S o lu b le S ta r c h e s i n F o rag e S a m p le s.
( M o is tu r e - f r e e b a s i s )
C u ttin g
T re a tm e n t
! Month*
Sample
Was C ol­
le c te d
Crude P r o t e i n
Brome
O rc h ard
T o ta l S o lu b le
S u g a rs
Brome O rch ard
b e x t r i n s and
S o lu b le
S ta r c h e s
Brome O rch ard
W eekly a t 1 ”
»
t! gtt
n
t! rjft
1 st
1st
4 th
3 5 .8 3
3 3 .6 0
3 3 .4 1
2 8 .8 3
2 4 .9 2
3 0 .0 9
1 .0 4
0 .3 9
0 .3 4
1 .6 4
1 .1 8
0 .2 7
0 .0 0
0 .0 0
0 .0 0
0 .1 0
0 .0 0
0 .0 0
B i-w e e k ly a t 3 ”
11
II git
n
n gn
1st
4 th
4 th
30*25
3 2 .3 0
2 9 .4 9
2 2 .8 9
2 8 .0 0
2 3 .0 3
4 .5 2
1 .3 1
0 .5 2
3 .2 7
0 .5 2
0 .8 7
0 .0 0
0 .0 0
0 .0 0
0 .0 0
0 .0 0
0 .1 1
M o n th ly a t 1"
n
it gti
1st
4 th
2 5 .2 5
2 8 .2 4
1 9 .1 9
2 2 .0 0
8 .0 0
2 .0 8
8 .1 4
1 .7 7
0 .2 4
0 .3 5
0 .2 9
0 .1 0
1 s t two
1 s t two
2 2 .0 2
2 4 .2 1
1 4 .9 8
1 5 .9 8
6 .6 0
6 .8 7
6 .7 5
6 .6 7
0 .1 2
0 .0 0
0 .1 0
0 .0 0
1 1 .4 3
1 5 .1 8
1 0 .6 0
1 6 .4 9
1 0 .2 8
1 .8 2
5 .3 7
0 .5 2
4 .4 2
3 .7 6
1 .8 0
1 .6 0
B i-m o n th ly a t 3"
11
11 git
I n i t i a l C heck
F i n a l Check
* U n e m o h th e q u a ls f o u r w eeks
The p r e s e n c e o f n i t r o g e n i n th e n u t r i e n t s o l u t i o n r e s u l t e d i n th e
c l i p p e d f o r a g e s a m p le s , an d a l s o th e f i n a l c h e c k s , b e in g h i g h e r i n
c ru d e p r o t e i n t h a n w ere th e i n i t i a l c h e c k s .
F re a u e n c y o f c u t t i n g a l s o
a f f e c t e d t h e p r o t e i n c o n te n t o f th e f o r a g e .
The more f r e q u e n t l y t h e
p l a n t s w e re c u t , th e h ig h e r t h e i r p r o t e i n c o n t e n t .
The to p s o f t h o s e p l a n t s w h ic h we r e c u t a t one o r 3 in c h e s e v e r y
w eek w ere v e r y low i n s o lu b le c a r b o h y d r a te s so o n a f t e r th e b e g in n in g
o f th e c u t t i n g p e r i o d .
Those w h ich w ere c u t l e s s f r e q u e n t l y had a p p r e ­
c i a b l e am ounts o f s o lu b le c a r b o h y d r a t e s i n t h e i r to p s d u rin g th e f i r s t
m o n th , and a l s o d u r in g t h e seco n d m onth i n th e c a s e o f th e p l a n t s
-
10 -
w h ic h w ere c u t once e v e r y e i g h t w e e k s .
A t th e end o f t h e f o u r t h m o n th ,
th e to p s o f a l 1 p l a n t s t h a t were a n a ly z e d , e v e n th e f i n a l c h e c k s , w ere
q u i t e low i n s o lu b le c a r b o h y d r a t e s .
