1969 SOD HEATING BOX EXPERIMENTS

A series of 11 sod heating box experiments were con-ducted during the 1969 growing season. The general methodsused were as described in the Development of Methods section.

Specific cultural treatments and results of each experiment

will be discussed in this section.The Merion Kentucky bluegrass sod used for the first

seven experiments, conducted from May 16 to June 24, 1969,was grown on organic soil at Green Acres Turf Farm, Mason,Michigan. The sod was produced by rhizome regrowth from a

sod field harvested in December, 1967. No irrigation oroverseeding was used in establishing this sod. It was mowedtwice weekly at a 2 inch height. The 1969 fertilizer appli-

cations were 400 lb/A of 5-20-20 in early April and 150 lb/Aof 45% N urea on May 1st. The sod was strong and of high

quality.

Experiment I (May 16, 1969)The cultural treatments included in this experiment

were (a) 2 versus 0.75 inch cutting heights and (b) 0.0,0.0055, 0.0275, and 0.0550 lb/A of N6benzyladenine. The

0.75 inch cutting height was done 2 days before harvest.

The N6benzyladenine solution was applied a few minutes

31

32

before harvest. The cutting and respiration inhibitortreatments were arranged in a randomized block factorialdesign with 2 replications. The Merion Kentucky bluegrasssod was harvested on May 16, 1969, and stored in heating

boxes under simulated load conditions for 4 days.Results and discussion.--The mean percent moisture

of the sod pieces at the beginning of the experiment was

63.1 (range 65.2 to 60.5%) and differences due to treatmentswere not significant. The air temperatures at 2 p.m. in the

greenhouse room where the sod was stored were as follows:

o

92

1274

24

81

48

76

72

74

9680

HoursOF

The main effect means for temperature, percent carbon diox-

ide, and percent oxygen are presented in Table 5.The mean temperature within the sod heating boxes

increased rapidly during the first 24 hours. The coolweather which began during the second day would explain thegradual decline in mean temperature during the last 3 daysof the experiment. Normally, the temperature would havecontinued to rise slowly. From 12 hours onward significantly

lower temperatures were recorded for the lower height of cut

treatment. The smaller quantity of respiring tissue is the

probable explanation for this response. The main effectmeans for N6benzyladenine levels did not show significant

differences in temperature until the fourth day. Then a

l!)Q)

.--I.0ro8

oL()u'lol!)I'

Q)N

~0

.~~Q)'tlro.--I

l!)>.

l!)IS!

0~

0Q).0

~Z

oQ)Ul

t1lH

ro::l

4-lH

000::r:

+l

Ul

.jJ~~Q)

H::ll/)roQ

)

~

33.0ro.--I

Nl!)Nl!)l!)

......-Ie-Ie

-Ie-Ie

-Ie-Ie

-Ie-Ie

-Ie-Ie

iCiC

iCOOl!)~""~""

Q)

H::l.jJroH_Q

)~0..08

........Q)8

.0roOL()N......

NoCJ

0001'

l!)L()l!)

00O

N...

""~~

No

34

significant decrease in temperature with increased N6ben-zyladenine interaction occurred for temperature during thelast 3 days of storage (Table 6). Examination of the simpleeffects for N6benzyladenine showed that the 0.055 lb/A rateof N6benzyladeni~e reduced temperatures significantly when

applied to a low cut sod. Low mowing in the presence of

0.0055 lb/A and 0.0550 lb/A of N6benzyladenine reduced tem-I

tperature significantly. Based on these results the 0.055lb/A rate of N6be'nzyladenine was used in further 1969 sod

heating box experiments.The percent carbon dioxide determined in the sod

stack in the sod heating boxes was significantly lower forthe low cutting height treatment at 72 hours (Table 5). The

reduced amount of respiring plant tissue present provides asatisfactory explanation. The 48 hour gas samples were notanalyzed because of equipment breakdown. The mean percent-ages of carbon dioxide were similar at all three sampling

times. Statistically significant differences in percentcarbon dioxide in relation to the N6benzyladenine rates wasfound at 72 hours. Significantly more carbon dioxide wasfound where 0.0275 lb/A of N6benzyladenine was applied thanfor 0.0550 lb/A, but it seems unlikely that these results

are physiologically valid.The percent oxygen was significantly greater for the

lower height of cut after 72 and 96 hours (Table 5). Less

oxygen was required when less plant tissue was respiring.

35

<SJ-...

......

.....M

.....

...III

Ll'lM

00M

O>t

IIII

'<l'N

'<l'N

Ll'l

.....'<l'~

IIII

II

s::0...

N...

......

'tlIII

....M

NO

NO

OJI

...,'<l'

OM

O'<l'

OM

enIII

II

II

II

OJ:>I-lIIIen

N..c

...,III

NO

NO

Ll'l0

UI

'tlOJ

MM

.....N

...............

0....

IIII

II

en....r.:!

en...

......

enOJ

........

......

III.....

III....

M1/10

0....

I-la.

I>t

0'

e'<l'

01/101/1

O'<l'

.....OJ

.....III

II

IOJ

:300

:>.....

.......Q

...,.....

u>t

IIItO

O1/10

M....

OJ..>:

Ia.

UM

...............0

.....0en

:3III

II

II

IOJ

...,I-l

s::OJ~

:.::.....

III'<l'0

....0

N....

...,s::

I.....

0N

.....N0

.....0

..........

.....III

II

I.....

I-l..Q

Q)III

~..Q0

s::...

......

I-l0

......

...a.

en0

I/1NM

000tO

l/1Men

>t1/1

'<l'....

s::III

1/1III

~~cpg~cp

to.........

00'0

~0

tOtO

I.....

.....""'<l'

"-Q)

u..Q

:>III

I-l.....

Q)I-l

01/1

01/11/1000

1/11/10.....

Q)....

....M

...,Q)

NIII

....."'.....to

.............

I/1N.....

s::en

s::~

"'toI

tOtO

I00

toI

~.....

s::.....

0s::

Q).....

Q)'0

...,...,'0

......

...s::

Ill.....

III...

......

III1-l'O

.....1/1

NI/1

....N

ON

0Ll'l1/1

s::>t

1/1N

1/1Q)

0N

0III

'<l'tOl/1

0<SJ'<l'"''<l''<l'

0s::

us::

0"'to

I"'to

ItO

tOI

.....Q)

s::0'

..QQ)

Q)s::

<SJ..c

'0.....

Z...

...,III

a.tO

l/1M1/101/1

tON

\0.....

a......

...,>t.....

0III

NO

N"'

....N

to<SJNIII

N..c"''''

ItO

tOI

tOtO

Is::

enCl

Q)00

..Q'O..:l

\0Q)

Z...,s::

IIIIII

X.....

...,en

enen

..c:3

::c...,

...,...,

...,...,e

uu

u..c.....

0'_

Q)Q)

OJI-l

O'en

Cs::

1/1....

1/1....

1/1....

OJ.....

..........N

........N

........N

........0'

Q)I-l

...,~'r.:!

'r.:!'r.:!

I-l..c

Q)...,

00

0III

'0:3

OJQ)

OJ.....

g'S()

..........

.....a.

g.~

Q).....

eI-l

""'0.....

..........

III...,

Q)00

0000

:3I-l

enU

0OJ

Q)...,

en0'

u...,

enI-l

IIIs::

s:::3

....I-l

toN

\0OJ

III'0000

'<l'....

'"I-l

Us::

::c...,

OJ.....

III00

........

.........

.....s::'"

ClO

'<SJ...

.....'"...

00.....

...,s::r;;

...OJe

0<SJ

Q)I-lOJ

::l.....

ena.

..QIII

eIII

Q)Q)

Eo<:IE:

Eo<

36

The N6benzyladenine treatments did not affect oxygen usesignificantly.

The mean ppm ethylene found in the gas samples were0.66 and 0.32 for 24 and 72 hours, respectively. The lowvalues for ppm ethylene were not significantly related totreatments. The 48 and 96 hour gas samples were not ana-lyzed because of equipment breakdown.

The second major aspect of data was the sod recoveryafter being transplanted from the sod heating boxes. The

most important factor in the recovery data was that no brown-ing injury to the turfgrass leaves was detected visually

after transplanting. Two factors may account for thisresult. One is that the temperature levels within theheating boxes remained at relatively low, non-lethal levels.Secondly, the oxygen levels remained relatively high. Thepercent leaf cover was significantly higher when the sodwas cut at the standard 2 inch height (Table 7). The rootorganic matter production was lower at 24 hours than at 48hours. Root production was greatest at 48 hours and declinedthereafter. Root production was greater at the 2 inch cut.

Experiment II (May 21, 1969)This experiment compared the effects of (a) 2 inch

versus 0.75 inch cutting heights, (b) 0 versus 215 lb/A of

nitrogen, and (c) 0 versus 0.055 lb/A of N6benzyladenine onMerion Kentucky bluegrass sod harvested on May 21, 1969, and

stored under simulated load conditions for 4 days. The low

cutting treatment was done at 5 and 2 days prior to harvest.

Q)..-l.aro8

l,()I'

Q)N

s::0

.~s::Q)

'Urol,()

..-ll,()

:>10

N0

s::Q)

.a1.0Z

o

-s::.~

Q)

UltJ'l

l-Iro

::s4-ll-I

00

0::r:

.jJU)

37

OOl,()OO

OOOOOON

Ol,()Ol,()

OOl,()Nl,()....

ooNI.O

N1'000000

oj(oj(

oj(oj(

oj(oj(

oj(l,()ONl,()

OMMOO00000'\00

1.O..-ll,()00....

..-l<::f'r--r--1'1'001'

l-IQ)::-ou4-lroQ)

....:I

,l,()oo..-lQ)

•..c:Q).jJtJ'lro.jJ

l-Iro

0.jJ.jJ

Uls::ro4-lU

0.~4-l

Ul

.~l-I

s::::stJ'lO

.~..c:

Ul'0

Q)Q)

l-I.jJro

ros::Ul

tJ'ls::.~ro

Ul

Q.!Q)

~'O

.jJl-I

U0

Q)4-l4-l4-lQ):>1..-ls::

Q).~

::-ro.~S.jJus::

Q)Q)

0.

Q)Ul

~Q)

.jJl-IQ

)

.a:>1

Ul.jJQ).~U..-ls::.~Q).al-I

roQ).a

4-l0

4-ll-I

.~0.

Qoj(4-l

oj(0

'..-loj(

Q)::-,

Q)+-..-l..-l

o

38

The nitrogen fertilizer treatment was applied 5 days beforeharvest. The N6benzyladenine solution was sprayed on

immediately before harvest. The cultural treatments werearranged in a randomized block factorial design having 2replications.

Results and discussion.--The mean percent moistureof the sod at harvest time was 65.6. None of the treatmentssignificantly affected the moisture content. The air tem-peratures at 2 p.m. in the greenhouse room where the sod was

stored were as follows:

671

24

80

48

9072

899669

Hours

The changes in temperature in the sod heating boxes

are presented in Table 8. The mean temperature increasedsteadily to 850 F during the first 48 hours of storage and

then leveled off. The 0.75 inch cutting height gave asignificant decrease in temperature after 12 hours. Thenitrogen and N6benzyladenine treatments did not affect

temperature.The mean percent carbon dioxide found within the sod

stacks increased during the first 48 hours and then declined

(Table 9). The low cutting treatment resulted in signifi-

cantly lower levels of carbon dioxide during the first 24hours. Nitrogen rate did not affect carbon dioxide levelssignificantly, but at 48 hours the trend was toward a higher

39

,+.l

>tO...-lQ)

Q)4-l

~4-l

•..-1Q)+.lot::

Q)•..-1

0..CO

UJS

Q)HLl'lo

t::Q)Q)

>t

~+.l+.l...-1Q)...-l.0

...-1.0

UJCO

Q).oo

0t::

HQ)

0..HQ)4-l

4-l0

4-l•..-1...-lC

lQ)

iC~

iCQ)

...-l

oQ)

...-ltJI•

COHQ)

0..c+.l+.l

UJ

+.l4-lCO

0+.l

UJt::

HCO

::lo

0•..-1

..c4-l•..-1

'0t::

Q)tJI+.l

•..-1CO

IIIt::tJI

Q)•..-1

HUJ

COQ)'0

UJt::H

CO0

Q)4-lS

......

Q)

H::l+.lCOH

_Q

)~0..0S

-OJ

E-I

-ICiC

iCiC

+-iC

iCiC

iCiC

\.O...-lCTIl""-NCO

MNCTlcol""-CTI......

...-l'<tO'<tLl'lLl'll""-l""-coco

COCO

o

Q)

UJtJI

HCO

::l4-lH

000:I::

+.lUl

LI'lLl'lo+.lt::Q

)

SQ)

H::lUJCOQ)

~

tJI-0

t::t::

•..-1•..-1

+.l-+.l::lCJ

N Ll'l...-l

t::N

OJ_

tJllCX:0

..

..

..

..

