1985
Iowa
Turfgrass
Research
Report

Cooperative Extension Service

E'5 Iowa State University
Ames, Iowa 50011
FG-451 | July 1985

Introduction

The following research report is the fifth yearly publication of the
results of turfgrass research projects performed at Iowa State University.
The first was published for the 1981 field day, which was held June 18, of
that year. The others were published in conjunction with the 1982, 1983, and
1984 field days.
The first cultivar and management studies at the field research area were
seeded in August of 1979, and many of these investigations are now in their
sixth season. The area has been expanded every year and by 1983 there were
4.2 acres of irrigated and approximately 3.0 acres of non-irrigated research
area. Funding was obtained in 1983 to add 2.7 acres of irrigated research
plots to the existing site. This construction was completed in the spring of
1985. We would like to thank Tri-State Turf and Irrigation Company and the
Toro Company for providing irrigation equipment for the new site at cost to
Iowa State University.
The expansion which has taken place since 1979 would not have been
possible without the cooperation of the Iowa Agriculture Experiment Station,
the Iowa Turfgrass Institute, the Iowa Golf Course Superintendent's
Association, and the Iowa Professional Lawn Care Association. We would like
to thank each of you who helped to develop the program over the past six
years.
We would also like to acknowledge Kenneth Diesburg, Brian Maloy, Zachary
Reicher, Mike Null, Richard Moore, Paul Johnson, Scott Harvey, and all the
others who have been employed at the field research area in the past year for
their efforts in building the program.

Edited by Nick Christians, associate professor, turfgrass science; Michael
Agnew, assistant professor, turfgrass extension; and Gene Hettel, extension
communications specialist.

Table of Contents

ENVIRONMENTAL DATA ...................................................

1

TURFGRASS RESEARCH PLOTS .............................................

4

NEW FIELD RESEARCH A R E A S ....................................

5-6

SPECIES AND CULTIVAR TRIALS
The 1984 Results of High- and Low-Maintenance Kentucky
Bluegrass Regional Cultivar Trials ............................

7

Kentucky Bluegrass Cultivar Evaluations ..........................

12

Regional Perennial Ryegrass Cultivar Evaluation ..................

14

Perennial Ryegrass Cultivar Evaluations ..........................

16

Fine Fescue Cultivar T r i a l ..................................

17

Fine Fescue Management Study

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

20

Tall Fescue Management Study

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

22

Bentgrass Management Study

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

25

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

27

FERTILIZER INVESTIGATIONS
Nitrogen X Potassium Study

The Reduction of Ammonia Volatilization from Turfgrass
Areas Treated with Surface-AppliedU r e a ............................ 30
Evaluation of Different Granular Nitrogen Sources for
Fertilization of Kentucky Bluegrass Turf .......................

32

Evaluation of Liquid Fertilizer Programs on Three
Kentucky Bluegrass Cultivars ..................................

34

HERBICIDE STUDIES
1984 Preemergence Annual Grass ControlStudy

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

37

1984 Postemergence Annual Grass Control Study .....................

39

1984 Broadleaf Weed Control and Postemergence
Crabgrass Control Study ........................................

42

Rubigan Field Study - 1 9 8 4 ...................................... 44
Selective Control of Tall Fescue in Kentucky
Bluegrass Turf with Chlorsulfuron ...............................

47

Chlorsulfuron Experiments ........................................

52

GROWTH RETARDANT INVESTIGATIONS
Effects of Five Growth Retardants on the Vegetative
Growth of Kentucky Bluegrass — 1983 - 1984 ......................

55

TURFGRASS DISEASE RESEARCH
Result of 1984 Turfgrass Disease Control Trials ...................

61

MANAGEMENT STUDIES
Sod Reestablishment Study ........................................

63

Dormant Seeding Study ............................................

65

Influence of Soil Compaction on 49 Kentucky
Bluegrass Cultivars ............................................

67

INTRODUCING
The Iowa State University Personnel
Affiliated with the Turfgrass Research Program

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

COMPANIES AND ORGANIZATIONS which have made donations to the
Research P r o g r a m ..........................

68

69

Environmental Data
RELATIVE HUMIDITY 1984

DATE

MAXIMUM EQUALS STAR SYMBOL
MINIMUM EQUALS DASHED L I NE AND DIAMOND SYMBOL
AMES-5 DAY AVERAGES

1

TEMPERATURE 1984

DRTE

MRXIMUM EQURLS STRR SYMBOL
MINIMUM EQURLS DRSHED L I NE RND DIRMOND SYMBOL
RMES-5 DRY RVERRGES

2

RAINFALL 1984

zuxitun
444444555555666666777778888889999990

001122001122001122001220011220011220
494949494949383838383382727271616161
MGNTHDAY

AMES

3

Wildflower and
Native Grass
Establishment Study

Buffalograss Study

Fall
Fertilization
Study

Premium

Baron

Parade
IS I

Tall Fescue
Control
Study

Baron
N & K Study
Phosphorus
Fertilization
Demonstration

Sod Production Study
o

Tall Fescue
Tall Fescue
Management
Study

Baron

</>

P. Ryegrass
Cultivar Evaluations

Turfgrass
Research
Plots

Sod Blend

Tall Fescue
Control
Study

Fine
Fescue
Management
Study

Sod
Re-establishment

B.G. Weed Control Study
Buffalograss Management Study
Texoka

Kentucky
Bluegrass
Compaction

Common

Sharps

Perennial
Ryegrass
Cultivar
Evaluations

Study

Non-Irrigated j

Irrigated

Tall FescueKentucky
Bluegrass
Seed Mixtures

Kentucky1Bluegrass
Management Study
Non-Irrigated J

Irrigated

Perennial Ryegrass
Management Study

Fine
Fescue
Cultivai
Trials I
I

Baron
I___
Aeration

Stijudy__

Park
Bentgrass
Cultivar
Study

Creeping
Bentgrass

Tall Fescue
Regional Trials
Enmundi

Emerald

Penneagle

Penncross

Fungicide
Trials

Fall
Topdressing
Study

Emerald

Penneagle

Penncross

Iron
Nitrogen
Study

Pythium
Control
Study

Fall
Topdressing
Study

Controlled Release
Nitrogen
Fertilization
Study

Growth
Retardant
Study

I

Park
Griowth Retardan

I

Iron
Nitrogen
Study

Timing Study

N
Building

4

Regional Kentucky
Bluegrass Study
"Low Maintenance”

I
I

Total Area

Map of Field Research Area
Established in the Fall of 1981

<r

ID
ID

c

CO

in

Sujpijng 90 ueu9 )u;e|/\|

5

1

39,215 ft
0.90 Acres

New Field Research Areas

->
A

CM

Total Area = 2.7 acres

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3«

The 1984 Results o f High- and
Low-Maintenance Kentucky
Bluegrass Regional Cultivar Trials
N. E. Christians

In 1980, the United States Department of Agriculture (USDA) initiated a
regional Kentucky bluegrass cultivar trial which is presently being conducted
at most of the northern agricultural experiment stations. The test consists
of 84 cultivars, with each cultivar replicated three times.
Two separate trials are underway at Iowa State University. One is a
high-maintenance study which receives 4 lb N/1000 ft^/yr and is irrigated as
needed, and the other is a low-maintenance study that receives 1 lb N/1000 ft^
in September and is not irrigated. The objective of the high-maintenance
study is to investigate the performance of the 84 cultivars under a cultural
regime similar to that used on home lawns in Iowa. The objective of the low
maintenance study is to observe the performance of the 84 cultivars under
conditions similar to those which would be used in a park, school yard, or
other low-maintenance area. The low-maintenance study was established in
September 1980 and the high-maintenance study in August 1981.
Majestic was the highest rated Kentucky bluegrass cultivar in 1984 in the
high-maintenance trial (Table 1). Majestic was also the top rated cultivar in
1983.
Other high rated cultivars in 1984 included Merit, Midnight,
Bonnieblue, and Ram-I.
The highest rated cultivars in the low-maintenance trials were K3-162, S21, South Dakota Common, Kenblue, and Vantage (Table 2). Note that these
cultivars were among the poorest in the high-maintenance trial. It should
also be noted that Majestic ranked 67th in the low-maintenance trial, Merit
ranked 52nd, and Midnight ranked 30th. Only Ram-I had a fairly high ranking
in both high- and low-maintenance trials.
The choice of cultivars clearly depends on the type of care the area is
likely to receive after establishment, and proposed use should be carefully
considered before cultivars are selected.