The d a ta i n d i c a t e a g r a d u a l u s in g
up o f th e s u r p lu s c a r b o h y d r a t e s , w ith t h e sp e e d o f c a r b o h y d r a te d e p le ­
t i o n i n c r e a s i n g w ith i n c r e a s e i n s e v e r i t y o f c u t t i n g t r e a t m e n t .
M ost o f t h e s o lu b le c a r b o h y d r a te s w ere i n th e form o f s u g a r .
No
i n s o l u b l e , o r t r u e , s t a r c h w as fo u n d i n any o f th e f o r a g e s a m p le s .
FIELD STUDIES
On A u g u st 1 6 , 1S37, a s e r i e s o f f i e l d p l o t s was sown on th e
M ic h ig a n S t a t e C o lle g e Farm , n e a r E a s t L a n s in g .
T h ere w e re tw o p l o t s
o f e a c h o f th e f o llo w in g :
Smooth brom e g r a s s
O rch ard g r a s s
A l f a l f a - sm ooth brome g r a s s m ix tu re
A l f a l f a - o r c h a r d g r a s s m ix tu r e
K entucky b lu e g r a s s
K entucky b l u e g r a s s - w h ite c lo v e r m ix tu r e
I n t h e s p r in g o f 1 938 , t h e s e p l o t s w ere each d i v i d e d i n t o f o u r
e q u a l p a r t s , 15 f e e t lo n g a n d 10 f e e t w id e .
One o f t h e s e s m a l le r a r e a s
i n e a c h p l o t was c u t a t a p p r o x im a te ly one in c h a b o v e th e g ro u n d w ith a
p o w e r-d riv e n law n mower; a seco n d and t h i r d w ere c u t a t 3 a n d 6 i n c h e s ,
r e s p e c t i v e l y , w ith a h o r s e - d r a w n mower; an d th e f o u r t h was l e f t t o b e
c u t l a t e r f o r h a y i n th e u s u a l m a n n er.
The p l o t s w h ic h w ere c u t a t o n e, 3 , and 6 i n c h e s , r e s p e c t i v e l y ,
w e re c u t s e v e n tim e s d u r in g 1 9 3 8 .
u u r in g 1939 th e p l o t s w h ic h w ere c u t
a t one in c h w ere c u t s i x t i m e s , w h ile th o s e w h ich w e re c u t a t 3 an d 6
-1 1 -
in c h e s w ere c u t o n ly f i v e tim e s e a c h .
The l e n g t h o f i n t e r v a l b e tw e e n
s u c c e s s iv e c u t t i n g s dep en d ed upon th e r a t e o f fo r a g e g ro w th and i n ­
c r e a s e d a s th e r a t e o f g ro w th d e c r e a s e d .
The h a y p l o t s w ere c u t tw ic e
each se a so n .
The t o t a l y i e l d s o f f o r a g e , i n p o u n d s o f d ry m a t t e r , h a r v e s te d
from th e s e p l o t s i n 1938 and 1939 a r e g iv e n i n T a b le 6 .
a r e a l s o c a l c u l a t e d on t h e a c r e b a s i s .
T hese y i e l d s
W ith one e x c e p tio n ( t h e p u re
K entucky b l u e g r a s s p l o t s i n 1 9 3 8 ), th e p l o t s w hich w ere c u t a t 3 in c h e s
o u ty ie ld e d th o s e t h a t w ere c u t a t 6 i n c h e s ; and i n many i n s t a n c e s , th e
p l o t s c u t a t one in c h o u ty ie l d e d th o s e c u t a t s i x i n c h e s .
W ith a few e x c e p tio n s , th e h a y p l o t s f a r o u ty ie ld e d t h e c o r r e s p o n d ­
in g p l o t s w hich w e re c u t more f r e q u e n t l y .
Hay y i e l d s w ere c o n s i d e r a b l y
g r e a t e r when a l f a l f a was p r e s e n t th a n i n p l o t s c o n t a i n in g no a l f a l f a .