.H.o

+.l...-l•..-1-Z

0

coQ)...-l.0coE-I

Q)-

'tJllCX:

CTICOt:Q\.OH

\.0CTI

OZ...-l+.l-UJ

40

of-_

.-4oII)

o -W

00'1.-4

I'll'l-lo

W+J

.cen

+J~

+J0

I'llen

+Jl-l

c:::l

I'll0u.c

..-1~'O..-1

WC

+J0'1

I'll..-1

c:en

0'1......

WUl

l-lW

I'll'0

enl-l

c:0

I'll~

~->.

+J.-4u

WW

>~

..-I~

+JW

UWc:

0....-1

Ul

I'llWE

l-l

c:-

W>.

W+J

~......

+J.-4JL~I'llen.oW

0U

l-lc:

0..Wl-l~W

0~~.-4..-1

Wo

>iC

Wof<

.-4of<

'<:t:r:C'\lCJE0..0..

0.-40.-40

0.-40.-40

0.-40.-40

iCiC

iC-Ie

-Ie-Ie

iC-Ie

-Ie'<:tCOC'\lOOMCOC'\ll'N

C'\lo*

iCiC

iCCO~~co~.....

l''<:t'<:t'<:t1I)

C'\loCJ

*

II)II)oo oW

en0'1

l-lI'll

::l~l-l

000

:r:+JU

l

CII)

W_.-4

0'IlCt:C'\l

0"'-l-l.o+J.-4•.-1-Z

~W.-4.0I'll8

41

carbon dioxide level at the high nitrogen rate. TheN6benzyladenine did not affect the carbon dioxide level.

The percent oxygen data are presented in Table 9.During the first 24 hours, more oxygen was present in sodheating boxes containing sod cut at 0.75 inch. This indi-

cates that less respiration occurred where less green tissuewas present. These differences had disappeared after 2 days.Less oxygen was found where the sod received the high nitro-gen treatment at the 7.5 and 48 hour sampling times. This

suggests that the high nitrogen rates increased respiration.At all sampling times, more oxygen was present where theN6benzyladenine had been applied, but the differences weresignificant only for the 24 hour measurement. These results

provide some evidence for inhibition of respiration byN6benzyladenine.

The mean ppm ethylene found in the atmosphere withinthe stack of heating sod did not follow a consistent patternover time (Table 9). Cutting height did not affect ethylenelevels, except at the 7.5 hour measurement when less ethyl-ene was found where the sod was cut at 0.75 inch. The highnitrogen treatment markedly stimulated ethylene production.

N6benzyladenine did not affect ethylene levels.

The data gathered to evaluate the recovery of sodafter storage under simulated shipping conditions and trans-

planting to pots in the greenhouse are presented in Table 10.

42

No leaf injury was observed, except for sod which had been

stored for 96 hours. More leaf injury was observed for sodtreated with the high rate of nitrogen. Leaf injury tendedto be greater at the low cutting height and less for sod

treated with N6benzyladenine. The mean percent leaf coverafter 20 days growth in the pots declined as time of storageincreased to 72 hours. The percent le~f cover was the samefor sod stored 72 and 96 hours. Cutting height treatmentsdid not affect the leaf cover results. However, the 2 inchcutting treatment tended to result in better leaf cover for

sod stored 72 hours. Nitrogen rate did not affect the per-cent leaf cover, except for sod which had been stored for72 hours. Then the leaf cover was lower for sod treatedwith the high nitrogen rate. N6benzyladenine treatment didnot affect leaf cover although the leaf cover tended to be

greater for sod stored 96 hours and treated with N6benzyl-

adenine.The mean root production was similar for sod stored

1, 2, and 3 days (Table 10). The mean root production wasmuch less for sod stored 4 days. Cutting height did notaffect root production. The root production was greater atthe high nitrogen rate for sod stored one day. Nitrogenrate did not affect root production for longer storage times.N6benzyladenine treatments did not affect root production.

Table 10. Percent leaf kill, percent leaf cover, and root production after storage in relation to cutting height, nitrogen rate, and N"benzyladenine treatments on Merion Kentucky bluegrass sod harvested on May 21, 1969, after storage under simulated shipping conditions for 4 days

% Leaf cover

Hours of

Cutting Ht. (in)

Nitrogen (lb/A)

24 48 72 96

85.6 82.8 70.6 71.9

88.1 83.8 77.5 71.9

85.0 81.9 63.8t 71.9

95.0 80.6 78.8 76.9

88.1 85.0 62.5* 66.9

N6BA (lb/A)

Measurement

% Leaf kill

Storage

96

Mean

5.9

2

4.4

3/4

7.5t

0

3.1

215

8.8**

0

7.4

.055

4.4t

88.8 80.6 66.9 63.8

84.4 85.0 74.4 80.0t

Root organic matter (mg/pot)

24 48 72 96

90 82 92 49

96 81 104 58

83 84 81 41

73 99 80 44

106* 66 105 54

95 72 89 49

84 93 96 50

t, *, **Differences between main effect means are significant at the and .01 level of probability, respectively, for designated hours of storage.

10, .05,

44

Experiment III (May 29, 1969)This experiment compared the effects of (a) 0 versus

0.055 lb/A of N6benzyladenine and (b) 2 inch versus 0.75

inch cutting at 10, 5, and 1 day before harvest. The N6ben-zyladenine solution was sprayed onto the plots 5 days before

harvest. The 0.75 inch mowing for the 10 days before har-vest treatment was done at 10, 5, and 1 days before harvest.The 0.75 inch mowing for the 5 days before harvest treatmentwas done at 5 and 1 days before harvest. The treatmentswere arranged in randomized block factorial design. Manyseedheads were showing in the turf. The sod was harvestedon May 29, 1969 and stored under simulated shipping condi-

tions for 5 days.For this and subsequent sod heating box experiments

the boxes were insulated with aO.62 inch layer of polyure-

thane foam.Results and discussion.--No difference in turfgrass

appearance due to the N6benzyladenine treatment was detected.At harvest time the turfgrass mowed at 0.75 inch 10 daysearlier appeared to have less green leaf tissue than turf-

grass mowed short 5 days before harvest because the browningfrom scalping was more fully developed. Among the shortmowed plots those cut the day before harvest appeared the

greenest on May 29. The sod cut regular~~ at 2 inches hadthe best appearance. The mean percent moisture of the sodat the beginning of the experiment was 66.9 and no signif-

icant differences occurred among the treatments.

45

The main effect means for changes in temperature,percent carbon dioxide and oxygen, and ppm ethylene thatoccurred in the sod heating boxes are presented in Table 11.

The mean temperatures increased to about 950 F atthe 24, 48, and 72 hour times and then declined. The airtemperatures at 3 p.m. in the greenhouse room were as follows:

o78

24

100

48

98

72

90

96

78

12072

Hoursof

The lower air temperatures during the last two days explainthe decline in sod temperatures. The N6benzyladenine treat-ment did not affect temperature significantly. But the tem-peratures were always somewhat higher where N6benzyladeninewas applied, and statistical significance was approached(0.082 level) for the 48 hour temperatures. Temperaturesin relation to mowing height and times were significantlyhigher for the 2 inch treatment at 0 and 96 hours.

N6benzyladenine treatment did not affect carbondioxide release from the sod. After 24 hours a highlysignificant difference in CO2 levels in relation to mowingtreatments were found. Sod that had been severely defoli-

ated only one day before harvest released the most CO2,The plants which had 5 days to heal after low cutting

released the least CO2, In spite of the fact that the plots

cut at 0.75 inch 10 days before harvest appeared to have theleast green leaf tissue this sod released the same amount ofCO2 during the first 24 hours as sod regularly mowed at 2

Table 11. Temperature (°F) changes occurring during storage related to N benzyladenine and time and height of cutting treatments on Merion Kentucky biuegrass sod harvested on May 29, 1969, and stored under simulated shipping conditions for 5 days

Measurement

Temp. F

% co 2

% o 2

ppm C2H4

Hours of

S t o r a g e

0 24 48 72 96

120

24 48 72 96

120

24 48 72 96

120

24 48 72 96

120

Mean

8 5 . 0 9 4 . 0 9 5 . 0 9 5 . 8 9 3 . 2 8 7 . 3

1 3 . 3 1 3 . 7 1 6 . 2 1 7 . 5 1 6 . 4

3 . 6 2 . 3 2 . 8 3 . 0 3 . 3

2 .66 1 .79 1 .37 0 . 6 2 0 . 6 8

N 6 BA ( lb /A)

0

8 4 . 7 9 3 . 0 9 3 . 8 9 5 . 2 9 2 . 4 8 6 . 4

1 3 . 3 1 3 . 2 1 6 . 4 1 8 . 0 1 6 . 1

3 . 8 2 . 3 2 . 4 2 . 0 3 . 5

3.10 2 . 0 6 1 .63 0 . 6 5 0 . 7 1

.055

8 5 . 2 9 4 . 9 9 6 . 3 t 9 6 . 3 9 3 . 9 8 8 . 2

1 3 . 3 1 4 . 2 1 6 . 1 1 7 . 1 1 6 . 6

3 . 5 2 . 3 3 . 2 4 . 1 * 3 . 1

2 . 2 1 1 . 5 2 t 1 .10* 0 .60 0 . 6 3

C u t t i n g

2

2

8 6 . 6 9 6 . 1 95 .0 9 8 . 9 9 6 . 6 8 7 . 5

1 3 . 5 1 5 . 7 1 7 . 2 1 8 . 5 1 7 . 4

3 . 3 2 . 3 1 . 9 2 . 2 2 . 2

2 .88 2 .17 1.72 0 . 9 2 1.05

H t . ( in )

0 . 7 5

10

8 4 . 0 9 3 . 0 9 5 . 8 9 5 . 6 9 2 . 1 8 7 . 5

1 3 . 5 1 3 . 8 1 5 . 5 1 7 . 9 1 6 . 4

3 . 7 2 . 2 3 . 8 3 . 0 3 . 3

2 .85 1.48 1.17 0 . 6 2 0 . 5 8

and Time

0 . 7 5

5

8 4 . 6 9 4 . 9 9 6 . 4 9 5 . 8 9 3 . 1 8 7 . 5

1 1 . 0 1 1 . 0 1 6 . 2 1 6 . 1 1 5 . 3

4 . 6 1 . 9 3 . 0 4 . 7 4 . 4

1.70 1.70 1 .22 0 . 4 5 0 . 5 0

(days)

0 . 7 5

1

8 4 . 6 * * 9 1 . 2 93 . 0 9 2 . 8 9 0 . 8 * 8 6 . 9

1 5 . 3 * * 14 .2 1 6 . 1 1 7 . 6 * 1 6 . 2

2 . 9 2 . 7 2 . 4 2 . 2 3 . 4

3.20 1.82 1.35 0 . 5 0 * 0 .58

4̂

t, *, **Differences between main effect means are significant at the .10, .05, and .01 level of probability, respectively, for designated hours of storage.

47

inches. At the 96 hour measurement the percent CO2 withinthe sod stack for sod cut at 0.75 inch 5 days before harvestwas lowest and that cut at 2 inch was highest. Consistentreciprocal, though nonsignificant, levels of oxygen werefound at 24 and 96 hours.

The main effect mean for percent 02 was signifi-cantly higher for the N6benzyladenine treatment at 96 hours.Cutting treatments did not affect the oxygen levels signifi-cantly.

The mean ppm ethylene found steadily among the 24to 96 hour measurements. At all times less ethylene wasfound where the sod was treated with N6benzyladenine. Thisdifference was significant at 72 hours and approached sta-tistical significance at 48 hours. Sod cut at 2 inchesreleased more ethylene at the last 4 times of measurement.This difference was significant for the 96 hour measurement.

In three instances significant N6benzyladenine xmowing treatment interactions occurred for data gatheredwithin the sod heating boxes (Table 12). Higher tempera-tures occurred for the 0.75 inch 10 day and 0.75 inch 5 daycutting treatments when N6benzyladenine was present. Some

form of respiration must accompany energy release. The mostimportant feature of 96 hour percent 02 interaction was thatmore oxygen was present for the 10 and 5 day 0.75 inch cut-

ting treatments. This combination of higher temperatures andoxygen levels suggests the possibility that N6benzyladenine

48

Table 12. Significant (.05 level) N6benzyladenine x cuttingheight interactions on Merion Kentucky bluegrasssod harvested on May 29, 1969, and stored undersimulated shipping conditions

Cutting Ht. (in) & Time (days)Hours

N6BA2 0.75 0.75 0.75

ofMeasurement Storage (lb/A) 2 10 5 1

Temp. (oF) 96 0 97.8 89.2 90.8 92.0.055 95.5 95.0 95.5 89.5

96

48

o.055

o.055

1.82.6

2.801.55

1.54.6

1.501.45

1.77.7

2.550.85

2.81.7

1.402.25

promoted anaerobic respiration when relatively small amountsof green leaf tissue were present.

The interaction for ppm ethylene at 48 hours showedthat N6benzyladenine decreased ethylene evolution for the 2inch and 0.75 inch 5 day mowing treatments and increased itfor the 0.75 inch 1 day mowing treatment.