7

Table 1.

The 1984 quality ratings for the high-maintenance regional Kentucky
bluegrass test established in fall 1981.

Cultivar

Apr

May

June

July

Aug

Sept

Oct

Mean

1. Majestic
2. Merit
3. Midnight
4. Bonnieblue
5. Ram-I
6. N535
7. Bristol
8. Eclipse
9. Glade
10. PSU-150
11. Mer pp 300
12. Nassau
13. Baron
14. Enmundi
15. BA-61-91
16. Adelphi
17. Victa
18. Fylking
19. CEB VB 3965
20. 239
21. SV-01617
22. Aspen
23. MLM-8011
24. Sydsport
25. Barblue
26. Nugget
27. Kimono
28. Admiral
29. Escort
30. K3-179
31. Birka
32. Cheri
33. PSU-1733
34. Parade
35. Bono
36. Mosa
37. Columbia
38. Argyle
39. Shasta
40. K3-178
41. Trenton
42. Rugby

6.7
6.0
5.0
7.3
5.3
6.3
6.3
6.7
5.0
6.3
5.7
6.0
5.0
5.7
5.3
6.3
5.3
6.0
5.3
6.0
5.0
6.0
5.3
6.7
5.7
5.3
4.7
6.0
5.3
6.7
5.3
6.0
6.3
5.7
5.3
5.0
5.7
6.7
6.0
6.3
5.7
6.0

8.3
7.0
6.0
6.3
6.7
8.3
7.0
7.0
6.0
7.7
7.3
6.3
6.3
7.3
6.7
7.3
6.7
5.3
7.0
6.3
5.7
7.3
8.3
5.3
7.7
5.7
6.3
6.0
6.0
5.7
5.7
6.0
6.7
5.7
5.3
6.0
5.7
4.7
6.3
6.0
6.3
6.7

7.7
7.7
8.0
7.7
6.7
7.3
7.3
7.0
7.0
7.0
6.7
6.0
7.0
6.7
7.7
7.0
7.7
7.0
7.0
5.7
6.3
6.7
7.3
6.3
6.7
7.3
7.0
6.3
7.0
6.7
6.7
6.0
6.3
6.0
6.7
7.0
6.3
6.3
6.0
5.7
6.0
5.7

7.3
7.3
7.7
6.7
7.3
7.3
6.7
6.0
6.3
5.7
6.7
6.3
6.7
6.0
7.3
5.7
6.0
6.7
5.7
6.0
6.7
6.3
5.7
6.0
5.7
6.0
6.0
5.7
6.0
6.0
6.0
5.7
5.7
5.7
5.0
6.7
5.7
5.3
5.7
6.0
5.3
5.0

7.3
7.3
7.7
7.0
7.7
6.3
6.7
7.7
6.7
7.3
6.7
6.7
7.3
7.0
6.3
6.3
6.3
6.3
7.3
6.7
7.0
6.3
6.0
7.3
6.3
7.0
7.0
6.7
6.7
6.3
6.7
7.0
6.0
7.3
6.0
6.3
6.3
7.0
6.0
5.7
6.3
6.0

7.3
7.0
8.3
7.3
8.3
6.0
7.3
7.0
8.3
7.0
7.0
7.3
7.3
7.0
6.7
5.7
6.3
7.0
5.7
7.3
7.3
5.7
6.0
6.3
6.3
6.0
5.7
6.7
6.3
6.0
6.0
5.7
5.0
6.7
8.0
5.7
6.0
6.7
5.7
6.0
6.0
5.7

7.0
8.7
8.3
8.3
8.0
7.3
8.0 •
7.3
8.7
7.3
8.3
8.7
8.0
7.0
7.0
8.0
7.7
7.0
7.3
7.0
6.7
6.7
6.3
6.7
6.7
6.7
7.3
6.7
6.7
7.0
7.3
7.0
7.7
6.3
7.0
6.7
7.7
6.3
7.0
7.3
6.7
6.7

7.4
7.3
7.3
7.2
7.1
7.0
7.0
7.0
6.9
6.9
6.9
6.8
6.8
6.7
6.7
6.6
6.6
6.5
6.5
6.4
6.4
6.4
6.4
6.4
6.4
6.3
6.3
6.3
6.3
6.3
6.2
6.2
6.2
6.2
6.2
6.2
6.2
6.1
6.1
6.1
6.0
6.0

(Continued on next page)

8

Table 1.

(Continued)

Cultivar

Apr

May

June

July

Aug

Sept

Oct

Mean

Banff
Dormie
Geranimo
WW Ag 478
Charlotte
Apart
Mer pp 43
Mystic
Kl-152
Holiday
Touchdown
Vanessa
Piedmont
A-34
Mona
PSU-190
Welcome
WW ag 480
A 20
SH-2
Merion
Bayside
225
Monopoly
Plush
WW Ag 463
Harmony
Vantage
Enable
NJ 735
Wabash
S-21
A 20-Ga
K3-162
A 20-6
H-7
1-13
S D Common
Cello
Lovegreen
American
Kenblue

5.7
6.7
6.0
4.3
5.3
5.7
6.3
6.3
6.7
4.3
5.0
5.7
7.7
7.3
5.3
6.0
5.0
5.7
5.0
5.7
5.7
6.3
5.3
5.7
4.3
5.0
4.3
7.3
5.3
6.0
8.0
7.0
5.7
8.0
5.3
5.3
5.3
6.3
5.3
5.0
4.3
6.7

6.7
7.0
5.7
6.0
5.7
5.3
5.0
5.7
6.0
6.7
6.0
6.0
5.0
5.3
6.3
5.0
5.7
5.3
7.0
6.3
5.7
5.3
5.7
5.3
5.7
6.0
5.3
4.7
5.7
5.7
5.7
4.7
6.3
4.3
6.7
6.0
5.7
4.3
5.7
5.7
5.7
4.3

6.0
7.0
6.7
7.0
6.0
6.3
6.3
6.3
6.0
6.3
5.3
6.7
5.3
6.7
5.7
5.3
5.7
6.3
7.0
6.3
5.7
5.7
5.7
5.3
6.3
5.3
6.7
6.0
5.7
5.7
5.3
5.0
6.0
5.0
6.3
6.0
6.0
4.3
5.3
6.3
5.3
4.3

5.3
6.0
6.0
6.3
6.0
5.7
5.0
6.0
5.3
6.3
5.3
5.3
5.0
5.0
5.3
6.0
5.7
5.0
5.3
5.3
5.7
5.7
5.7
5.3
6.0
5.3
5.3
4.7
5.3
5.0
5.0
4.0
5.0
4.0
4.7
5.0
5.0
4.0
5.0
4.7
5.0
3.7

6.3
6.0
6.3
6.0
5.7
6.3
6.3
6.7
5.7
6.3
6.7
6.3
6.3
5.7
6.7
6.0
5.7
7.0
5.3
5.7
6.3
6.0
5.3
6.0
7.0
6.3
6.7
5.7
6.0
6.7
5.0
6.0
5.3
4.7
5.7
5.0
4.7
5.7
5.3
5.3
4.3
5.3

5.3
4.3
5.3
6.0
7.3
6.0
5.3
5.0
5.3
5.3
6.7
5.7
5.3
5.0
5.3
6.3
6.0
5.0
4.3
4.3
5.3
5.7
5.3
4.7
4.3
5.7
5.0
5.0
5.7
5.0
4.3
5.3
4.7
6.3
4.3
4.0
4.3
6.0
4.0
4.3
5.0
5.3

6.3
5.3
6.0
6.7
6.0
6.3
7.3
6.3
6.7
6.0
6.3
5.7
6.7
6.3
6.7
6.0
6.7
6.3
6.7
6.7
6.0
6.0
7.3
7.7
6.0
6.3
6.7
6.7
6.3
6.0
6.0
7.3
6.3
6.7
5.7
5.7
6.3
6.3
5.7
5.3
6.3
5.3

6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
5.9
5.9
5.9
5.9
5.9
5.9
5.8
5.8
5.8
5.8
5.8
5.8
5.8
5.8
5.7
5.7
5.7
5.7
5.7
5.7
5.7
5.6
5.6
5.6
5.6
5.5
5.3
5.3
5.3
5.2
5.2
5.1
5.0

LSD

1.3

1.3

1.2

1.2

1.4

1.5

1.6

0.7

43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.