The low y i e l d s p ro d u c e d by th e p u re g r a s s p l o t s i n 1939 r e f l e c t e d t h e
d e f i c i e n c y o f s o i l n i t r o g e n a s w e ll a s t h e d r y s e a s o n .
The d a r k e r
g re e n c o l o r and m ore v ig o ro u s g ro w th o f th e g r a s s e s w hen g ro w in g w ith
a legum e i n d i c a t e d t h a t th e legum e m s m aking some a d d i t i o n a l n i t r o g e n
a v a i l a b l e to t h e g r a s s e s .
On a l l b u t th e a l f a l f a and th e a l f a l f a - g r a s s h a y p l o t s , m o st o f
th e a n n u a l f o r a g e w as p ro d u c e d b e f o r e th e m id d le o f J u n e .
The se c o n d
c u t t i n g s o f a l f a l f a and o f a l f a l f a - g r a s s h a y s w ere o n ly a b o u t o n e - h a l f
a s l a r g e a s th e c o r r e s p o n d in g f i r s t c u t t i n g s .
J u d g in g from th e t h i n n i n g o u t o f th e s t a n d s , a l l s p e c i e s , e x c e p t
b l u e g r a s s and w h ite c l o v e r , w ere i n j u r e d seme by f r e q u e n t c u t t i n g a t
one i n c h , a lth o u g h th e f o r a g e y i e l d s from t h e s e p l o t s com pared f a v o r ­
a b ly w ith th o s e made by th e p l o t s w h ic h w e re c u t a t h ig h e r l e v e l s *
-1 2
TABLE 6 .
Summary o f T o ta l S e a s o n a l Y ie ld s o f F o ra g e i n
P ounds o f D ry M a tte r
(A v e ra g e o f Two P l o t 3 .)
S p e c ie s
Brome G ra s s
ti
»
tt
tt
it
it
O rc h ard G ra ss
tt
it
tt
it
tt
it
A lfa lfa
it
it
tt
A l f a l f a - B r ome
tt
tt
»
it
tt
tt
A lfa lfa -O rc h a rd
tt
tt
n
tt
tt
tt
Ky* B lu e g r a s s
tt
tt
tt
tt
it
n
Ky. B lu e g r a s s
an d Yvhite C lo v e r
ti
n
it
C u t­
tin g
H e ig h t
19 ’38
P e r P lo t
:
P e r A cre
B a s is
1939
P e r P l o t P e r A c re
B a s is
1 in c h
3 in c h e s
6
"
h ay
6*87
9 .1 4
8 .7 8
1 1 .7 7
1 9 9 5 .0 5
2 6 5 4 .2 6
2 5 4 9 .7 1
3 4 1 8 .0 1
3 .9 6
4 .6 0
3 .5 4
4 .4 0
1 1 4 9 .9 8
1 3 3 5 .8 4
1 0 2 8 .0 2
1 2 7 7 .7 6
1 in c h
3 in c h e s
6
"
hay
5 .4 4
7 .7 7
5 . 96
8 .8 6
1 5 7 9 .7 8
2 2 5 6 .4 1
1 7 3 0 .7 8
2 5 7 2 .9 4
3 .2 0
2 .6 7
1 .0 9
3 .0 8
9 2 9 .2 8
7 7 5 .3 7
3 1 6 .5 4
8 9 4 .4 3
1 in c h
3 in c h e s
6
11
hay
8 .2 0
9 .4 2
7 .8 9
1 3 .2 6
2 3 8 1 .2 8
2 7 3 5 .5 7
2 2 9 1 .2 6
3 8 5 0 .7 0
4 .5 0
5 .2 5
4 .7 0
1 0 .9 9
1 2 4 8 .7 2
1 5 2 4 .6 0
1 3 6 4 .8 8