The main effect means for recovery of the sod afterremoval from the sod heating boxes are presented in Table 13.As storage time increased the mean values for percent injury

increased. The mean values for leaf cover after 20 days androot production decreased as the number of days in storage

increased. N6benzyladenine significantly decreased the per-

cent leaf kill for sod stored 120 hours. The decreased leaf

Table 13. Percent leaf kill, percent leaf cover, and root production in relation to N6benzyladenine and time in days before harvest, and height of cutting treatments on Merion Kentucky bluegrass sod harvested on May 29, 1969 after storage under simulated shipping conditions for 5 days

M e a s u r e m e n t

% Lea f k i l l

% L e a f c o v e r

R o o t o r g a n i c m a t t e r (mg /po t )

H o u r s of

S t o r a g e

72 9 6

120

24 48 72 96

1 2 0

24 48 72 96

1 2 0

Mean

8 . 8 4 5 . 3 9 0 . 9

7 6 . 9 5 5 . 0 3 2 . 8 1 2 . 2

4 . 4

4 9 47 35 18 20

e. vr BA

( l b / A )

0

9 . 4 5 0 . 0 9 8 . 1

7 6 . 2 5 8 . 1 2 6 . 2 1 3 . 1

2 . 5

- 48 4 3 27 24 14

. 0 5 5

8 . 1 4 0 . 6 8 3 . 8 *

7 7 . 5 5 1 . 9 3 9 . 4 1 1 . 2

6 . 2

50 5 2 4 2 12 26

C u t t i n g

2

2

7 . 5 6 0 . 0 8 7 . 5

7 3 . 5 4 7 . 5 1 7 . 5

1 . 2 2 . 5

68 4 2 17

1 10

H t . (

0 . 7 5

10

1 2 . 5 5 2 . 5 9 8 . 8

8 0 . 0 6 0 . 0 2 1 . 2

7 . 5 3 . 8

4 4 4 4 30 1 4 1 1

in) & Time

0 . 7 5

5

6 . 2 5 0 . 0 9 0 . 0

8 1 . 2 5 1 . 1 5 5 . 0 1 7 . 5

7 . 5

36 48 4 8 30 4 7

(day)

0 . 7 5

1

8 . 8 1 8 . 8 t 8 7 . 5

7 5 . 5 6 1 . 2 3 7 . 5 2 2 . 5

3 . 8

4 9 5 6 4 4 29 10

^ <£>

t, *Differences between main effect means are significant at the .10 and .05 level of probability, respectively, for designated hours of storage.

50

kill for sod cut at 0.75 inch 1 day before harvest andstored 96 hours was approaching statistical significance.Percent leaf cover and root production were not affected bythe two cultural treatments.

Experiment IV (June 4, 1969)

This experiment compared the effects of (a) 2 versus0.75 inch cutting heights, (b) 0 versus 215 lb/A nitrogen,and (c) 0 versus 0.055 lb/A of N6benzyladenine. The 0.75

inch cutting was done 5 and 1 days before harvest. Thenitrogen was applied 5 days before harvest. 6The N benzyl-adenine was applied immediately before harvest. These treat-

ments were arranged in a randomized block factorial design.This study was conducted during the period of maximum seed-head development for Merion Kentucky bluegrass. A heavy

stand of well-developed seedheads was present in the plotscut at 2 inches. Most of the seedheads were removed by the

0.75 cutting treatment. The sod was harvested on June 4,1969, and stored under simulated load conditions for 4 days.

Results and discussion.--The mean percent moistureof the sod at the beginning of the experiment was 67.6. Thepercent moisture where sod was cut at 2 inches was 68.3 ver-sus 66.~/o for low cut sod; this difference was significantat the 5% level. The mean percent moisture of the sod after4 days of storage was 65.2 and none of the main effect meanswere significantly different. The sod cut at 2 inches had

65.0% moisture which showed that it dried slightly faster.

51

This loss of only 2.5% moisture during the experiment shows

that the rate of drying during storage was very small. Itseems clear that drying of the sod during storage did notcontribute to sod injury.

The air temperatures at 2 p.m. in the greenhouseroom where the sod was stored were as follows:

o

77

6

77

1278

24

85

48

86

72

1219677

Hoursof

The main effect means for changes in temperaturethat occurred during storage are presented in Table 14.The mean temperature rose steadily over a 200 F range duringthe 4 days. The sod cut at 0.75 inch had a lower tempera-

ture at every measuring time than sod cut at 2 inches. Thedifferences were significant at 0, 3, 6, and 12 hours andapproached significance at 24 and 96 hours. The sod tempera-ture was higher at every measurement where high rate ofnitrogen was applied. The differences were significant at 0,

6, 12, and 24 hours and approached significance at 3 hours.The N6benzyladenine treatment did not affect temperature.

The main effect means for changes in percent carbon

dioxide and oxygen during storage are presented in Table 15.The mean percent CO2 present increased very rapidly duringthe early hours of storage and then reached an equilibrium

at about l~~. Conversely, the mean percent 02 contentdecreased very rapidly during the early hours of storage

Table 14. Temperature ( Fl changes occurr nitrogen, and N benzyladenine t sod harvested on June 4, 1969, conditions for 4 days

Cutting Ht. Hours (in) of

S t o r a g e Mean 2 0 .75

0

3

6

12

24

48

72

96

69 .2

71 .2

73 .3

77.2

8 0 . 8

8 7 . 1

8 8 . 0

89 .0

70 .1

72 .3

74.8

78.6

81 .8

8 8 . 2

8 8 . 6

89 .6

6 8 . 4 *

70 .0*

7 1 . 8 *

75 .8*

7 9 . 9 t

8 6 . 0

8 7 . 4

8 8 . 4 t

ng during storage in relation to mowing, eatments on Merion Kentucky bluegrass nd stored under simulated shipping

Nitrogen N BA (lb/A) (lb/A)

0 215 0 .055

68 .5

70.2

72 .1

75.8

79 .3

8 6 . 5

88 .0

8 8 . 6

70 .0*

7 2 . l t

74 .4*

78 .7*

8 2 . 4 * *

87 .8

8 8 . 1

8 9 . 4

69 .0

70 .9

73.0

77.0

8 0 . 4

86 .6

87 .8

8 9 . 4

69 .5

71 .4

73.6

77.4

8 1 . 2

8 7 . 7

88 .2

8 8 . 7

t, *, **Differences between main effect means are significant at the .10, .05, and .01 level of probability, respectively, for designated hours of storage.

Table 15. Percent carbon dioxide, percent oxygen changes occurring during storage in relation to cutting height, nitrogen rate, and N benzyladenine treatments on Merion Kentucky bluegrass sod harvested on June 4, 1969 and stored under simulated shipping conditions for 4 days

Measurement

Hours of

Storage Mean

Cutting Ht, (in)

2 0.75

Nitrogen (lb/A)

0 215

N6BA (lb/A)

.055

% CO, 0 3 6 12 24 48 72 96

4 12 14 15 17

.6 2 ,7 6 .3 19.0

18.2 19.1

5 . 1 13.7 1 6 . 1 16 .3 17 .4 19 .4 18 .5

4 . 2 * * 1 0 . 8 * 1 3 . 3 * 15 .0** 17 .3 18 .6* 1 7 . 8 *

4 . 7 12.6 14 .6 15.8 17 .7 18 .9 1 8 . 1

4 . 6 11 .9 14 .7 15.5 17.0 19 .1 18 .2

4 . 7 11.8 14 .8 15 .4 17 .3 1 9 . 1 18 .2

4 . 6 12 .7 14 .6 15 .8 17 .4 18 .9 1 8 . 1

19.6 18.5** 18.8 19.3 19.2 19.0

% O. 0 3 6 12 24 48 72 96

14.9 .2 .1 .3 .0 .8 .9

14.4 15.3t

1.7

5 . 9 3 . 1 2 . 2 2 . 0 1.8 1.7 1.6

8 .7* 5 . I t 2 . 5 2 . 1 1.8 2 . 1 1.8

14.6 15.1 7 . 5 4 . 7 2 . 4 1.8 1.8 1 .9 1.8

7 .0 3 . 5 2 . 3 2 . 2 1.7 1.9 1.6

14.6 15.2 7 . 2 4 . 1 2 . 4 2 . 0 1.8 1.8 1.8

7 . 2 4 . 1 2 . 3 2 . 1 1.8 2 . 0 1.6

t, *, **Differences between main effect means are significant at the .10, and .01 level of probability, respectively, for designated hours of storage.

05,

54

and reached an equilibrium at about l.~~. These reciprocal

changes in percent CO2 and 02 were the result of aerobic

respiration.At all times of measurement the percent CO2 found

was lower for sod cut at 0.75 inch. These differences weresignificant except for the measurements taken after 24 hours

of storage. The percent 02 content was greater for sod cutat 0.75 inch at all times of measurement except at 48 hours.The difference was significant only for the measurementtaken at 3 hours. For measurements taken at 0 and 6 hoursthe differences approached significance. The fact that lessrespiring tissue was present after cutting at 0.75 inchexplains these results. Nitrogen and N6benzyladenine treat-ments did not affect CO2 and 02 levels in the sod heating

boxes.The main effect means for ppm ethylene found during

the course of the experiment are presented in Table 16. Themean ppm ethylene present increased erratically over time toa maximum of 2.21 ppm at 48 hours then decreased sharply.For sod cut at 0.75 inch the amount of ethylene found wasless than for sod cut at 2 inches except for the 48 hourmeasurement. The differences were significant for measure-ments taken at 0, 3, 6, and 12 hours and nearly significant

at 96 hours. The reduced amount of respiring tissue presentexplains these results satisfactorily. More ethylene wasfound at all times of measurement where the sod had beentreated with the high nitrogen application. The differences

Table 16. Ppm ethylene changes occurring during storage in relation to cutting height, nitrogen rate, and N^benzyladenine treatments on Merion Kentucky bluegrass sod harvested on June 4, 1969, and stored under simulated shipping conditions for 4 days

Cutting Ht. Nitrogen N BA Hours (in) (lb/A) (lb/A) of

Storage Mean 2 0.75 0 215 0 .055

0

3

6

12

24

48

72

96

0 . 4 8

0 . 7 9

0 . 5 7

1 .94

1 .91

2 . 2 1

0 . 8 8

0 . 8 6

0 . 5 8

0 . 9 9

0 . 7 8

2 . 6 5

2 . 2 5

2 . 1 2

1 .02

0 . 9 9

0 . 3 9 *

0 . 5 9 * *

0 . 3 6 * *

1 .24**

1.58

2 . 2 9

0 . 7 4

0 . 7 2 t

0 . 3 9

0 . 4 5

0 . 3 0

1 .82

1 .54

1 .59

0 . 5 6

0 . 5 8

0 . 5 8 *

1 .12***

0 . 8 4 * *

2 . 0 6

2 . 2 9

2 . 8 2 *

1 .20*

1 .14**

0 . 4 5

0 . 7 8

0 . 5 8

1 .99

2 . 1 8

2 . 3 6

0 . 9 0

0 . 9 4

0 . 5 1

0 . 8 0

0 . 5 6

1.90

1 .65

2 . 0 5

0 . 8 6

0 . 7 8

t, *, **Differences between main effect means are significant at the .10, .05, and .01 level of probability, respectively, for designated hours of storage.

56

were significant for the 0, 3, 6, 48, 72, and 96 hour mea-surements. Note that the high nitrogen treatment resulted

in higher temperatures but did not affect CO2 and 02 levels.One possible explanation for these results is that highnitrogen promotes a form of anaerobic respiration which hasethylene as an end product. The main effect means for eth-ylene levels in relation to N6benzyladenine treatment werenot significantly different.

At 96 hours a significant nitrogen x N6benzyladenineinteraction showed that N6benzyladenine decreased temper-ature in the presence of high nitrogen and that in theabsence of N6benzyladenine high nitrogen increased temper-ature (Table 17). At 72 hours a significant cutting heightx N6benzyladenine interaction showed that with low mowingN6benzyladenine increased temperature (Table 18).

Table 17. Significant (.05 level) nitrogen x N6benzyladenineinteraction on Merion Kentucky bluegrass sod har-vested on June 4, 1969, and stored under simulatedshipping conditions

Hoursof

Measurement Storage

96

Simple Effects

N6BA(lb/A)

Nitrogen Simple(lb/A) 0 .055 Effects

0 88.1 89.1 1.0

215 90.6 88.2 -2.4*

2.5* -0.9

*Differences are larger than LSD at the .05 level ofprobability.

57

Table 18. Significant (.01 level) mowing x N6benzyladenineinteractions on Merion Kentucky bluegrass sodharvested on June 4{ 1969, and stored undersimulated shipping conditions

Simple Effects

Measurement

Hoursof

Storage

72

Cutt ing Ht.( in)

2

0.75

N6BA(lb/A)

Simple0 .055 Effects

89.8 87.5 -2.3

85.9 89.0 301*

0.1 1.5

*Differences are larger than LSD at the .05 level ofprobability.