0.05

9

Table 2.

The 1984 quality ratings for the low-maintenance regional Kentucky
bluegrass test established in the fall of 1980.

Cultivar

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.

K3-162
S-21
S D Common
Kenblue
Vantage
Argyle
Monopoly
Ram-I
Fylking
Piedmont
Mosa
Wabash
PSU-190
N535
PSU-173
Parade
Touchdown
Vanessa
Mer pp 300
Kimono
Baron
Enmundi
WW Ag 463
K3-178
Plush
MLM-18011
CEB VB 3965
Aspen
WW Ag 478
Midnight
BA-61-91
Trenton
Charlotte
SU-01617
Geronimo
Welcome
Harmony
A-34
Eclipse
K3-179
Barblue
Birka

Apr

May

June

July

Aug

Sept

Oct

Mean

7.7
6.7
6.7
6.7
7.0
7.0
4.7
5.0
5.3
6.7
4.7
5.7
4.0
5.3
4.7
4.7
5.0
4.3
5.0
3.7
3.7
5.0
4.3
4.7
4.0
5.0
4.3
4.7
5.0
4.7
5.0
4.0
5.0
4.3
4.3
4.3
4.3
4.7
4.7
5.3
5.3
4.7

7.0
7.0
6.0
5.3
6.7
6.0
4.7
4.7
5.3
5.7
4.7
6.3
4.0
5.7
4.3
5.0
4.7
4.7
4.7
4.0
4.3
4.3
4.3
5.0
4.0
4.3
3.7
4.3
3.7
4.7
5.3
4.7
4.7
4.7
5.3
4.3
4.0
5.7
4.0
5.0
3.7
5.0

4.7
5.0
4.3
4.7
4.3
4.3
5.7
6.3
6.0
4.3
5.0
5.0
5.0
5.7
5.0
4.3
5.0
5.0
5.7
5.3
5.7
6.0
5.0
5.3
5.7
5.3
5.0
6.0
6.0
5.3
5.3
5.3
4.7
5.7
5.0
5.3
4.7
4.3
4.7
5.0
5.0
6.0

6.7
6.7
6.7
6.0
5.7
5.7
5.3
5.0
5.3
5.0
5.0
4.7
5.0
5.3
5.7
5.3
5.0
5.0
5.3
4.7
5.3
5.3
5.7
4.7
4.7
5.3
5.3
5.3
5.3
5.0
5.3
5.3
4.7
5.0
5.0
5.0
5.3
4.7
5.3
5.3
5.3
5.0

5.0
4.3
4.3
5.3
5.0
4.7
5.3
4.7
4.3
4.0
5.3
3.3
5.0
4.7
4.3
4.7
4.3
5.0
4.3
5.0
4.3
4.3
5.0
4.7
5.0
4.0
4.3
4.0
4.3
4.7
3.7
4.3
3.7
3.3
3.7
4.0
3.7
3-3
4.3
3.7
3.3
3.3

4.7
5.0
5.3
5.0
4.7
4.7
4.7
5.3
4.3
4.0
4.3
3.3
4.3
3.0
3.7
3.7
3.3
3.7
3.7
4.7
4.0
3.0
3.0
3.7
4.3
3.7
4.0
3.7
3.0
3.0
3.0
3.3
3.7
3.3
3.0
3.7
3.3
3.3
3.3
2.7
3.3
3.0

6.3
6.3
6.3
6.3
5.7
5.3
5.0
5.3
4.7
5.0
5.3
5.0
6.0
3.7
5.0
5.3
5.3
5.3
4.3
4.7
5.0
4.3
4.7
4.3
4.0
4.0
4.7
3.7
4.3
4.3
3.7
3.7
4.3
3.7
4.0
3.7
4.7
4.3
4.0
3.3
4.3
2.7

6.0
5.9
5.7
5.6
5.6
5.4
5.0
5.0
5.0
5.0
4.9
4.8
4.8
4.8
4.7
4.7
4.7
4.7
4.7
4.6
4.6
4.6
4.6
4.6
4.5
4.5
4.5
4.5
4.5
4.5
4.5
4.4
4.4
4.3
4.3
4.3
4.3
4.3
4.3
4.3
4.3
4.2

(Continued on next page)

10

Table 2.

(Continued)

Cultivar

Apr

May

June

July

Aug

Sept

Oct

Mean

43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.

239
PSU-150
Banff
Dormie
Merion
Kl-152
Adelphi
Glade
Cheri
Merit
Sydsport
Bayside
Mystic
Aspen
WW Ag 480
Bonnieblue
Shasta
Apart
Mer pp 43
Enable
225
Admiral
Escort
Rugby
Majestic
H-7
Victa
Holiday
Cello
Nugget
A20-6
American
1-13
Columbia
NJ 735
Nassau
A20
A20-6A
Mona
Lovegreen
Bristol
SH-2

5.3
4.3
4.3
5.0
5.0
5.0
4.3
4.3
4.0
4.3
4.3
4.7
4.7
4.0
4.7
4.3
4.0
4.7
4.0
3.5
5.3
4.7
4.3
4.3
4.0
4.0
3.7
3.7
4.0
4.0
3.7
3.0
4.0
3.7
3.7
3.3
3.7
4.0
3.7
3.3
3.3
4.0

4.7
4.7
4.0
4.7
4.3
4.3
4.3
4.7
4.3
4.7
4.0
5.3
4.0
4.0
4.0
4.0
4.3
4.3
3.7
3.3
4.7
4.0
4.0
4.3
4.3
3.7
3.7
3.7
3.7
3.3
3.3
2.5
3.7
3.7
3.0
3.7
3.3
3.7
3.0
3.0
3.0
3.3

5.0
5.7
5.0
4.7
4.7
5.0
4.7
5.3
4.7
3.7
5.0
5.0
4.7
5.7
4.0
4.3
4.7
4.3
4.7
4.8
4.3
5.3
5.3
4.7
4.3
4.0
3.7
5.7
5.0
4.7
4.7
4.0
4.0
4.3
3.7
4.3
3.7
4.0
3.7
4.0
4.3
4.0

4.7
5.0
4.7
4.7
4.7
4.3
4.7
5.3
4.7
4.7
4.3
4.3
4.3
4.3
4.0
4.3
4.7
4.7
5.0
4.0
5.0
4.7
5.0
4.7
4.7
4.3
4.0
4.7
4.7
5.0
4.0
4.5
4.7
4.0
4.0
4.3
4.3
4.0
4.0
4.0
3.7
4.0

3.3
3.3
4.0
4.0
3.7
4.0
4.0
3.3
3-3
4.0
3.7
2.7
3.7
4.0
3.7
3.3
3.7
3.0
3.7
4.0
3.3
3.7
3.7
3.7
3.3
3.3
4.0
3.3
3.3
3.3
3.7
3-5
3.3
3.7
4.0
3.0
2.7
3.0
3.7
3.3
3.7
3.0

2.7
3.7
3.0
3.0
3.0
3.3
3.0
2.7
3.3
4.0
3.0
3.3
3-3
2.7
3.3
3.3
2.7
2.7
3.3
3.5
2.7
3.0
2.7
2.7
3.0
3.0
4.3
2.3
2.7
2.3
3.7
3.5
2.3
3.0
2.7
2.7
3.3
2.0
2.3
2.7
2.7
2.3

3.7
3.0
4.3
3.7
4.0
3.3
3.7
3.0
4.3
3.7
4.3
3.3
4.0
3.7
4.3
4.3
3.7
4.7
3.7
5.0
3.0
3.0
3.3
3.0
3.3
4.7
4.0
3.0
3.3
3.0
3.0
4.0
3.0
3.0
4.0
3.0
3.3
3.0
3.3
3.7
3.3
3.0

4.2
4.2
4.2
4.2
4.2
4.2
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
3.9
3.9
3.9
3.9
3.8
3.8
3.7
3.7
3.6
3.6
3.6
3.6
3.5
3.5
3.4
3.4
3.4
3.4
3.4

LSD

1.7

1.6

1.6

1.4

1.4

1.4

1.6

1.0

0.05

11

Kentucky Bluegrass
Cultivar Evaluations
N. E. Christians

The 49 Kentucky bluegrass cultivars located in section two of the
turf grass research area were seeded in the fall of 1979. These plots were
fertilized at a rate of 4 lb N/1000 ft2 (urea) in both the 1980 and 1981
seasons and with 4 lb N/1000 ft2 (SCU) in 1982, 1983, and 1984. No
insecticides or fungicides have been used on the area. Irrigation was applied
as needed to prevent drought. The results of the 1984 evaluations are listed
in Table 3.
The values listed under each month are the averages of ratings made on
three replicated plots. Yearly means of all the months in which data were
taken are listed in the last column. The first cultivar received the highest
average rating for the entire 1984 season. The cultivars are then listed in
descending order of average quality.
Midnight received the highest overall rating in 1984. It was followed in
order by Ram-I, Aspen, K3-160, Cheri, and Glade. The lowest rated cultivars
in this trial included (WTN) H-7 and A-34. It is surprising that A-34 ranks
so low in this trial. This cultivar has proved to be very well adapted to
many parts of the midwest. It is important that local testing results be used
in making decisions on which cultivars to use.