3 1 9 1 .5 0
1 in c h
3 in c h e s
6
"
hay
8 .5 4
1 3 .0 1
9 .3 6
1 4 .5 5
2 4 8 0 .0 2
3 7 7 8 .1 0
2 7 1 8 .1 4
4 2 2 5 .3 2
5 .2 0
6 .2 3
5 .7 3
1 6 .2 7
1 5 1 0 .0 8
1 8 0 9 .1 9
1 6 6 3 .9 9
4 7 2 4 .8 1
1 in c h
3 in c h e s
6
"
hay
1 0 .5 8
1 1 .6 6
1 0 .3 3
1 4 .1 8
3 0 7 2 .4 3
3 3 8 6 .0 6
2 9 9 9 .8 3
4 1 1 7 .8 7
5 .8 4
4 .7 7
3 .9 9
1 3 .3 2
1 6 9 5 .9 4
1 3 8 5 .2 1
1 1 5 8 .7 0
3 8 6 8 .1 3
1 in c h
3 in c h e s
6
"
hay
2 .2 0
4 .2 9
4 .2 9
5 .4 6
6 3 8 .8 8
1 2 4 5 .8 2
1 2 4 5 .8 2
1 8 8 5 .5 8
1 .8 2
1 .7 2
0 .7 7
2 .3 8
5 2 8 .5 3
4 9 9 .4 9
2 2 3 .6 1
6 9 1 .1 5
1 in c h
3 in c h e s
6
"
hay
4 . oO
6 .9 1
5 .6 3
8 .6 2
1 3 3 5 .8 4
2 0 0 6 .6 6
1 6 3 4 .9 5
2 5 0 3 .2 5
3 .3 3
3 .9 3
1 .7 9
4 .1 2
9 8 1 .5 5
1 1 4 1 .2 7
5 1 9 .8 2
1 1 9 6 .4 5
C u t t i n g a t 3 in c h e s re d u c e d t h e s t a n d o f a l f a l f a b u t c a u s e d no p erm a­
n e n t i n j u r y to t h e g r a s s e s *
C u tti n g a t 6 in c h e s d id n o t re d u c e t h e
-1 3 -
t h i c k n e s s o f a n y o f t h e s t a n d s , b e c a u s e a d e q u a te p h o t o s y n t h e t i c t i s s u e
re m a in e d b e lo w th e c u t t i n g l e v e l t o s u p p ly t h e c a r b o h y d r a t e r e q u i r e ­
m e n ts o f t h e p l a n t s .
K e n tu ck y b l u e g r a s s and -vtiiite c l o v e r p ro d u c e d
c o n s i d e r a b l e g r e e n t i s s u e c l o s e to t h e g ro u n d an d w ere a b l e t o m a n u fa c ­
t u r e s u f f i c i e n t c a r b o h y d r a t e s to m a i n t a i n p l a n t v i g o r w hen c u t a t a
h e i g h t o f o n ly one i n c h .
DISCUSSION
A lth o u g h c l o s e c u t t i n g o f g r a s s e s u s u a l l y r e s u l t s i n a n i n c r e a s e
i n th e r a t e o f p l a n t g ro w th f o r a s h o r t t i m e , f r e q u e n t r e p e t i t i o n o f
su c h t r e a t m e n t c a u s e s a g r a d u a l d e c l i n e i n p l a n t v i g o r , f o r a g e y i e l d ,
an d r o o t p r o d u c t i o n , d u e to c a r b o h y d r a t e d e f i c i e n c y .
f ic ie n c y o ccu rs a f t e r th e p la n t has u sed up i t s
C a r b o h y d ra te d e ­
c a rb o h y d ra te r e s e r v e s
and i s u n a b le to s u p p ly s u f f i c i e n t c a r b o h y d r a t e s b e c a u s e o f t h e f r e ­
q u e n t re m o v a l o f i t s p h o t o s y n t h e t i c t i s s u e .