The main effect means for data collected after the

sod was transplanted to the pots are presented in Table 19.

After 48 hours of storage only a small amount of leaf injury

was present. This injury was worse for the 2 inch cutting

height, high nitrogen level, and N6benzyladenine treatments.

A substantial increase in leaf injury occurred after 72

hours of storage. Significantly more injury occurred on sod

treated with high nitrogen. The mean leaf injury was 85.~~

after 96 hours of storage, but the difference resulting from

mowing treatments was small.

The mean percent cover after 20 days of growth in

the pots decreased steadily in relation to increased time of

storage. Even though no injury was detected after 24 hours,

the percent cover was significantly less for sod cut at 0.75

o+JI:

I:0

o.~

....~

...Q)

+JQ)'OI1l~

I:~

::1Q)

I:.

..0

Q)0'

I:Ul

I1l.~

+J...

I:0

I:Q)+Jo

EU

l.~

+J+J

I1l...

oQ)

Q)::1

...+J

'O+J1l-jo

I1l...

Q)0..1:.~

(J'l+JI:\.O0Q)(J'lO

'O~

...I1l~

-'0

>,~

I:N

I1lI:

-~...\.0Q)Z>

I:~

0'0

001:'"I1l'0

0Il-j

Q)

Il-jI1l

-+J

Q)Q)

UlUl

~+JQ)I:I1l>0

+J.......

~I:

I1l+J

Q)

I:.c.~

oQ

)'0

...0''0

I:Q)

0000..

...U

l0

+J_.~

Ul

0'

~I:UlI:~

11l.~.~

_...

0..~

+J0

'0..

.cQ

).~Il-j

0'::1.c11l.~

~Ul

Q)Q),O~.c

'0>,Q)

+JO'~+J

I:I:

0I1l

Q).~

::1~

O+J+.l::l...+.lI:EQ)

::lQ).~

o.O~Ul

LflLflaaLflI:

~Q)_

NO

'~0'--

....0+.l~.~~Z

a

0'_

aI:

I:.~

.~+.l~+.l::lU

N

58

of-of-

~oo~o

-Ie+-

~oooo

0000\.0\.0....

oo~LflLfl(J'lLflN

...Q)>oo

LflaQ).c

Q)

+.l0'I1l+.l

...I1l

0+.l+.l

UlCI1lIl-jo

0.~Il-j

Ul.~

...C

::l0'0.~

.cU

l'0

Q)Q)

...+.lI1l

I1lCU

l0'

c.~I1l

UlQ)

Q)E'O

>,

Ul+.lQ)

.~O

~c.~Q),O...

I1lQ),O

Il-j0

Il-j...

.~0..

Cl

-IeIl-j

-Ie0

-~i<Q)>

-Q)

+-~~a'0CI1l

59

inch. This represents a lack of full development of newleaves. More leaf cover was observed after 48 hours on sodoriginally cut at 0.75 inch. The difference approached sig-nificance for sod stored 48 hours. Significantly less leafcover was present for sod treated with the high nitrogen

level and stored 48 and 72 hours.Root organic matter production was not affected by

the treatments.

Experiment V (June 11, 1969)This experiment compared the effect of (a) 0 versus

0.055 lb/A of N6benzyladenine and (b) 0 versus 215 lb/A ofnitrogen. The N6benzyladenine solution was sprayed onto theplots a few minutes before harvest. The nitrogen fertilizerwas applied 4, 8, and 18 days before harvest. All plotswere cut at 2 inches 2 days before harvest. The mowingfrequency had been twice per week. The cultural treatmentswere arranged in a randomized block factorial design. Onlya few seedheads were present. The sod was harvested onJune 11, 1969, and stored in the sod heating boxes for 3

days.Results and discussion.--No response to nitrogen

Was visible at harvest time. The mean percent moisture at

harvest was 64.9. The air temperatures at 2 p.m. in thegreenhouse room where the sod was stored were as follows:

o

96

6

88

12

76

24

98

48

92

72

93

Hours~

60

The mean temperatures in the sod heating boxes were

as follows:

o

746

79.7

1284.2

24

88.1

4893.1

72

90.1

Hours

~

The temperatures were not affected by the treatments.

The main effect means for levels of carbon dioxide,

oxygen, and ethylene found in the sod heating boxes are

presented in Table 20. The mean percentages for CO2 and 02

show that CO2 levels increased to 16.2% within 6 hours while

the 02 levels decreased to 1.8%. The mean ppm ethylene

increased steadily to 4.0 ppm at 24 hours then decreased.

The main effect means for N6benzyladenine were never sig-

nificantly different.

Initially, the CO2 percentage was significantly

higher where 215 lb/A of nitrogen was applied 18 days before

harvest than for the other nitrogen treatments. More respi-

ration occurred initially where this treatment was applied.

Thereafter, nitrogen treatments did not affect CO2 levels

significantly. The percent 02 at the zero hour of measure-

ment was significantly greater where no nitrogen was applied

than where 215 lb/A nitrogen was applied 18 days before har-

vest. Between 6 and 48 hours the 02 levels were quite low

and not significantly different. The increased 02 level

found at 72 hours probably resulted from having the sad

oN<11~.0f1lE-<

III...C<11I::...

Lf'lf1l

~00

<11N

~E-<C<110'1o~...Lf'l

....~

'1'Z

No

U"lU"looCt1l<11::0::<11

III0'1

~lU

:1.....

~000::c:

...Ul

......f1l+-

+-MooO'1'Lf'lLf'l1'1'1'000\0

I""""lI""""l.....

NP"""4

.0lJ'Moo\0'1'

N......

'1'Lf'lLf'l1'00Lf'lI""""ll""""ll""""l

...........

.0\0\0

Lf'l1''1'\0

'1'Lf'lLf'l1'lJ'Lf'l....-4....-4

.................

.0Lf'lMLf'l'1'ooU"lU"l\O\OooooU"l

I""""ll""""l......

r""1......

MO~~M\OLf'l\O\O

00lJ'U"l

I""""l......

.-I.....I......