12

Table 3.

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.

The 1984 quality ratings for the Kentucky bluegrass
established in the fall of 1979.

cultivars

Cultivar

May

June

Quality Ratings
Sept
Aug
July

Oct

Mean

Midnight
Ram I
Aspen
K3-160
Cheri
Glade
Fanfare
Vantage
Bristol
Adelphi
Arista
Victa
Bonnieblue
suo
P-164
America
Baron
Enmund
Aquilla
Merion
Kimono
Escort
Sydsport
Senic
Touchdown
Sving
Nugget
N-535
Fylking
Merit
Columbia
Plush
Barbie
Common
Park
Pennstar
A-20-6
A-20
Birka
Rugby
Parade
BFB-35
Wabash
Majestic
Trenton
(WTN) IS-13
K76-86-4
A-34
(WTN) H-7

7.7
6.7
6.7
6.7
6.7
7.0
7.0
5.7
6.7
7.0
6.7
6.3
6.3
7.3
7.0
8.0
6.3
7.0
6.0
5.7
6.3
6.7
6.0
6.3
6.0
6.7
7.7
6.0
5.7
5.7
6.3
7.0
5.7
5.7
5.7
6.7
7.3
7.0
6.3
6.3
5.7
6.7
5.3
5.7
5.7
6.3
5.3
6.0
6.0

9.0
7.3
7.3
8.3
7.0
8.3
8.3
7.7
7.0
8.3
7.7
7.3
6.7
7.7
7.3
6.3
8.3
7.7
8.0
7.3
7.0
7.7
7.3
7.0
7.0
7.0
7.3
7.3
7.0
8.0
5.3
6.7
7.0
7.0
6.3
6.0
7.0
6.7
6.3
6.3
6.0
6.3
6.7
6.0
5.3
6.7
5.3
6.7
6.7

9.0
7.7
7.7
7.3
6.7
7.3
6.0
8.0
6.7
6.7
6.0
6.3
7.3
7.0
7.3
6.0
6.0
6.0
6.0
6.7
6.3
6.0
7.3
7.0
7.0
6.3
6.3
7.0
6.3
6.3
6.3
6.3
6.0
6.3
6.3
7.0
5.3
5.3
5.7
5.7
5.7
5.0
5.7
6.3
5.7
5.3
5.7
5.3
5.0

8.0
7.0
6.3
6.0
7.3
6.7
6.0
7.7
7.0
6.3
6.7
7.0
7.0
6.3
6.7
7.0
6.7
7.3
6.7
6.7
7.0
7.3
6.3
7.0
6.3
6.3
6.0
6.7
6.7
6.3
6.7
5.7
6.3
6.7
6.3
6.0
5.0
5.0
6.0
5.7
5.7
5.3
5.0
6.0
5.3
5.3
6.0
5.3
5.0

9.0
8.3
8.0
7.3
8.3
6.7
8.3
7.0
7.3
7.3
7.7
7.7
7.7
7.3
6.7
7.0
7.3
6.7
8.0
7.7
7.0
6.0
6.7
6.0
6.7
7.3
6.0
6.7
7.7
7.3
7.7
6.7
7.0
5.7
6.0
6.3
6.7
6.7
6.0
6.3
6.7
6.3
7.3
6.0
7.0
5.3
6.7
6.3
5.0

8.0
8.3
8.0
8.0
8.0
7.7
7.7
7.0
8.3
7.3
7.7
7.7
7.7
7.0
7.0
7.3
6.7
7.0
6.7
7.0
7.0
7.3
6.3
7.0
7.0
6.3
7.0
6.3
7.0
6.3
7.0
7.0
6.3
6.7
7.3
6.0
6.7
6.7
7.0
6.7
7.0
6.7
6.3
6.0
6.3
6.7
6.3
6.0
6.3

8.4
7.6
7.3
7.3
7.3
7.3
7.2
7.2
7.2
7.2
7.1
7.1
7.1
7.1
7.0
6.9
6.9
6.9
6.9
6.8
6.8
6.8
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.6
6.6
6.4
6.3
6.3
6.3
6.3
6.2
6.2
6.2
6.1
6.1
6.1
6.0
5.9
5.9
5.9
5.9
5.7

LSD

1.1

1.4

1.4

1.3

1.6

1.5

0.7

0.05

13

Regional Perennial Ryegrass
Cultivar Evaluation
K. L. Diesburg and N. E. Christians

This trial is part of a national study coordinated by the USDA.
It was
established during September 1982, in conjunction with several identical
trials across the country. The purpose is to identify regional adaptation of
the 48 cultivars tested. Cultivars are evaluated each month of the growing
season for turf quality and disease infestation.
The average yearly
performance of a cultivar is most important.
The trial is maintained with 4 lb N/1000 ft2 through the growing season
and is irrigated as needed. Standard, single applications of preemergence
herbicide in May and broadleaf herbicide in September are used to prevent
weeds. The entire area is maintained at a 2-inch mowing height.
Differences in turf quality among cultivars were least in April (Table
4). By June, the greatest differentiation a.,long cultivars had occurred. The
only cultivars superior over the whole season were Manhattan II, M382, Repelí,
and BT-I.

Table 4.

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
1314.
15.
16.
17.
18.
19.

Turf quality3 and disease ratings of perennial ryegrass cultivars.

Cultivar

April

May

June

July

Aug

Sept

Oct

Nov

Mean

Manhattan II
M 382
Repelí
BT-I
SWRC-1
HR-1
Palmer
Prelude
Yorktown II
LP 702
Ranger
Fiesta
282
Gator
Blazer
Regal
Birdie
HE 178
Diplomat

6.0
5.7
6.0
5.0
5.7
5.3
6.3
6.0
6.3
6.7
6.0
7.0
5.7
6.0
6.3
5.0
6.3
4.7
5.7

8.0
6.3
7.7
7.3
6.0
6.3
6.3
6.3
6.7
7.3
6.7
5.7
7.7
7.3
6.3
5.7
6.7
6.7
5.7

9.0
9.0
8.0
8.7
7.7
7.3
8.0
7.7
7.7
7.3
7.7
7.0
7.7
7.0
7.7
7.7
7.3
8.3
7.0

8.0
8.3
6.7
7.3
6.7
7.3
6.7
7.0
6.3
6.7
5.7
7.0
6.0
6.7
5.3
7.3
6.7
6.7
5.7

8.7
7.7
8.7
8.0
8.0
7.7
8.0
8.0
7.7
7.3
7.7
8.0
7.0
7.3
7.7
7.0
8.3
8.0
7.7

7.7
8.3
7.3
6.7
7.7
8.0
6.3
6.3
6.3
6.0
6.3
6.3
7.3
6.3
6.3
7.0
5.0
5.7
6.7

9.0
9.0
8.7
9.0
8.7
8.7
8.0
8.3
8.3
7.7
8.3
8.3
8.0
8.3
7.7
8.0
8.3
7.7
7.7

6.3
6.3
5.0
5.3
5.7
5.3
5.7
5.7
5.7
5.7
6.0
5.0
5.3
5.0
5.7
5.0
4.3
4.0
5.3

7.8
7.6
7.3
7.2
7.0
7.0
6.9
6.9
6.9
6.8
6.8
6.8
6.8
6.8
6.6
6.6
6.6
6.5
6.4

(Continued on next page)
14

Table 4.

20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.