T h is c o n d i t i o n w as m ore
a c u t e i n t h e g re e n h o u s e t h a n i n t h e f i e l d b e c a u s e t h e s u p p l i e s o f
m o is tu r e a n d n i t r o g e n w e re more a d e q u a te i n t h e g r e e n h o u s e , r e s u l t i n g
i n a m ore r a p i d d e p l e t i o n o f th e c a r b o h y d r a t e r e s e r v e s .
A ls o , b e c a u s e
o f t h e d i f f e r e n t m e th o d s u s e d i n c u t t i n g , t h e g re e n h o u s e p l a n t s w h ich
w e re c u t a t one i n c h w e re m ore n e a r l y d e f o l i a t e d t h a n w ere t h o s e c u t
a t one in c h i n th e f i e l d .
I n th e g re e n h o u s e t h e l e a v e s w e re r a i s e d
an d c u t o f f a t th e d e s i g n a t e d h e i g h t , w h e r e a s , i n th e f i e l d , l e a v e s
t h a t w ere l y i n g f l a t on th e g ro u n d e s c a p e d c u t t i n g .
L ow -grow ing f o r a g e p l a n t s , s u c h a s K e n tu ck y b l u e g r a s s a n d w h ite
c l o v e r , p ro d u c e m ore p h o t o s y n t h e t i c t i s s u e c l o s e t o th e g ro u n d t h a n i s
t h e c a s e w i t h m ore u p r i g h t p l a n t s ,
g r a s s , an d a l f a l f a .
su c h a s sm ooth brom e g r a s s , o r c h a r d
As a r e s u l t o f t h i s g r e e n g ro w th c l o s e to t h e
-1 4 -
g ro u n d , th e K entucky b lu e g r a s s and w h ite c l o v e r s ta n d s w ere n o t n o t i c e ­
a b ly i n j u r e d by f r e q u e n t c u t t i n g a t a h e i g h t o f one in c h w ith a law n
mower*
V /hile c u t t i n g d o e s n o t e x a c t l y s im u la te g r a z i n g , th e p r e s e n t e x ­
p e rim e n t d o e s g iv e some i n d i c a t i o n s a s to how f o r a g e p l a n t s may re s p o n d
to d i f f e r e n t sy ste m s o f g r a z in g .
K en tu ck y b l u e g r a s s and w h ite c lo v e r
c a n be g ra z e d c o n tin u o u s ly a t a lo w e r l e v e l th a n c a n sm ooth brome g r a s s ,
o r c h a r d g r a s s , a n d a l f a l f a w i th o u t p e rm a n en t i n j u r y to t h e s t a n d .
The
a n n u a l y i e l d o f d r y m a tte r p ro d u c e d by m o st tam e p a s t u r e s i s lo w e r ,
u n d e r a n y sy stem o f g r a z i n g , t h a n c o u ld be o b ta in e d i f th e fo r a g e w ere
h a r v e s te d f o r h a y .
U nder th e c l i m a t i c c o n d i t i o n s p r e v a i l i n g i n s o u th e r n M ic h ig a n ,
t h e r e i s v e ry l i t t l e
g ro w th o f p e r e n n i a l
g r a s s e s and s h a llo w - r o o te d
le g u m e s, su ch a s w h ite c l o v e r , d u rin g th e h o t , d r y m onths o f J u l y an d
A u g u s t.
A l f a l f a , h a v in g a d eep r o o t s y s te m , does make some g ro w th d u r­
in g t h i s p e r i o d , b u t a t a s lo w e r r a t e t h a n d u r in g May and J u n e .
The p u b lis h e d r e s u l t s o f s e v e r a l e x p e r im e n ts ( C a r r i e r a n d O ak ley
m
( 2 ) , H e in and Cook ( 4 ) , and o t h e r s ) i n d i c a t e t h a t a l t e r n a t e g r a z in g h a s
v e r y l i t t l e a d v a n ta g e , i f a n y , o v e r c o n tin u o u s g r a z i n g .