\ONN~MI'U"l\O

\000lJ'U"l

~~~~~

Nou()€.

61.......a+-u

l''1'Ol'l'N~~N

~~N~.0t1l

.0'1'\OOooU"lM

.0t1lt1l

0000000\0'1'N~~N~N~t1l

t1llJ'~Moo\OU"l

No()€.

......

......

.0.0.0

t1lf1lf1lt1l

t1lf1l

OONOOOOOU"looNI'U"l\OOONM'1'NN

.0.0.0

f1lt1lf1lf1lt1l

f1lOU"lOU"lNOO'1'I'MNI'~~NU"lMN

.0.0

.0t1l

f1lf1lt1lf1lf1l

000000U"l00\0'1''1'0'1'O~MMMN

.o.o.of1l.o.oON

NooU"looU"ll'oo\O~\OOO~N~~

~U"l'1'~O'1'oo\OO'1''1'NO~M'1'NN

~U"l~lJ'000ooMooU"lU"lNO~NMNN

~ONOONooU"llJ'OU"lNO~N'1'NN

'1'::c:NUI::0

.0

.

~<11o..c:....'0:>'

C.oIII'0-

<11U"l3~00<11.~

:>~<11

-0

~0

.....~

()€.lIlLf'lC

<11f1l...

Z~f1l...

......lIlt1lU

<11<11'"

........C

.....<11f1l<1lO"U

C....

Ct1l

..........p:;

.....lU

C::O::<11

0'1~

....0

.(I)

••~

<11'"<11O"~~

f1l:1

f1l~::O::lIl...

<IlC

III-t1l

C~

'()~C

...III

:1U

~Cl

<11:1

..

..

.0

0.......c:...

<11'00'1C

<11C

.,...+J

.....f1lt1l'OI::C

~0'10

c....U

<11IIIU

<11<11

f1l3'0

......~~~.....~

III<11

<11-.....

U:>......

C~

...<11<11'0~

:><11

.....:>.

........~

.....U

.......<11

CC

l0.

lU...

IIIU

...<11

...~

.........

..._C

:>'0'1-

....+-

<Il~........0

0f1lC.0o

<11~

~0.f1l

62

heating boxes open a little longer than usual while removing

the 48 hour sod pieces.The ethylene level was always numerically lowest

where no nitrogen was applied. However, it was usuallystatistically equal to one or more of the 215 lb/A nitrogentreatments according to Duncan's Multiple Range Test.

The main effect means for percent leaf kill, percentleaf cover, and root production of sod that had been stored24 hours were not significantiy different (Table 21). Onlya small degree of injury (9.1%) occurred during the first24 hours of storage. The average leaf kill was about 90%for sod that had been stored 48 and 72 hours. However, thesod that received no N6benzyladenine and the "zero" nitrogentreatment showed less injury during storage. The 48 and 72hour main effect means for percent leaf kill, percent leaf

cover, and root production illustrate this.

Experiment VI (June 17, 1969)This experiment compared (a) 0 versus 0.055 lb/A of

N6benzyladenine and (b) 2 versus 0.75 inch cutting heights.The N6benzyladenine was applied just prior to and 5 and 10

days before harvest. The 0.75 cutting was done 5 daysbefore harvest. The cultural treatments were arranged in arandomized block factorial design. The sod was harvested onJune 17, 1969, and stored in the sod heating boxes for 4

days.

63

~III

........>.

itit

itc:

.010

itit

itO

MM

'0it

it+

-itit

M.,..lM

000C

O00

ita

+.ILfl

CO

.f-•

a0

10Q

)M

M000

CO

OO

.....0

a+.I

()c:

IIIN

MO

Ol'

Lfl.,..l

='+.I

MM

'0c:

M~

c:c

00.

~10

.,..lo.c:

+.I10

0+.I

LflCO

OC

OLflO

a10

10Lfl

CO

.....M

c:'OQ

)M

l'CO

OM

NO

CO

Na

Q)

Q)

Q)

...N

0'\0C

OLfl

...0"+.1

E-<M

Q)

0III

III.e

c: ...Q

)>.

c:.oJ

.,..l+.I

>10

Q)

.,..l...'00"

NO

CO

OLflO

.oJc:

c:10

0Lfl

o::t10

0.eM

...M

MO

CO

aNa

.....N

a.,..l~

+.IN

MO

O'\

0'\C

O.oJ

+.I0'0

....,..l

MC

()0

0Z

10='

~1Il~

()

'0....

O.,..l

IIIIII

LflCO

NN

LflO....

Q)

...+.1III

c:....

0"0.

100

0l'M

MID

l'O.....

o::tLfl

C10

'0....

,..lLflID

CO

NM

LflMLfl

0"1-4+.I

c:0"+.1

....0

010

Q)

.,..l1Il.oJ

0=''0

III...

IIlMc:

Q)

Q).o

01-4....

'0+.1()

itit

it10

0c:

10>.

itit

•10...~

0"it

it•

•III

III()

c:Lfl

Ocoo::t

Lfl0'10

•C

1-4,

c:='....

-Lfl

. ..4.•

10='

...Q

)+.I0.

~~0

OcoO

'\l'

.....a

.........a

~0

Q)

O"c:

0.CO

........M

O'\O

'IC

OID

.e

>0

Q)

....ID

.00

...~.c:ZM

.oJC

()+.IIII

UQ

)....

c:M

LflID0'1

.....0

Q)

::.-....

c:0'0

.......

10.,..l

Q)

aC

Ol'O

.....o::tLfl

OC

OC

O....

0'

Q)'O

...+.1l'C

OC

O.....

ID....

NQ

)

Mc:

Q)

101-4

IO~M

,-0

-+.I

='.........

C:+.I

c:E

rvQ

)c:

0.

..

.E

()Q

)III

c:M

....O

l'....

Lfl>..

...E+.I

10c

....Q

)+.IIII...

Q)

0'1C

O0

'<1'1I)N

o~'<1'

Q)

Q)

0.10Q

)Q

)~

CO

0'1II)

ID....

Q)

::.-Q

)>'0:J

...'....

...c:

..+.I

M+.I

10='

15(j

M.c:

~....

Q)

'0~

c:Q

)Q

)VI

III

....... ...Q

)Q

)Q

)

....c:

00

III0"

U...

10Q

)....

+.I1-4

10,"

Q)'O

Q)III

='~1-4

'<1'CO

N'<1'

II),,~

""to:,1""<:

Q)

....10.0

00

0N

"1'l'N

""tl'N

""tr-

...:-..

....'0

.....+.I

Q) ...,

.....+.I

>.1Ilc:

CJ)......

c:N

>.10..........

Q)

c:10

........

()Q

)'00'\'

0.D

.....Q

ID..

,..<IN

)c:0'\

...Q

c..Z

...........

J..

0+.I

....Q)

...c:

....>

c,.....,

Q)

....0

.r..tI

':...,

+-."

....E

.!1t.U

>.

.-...,..

'4..iJ

J

NQ)

r:...

Q),..~

1-4....

~v:: ..

Q)

='10

,',,/.;

.-....

IIIQ

)0

0...,

,..E0

..Qro

...:l...:IN

')E

::.-ro

Q)S

Q)

E-<~

"*'*

a::-'

..

64

Results and discussion.--No response to N6benzylade-

nine was visible at harvest time. The mean percent moisture

was 63.7. The air temperatures at 2 p.m. in the greenhouse

room where the sod was stored were as follows:

o

90

6

80

12

66

24

98

48

102

72

96

96

108

Hoursof

The mean temperatures ln the sod heating boxes were

as follows:

o

68.2

6

71.4

12

76.7

24

82.0

48

88.3

72

91. 2

96

90.1

Hoursof

The temperatures were not affected by the treatments.

The main effect means for percent CO2 and 02 found

over time in relation to cutting height are presented in

Table 22. More carbon dioxide and less oxygen was found

during the first 72 hours of storage where the sod was cut

at 2 inches. The differences in main effect means were

significant at 48 hours for carbon dioxide and 24 hours for

oxygen. These results gave strong evidence for a reduced

rate of aerobic respiration where the sod was cut at 0.75

inch.

The mean ppm ethylene ln the sod heating boxes were

as follows:

o

0.28

12

0.21

24

1. 31

48

1. 26

72

1. 13

96 Hours

1.04 ppm C2H4

65

Table 22. Percent carbon dioxide and oxygen changes occur-ring during storage in relation to cutting heighton Merion Kentucky bluegrass sod harvested onJune 17, 1969, and stored under simulated ship-ping conditions for 4 days

Percent Carbon Dioxide Percent Oxygen

Hoursof

Storage Mean

Cutting Ht.{in)

2 0.75 Mean

Cutting Ht. (in)

2 O. 75

o

6

1224

48

72

96

2.9

lL8

14.0

16.9

17.3

18.4

1206

3.3

1300

1502

17.3

18.0

18.7

12.4

206**

10.7**

12.8***

16.4*

16.6*

18.0t

12.7

17.0

7.4

4.5

2.0

2.7

2.5

3.5

16.5

5.9

3.1

1.72.1

2.2

3.7

17.5*

900***

5.8 **2.4*

3.3

3.2

t, *, **, ***Differences between main effect meansare significant at the .10, .05, .01, and .001 level ofprobability, respectively, for designated hours of storage.

66

The main effect means were not significantly different. At

48 hours the mean ppm ethylene in relation to N6benzylade-nine treatments were as follows:

0.85 2.60 1.15 0.04 ppm C2H40.0 .055 .055 .055 lb/A N6benzyladenine

0 5 10 application time in daysbefore harvest

The differences between the main effect means were signif-icant at the .10 level of probability. The ppm ethylene

means were similar at 72 hours. This suggests that N6ben-zyladenine may have more effect on ethylene production when

applied immediately before harvest.The percent leaf kill and root organic matter pro-

duction data are presented ~n Table 23. The percent leaf

kill tended to be less for sod cut at 0.75 inch. Also,the root production was less for sod cut at 0.75 inch. Thedegree of injury was quite low. Apparently, the sod cut at2 inches was able to photosynthesize more carbohydrates forroot production than sod cut at 0.75 inch. The mean percentleaf cover 20 days after transplanting was 92, 83, 69, and56 after 24, 48, 72, and 96 hours of storage, respectively.

Less injury occurred after 4 days of storage in this exper-iment than for other experiments. Possible explanationsinclude (1) more than 6 weeks since a nitrogen applicationto the sod field, (2) no nitrogen in experimental treatments,

(3) no seedhead production occurring. The initial soil and

greenhouse temperatures were similar.

67

Table 23. Percent leaf kill and root production in relationto cutting height on Merion Kentucky bluegrasssod harvested on June 17, 1969, after storageunder simulated shipping conditions for 4 days

Root Organic Matter(mg/pot)

Cutting Ht.( in)Hours

ofstorage

Percent Leaf KillCutting Ht.

( in)

Mean Mean 2 0.75

24

48

7296

000

009

2.8

3000

000

L9

5.6

000

ooOtOoOt

20.0

0043

.093

.110

.079

.059

0122

.130

.079

.026**0064**

.091

0078

t, **Differences between main effect means are signif-icant at the .10 and .01 level of probability, respectively,for designated hours of storage.

The most important result of this experiment was

that N6benzyladenine application at harvest or 5 or 10 days

before harvest did not significantly affect temperature,

carbon dioxide, oxygen, or ethylene levels during storage

or leaf injury and cover and root production after trans-

plantingo

Experiment VII (June 24, 1969)

This experiment compared 5 mowing treatments.

They were cutt ing to (a) 0.50 inch the day of harvest., (b)

0.75 inch the day of harvest, (c) 0075 inch 5 days before

harvest, (d) 0.75 inch 10 days before harvest, and (e) the

normal 2 inch height. The sod cut at 0050 inch was severely

68

defoliated with scarcely any green leaves remaining. The

treatments were arranged in a randomized block design having

three replications. The sad was harvested on June 24, 1969,

and stored in the sad heating boxes for 4 days.

Results and discussion.--The mean moisture content of

the sad at harvest was 65.4%. The air temperatures at 2 p.m.

in the greenhouse where the sad was stored were as follows:

o

756

74

24

106

48

99

72

78

96

92

Hoursof

The main effect means for temperatures are presented

in Table 24. The mean temperature increased rather slowly

during the first 24 hours, but increased more rapidly during

the second day. The sad mowed at 2 inches had the highest

temperature at all times of measurement. The temperature of

the sad cut at 2 inches was significantly higher than for

low cut sad during the first 24 hours. None of the main

effect means for the low cutting treatments were signifi-

cantly different. Sad having the most green leaf tissue

present had the highest temperatures.

The main effect means for percent carbon dioxide and

oxygen are presented in Table 25. The rate of increase in

CO2 level and the rate of decrease in 02 level over time was

slower in this experiment than in the previous ones. Also,

the level of 02 remained somewhat higher than usual. There

Was significantly more CO2 present in boxes containing sad

cut at 2 inches than for any of the lower cutting heights

69

Table 24. Temperature (OF) changes occurring during storagein relation to cutting heights and times on MerionKentucky bluegrass sod harvested on June 24, 1969,and stored under simulated shipping conditions for4 days

Cutting Ht. (in) andTime (days before harvest)

Hoursof

Storage

o

3

6

9

24

48

72

96

Mean

69.471.1

72.474.277.887.5

93.094.4

0.50o

69.3b70.8b72.Db73.7b77.3b87.0

92.294.5

0.75D

69.3b71. Ob

72.3b74.0b77.2b86.7

92.593.8

0.755

69.2b70.7b72.0b73.8b77.7b88.293.395.3

0.7510

69.3b70.8b7l.8b73.5b77.3b85.592.393.0

22

70.0a*72.2a**73.7a**76.2a***79.7a*90.094.595.4

*, **, ***Differences between main effect means aresignificant at the .05, .01, and .001 level of probability,respectively, for designated hours of storage.

70

Table 25. Percent carbon dioxide and oxygen changes occur-ring during storage related to cutting treatmentson Merion Kentucky bluegrass sod harvested onJune 24, 1969, and stored under simulated ship-ping conditions for 4 days

Cutting Height (in) and Time (days)Hours 0.50 0.75 0.75 0.75 2of

Data Storage Mean 0 0 5 10 2

% CO2 0 3.0 3.3 3.0 2.8 2.7 3.33 7.4 7.3bc 7.6b 6.8c 6.3c 9.1a**6 10.8 10.3c 10.9b 10.0cd 9.6d 13.3a**9 13.6 12.5 14.3 13.3 12.8 15.2

24 17.3 16.5 17.4 16.9 11.1 18.648 16.5 16.2 16.B 16.1 16.1 16.972 19.5 19.2 19.4 19.1 19.0 20.696 20.6 18.9d 20.3b 19.3cd 19.8b 24.5a**

------------------------------------------------------------% °2 0 16.6 16.2 16.4 16.7 17.1 16.51

3 10.0 9.9c 9.9c 11.0b 11.Sa 1.8d**6 6.3 7.7ab 5.4c 7.2b 8.0a 3.4d**9 4.7 5.9 4.4 4.5 5.5 3.21

24 4.3 6.4a 4.'Sb 4.2bc 3.6cd 2.9d*48 3.1 3.9 3.5 3.0 2.1 2.7172 2.3 2.6 2.5 2.0 2.3 2.296 2.4 3.1 2.5 2.9 2.0 1.1

t, *, **Differences between main effect means aresignificant at the .10, .05, and .01 level or probability,respectively, for designated hours of storage. Main effectmeans followed by the same letter are not significantlydifferent according to Duncan's Multiple Range Test at the5% level.