(Continued)

Cultivar

April

May

June

July

Aug

Sept

Oct

Nov

Mean

Acclaim
Omega
Derby
IA 728
Manhattan
Barry
HE 168
Dasher
Pennfine
LP 736
WWE 19
Cockade
NK 80389
Pennant
Elka
LP 792
Cigil
2 EE
Citation
Premier
2 ED
NK 79309
NK 79307
Crown
LP 210
Delray
Cupido
Pippin
Linn

5.0
5.3
5.3
4.0
6.7
5.7
6.3
5.7
4.3
5.0
7.0
5.3
4.7
5.0
4.3
4.7
5.3
5.3
5.0
4.7
3.0
4.3
2.7
4.7
5.7
3.3
6.0
5.7
2.3

5.3
6.7
6.0
6.7
6.7
5.3
5.3
5.3
4.3
5.0
6.3
6.7
5.3
4.7
6.3
5.3
5.3
4.7
4.3
4.3
4.0
5.3
4.0
5.0
6.7
4.0
6.0
5.0
2.0

7.3
7.3
7.3
7.3
7.3
7.7
7.7
6.7
7.3
7.7
6.7
6.7
7.7
6.7
8.0
7.0
7.3
7.0
7.3
6.7
7.7
7.0
7.7
7.3
6.3
7.7
6.3
6.3
4.0

7.3
6.0
6.0
7.0
4.3
6.0
7.0
5.3
7.3
6.3
4.7
4.7
5.0
6.0
5.3
6.0
5.3
6.3
6.3
6.0
7.0
6.0
6.7
5.7
5.3
5.7
3.3
6.0
2.7

8.0
7.3
8.0
8.3
7.0
6.7
8.0
7.3
8.7
7.0
7.7
7.0
7.3
8.0
6.7
7.7
7.3
7.3
7.0
6.3
7.3
6.3
7.3
7.0
7.3
7.7
6.3
5.3
4.3

6.0
6.3
6.7
5.3
5.7
5.7
4.0
6.3
5.7
6.0
4.3
5.3
6.0
6.0
5.0
5.0
4.7
6.7
5.3
6.3
6.3
6.3
6.7
4.7
4.0
4.7
3.3
3.3
2.7

7.3
7.3
7.7
8.0
7.7
8.0
7.0
8.0
7.7
7.3
7.0
7.3
8.3
7.7
8.3
7.7
8.0
6.7
7.7
7.7
7.7
7.3
8.0
7.3
6.7
7.7
6.3
5.3
4.0

5.0
4.7
4.3
4.3
5.0
4.3
4.3
4.7
4.3
4.7
5.0
5.7
4.3
5.0
4.7
4.3
4.3
3.7
5.3
5.7
4.0
4.7
4.3
4.3
4.3
3.3
4.7
3.3
2.0

6.4
6.4
6.4
6.4
6.3
6.2
6.2
6.2
6.2
6.1
6.1
6.1
6.1
6.1
6.1
6.0
6.0
6.0
6.0
6.0
5.9
5.9
5.9
5.8
5.8
5.5
5.3
5.0
3.0

Experiment Mean

5.3

5.8

7.3

6.1

7.4

5.9

7.7

4.8

6.3

LSD (oc= 0.05)

1.8

2.0

1.1

1.6

1.3

1.7

0.9

1.3

0.8

£

Ratings based on a scale of 1 to 9; 9i = best, 6 = acceptable, 1 :: worst
quality.

15

Perennial Ryegrass
Cultivar Evaluations
N. E. Christians

The 22 perennial ryegrass cultivars in this trial were among the first
plots to be established after the renovation of the field research area in
1979. The study has been maintained since that time at a 2-inch mowing height
and is fertilized with 4 lb N/1000 ft^/yr. The area receives no fungicide or
insecticide applications.
Yorktown, Diplomat, Regal, and Citation received the highest overall
quality ratings in 1984. However, there was little observable difference
among the first 13 cultivars listed (Table 5). NK-100 and Linn received the
lowest ratings in 1984.

Table 5.

The 1984 quality ratings for 22 perennial ryegrass cultivars
established in 1979.

Quality Ratings
May

June

July

Aug

Sept

Oct

Mean

Yorktown
Diplomat
Regal
Citation
Belle
Fiesta
Medalist North
Delray
Derby
Blyes
Loretta
Elka
Pennfine
Caravelle
Manhattan
K5-88
K5-94
Goalie
J186 R24D
NK-200
Linn
NK-100

6.3
5.7
5.7
6.3
6.0
5.3
5.0
5.0
5.0
6.3
7.3
7.3
5.3
5.7
5.3
4.3
5.0
5.3
5.0
5.0
3.3
3.7

7.0
7.0
8.0
6.3
7.7
6.3
6.7
6.7
6.7
5.0
7.3
6.0
7.0
5.7
5.0
5.7
4.3
3-7
4.3
4.7
5.3
4.0

6.7
6.3
6.3
7.3
6.3
7.7
6.7
6.7
5.7
6.3
5.3
5.3
6.0
6.0
5.3
5.7
5.3
5.7
5.0
5.0
3.3
4.0

8.0
8.0
6.3
6.3
7.3
7.0
6.3
7.3
7.7
7.0
6.3
6.3
6.7
7.0
7.0
5.7
5.7
6.0
5.7
4.3
5.3
4.3

8.3
7.3
6.7
7.7
7.0
7.7
8.0
6.7
7.3
7.7
6.3
7.3
6.0
6.0
6.0
6.3
7.0
6.7
6.3
6.0
5.3
5.7

6.7
7.0
7.7
7.0
6.7
6.0
6.3
6.7
6.7
6.3
5.7
5.3
6.3
6.0
6.0
6.7
6.7
5.7
5.0
6.0
5.0
5.0

7.2
6.9
6.8
6.8
6.8
6.7
6.5
6.5
6.5
6.4
6.4
6.3
6.2
6.1
5.8
5.7
5.7
5.5
5.2
5.2
4.6
4.4

LSD

1.4

1.9

1.7

1.6

1.6

1.7

0.9

Cultivar

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.

0.05

16

Fine Fescue Cultivar Trial
K. L. Diesburg and N. E. Christians

This trial has produced its second year of data after being established
in fall 1982. The purpose is to identify regional adaptation of the 32
cultivars and blends tested. Cultivars are evaluated each month of the
growing season for turf quality and disease infestation. The average yearly
performance of a cultivar is most important.
The trial is maintained at a 2-inch mowing height with 4 lb N/1000 ft^
through the growing season and is irrigated as needed. A standard single
application of phenoxy herbicides in September is used to prevent weeds.
Disease damaged several of the cultivars in this study in 1983 and 1984.
The symptoms observed were not typical of any of the common turfgrass
diseases. The pathogens identified in the diseased areas were Rhizoctonia
sp., Sclerotinia sp., and Collectotrichum sp. The most susceptible cultivars
were Ruby, Pennlawn, Fortress, Ensylva, Duar, Banner, and Jamestown (Table 6).
All other entries had varied degrees of disease resistance with NK79189,
NK80347, and Checker showing the least damage. Poor initial stands plus
diseases resulted in nearly complete loss of stand in some plots. The open
areas were subsequently replaced by invading bluegrass. Table 6 shows that
Tournament, Duar, Scaldis, Waldina, and NK80348 had the most bluegrass
infestation.
Experiment means in Table 7 indicate the average performance of all
cultivars. Fine fescues in central Iowa generally have lower turf quality in
August and best turf quality in October. The November data were taken after
heavy frosts. They show that NK79189, Jamestown, Banner-Checker, Shadow, and
NK80346 were able to hold their color better than the other cultivars.
The best cultivar through the growing season was Shadow followed closely
by Scaldis-Atlanta, Checker, and Barfalla. The LSD for growing season means
indicates, however, that the top 27 cultivars were not statistically different
from one another. Monthly data show that Scaldis-Atlanta excelled in early
spring, NK79189 was superior in early summer; Dawson did well in late spring
and early fall; and Jamestown was best throughout fall. Barfalla ranked high
from April through October retaining its high turf quality in the heat of mid­
summer while Shadow and Checker had lower quality during August.

17

Table 6.

Turf quality ratings3 of fine fescue cultivars and blends.
Turf Quality

Cultivar

April

May

June

July

Aug.

Sept

Oct.

Nov.