The r e s u l t s o f
th e p r e s e n t e x p e r im e n t, w i t h g r a s s e s i n th e g re e n h o u se and w i t u a l f a l f a
i n th e f i e l d , h o w e v er, i n d i c a t e t h a t w h ere m o is tu r e i s s u f f i c i e n t t o
k eep th e f o r a g e p l a n t s g ro w in g th r o u g h o u t th e e n t i r e g r a z in g s e a s o n ,
some sy stem of r o t a t i o n g r a z in g w h ich a llo w s f o r e a c h p a s t u r e to b e
g ra z e d r e l a t i v e l y c l o s e , fo llo w e d by a r e s t p e r io d s u f f i c i e n t l y lo n g
f o r th e p l a n t s t o make a good r e c o v e r y , w i l l g iv e a g r e a t e r y i e l d o f
h ig h e r q u a l i t y f o r a g e th a n c a n be o b ta in e d u n d e r an y i n t e n s i t y o f
c o n tin u o u s g r a z in g #
Such s y s te m s o f r o t a t i o n g r a z in g a r e now b e in g
p r a c t i c e d on some o f t h e i r r i g a t e d p a s t u r e s o f t h e P a r W est#
A v a ila b le n itr o g e n i s
one o f t h e m o st common l i m i t i n g f a c t o r s i n
t h e g ro w th o f p a s t u r e g r a s s e s .
n u t r i e n t s to
I t i s a l s o one o f t h e m o st e x p e n s iv e
s u p p ly i n t h e fo rm o f c o m m e rc ia l f e r t i l i z e r .
T h is a v a i l ­
a b l e n i t r o g e n c a n o f t e n be m ore c h e a p ly f u r n i s h e d t o g r a s s e s b y le g u m e s
g ro w in g v d th th e g r a s s e s .
W h erev er p r a c t i c a b l e , th e aim s h o u ld be t o
e s t a b l i s h and m a i n t a i n a m ix tu r e of le g u m e s a n d g r a s s e s r a t h e r t h a n a
s tr a ig h t g ra ss p a s tu r e .
The c h e m ic a l a n a l y s e s i n th e p r e s e n t e x p e r im e n t a r e n o t v e r y com­
p r e h e n s i v e , b u t th e y do i n d i c a t e t h a t y o u n g , r a p i d l y g ro w in g g r a s s ,
w e l l s u p p l i e d w i t h n i t r o g e n and m o i s t u r e , i s v e r y h ig h i n c ru d e p r o ­
t e i n c o n t e n t a n d r e l a t i v e l y low i n s o l u b l e c a r b o h y d r a t e s .
th is is
P e rh a p s
one r e a s o n why such f o r a g e i s o f t e n lo w e r i n f e e d i n g v a lu e
t h a n g r a s s w h ic h i s a l i t t l e
m ore advanced i n m a t u r i t y .
A r c h ib a ld ( l ) , V /ill a r d ( 7 ) , and o t h e r s h a v e s u g g e s te d t h a t d i f f e r ­
e n c e s i n p a l a t a b i l i t y among c e r t a i n f o r a g e s p e c i e s w e re a s s o c i a t e d iv ith
d i f f e r e n c e s i n c h e m ic a l c o m p o s i tio n .
M ost o f th e i n v e s t i g a t o r s who
h a v e com pared sm ooth brom e g r a s s and o r c h a r d g r a s s i n p a l a t a b i l i t y h a v e
c o n s i d e r e d brom e th e m ore p a l a t a b l e , e s p e c i a l l y i n t h e l a t e r s t a g e s o f
g r o w th .
I n th e p r e s e n t e x p e r im e n t, brom e g r a s s s a m p le s w ere g e n e r a l l y
som ew hat h i g h e r th a n o r c h a r d g r a s s i n c ru d e p r o t e i n and c a lc iu m ; a n d ,
i n some i n s t a n c e s , brcrue g r a s s a l s o h a d a h i g h e r s u g a r c o n t e n t .