71

at the 3, 6, and 96 hour CO2 measurements. The pattern of

differences among sod cut low was not consistent. Signif-icantly less 02 was present for the sod cut at 2 inches atthe 3, 6, and 24 hour measurements. The pattern of differ-

ences in 02 levels among sod mowed low was not consistent.The level of 02 was significantly higher for sod cut at 0.50inch than for sod cut at 0.75 inch after 24 hours of storage.In general the sod cut at 0.50 inch was statistically equal

in CO2 and 02 level to one or two of the 0.75 inch mowingtreatments according to Duncan's Multiple Range Test. Again,

the evidence shows that CO2 and 02 levels were closelyrelated to the amount of respiring tissue present.

No ethylene was found in gas samples collected at

0, 3, 6, and 9 hours. only 0.27 ppm ethylene was found insamples collected at 24 hours. None of the main effectmeans were significantly different. The Varian Aerographwas not working when the 48, 72, and 96 hour samples werecollected. Nevertheless, the very low levels of ethylenefound at the beginning of the experiment suggest that thelevels would also have been low at the end of the experiment.This sod had not received any nitrogen fertilization sinceMay 1, 1969. Generally when the level of nitrogen nutrition

was low in these experiments the ethylene content during

storage was also low.The main effect means for percent leaf kill and

cover and root production are presented in Table 26. Sodwas not removed from the boxes after 24 hours because of the

Table 26. Percent leaf kill, percent leaf cover, and root production in relation to cutting treatments on Merion Kentucky bluegrass sod harvested on June 24, 1969 after storage under simulated shipping conditions for 4 days

Cutting Ht. (in) and Time (days)

Data

% Leaf k i l l

% Leaf cover

Root o r g a n i c m a t t e r (mg/pot)

Hours of

S t o r a g e

48 72 96

48 72 96

48 72 96

Mean

10.0 22 .7 51 .3

74.0 67 .7 53 .0

40 75 38

0.50

0

0 . 0 0 . 0 b

1 6 . 7

55 .0b 66 .7 6 6 . 7

28 41 52ab

0 .75

0

11.7 13 .3b 55 .0

75.0a 76.7 60 .0

32 116

49ab

0 .75

5

15.0 15 .0b 60 .0

75.0a 71 .7 55 .0

34 72 13cd

0 .75

10

8 . 3 18 .3b 30.0

8 1 . 7 a 8 3 . 3 78 .3

43 8 2 69a

2

2

15.0 66 .7a* 9 5 . 0 t

83 .3a** 4 0 . 0 t

5 . 0 t

64 63

4d*

- j

to

f, *, **Differences between main effect means are significant at the .10, .05, and .01 level of probability, respectively, for designated hours of storage. Main effect means followed by the same letter are not significantly different according to Duncan's Multiple Range Test at the 5% level.

73

slow temperature increase. An average of only 10% leaf killwas observed on sod stored 48 hours. Sod stored 72 hoursaveraged 22% leaf kill. Significantly more sod injuryoccurred when cut at 2 inches than for any of the lowermowing treatments. Even though no injury was observed onsod cut at 0.50 inch, its percent injury was not statisti-cally different according to Duncan IS Multiple Range Test

from that for the 0.75 inch mowing treatments. While notstatistically significant, the trend was similar for sod

stored for 96 hours.The percent leaf cover 20 days after transplanting

was significantly less for sod cut at 0.50 inch than for

higher heights of cut for sod stored 48 hours. Trends inthe data for sod stored 72 and 96 hours suggested that the2 inch cutting height resulted in greater injury. Thistrend in the leaf cover data compliments the results of the

leaf kill estimates.The significant results for rooting of sod stored

96 hours do not reveal a pattern that can be explained.The overall results of this experiment showed that

low mowing within a few days of sod harvest was beneficial.The exact time and height of the low mowing were not

critical.

74

Experiment VIII (July 30, 1969)

The Merion Kentucky bluegrass sod used in thisexperiment and the August 4, 1969 experiment came from adifferent field at Green Acres Turf Farm, Mason, Michiganthan the sod used in the previous 1969 experiments. Thisfield was seeded to Merion Kentucky bluegrass on August 12,1968. Four hundred lb/A of 6-24-24 fertilizer was tilledinto the organic soil during seedbed preparation. An addi-tional 400 lb/A of 5-20-20 fertilizer was broadcast over thesod in early April of 1969. On .April 21, May 5, June 2, andJune 30, 1969, 150 lb/A of 45% N urea fertilizer was broad-cast. The appearance of the sod was excellent. Its texturewas finer than that of the sod used in the earlier 1969experiments. Although the sod strength was adequate formarketing, it was not as strong as the sod used in the

earlier experiments.This experiment compares the effects of (a) 2 versus

0.75 inch cutting height, (b) 0 versus 215 lb/A nitrogen,and (c) 0 versus 0.055 lb/A of N6benzyladenine. The 0.75inch mowing was done 7 and 2 days before harvest. The nitro-gen was applied 7 days before harvest. The N6benzyladeninesolution was applied 2 days before harvest. The sod was tohave been harvested on July 28, 1969, but a sod cutter break-

down and rain caused a two day delay. The cultural treat-ments were arranged in a randomized block factorial design.

75

Results and discussion.--No response to either nitro-gen or N6benzyladenine treatments was visually detectable atharvest time. The mean percent moisture was 59.4. The sodcut at 2 inches had 61.5% moisture, while the sod cut at0.75 inch had 57.4%. This difference in percent moisture atharvest was significant at the 0001 level of probability.

The air temperatures at 2 p.m. in the greenhouse

room where the sod was stored were as follows:

0 3 9 24 48 72 Hours

96 88 78 88 92 96 of

T~ mean temperatures in t~ sod heating boxes were

as follows:

0 3 9 24 48 72 Hours

87.3 89.2 93.2 9504 94.7 94.9 of

The main effect means were not significantly different. The

initial sod temperature was higher than usual. Also, moresod injury occurred within 48 hours. These two factors mayhave prevented significant temperature differences from

developing.The main effect means for percent carbon dioxide and

oxygen and ppm ethylene levels occurring during storage are

presented in Table 27. At all times of measurement, except24 hours, the percent CO2 levels were significantly lowerfor sod cut at 0.75 inch. Nitrogen and N6benzyladenine

treatments did not affect either CO2 or 02 levels.

76

L()o r-l

'0

~0

~

,OJ

001

r-lIU

•l-Io

OJ+J,C[J)+J

4-l+J

0IU

[J)+Jl-Ic:

:1IU

0O

,C•.-14-l'U-.-IOJC:+J011U

•.-1c:

[J)01

•.-1OJ

[J)l-IOJIU

'U

[J)l-I

c:0

1U4-l~

':>t+Jr-lo

OJOJ:>

4-l..-14-l+-iOJ

0OJc:

0..•.-1

[J)IU

OJE!

l-Ic:OJ

:>tOJ+J~

..-I+Jr-lOJ-.-I

..Q..QIU[J)..QOJ

0o

l-Ic:

0..OJl-I4-lOJ

04-l4-lr-l-.-IOJt:l

:>~

OJ~r-l~

OONOr-l

.....

OONr-lr-l

OONOr-l

OONr-lr-l

.....

II••••

OONOr-l

Or-lMr-lr-l

00

00

0

No r-lOOOOO

OOr-l0

l""-O'\•

00

•Q

I.O~NNr-l

••

•0

•

OMl""-l""-l""-r-lr-lr-lr-lr-l

+-NN

OO

~L()

•0

•0

•

oC't'H.ol""-l""-

r-lr-lr-lr-lr-l

N

8'*

N o L()

L()oOJ

[J)01

l-IIU

:14-ll-I

000

i:Il+JU

l

+Ji:IlL

()l""-

01.........C:C:

0-.-1

•.-1+J

......+J:1C

)

OJr-l..QIUE-l

77

Significantly more oxygen was found for sod cut at 0.75 inch

at all times of measurement. The ppm ethylene was signifi-cantly lower for sod cut at 0.75 inch, except for the 3 hourethylene measurement. The high nitrogen application, whichusually stimulated ethylene production in earlier experi-ments, did not affect ethylene levels •. Ethylene levelstended to be higher for high nitrogen levels at the 3 and48 hour measurements. Significantly more ethylene was pres-ent at the 9 hour measurement where the sod had been treatedwith N6benzyladenine.

A significant cutting height x N6benzyladenineinteraction occurred for ppm ethylene measured after 9 hours(Table 28). N6benzyladenine applied to sod cut at 2 inchessignificantly increased ethylene level. Cutting at 0.75inch significantly decreased the ethylene production of sod

Table 28. Significant (.05 level) cutting height x N6ben-zyladenine interaction for ppm ethylene measuredafter 9 hours of storage of Merion Kentucky blue-grass sod harvested on July 30, 1969, and storedunder simulated shipping conditions for 3 days

N6BA (lb/A)Simple

Cutting Ht. (in) 0 0.055 Effects

2 0.75 1.48 +0.73**

0.75 0.25 0.20 -0.05

Simple Effects -0.50 -1. 28**

**Differences are greater than LSD at .01 level.

78

treated with N6benzyladenine. In other words, sod cut at2 inches and treated with N6benzyladenine produced the mostethylene in this instance. This interaction was not sig-nificant for later ethylene measurements and the only trendwithin those interactions was for higher ethylene levelswith the 2 inch cutting height.

The main effect means for percent leaf kill andcover and root production after storage are presented inTable 29. Less leaf kill occurred on sod cut at 0.75 inchand the difference was significant after 48 and 72 hours ofstorage. Conversely, more leaf cover was present for lowcut sod. Neither nitrogen nor N6benzyladenine treatmentsaffected the percent leaf kill or cover. Root productionwas quite low. Low cut sod stored for 48 hours produced

significantly more roots than sod cut at 2 inches. Sodtreated with N6benzyladenine produced significantly lessroot organic matter than untreated sod after 24 hours of

storage. Nitrogen level did not affect rooting.Nitrogen fertilization did not affect any of the

measurements taken during the course of the experiment.This was unusual. In previous experiments nitrogen levelaffected temperature, gas levels (especially ethylene), and

percent leaf kill and cover. The "zero" nitrogen sod hadalready received 290 lb/A of nitrogen during 1969. Perhapsthe sod was already so heavily fertilized with nitrogen that

response to additional nitrogen could not occur. The highinitial sod temperature (870 F) was a more likely cause for

0'1N(I)~,.Qf{j

E-i

11)11)oo11)~s::

N(1)-tJH:C;0

..

..

..

..

..

H,.Q.j..J~.r-!

........

Zo

tJ'I_s::s::

.r-!.r-!

.j..J........

.j..J::sCJ

(I)m

tJ'IH

f{j::s4-l

H000III

.j..JU

)

79

11)0'0

OI1

)N...-Ie-Ie

-IeNOOOO...

\DOOOON\DOO

NO

O

~O

OM

OO~r-I

r-Ir-I•.-1~4-lf{j(I)

H

I00

\Dr-I

J•••

I0

00

MI

11)NIIIII

11)0'11)

III'\DN

I\D

r-IIIIIII

O\D

O'I

II11)11)r-I

I11)r-I

IIIIIN

O'oo

IIr-Ir-IM

II'

NIIIIII

-Ie-Ie

I-Ie

-IeI

0011)

\DI

•••I

00I'

11)I

\DM

II

11)001'0

011)r-IOOOOMOON\Dr-I

H(I)

:>o(J

4-lf{j(I)H

NI'~.-Ir-Ir-I

-Ie-Ie-Ie00011)~r-I

0'00

00000N

11)o(I).c..j..J(J)tJ'I.j..J

f{jf{j

Ho.j..J.j..Js::mf{j(J4-l

.r-!0

4-l.r-!m

s::HtJ'I::S

.r-!0

m.c(1)"0H

(I)f{j.j..Jtom

s::S::tJ'If{j.r-!(I)m8

(J)"0

.j..J(JH

(I)0

4-l4-14-1(I)

~:>t

S::r-I.r-!

(I)f{j:>8

.r-!.j..Js::

(J(J)

(I)(I)

P-l3:m

.j..JQ

)(I)

H,.Q

~m:>t(I).j..J(J.r-!S::r-IQ

).r-!H,.Q(I)

f{j4-l,.Q4-10.r-!

Ht:lP-l-Ie-Ie

4-1-Ie

0~r-I

-Ie(I)

-Ie:>Q)

~r-I-Ie

r-Ioo

80

masking or lack of nitrogen response. In the August 4, 1969experiment which used the same sod source the high nitrogentreatments resulted in significant changes in gas levels andpercent leaf kill and cover and root production; the meaninitial sod temperature was 780 F.

Experiment IX (Auqust 4, 1969)

This experiment compared the effects of (a) harvesttime (9 a.m. vs 2 p.m.) and (b) 0, 130, and 215 lb/A ofnitrogen. The sod was cut in the field at 9 a.m. and 2 p.m.and the boxes were closed in the greenhouse by 10 a.m. and3 p.m., respectively. The measurements were made separately

for sod cut at 9 a.m. and 2 p.m. The nitrogen was applied5 days before harvest. The treatments were arranged facto-rially in a randomized block design. The sod was from thesource described for the July 30, 1969 experiment. The sodwas harvested on August 4, 1969, and stored in the sod heat-

ing boxes for 3 days.Results and discussion.--No response to nitrogen was

visible at harvest time. The mean percent moisture was 61.0and the main effect means were not significantly different.

The air temperatures at 2 p.m. in the greenhouse room where

the sod was stored were as follows:

o95

3

95

6

87

9

75

24

95

48

105

72

100

HoursOF

81

The main effects means for temperature are presentedin Table 30. Initially the sod harvested at 9 a.m. was 100 Fcooler than that harvested at 2 p.m. This has great practi-cal significance for sod producers and shippers. Clearly,early morning harvesting gives an extra margin of protectionagainst sod heating damage during shipment. After 24 hoursthe sod harvested in the morning was 60 F cooler. Ab~verytime of measurement sod harvested in the morning was coolerthan sod harvested in the afternoon and the difference wasstatistically significant during the first 48 hours. Therate of heating was greater for sod harvested in the morning.After 72 hours of storage the initial 100 F difference was