Mean15

Shadow
Cc
Checker
C
Barfalla
C
Scaldis-Atlanta
Jamestown
C
Dawson
CR
CR
NK79189
FOF-WO
S
Koket
C
CR
NK79191
NK80346
CR
Banner-Checker
Atlanta
C
CR
NK80345
Aurora
H
Ensylva
CR
Agram
C
Biljart
H
Banner
C
Fortress
CR
CR
NK80347
NK80348
CR
Dawson-Pennlawn
NK79190
CR
Waldina
H
Highlight
C
Scaldis
H
Wintergreen
C
Pennlawn
CR
Tournament
H
Ruby
CR
Duar
H

8.0
7.0
7.7
8.3
7.7
7.7
4.0
7.3
8.0
7.0
6.3
7.3
7.7
6.7
7.3
7.3
6.7
7.3
7.3
7.0
6.0
4.7
5.0
6.0
7.0
6.7
6.7
5.7
6.7
5.3
4.7
3.0

7.3
7.3
7.3
8.3
6.7
8.3
7.0
8.0
6.7
6.3
6.3
7.7
7.3
7.3
7.3
5.3
6.3
7.0
6.7
4.3
7.0
7.0
5.7
7.0
6.7
6.3
7.0
6.0
4.7
5.7
4.7
2.0

7.3
7.3
7.0
7.3
7.3
9.0
8.3
6.7
6.3
6.3
8.0
7.0
7.3
9.0
5.7
8.3
6.0
6.3
7.7
7.0
6.7
7.3
7.0
7.0
4.7
6.3
5.0
5.7
5.7
4.0
5.0
2.7

7.0
7.7
7.7
6.0
5.0
4.7
7.7
6.3
5.7
7.3
7.0
4.7
5.0
5.3
5.7
5.3
7.3
6.3
5.3
6.3
7.0
7.3
7.0
7.0
7.0
5.3
6.7
4.3
5.3
5.7
5.0
6.3

6.3
6.3
7.0
6.7
4.7
4.7
6.0
6.0
7.0
7.0
6.0
5.3
5.0
6.0
5.0
4.7
6.3
5.7
4.3
5.7
6.7
7.3
7.0
6.0
5.7
5.3
6.0
4.3
5.7
5.7
5.7
6.3

6.3
7.3
6.7
7.0
8.7
8.3
7.7
7.0
7.3
7.7
7.0
6.7
7.3
7.7
7.7
7.0
7.7
7.3
6.7
7.7
6.7
6.3
5.7
6.0
5.3
6.0
5.7
6.7
6.0
3.7
4.3
3.0

8.3
8.0
7.3
7.3
8.7
8.7
8.3
6.7
7.7
7.3
7.3
8.3
8.0
7.3
8.0
8.7
7.7
7.3
8.3
8.0
6.7
7.0
7.7
7.7
6.0
7.7
6.0
8.0
7.0
5.0
5.7
3.3

5.7
4.7
5.0
4.7
6.3
4.0
6.3
5.3
5.0
4.7
5.7
6.3
5.3
3.3
5.0
5.0
4.3
4.7
5.3
5.0
4.0
3.3
5.3
2.7
4.7
3.3
3.7
4.7
4.7
2.0
2.0
1.3

7.0
7.0
7.0
7.0
6.9
6.9
6.9
6.7
6.7
6.7
6.7
6.7
6.6
6.6
6.5
6.5
6.5
6.5
6.5
6.4
6.3
6.3
6.3
6.2
5.9
5.9
5.8
5.7
5.7
4.6
4.6
3.5

Experiment Mean

6.6

6.5

6.6

6.2

5.9

6.6

7.3

4.5

6.3

LSD

1.8

1.7

1.8

3.2

2.5

2.5

2.4

2.1

1.3

a
b

(<<= 0.05)

Quality rated on a scale of 1 - 9; 9 = best quality and 1 = poorest
quality.
Average of monthly quality ratings.
Chewings (C), creeping red (CR), sheep (S), or hard (H) fescue.

18

Table 7.

Disease ratings3 and percent of plot area invaded by Kentucky
bluegrass in fine fescue cultivars and blends.

Disease*5

Bluegrass

May

June

Mean

Percent

8.0
8.3
7.7
8.7
7.3
8.0
9.0
9.0
8.3
6.0
7.0
7.7
8.0
8.7
8.3
6.3
7.3
8.3
6.7
5.3
8.3
8.0
6.0
7.3
8.3
7.7
8.7
9.0
*».3
7.7
4.0
5.3

6.7
7.7
7.3
6.7
5.0
5.3
7.3
6.3
6.7
7.0
6.0
5.0
5.0
6.0
6.3
5.3
7.0
7.3
5.3
6.0
7.7
7.0
7.7
7.0
7.3
5.3
7.0
4.0
5.0
7.3
5.3
6.7

7.3
8.0
7.5
7.7
6.2
6.7
8.2
7.7
7.5
6.5
6.5
6.3
6.5
7.3
7.3
5.8
7.2
7.8
6.0
5.7
8.0
7.5
6.8
7.2
7.8
6.5
7.8
6.5
4.7
7.5
4.7
6.0

0
0
0
0
0
0
3
20
0
7
7
0
0
3
17
0
0
13
0
0
17
27
0
13
33
0
40
0
0
53
0
40

Experiment Mean

7.5

6.3

6.9

9

LSD

1.4

3.2

1.8

29

Cultivar

Shadow
Checker
Barfalla
Scaldis-Atlanta
Jamestown
Dawson
NK79189
FOF-WC
Koket
NK79191
NK80346
Banner-Checker
Atlanta
NK80345
Aurora
Ensylva
Agram
Biljart
Banner
Fortress
NK80347
NK80348
Dawson-Pennlawn
NK79190
Waldina
Highlight
Scaldis
Wintergreen
Pennlawn
Tournament
Ruby
Duar

k

(0<= 0.05)

Cc
C
C
C
CR
CR
S
C
CR
CR
C
CR
H
CR
C
H
C
CR
CR
CR
CR
H
C
H
C
CR
H
CR
H

Disease rated on a scale of 1 - 9; 9 = no disease and 1 = most disease.
Symptoms due to a combination of Rhizoctonia sp., Sclerotinia sp., and
Collectotrichum sp.
Chewings (C), creeping red (CR), sheep (S), or hard (H) fescue.

19

Fine Fescue Management Study
N. E. Christians

The fine fescue management study includes the following cultivars:
1.

Pennlawn Red Fescue

6.

Dawson Red Fescue

2.

Scaldis Hard Fescue

7.

Reliant Hard Fescue

3.

Ruby Red Fescue

8.

Ensylva Red Fescue

4.

Atlanta Chewings Fescue

9.

Highlight Chewings Fescue

5.

K5-29 Red Fescue

10.

Jamestown Chewings Fescue

Each cultivar is maintained at two mowing heights: 1 and 2 inches. Each
plot is also divided into two fertilizer treatments: 1 and 3 lb N/1000 ft^,
applied as IBDU. The study was established on September 8, 1979, and is
irrigated as needed.
The quality ratings in Table 8 are the means of monthly observations
taken from May to October averaged over both mowing heights. Cultivar plots
treated with 3 lb N/1000 ft^/yr were observed to have higher quality ratings
than those receiving 1 lb N/1000 ft^/yr for each of the grasses at both the 1and 2-inch mowing heights.
Reliant, Dawson, Atlanta, and Scaldis were the best cultivars at all
nitrogen levels and mowing heights. Atlanta performed best at 3 lb N/1000
ft^/yr at the 2-inch mowing height and Reliant was the best cultivar at the 1inch mowing height.

20

Table 8.

The effects of mowing height and nitrogen fertilizer on the quality
of 10 fine fescues.

Mowing Height
2 inch
1 inch
N Rate
N Rate
1 lb
3 lb
Fib3
3 lb

Overall
Mean

1.

Pennlawn Red Fescue

4.2b

5.3

4.7

5.8

5.0

2.

Scaldis Hard Fescue

5.4

6.8

5.3

6.6

6.0

3.

Ruby Red Fescue

3.1

4.3

3.9

5.1

4.1

4.

Atlanta Chewings Fescue

5.2

7.2

5.5

7.6

6.4

5.

K5-29 Red Fescue

3.2

4.3

3.8

5.0

4.1

6.

Dawson Red Fescue

5.6

7.0

5.9

7.3

6.5

7.

Reliant Hard Fescue

5.8

7.7

5.8

7.4

6.7

8.

Ensylva Red Fescue

4.3

5.6

4.8

6.4

5.3

9.

Highlight Chewings Fescue

3.8

4.2

4.3

4.6

4.2

10.