T hese
d i f f e r e n c e s d id n o t a p p e a r g r e a t e n o u g h > h o w e v e r, t o a c c o u n t f o r a n y
m ark ed d i f f e r e n c e s i n p a l a t a b i l i t y .
-1 6 -
SUMMARY
Sm ooth brom e g r a s s and o r c h a r d g r a s s w e re c u t a t h e i g h t s o f 1 , 3 ,
6 , 9 , a n d 12 i n c h e s a n d a t i n t e r v a l s o f 1 , 2 , 4 , a n d 8 w e ek s i n t h e
g re e n h o u se .
I n th e f i e l d t h e y w e re gro w n a lo n e an d i n m i x t u r e s w ith
a l f a l f a an d vrere c u t fro m f i v e t o s e v e n tim e s p e r y e a r a t h e i g h t s o f
1 , 3 , and 6 in c h e s an d tw ic e f o r h a y .
The f i e l d t r i a l s a l s o i n c lu d e d
p l o t s o f K e n tu ck y b l u e g r a s s a n d a m ix tu r e o f b l u e g r a s s and w h i te c l o v e r ,
F r e q u e n t c l o s e c u t t i n g i n t h e g re e n h o u s e s t i m u l a t e d t h e g ro w th o f
f o r a g e f o r a s h o r t tim e b u t so o n r e s u l t e d i n d e c r e a s e d y i e l d s o f o o th
f o r a g e an d r o o t s .
The o t h e r c u t t i n g t r e a t m e n t s i n t h e g re e n h o u s e d id
n o t h a v e a n y m a rk e d e f f e c t s u p o n t h e t o t a l y i e l d o f f o r a g e o r u n d e r ­
g ro u n d p a r t s .
I n t h e f i e l d p l o t s , c u t t i n g f o r h a y r e s u l t e d i n th e g r e a t e s t s e a ­
s o n a l y i e l d s o f f o r a g e ; b u t t h e p l o t s w h ic h w e re c u t a t 3 in c h e s o u t y i e l d e d th o s e c u t a t 6 i n c h e s .
L egum es, by s u p p ly in g n i t r o g e n , h a d a
s t i m u l a t i n g i n f l u e n c e u p o n t h e g ro w th o f th e g r a s s e s .
The c h e m ic a l d a t a i n d i c a t e t h a t y o u n g , r a p i d l y g ro w in g g r a s s e s ,
w e l l s u p p l i e d w ith n i t r o g e n an d m o i s t u r e , a r e v e r y h ig h i n c ru d e
t e i n b u t r e l a t i v e l y lo w i n s o l u b l e c a r b o h y d r a t e s .
-1 7 -
pro­
LITERATURE CITED
1.
A r c h i b a l d , J . G ., " S t u d i e s i n th e C h e m istry o f P a s t u r e G r a s s e s * ”'
M a s s a c h u s e tts A g r i c u l t u r a l E x p e rim e n t S t a t i o n B u l l e t i n 347 ( a n n u a l
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1914.
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P l a n t s a s a F a c to r i n Range M an ag em en t.” C a l i f o r n i a A g r i c u l t u r a l
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on B e e f P r o d u c t i o n an d P l a n t P o p u l a t i o n o f P a s t u r e s a t B e l t s v i l l e ,
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o f O rg a n ic F oods i n B a h ia G r a s s ." F l o r i d a A g r i c u l t u r a l E x p e rim e n t
S t a t i o n T e c h n ic a l B u l l e t i n 2 1 9 , 1 9 3 0 .
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L e u k e l, W. A. and R. M. B a r n e t t e , " C u ttin g E x p e rim e n ts w ith B a h ia
G ra s s Grown i n L y s i m e t e r s ." F l o r i d a A g r i c u l t u r a l E x p e rim e n t
S t a t i o n T e c h n ic a l B u l l e t i n 2 8 6 , 1935*
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Wyoming A g r i c u l t u r a l E x p e rim e n t S t a t i o n B u l l e t i n 1 9 9 , 1933*
-1 8
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