o .reduced to only 1.5 F. This suggests that as temperaturesincrease within the sod stack the rate of energy release

from respiration decreases.The main effect means for percent carbon dioxide and

oxygen and ppm ethylene changes occurring during storage arepresented in Table 31. Significantly higher levels of CO2were found at 3 and 6 hours for sod harvested at 2 p.m.Significantly less 02 was present after 3 hours of storagefor sod harvested in the afternoon. As noted above, thetemperatures were higher for.sod harvested in the afternoon.These results suggest that sod harvested in the afternoonhad a higher rate of respiration during the early hours of

storage.

82

Table 30. Temperature (oF) changes occurring during storagein relation to time of harvest and nitrogen treat-ments on Merion Kentucky bluegrass sod harvestedon August 4, 1969, and stored under simulatedshipping conditions for 3 days

Harvest Time Nitrogen (lb/A)Hoursof

storage

o3

6

9

24

48

72

Mean

78.3

80.5

83.1

85.8

90.5

94.5

95.6

9 a. m.

73.5

74.5

77.6

80.6

87.8

92.794.8

2 p.m.

83.1***

86.5***

88.6***

91. 9***

93.3**

96.3**

96.3

o

78.1

80.283.0

85.9

89.5

94.0

94.9

130

78.2

80.9

83.0

85.5

90.4

94.1

94.5

215

78.5

80.4

83.3

86.191.8

95.4

96.4

**, ***Differences between main effect means aresignificant at the .01 and .001 level of probability,respectively, for designated hours of storage.

83

OOMN.-l

.....OOMN.-I

.....

.....OON.-IO

I'I'NI'O"'d'I'ONOO.....

OOMNO

1010

10OONL{)NO1.00

ex:>"'d'.-l......

O,.t-lMN.-l

oj(ole

-Ie-Ie

-Ieole

oj(oj(

l1Jl1J

l1J00

L{)NL{)

0L{).-l1.000

II••••

O.-lM('I").-l

..0.0..0

NNOOOOO.-l"'d'.qrO)

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIII,IIII

No'* .....L{)NN.-l.-l

oj(oj(oj(<:;f'N<:;f'OO<:;f'•

••

'1<:;f'NN.-l.-l

.....1'('1")N

N.-l

1'1.00).-100•••••

I.ONNN.-I

..0..01.000)0000.....

<:;f'NN.-I.-I

oj(oj(oj(

..0..0(00)1.00)00.....

<:;f'.-IN.-I.-I

<:;f'.-I0)L{)<:;f'..

,..O)('I")L{)OOOO

.-1.-1.-1.-1

.....

N

8'* OO<:;f'.-I0)0)

.....0<:;f'1.O

I'I'

.-1.-1.-1.-1.-1

oj(oj(

oj(oj(

oj(ole

oleoj(

NI'('I")<:;f'<:;f'.....

NL{)I.OI'I'.-1.-1.-1.-1.-1

oj(oj(

..0oj(

1010

4-

0)L{)OO

1.0('1")......

O<:;f'L{)OOOO.-1.-1.-1.-1.-1

1010

.-I01.0N.-I

......-IL{)I.OOOOO.-1.-1.-1.-1.-1

..0..0

('1")1'00('1")o L{).-INo('I").-IOJ

{/}lJI

~10

::s4-1

~0

00

l:Il.j.JCf.l

.-IMOJ...-l..0108

84

The CO2 levels in relation to time of harvest werenot different at 24 hours. The sod harvested in the morninghad released more CO2 after 48 and 72 hours of storage.This suggests that sod harvested at 9 a.m. had a higher rateof respiration during the last 2 days of the experiment.Sod harvested in the morning heated faster than sod harvestedin the afternoon. This was also evidence for a higher rateof respiration for sod harvested in the morning.

Nitrogen levels affected the levels of CO2 and 02significantly. More CO2 was evolved where nitrogen treat-

ments had been made. The CO2 level for the zero nitrogentreatment was significantly lower after 6 hours than for the130 lb/A nitrogen treatment. The CO2 level for the 215 lb/Anitrogen treatment was intermediate. Both the 130 and 215lb/A nitrogen treatments resulted in higher levels of CO2than the zero nitrogen treatment at 48 hours. The trend

was similar after 72 hours. Less 02 was found at 3 and 6hours for sod treated with 130 and 215 lb/A of nitrogen.These results indicate that nitrogen stimulated respiration.

The significant harvest time x nitrogen rate interactionsuggests that, at 6 hours, nitrogen was effective in stim-

ulating respiration only at the higher temperature present

for sod harvested at 2 p.m. (Table 32).In spite of the fact that large differences in

temperature were present, time of harvest did not affectethylene production. Less ethylene was found for the zero

85

r::N

0I

III~

M:>1

•...l:;j

I~

E..j.l

M0

0•.-1

Q)....l

II)III

II

~~

II)..j.l

•.-1

r::~

CJ..0

oQ)

Q)III

~~

ole..0

'0~

IIIN

'"0

53

rz:lI

~M

0~

0..•...l

Q)III

I..j.l'O

~~

CJQ)

~0

III~

~0

•.-1~

ole~

Q)..j.l-

tI)III

oleQ)

..j.lII)

ICCI

~N

:>r::

.........N

Q)•...l'0

..0III

0N

~r::

~Q)

III~

..j.l..

0Ill'"

r::~~

Q)ole

'"8'

ole'0

r::~I/)

MCD

N~

r::Q)

~~

III.

IIItTt ..

..j.lN

N~

MO~

•.-1....

~I/)

~z

0..j.l..j.l•.-1

II)r::

:;jole

Q)tTt

ole..c::

><:;j

0N

~I/)

~..j.l

ICCM

III

~r::

~M

~'M

..j.l~

~III

•.-10

..j.lQ

'0tI)

..j.lQ)

ole..:t

1I)..j.l0

MM

Q)II)

~r::

:>Q)

0III

M~

~III

~:>

~~

..c::III

~..j.l

..c::1llII)..c::r::

~-

0Q)

~'O

....l..j.l

tTtQ)O..j.l

II).

.~

:>11)

•.-1~

~E

SIII

Q)'0

~~1I)r::

~•...l

III0..

II)0

1llE-!Q)

I/)III

CJ::x::

'"N

~0

~III

.tTttTt

---Q)

r::II)

:;j•.-I

Q)..j.l

~0..

Q)II)

CJ

r::..o0..

II)tTt

..j.lr::

III•.-1

~III

CJQ)

CJ:>1..c::

:;j~~

Q)~

•...l~II)

0o

0~

Q)

~CJ

::x::..j.l

~~

•.-1:;j

'0tI)

rz:l~

r::..j.l

Q)•.-1

tTtr::..j.lQ)

Q•...l

Q)III

~ole

tI)~~

~ole

:>1..j.l

~r::

•.-1..Q)

Q)tI)

ole:>

NS

•.-1

MQ)

..j.l

~CJ

Q):;j

NQ)

~II)

80..

..0III

II)

III~

Q)

E-!'*

~

86

nitrogen treatment at all times of measurement. The dif-ferences were significant at 3, 6, and 48 hours (Table 31).Ethylene production was independent of temperature and wasgreatest where supraoptimal levels of nitrogen were applied.

The main effect means for percent leaf kill andcover and root production are presented in Table 33. Har-vest time affected temperature and CO2 and 02 levels duringstorage, but these effects were not reflected in the percentleaf kill and cover data. An unusually high percent of leafkill (6l.~~) had occurred after 24 hours of storage. TheCO2 levels were about the same. Perhaps these two factorsmasked the effect of harvest time (temperature) on leaf kill.Nearly all the plants were dead after 48 hours of storage.There was a tendency for more root production from sodharvested at 2 p.m. after 24 hours of storage. Signifi-

cantly more leaf injury and less leaf cover and root pro-duction occurred for sod that received the supraoptimalnitrogen treatments.

Experiment X (Auqust 18, 1969)This experiment compared sod from two sod sources;

one source was from an MSU sod production fertilizationexperiment and the other was from a typical commercial sod

producer.The MSU sod production fertilization experiment was

conducted on organic soil at the Michigan State UniversityMuck Experimental Farm. This soil had received very little

87

rnrn

Crn

0ole

'0'1C

lOo..l

oleole

ole,Q

)C•..l

H4J

oleole

oleole

o0'I0..l

0'I•..l10

10.0.0

ole...-110'0

Q)Q

)'O000

NO

oleole

•H

HO

'I='CLl'l

.0.0o

010

...-I0

...-IM

O...-10

000Q

)4JUH

.oU

~N

0\0N

N..c:::rnu

0...-I

4J10

4J>1

0'1""-

4-lrn~c

.04J04J

U...l

...-I10

CH

='o...0

rnQ

)Q

)4J

0..10

1010.0

4JHH

4JC

...lC

00000

C='

Q)

4-lQ)..c:::

Q)

0..

10.01004-l

lO~rn

0'1M

Ll'l0000

Ll'l0U

..c:::4-l0

...-I000

Ll'l0

...l...l

CC

'OH

...-I...-I

4-l'O'O

o0

Q)

4J...l

Q)

...l...l

4J•..l

C4J

>14JH

IOZ

0'110...-1U

Q)...-I

.0.010

10...l

C4J

='~='000

OO

Nrn

0'1C

'08

1010

...l10

oC

...l0

Ll'lMM

\O000

Q)

rnU

HO

rn0\

0\r--

HQ

)...l0..

N10

'04-l

rnH

•..l4J4JQ

)rn

HC

OC

'OC

OO

lo

~C

104-l

...lH

='~

rn4J

.,

'010

'08

OO

MM

r-->14J

CQ

)Q

)~

.+-

4J...-I010

HH

0..000

00...-1O

ON

UQ

)C

4J0•..l

\00\\0

\0Q

):>

,4J

E-tN

...-I4-l

...lQ

)H

crn4-l4J

H.

Q)

Q)

4JQ

)U

10...-1:>

0'1'0rn

Q)

Q)

o0

CQ

).

Co..H

:>U

H10

:>8

r--Ll'lLl'lLl'l

...lrn

Q)

Q)

4JH

10Q

)4J...-I

4-l...l

'"10

10...-Ir--

r--N...-I~

8H

4JIO

C\O

:r:\00\

~0

Q)~

Q)

0\0\

...-IC

,...-ILl'l

...-1'0...-1Q

)>1C

Q)4J

Q)

Q)

4J10

,~

...le..c:::

C~

4J...-II04JQ

)Q

)Q

)'..lrn

u84JC

NO

\O0\...-10

.0.04J

H...l

rn10

10Q

)10

&4J

;Q

)...-Ir--o

r--NO

Ll'lMO

rn.0

..c:::~

\00\0Ll'l

MQ

)04J4J4J

='...-I

...-IU

Hrn

,rn~co..>1Q

)...-I

Q)

Q)

.oE-t...-I:>C

H4-l

...lH

0Q

)O'O

Q)

~10

4-lQ

)0'1

..c:::'OQ

)4-l...-l~C

4-lQ

)rn

0'1...l

Q)

010

1004JH

10C

l:>...-I~Q

)4J

rnrn

='4-lH

~OO

N~O

ON

~OO

Nole

Q)...-I

...-IQ

)>1000

N~r--

N~r--

N~r--

ole...-I

0Q

)C

:>10

:r:4J

ole4-l...-l

4JOH

'OtJ)

...-I0..

C...l

10,0

rn...l

Q)4J..c:::M

oIeOC

4JU

10ole

•10

...-IH

...-I'OH

Q)

='Q

)Q

)0

0''0

8~III

Hrn

4-lH

Uole

C4J

...-IQ

)•..l

104J

rnC

...-I:>

CU

-Q

)...l

010

4Jof-

,Q)C

M8

~U

O'IH

O...-I4-l

10M

Q)

HQ

)o..04-lU

H4-l

4-lo

4J""-

•Q

)C

Q)

='10

104J0'I

='...-I

rnQ

)Q

)4J108

,CC

l.0

10~

~08-

Ll'l...l10

Q)

00100

E-t~

~~

~•:E:

4J

88

fertilization prior to establishing the experiment and wasconsidered low in fertility. No fertilizer was applied tothe plots during seedbed preparation or during the fall of1968. Merion Kentucky bluegrass was seeded on August 25,1968, at a rate of 50 lb/A. The sod production experimentwas designed to compare the effects of 0, 90, 180, and 360lb/A of nitrogen on sod strength and appearance. Nitrogenfrom urea fertilizer was applied on June 10, July 10, andAugust 15, 1969. One-third of the total nitrogen (30, 60,and 120 lb/A) was applied at each date of application. Azero nitrogen plot was included in each of the 3 replica-tions. All the plots received one inch of irrigation waterafter each fertilizer application. Mowing was at a 2 inchheight twice a week. All plots had an adequate stand ofgrass. The sod in all plots was strong enough for easyhandling. The mean percent moisture of the 4 MSU sods was58.5 when harvested for use in the sod heating experiment

on August 18, 1969.The commercial sod was produced on organic soil at

the Ha1mich Sod Farm near East Lansing, Michigan. Aftertilling in 1,000 lb/A of 5-20-20 fertilizer during seedbedpreparation, the field was seeded to Merion Kentucky blue-grass at a rate of 50 lb/A on August 15, 1967. In early Mayof 1968, 250 lb/A of 16-8-8 fertilizer was applied. Prilledurea was applied at 200, 100, 200, and 50 lb/A on June 15and October 1 of 1968 and May 5 and August 1 of 1969, respec-tively. A total of 340 lb/A of nitrogen was applied during

89

the 2 year period of sod production. No irrigation was

used. Mowing was at a 2 inch height 3 times a week. This

sod had outstanding turfgrass quality and was in strong,

marketable condition. On August 18, 1969, the sod contained

68% moisture. This was significantly higher than for the

MSU sod.

The sod from the 2 sources differed in many respects.

Field history, moisture level, mowing and irrigation prac-

tices, age of the sod, and nitrogen fertilization levels

differed considerably. The appearance of the sod also

differed greatly. On a visual rating scale of turfgrass

quality (1 to 9: 1 = best) the commercial sod was rated 1

whereas MSU sod was rated, 2, 4, 6, and 8 for sod which

received 360, 180, 90, and a lb/A of nitrogen, respectively.

Figure 6 shows a comparison of the zero nitrogen-~SU sod

and the commercial sod.

The 5 sods were compared in a one-way analysis of

variance randomized block experiment having 3 replications.

The sod was harvested on August 18, 1969, and stored in the

sod heating boxes for 5 days. The boxes were left open

during the first 24 hours of the experiment because the

weights were too high in some boxes.

Results and discussion.--The air temperatures at

2 p.m. in the greenhouse room where the sod was stored were

as follows:

a

99

3

90

988

24

108

48

115

72110

9695

120

W2

Hours

~

90

Figure 6. Visual comparison of sod produced witho and 340 lb/A of nitrogen.

91

The main effect means for temperature are presentedin Table 34. The temperature increased progressively with

nitrogen level for 9 through 72 hours and commercial sod(designated as 340 lb/A of N in the tables) had the highesttemperature. At 96 and 120 hours the temperature increased

progressively with nitrogen level for the 4 MSU sods. Thetemperature of the commercial sod was lower. The commercialsod appeared to be the most actively growing and the temper-ature data suggests that it had the highest respiration rate.The commercial sod may have depleted its readily respirablecarbohydrates enough to result in a temperature drop after96 and 120 hours of storage. The overall results suggesta direct positive relationship between level of nitrogen