Jamestown Chewings Fescue

5.0

6.6

5.2

6.6

5.8

^

N rates are in lb N/1000 ft^/yr. The N source is IBDU.
Values are the means of monthly observations from May to October.

21

Tall Fescue Management Study
K. L. Diesburg and N. E. Christians

This study includes Kentucky 31 and four improved cultivars of tall
fescue; Falcon, Houndog, Mustang, and Rebel. It was seeded in September 1982,
but late spring freezing in 1983 delayed establishment. The first year in
which all managements could be done was 1984. Each cultivar is maintained at
2- and 3-inch mowing heights and is fertilized with urea at 0, 2, and 4 lb
N/1000 ft2/year.
Each of the improved cultivars had better turf quality than Kentucky 31.
Rebel and Mustang produced the highest quality turf followed closely by Falcon
and Houndog. Rebel excelled in the cooler temperatures of spring and fall
while Mustang performed best in the heat of summer (Table 9).
All cultivars produced higher quality turf at the 2-inch clipping height.
Performance levels of Falcon and Houndog were closer to Rebel and Mustang at
the 2-inch rather than at the 3-inch clipping height. Kentucky 31 had poor
turf quality throughout the growing season, but its ratings did not drop as
much as those of the improved cultivars going from the 2-inch to 3-inch
clipping height.
Each increment of applied N caused an improvement in turf quality for all
cultivars (Table 10). Greater improvement was shown from 0 to 2 than from 2
to 4 lb N/1000 ft2 . As the fertility level increased, the improvement of turf
quality going from the 3-inch to 2-inch clipping height was more apparent.
This interaction was most apparent during April, July, and September.
Improvement of turf quality at higher fertility levels for all cultivars
was due primarily to better color resulting from higher chlorophyll content
and less yellowing from disease. The improved cultivars also responded very
well to the 2-inch clipping height showing finer leaf texture and higher leaf
density. Kentucky 31 responded with finer leaves, but leaf density decreased
with a net small improvement of turf quality.
A 3 to 3 1/2-inch clipping height is traditionally recommended for
Kentucky 31 tall fescue turf. This cultivar was released in 1943 for forage
and land reclamation purposes. It is not as well adapted for turf as are the
new improved cultivars. The initial response of all perennial grasses to
lower clipping height is more diminutive growth giving a finer texture. Only
those adapted to the stress of close clipping will persist over many years.
Data from coming years will allow assessment of the persistence level of each
cultivar given these management treatments.

22

Table 9.

Means of turf quality ratings3 for tall fescue cultivars at two
clipping heights over all fertility levels.

_____________________ Ratings_____________________

Cultivar

Clipping
Height
(inches)

April

May

June

July

Aug

Sept

Oct

Nov

Mean

Rebel

2
3

5.2
3.9

5.8
4.9

6.2
6.0

5.3
4.4

5.8
4.9

5.3
4.7

5.3
4.4

3.3
2.6

5.3
4.5

Mustang

2
3

4.9
3.7

5.9
4.8

5.8
6.0

5.4
4.7

6.2
4.6

5.1
4.7

5.1
4.2

2.9
2.2

5.2
4.3

Falcon

2
3

5.0
3.4

5.9
4.8

6.4
6.0

5.6
4.4

5.4
4.6

5.1
4.4

5.1
4.4

2.6
1.9

5.1
4.2

Houndog

2
3

5.2
3.4

5.7
4.4

6.0
5.9

4.9
4.3

5.9
4.4

5.6
4.7

5.0
4.0

2.9
2.3

5.2
4.2

Kentucky 31

2
3

4.4
3.2

4.3
4.0

5.0
4.8

4.0
3.4

5.0
4.8

4.9
3.7

4.3
3.7

2.2
1.9

4.3
3.7

4.2
0.5

5.0
0.6

5.8
0.5

4.7
0.5

5.2
0.5

4.8
0.3

4.6
0.6

2.5
0.5

4.6
0.3

Experiment Mean
LSD (o(= 0.05)
£

Ratings based on a scale of 1 - 9; 9 = best, 5 = acceptable , 1 = worst
quality turf.

23

Table 10.

Season means of turf quality ratings for tall fescue cultivars at
two clipping heights and three fertility levels.

Applied N (lb/1000 ft2)
Clipping
Heights
(inches)

0

2

4

Mean

Rebel

2
3

3.7
3.2

5.5
4.7

6.7
5.5

5.3
4.5

Mustang

2
3

3.8
3.2

5.4
4.5

6.4
5.3

5.2
4.3

Falcon

2
3

3.6
3.0

5.4
4.4

6.4
5.3

5.1
4.2

Houndog

2
3

3.7
2.9

5.5
4.5

6.2
5.2

5.2
4.2

Kentucky 31

2
3

3.0
2.5

4.5
3.9

5.4
4.7

4.3
3.7

3.2

4.8

5.7

4.6

Cultivars

Cultivar
Mean

4.9

4.8

4.7

4.7

4.0
Experiment Mean

LSD
LSD

(6(= 0.05) between cultivars
(ot^= 0.05) between clipping

0.6

0.3

heights
(oC= 0.05) between fertility
levels

0.7

0.4

LSD

0.6

24

0.2

Bentgrass Management Study
N. E. Christians

The bentgrass management study was established in the fall of 1980.
includes the following species and cultivars:

It

Cultivar

Species
1.

Agrostis stolonifera Creeping Bentgrass

Emerald

2.

Agrostis canina Velvet Bentgrass

Kingstown

3.

Agrostis stolonifera Creeping Bentgrass

Penncross

4.

Agrostis stolonifera Creeping Bentgrass

Penneagle

5.

Agrostis stolonifera Creeping Bentgrass

Prominent

6.

Agrostis stolonifera Creeping Bentgrass

Seaside

Each cultivar planting is split into three fertility levels: 0.5, 0.8,
and 1.2 lb N/1000 ft'Vgrowing month. This results in a total N application
rate of 3.5, 5.6, and 8.4 lb N/1000 ft^/year. The area was managed as a golf
course green, with a 3/32-inch mowing height and with applications of
insecticides and fungicides as needed. Each cultivar is replicated four
times.
The spring of 1984 was very wet and the late summer was hot and dry,
although conditions were not nearly as hot or as dry as the 1983 season.
Penncross maintained the best season-long quality in 1984 (Table 11). It was
followed in order by Penneagle, Emerald, Prominent, Kingstown, and Seaside.
Only Penncross and Penneagle maintained an acceptable quality over the entire
season.
Each of the cultivars increased in quality as the N rate was
increased from 0.5, to 0.8, to 1.2 lb N/growing month (Table 12). However,
the increase in quality between 0.8 to 1.2 lb N was generally not worth the
additional application of nitrogen. Based on these results, the 0.8 lb
N/growing month treatment would be the recommended rate. The 0.5 lb N/month
rate was too low for most cultivars.

25

Table 11.

The 1984 quality ratingsa for six bentgrass cultivars with data
averaged over four replications and three fertility levels.

Cultivar

May

June

July

Aug

Sept

Oct

MEAN

1.

Penncross

5.8

6.8

6.8

7.3

7.4

6.5

6.8

2.

Penneagle

4.8

5.3

5.7

7.3

6.8

6.5

6.0

3.

Emerald

4.6

5.2

5.1

6.9

7.2

5.4

5.7

4.

Prominent

4.5

5.3

4.8

5.5

6.5

5.2

5.3

5.

Kingstown

4.4

4.9

5.1

6.2

5.2

5.2

5.2

6.

Seaside

4.2

4.4

4.0

4.8

4.8

3.7

4.3

0.6

1.3

1.2

1.1

1.3

0.9

0.6

LSD

0.05

£

Quality based on a scale of 9 - i; 9 = best quality, 6 = acceptable
quality, and 1 = lowest quality.

Table 12.

The effects of fertility level on the quality of six bentgrass
cultivars.

lb N/growing
Cultivar

0.5

0.8

1.2

1.

Emerald

5.2

5.8

6.1

2.

Kingstown

4.8

5.2

5.5

3.

Penncross

6.2

7.0

7.1

4.

Penneagle

5.8

6.1

6.2

5.

Prominent

4.8

5.5

5.6

6.

Seaside

4.0

4.0

5.0

LSD

0.05 for comparison of fertility levels within cultivar.