nutrition and respiration rate.The main effect means for percent carbon dioxide and

oxygen are presented in Table 35. The CO2 levels remained

lower than for the other experiments while the 02 levelswere higher. The unusually small changes in CO2 and 02levels during the first 24 hours was attributed to diffusion

losses because the boxes were open. Even after closing theboxes the CO2 level remained 5 to ~/o lower than in previous

experiments and the 02 levels remained about 5% higher.Apparently the rate of respiration of the sod used in this

experiment was unusually low.

92

Table 34. Temperature (OF) changes occurring during storagein relation to nitrogen applied during productionof Merion Kentucky bluegrass sod harvested onAugust 18, 1969 and stored under simulated ship-ping conditions for 5 days

Hoursof

Storage Mean o 90

Nitrogen (lb/A)180 360 340

o3

9

24

48

72

96120

82.084.4

88.090.493.493.194.693.7

82.283.786.2d

87.8d90.7c90.3c9l.7c90.8c

83.384.586.7cd88.7cd9l.7c91.8bc93.8b93.5b

82.584.087.8bc90.2bc93.3bc93.5abc95.3ab94.8ab

84.785.389.2ab

92.0ab95.0ab94.7ab96.7a96.3a

81.984.590.2a**93.2a**96.2a**95.3a*95.3ab**92.8bc**

*, **Differences between main effect means are signif-icant at the .05 and .01 level of probability, respectively,for designated hours of storage. Main effect means followedby the same letter are not significantly different accordingto Duncan's Multiple Range Test at the 5% level.

93

It)0

o.j.J

.

.......

No .......

.......

.......

..0..0.Q

IIIIII

IIIIII

1I)00Nf'Nr-lM

-Ie-Ie

-Ie-Ie

-Ietltl.Q

.QNqoqoO\f'\O\O.......

f'f'\Or-l\Oqoqor-lr-lr-l

.QIII

IIIIII

III.-I1I)\oII)qo

It)\0

CX)CX)CX)0\f'CX)1I).-Ir-l.-l

.......

NCX)ON\OCX)N.......

MNMr-lO\OMr-lr-lr-l

.......

.......

NoCJ*- NNNO\O\OM

r-lr-l

-II-II

-II-II

-Ie-Ie

-Ie-Ie

Illllllll+-

Ill+-

qoOM

N.-I0\

II).......

qoqoqo\oONqor-lr-lr-lr-l

s:::IIIQ

)

~ o o0\

o\0MoCX).-IQ)

(1)lJ'

~III

::l~~

000

:x::.j.JCIl

s:::Q)lJ'o~.j.J.~Z

II)MQ

).-I.QIII8

94

The commercial sod released significantly more CO2during the first 24 hours than any of the other sods. TheCO2 levels were similar among the MSU sods. Commercial sodused significantly more 02 during the first 24 hours thanany of the other sods (except zero nitrogen sod at 3 hours).The 02 levels were similar among the MSU sods. These corre-sponding results showed that the commercial sod was respir-ing faster than the other sods during the first 24 hours.

The CO2 level was significantly higher for the360 lb/A nitrogen treatment and the commercial sod than forany of the others at 96 hours. The zero nitrogen sod had asignificantly lower CO2 percentage than the other treatments

at 96 hours, except for the 180 lb/A nitrogen level. Simi-lar trends were evident at 120 hours. This also supportsthe hypothesis that respirable substrates were becoming lessavailable in the commercial sod near the end of the experi-

menteThe 02 percentage o~ the atmosphere within the sod

stacks decreased as the nitrogen levels increased at 96

hours of storage.The mean ppm ethylene were as follows:

9

.05

24

.05

48

.06

72

.14

96.04

120.05

Hours

These levels were much lower than usual. This was expectedsince the average level of nitrogen used on the sod in this

95

experiment was less than the zero nitrogen treatment ofother experiments.

The main effect means for percent leaf kill andcover and root production are presented in Table 36. Themean percent leaf kill increased slowly over time andreached about 7~~ after 5 days of storage. The nitrogenlevels did not affect leaf injury. A trend showing a step-wise increase in percent kill with increasing nitrogen

levels was present at 96 hours.The leaf cover was significantly lower on sod that

received the 2 highest nitrogen levels than for sod thatreceived the 2 lowest nitrogen treatments, for sod that hadbeen stored for 96 hours. Nitrogen treatment did not affect

leaf cover for the other times of storage.The root production for sod that had been stored 24

hours was higher for the sod treated with 0 and 90 lb/Anitrogen than for sod treated with 360 and 340 lb/A ofnitrogen. A similar trend was present for sod that had been

stored 96 hours.In summary, the sod grown with 0 and 90 lb/A of

nitrogen produced less heat during storage and more leafcover and roots after transplanting than commercial sod.Satari (1967) found that 5-month-old sod produced on organicsoil without nitrogen fertilization had high yields (a) ofrhizomes and roots, (b) total available carbohydrates, and(c) sod strength. He also found that 15 lb/A/month ofnitrogen gave a good balance of high sod strength, high

0)...-i..QroE-t

o\0Mo00s::

...-i0)tJIol-I.j..l

.,.,lz

o0'\

os::ro0)

~0)Ul

tJIl-I

ro::lI.!-ll-I000

::r:.j..l(/)

.j..ls::0)s0)l-I::lU

lro0)

~

O...-iO\OM...-i\OOO

.....O...-iO...-iM

lO..r

00001".....OOlOlO...-i

N\O

OMOOI"00000\0...-i...-iN...-ilO

.....

I.!-lro0)H

96

000OO...-i

000'\

0O'\lOlO

...-i

l-I0):>oUI.!-lro0)H

iC..Q+-

0000\01"1"...-i...-i...-i

N

s::lO

roo

Us::.j..l::l

'OUc:ls::

0)ro

I.!-l0I.!-l.j..l

00

)...-i

tJI•s::s::

.,.,l.,.,lO)ro'O:5~~

U.j..l

'Uro

0)ro

tJI.j..lro.j..ls::

l-Is::ro

00)

U.j..ll-I

.,.,lUl0)

I.!-lI.!-l

.,.,lI.!-lI.!-ls::

O.,.,ltJI

'0.,.,lUl

Ull-l:>t::l...-iO)O.j..ll-I..s::

s::ro

ro'OU

UlO).,.,l

S::.j..ll.!-lro

ro.,.,l<1!s::s::8tJ1tJ1

.,.,l.,.,l.j..lUl

UlU

0)0)

'0.j..l

I.!-l0

I.!-ll-lS::0)

0I.!-l0)s::

l-I'.,.,l

,ro...-iro:>t

0)S...-i

l-I:>

0)0)

0)S:::>.j..l...-i0)

.,.,l.j..l0).j..l0),*~U...-ilO

.j..l0)0)

0..0)0)

..QUlS..s::O)ro.j..l

Ull-I

Ul0)

.j..lU

,0)

ros::

:>t..s::O).j..l.j..l.j..ll-I',.,l

UlO)...-i

:>t0)

I.!-l.,.,l..QE-t

1.!-l..Q.,.,lro

'00)

c:l..QO)tJIiC

0~

s::l-I0

ro,

o.....-io:i

+-...-i

I.!-lOO)o

I.!-l...-i0..

...-iUl.,.,l0)S::.j..l:>ro...-i0)

0)::l

...-iS~

97

yield of rhizomes, roots, and total available carbohydrates,and desirable green color. The results of both experimentssuggest that it would be desirable to use less nitrogenduring the production of commercial sod.

Experiment XI (October 24, 1969)The objective of this experiment was to make a

quantitative determination of the available and storagecarbohydrates present during the sod heating process. Twosod heating boxes were used. The general methods of han-dling the sod were the same as for earlier sod heating box

experiments.The sod source was the commercial sod described for

the August 24, 1969 experiment. It was 2 years old, high inquality, and had received a total of 340 lb/A of nitrogenduring its production. The sod had an initial temperatureof only 430 F. Two light frosts had occurred in the field.The sod still had a dark green color but the low temperature

hardening process was probably under way.Turfgrass stems were collected for carbohydrate

analysis at the beginning of the experiment and after 1, 2,3, 5, 9, 11, and 13 days when sod pieces were removed fortransplanting as 6 inch diameter plugs. Individual plantswere torn from the center portion of the sod piece. Theroots were clipped off at the crown. Brown leaves werepeeled away and the remaining leaves were cut off at a 0.75inch height. The stems were dried in a forced air oven at

98

o100 C for 48 hours and ground through a 40 mesh screen ina Wiley mill. The ground stems were stored in small vialsat 700 F until the carbohydrate analysis was performed.

Okajima and Smith (1964) found that 85% of thestorage carbohydrates in common Kentucky bluegrass stembases were water soluble fructosans and reducing sugars.Therefore, the cold water extraction method was used (Smith,Paulsen, and Raguse, 1964). Each ground sample was redriedand a weighed portion of about 100 mg was shaken vigorouslyfor 1 hour in 15 ml of boiled distilled water in a 50 mlErhlenmeyer flask. The mixture was filtered through WhatmanNo. 1 paper under suction. The filtrate was made up of 50

ml in volumetric flasks with distilled water.The analysis for total available carbohydrate was

conducted as follows: a 1 ml aliquot of the diluted fil-trate was transferred to a 10 ml test tube. One ml of 0.2N H2S04 was added to hydrolyze glycosidic linkages infructosans and other nonreducing sugars. The solution washeated for 30 minutes in a boiling water bath and thencooled in ice water. Two ml of 3,5-dinitrosalicylic acidsolution was added to detect reducing sugar (Bernfeld, 1951).

The solution was heated for 15 minutes in boiling water bathand then cooled. The absorbance was measured with a ColemanSpectronic 20 spectrophotometer set at 540~. Two stan-dards, one containing 0.2 mg/ml and another containing 0.5mg/ml of Beta-D-fructose were analyzed with each group of12 samples. Duplicate determinations were made for each

99

sample. The percent total available carbohydrates (TAC)was calculated using the following equation.

[(Std2 - Stdl) A

% TAC = sAStd - AStd2 1

+ b ] ( dilut~~: x 100 1

where: Std2 = 0.5 mg/ml of fructoseStdl = 0.2 mg/ml of fructose

A = absorbance of samplesAStd = absorbance of standard

Wt = weight of sample (mg)s

b = correction for slope

Results and discussion.--The data collected duringthis experiment are presented in Table 37. The relationshipof percent TAC, leaf kill, and root production over time ispresented in Figure 7. The percentage of TAC in the stemtissue remained constant during the first 5 days of storageand then declined steadily. Leaf injury occurred after 3days of storage, increased rapidly from 20 to 9~~ between5 and 9 days of storage, and increased to 100% leaf killbetween 9 and 13 days of storage. The decline in TAC andthe increase in leaf injury were directly proportionalbetween 5 to 13 days of storage. The explanation for theoccurrence of leaf kill 2 days before the decline in TAC isthat leaf tissue was not included in the stem bases analyzed

Q)

~..0III~

.a-era.

Q)0

~-N~

o-

N_

8~Q

)0'1

l/)III

>.~~

III0

0o

.j..JCf)

100

00

00

00

CDN

0\

0\

I'I'

~MCD

10CD

0\CD

~I'

CDCD

CDCD

NM

0\

0\

0\

0I'

M~

0~

N~10

~~

lI'llI'l

CD..

oM

~I'

I'I'

~~

~~

~

o0

00

lI'lN

o0

0\I'

~N

~~

o0

00

lI'l0

~N

lI'l0

\

100

~CD

CDlI'l

..CD

I'I'

I'M

I'N

NN

NN

~

oN

MlI'l

I'0'1

o0

~N

10~

CDCD

CD0

.lI'l~

~~

lI'l0

0'10~

~CD

101

tt1}!

}ea'I

%=0

Lt'l0

NN

.r--

[/)~10C

l

Lt'l

o

=0

oo~

oo~

(~o

d/6

w) o00

ooN

oNo

oM

102

for TAC content. It seems likely that TAC levels in theleaves declined before leaf kill. The largest decline inroot production occurred after only 1 day of storage.Initially, root production appeared to be more sensitiveto sod temperature than to TAC. The low root productionafter 2 days occurred because of some unknown causes. Thedecline in root production that occurred between 5 and 13days of storage was approximately proportional to thedecline' in TAC. A good correlation existed among TACdepletion, increased leaf kill, and reduced root production,yet water soluble carbohydrates were not exhausted. Theextent, if any, of the contribution of carbohydrate deple-tion to sod injury can not be determined from this data.

Youngner and Nudge (1968) found 22% TAC in stembases of l3~eek-old Merion Kentucky bluegrass which hadgrown for 8 weeks with 450 F night and 600 F day tempera-tures and a 16 hour day with 3000 ft-c of light intensity.Initially, the Merion Kentucky bluegrass used in the Octo-ber sod heating study contained 28.6% TAC in the stem bases.The higher TAC value was expected because the sod was grow-ing in more intense light and was more mature. The sod tem-perature (430 F) was lower so more hardening was occurring.

The most unusual result of this experiment was thathigh percentages of leaf kill did not occur until after 9days of storage. This was 2 to 3 times longer than forearlier experiments. The lower initial respiration rate

103

and presumably higher levels of storage carbohydrates, be-cause the grass was partially hardened for winter, probablycontributed to the longer survival time. The build-up ofcarbon dioxide and depletion of oxygen was much slower thanusual. The initial sod temperature of 430 F was roughly

o30 F lower than for earlier experiments. The sod tempera-

ture increased to the high 80's after 3 days of storage, butthis temperature level was about 70 F lower than usual. Thegreenhouse air temperatures were 20 to 300 F lower and thisundoubtedly resulted in greater heat loss and reduced tem-perature build-up in the sod heating boxes. The lowertemperature levels provide the most likely explanation forthe longer storage life of the sod.