26

Nitrogen X Potassium Study
K. L. Diesburg and N. E. Christians

This study was initiated to observe the effects of nitrogen (N) and
potassium (K) on turf quality and vegetative growth of Kentucky bluegrass and
to evaluate the interactions between these two nutrients.
The area was seeded with 'Baron' Kentucky bluegrass in September 1979*
At the time of establishment, 1 lb P2OC/IOOO ft2 (as triple super phosphate)
and 0.5 lb N/1000 ft2 (as ammonium nitrate) were applied.
The area is
maintained in lawn condition including 2-inch mowing, pre- and postemergent
weed control, and irrigation as needed. No insecticides or fungicides have
been applied to the area.
The study is arranged as a complete factorial with four levels of N (0,
2, 3> and 4 lb/1000 ft2/year) and four levels of K (0, 2, 3, and 4 lb/1000
ft2/year). A randomized complete block design is used with 16 treatments and
three replications.
Urea is the N source, and KC1 is the source of K.
Treatments began in April 1981, and have continued with applications split
over late April, May, late August, and September.
Monthly ratings of turf quality and fresh weights of clippings are
presented in Table 13*
Benefit from K was not as great as that from
comparable amounts of N. The beneficial effect from increasing N application
levels was highly significant throughout the season for both turf quality and
clipping weight. Higher levels of applied K seemed to cause slightly better
turf quality in every month, but the differences were not significant.
Likewise clipping weights were numerically higher with increased rates of K,
especially between the 0- and 2-pound treatments, but differences were not
significant.
The need for a proper balance of N and K can be seen in Table 14.
Although there was little interaction between N and K, optimum stimulation of
grass growth from increments of applied N seemed to occur at 3 lb K/1000 ft2 .
Likewise optimum stimulation of grass growth from increments of applied K
seemed to occur at 3 lb N/1000 ft2.
Turf quality was reduced to such an extent at low N levels that Kentucky
bluegrass stands were thin enough to allow germination and establishment of
crabgrass.

27

Table 13.

Mean effects of Nitrogen (N) and Potassium (K) on vegetative growth
of Kentucky bluegrass.

Fresh Clipping Weights
N

K

Aug

7

Aug 24

Sept 14

Oct 3

Oct 20

Mean

grauis—
4
4
4
4

4
3
2
0

81.7
97.0
65.3
79.0

67.7
84.7
56.0
61.3

84.2
90.0
69.5
85.9

43.6
65.0
38.7
48.2

49.3
66.5
49.1
53.4

65.3
80.6
55.7
65.6

3
3
3
3

4
3
2
0

57.0
36.0
51.0
17.7

62.0
46.0
61.7
25.0

65.3
63.2
62.8
41.2

53.6
47.1
52.0
32.3

76.2
58.3
62.4
42.2

62.8
50.1
58.0
31.7

2
2
2
2

4
3
2
0

22.0
29.0
64.7
12.0

25.7
29.0
32.7
17.0

23.4
24.4
27.4
12.3

16.3
22.0
22.8
6.8

29.2
36.8
38.2
20.8

23.3
28.2
37.2
13.8

0
0
0
0

4
3
2
0

7.0
4.3
5.0
5.7

11.0
6.0
12.0
8.3

11.0
6.4
5.4
5.5

3.9
2.9
1.7
2.9

5.5
2.8
3.2
2.5

7.7
4.5
5.5
5.0

Experiment
Mean
39.6
LSD (oc= 0.05) 28.3

37.9
21.1

42.4
21.3

28.7
17.8

37.3
15.7

37.2
18.7

28

Table 14.

Mean affects of Nitrogen (N) and Potassium (K) on turf quality and
crabgrass infestion of Kentucky bluegrass.

_______________ Turf Quality Ratings9 ___________

N

K

April

May

June

July

Aug

Sept

Oct

Nov

Mean

July 24
Crabgrass
Ratings’3

4
4
4
4

4
3
2
0

6.3
6.3
6.3
6.3

7.3
8.0
7.3
7.0

8.7
9.0
9.0
8.7

7.7
8.3
8.3
8.3

6.0
6.3
7.3
7.0

5.7
6.7
6.0
6.3

6.0
6.7
5.7
7.0

3.7
4.7
4.7
4.3

6.4
7.0
6.8
6.9

1.0
1.3
1 .0
1.0

en en en en

4
3
2
0

5.7
7.0
6.0
6.3

5.3
5.3
5.7
5.3

8.0
7.7
7.0
7.3

7.0
7.3
6.0
6.3

6.3
5.7
6.0
5.3

7.7
7.3
7.3
7.7

7.7
7.7
7.3
7.0

5.7
4.7
4.7
5.3

6.7
6.6
6.2
6.3

1.3
1.3
1.3
2.0

2
2
2
2

c\ j c

4
3
2
0

5.3
6.0
6.0
5.7

5.0
4.7
5.3
5.0

6.3
7.3
6.7
6.0

5.3
6.0
5.7
4.3

4.7
5.7
4.3
3.7

5.7
6.0
5.7
4.3

6.7
6.3
6.7
5.0

5.0
4.3
4.7
3-3

5.5
5.8
5.6
4.7

2.7
1.0
2.7
2.7

o

4
3
2
0

3.7
3.7
3.0
3.3

3.7
4.0
2.7
3.3

3.7
3-0
3.0
3.3

3.0
3.0
2.7
3.0

3.3
2.3
2.3
2.7

3.7
3.0
2.7
3.0

3.7
3.3
2.7
3-0

2.7
2.0
1.7
1.7

3.4
3.0
2.6
2.9

4.3
4.7
6.0
6.0

5.3

6.5

5.8

4.9

5.5

5.8

3-9

5.4

2.5

0.5

0.7

0.8

0.7

0.7

0.6

0.8

0.4

0.9

3
3
3
3

\ j c \ j c \j
o

0
0
0
0

o
o

Experiment
Mean
5.4
LSD
(<*= 0.05) 0.6

a
k

II

—
1

29

o

r

Ratings based on a scale of 1 - 9 ; 9 = best, 6 = acceptable, 1 = poorest
turf.
crabgrass
Ratings based on a scale of 1 - 9; 9 = 100?, 5 = 50?,
stand.

The Reduction of Ammonia
Volatilization from Turfgrass Areas
Treated with Surface'Applied Urea
Y. Joo and N. E. Christians

Surface-applied urea involves the risk of considerable nitrogen (N) loss
to the atmosphere as gaseous ammonia. Rapid enzymatic hydrolysis may lead to
the formation of free ammonia, which leads to reduced N recovery by the plant.
The objectives of this field test were to observe the effects of the
urease inhibitor Phenylphosphoro-diamidate (PPD) and the effects of Magnesium
chloride on foliar burn and growth of Kentucky bluegrass turf treated with
surface-applied urea.
The cation Mg is believed to inhibit the rapid conversion of urea to
ammonia gas. The study was designed in a split-plot with repeated treatments
and measurements. The main plots included liquid urea applied at 0, 1, and 2
lb N/1000 ft^. The subplots included control, PPD at 1 and 2$ of the weight
of N, and Mg at 25% of the weight of N. The treatments were applied four
times June through September. The degree of damage to turfgrass foliage was
visually estimated after 3 days following each application. The rating scale
used ranged from 1 to 9; 9 = no visual burn. Ratings of five or less were
considered unacceptable.
There appeared to be little difference in foliar burn, however, various
effects of inhibitors were observed in treatments (Fig. 1). In the heat of
July, the Mg treatment resulted in significant foliar burn in the 2 lb N/1000
ft^ plots, but it reduced burn significantly in the 1- and 2-lb N/1000 ft^
treatments in the relatively cool temperatures of September.
Visual turf quality ratings and fresh weight of clippings were made weekly
for a total of five times after each application. There were positive effects
of PPD and Mg on the turf quality in September, but those effects were not
significant across all application dates.
The fresh weight of clippings averaged over the 5-week period following
treatment with 2% PPD was observed to increase 20 to 30$ at the 1- and 2-lb
N/1000 ft^ treatments in August and September.
This result indicates that 2%
PPD can have an effect on the N use efficiency of surface-applied urea on
Kentucky bluegrass turf.
Mg showed a 13$ to 25$ increase of clipping yield at the 1-lb N/1000 ft^
rate in August and September, but a 20$ decrease at the 2-lb N/1000 ft^ rate
in August. This result indicates that the cation Mg may have a positive
effect on the reduction of ammonia volatilization and increase urea N
efficiency with low concentration under cool temperature conditions. However,
Mg may increase phytotoxicity of fertilizer solutions at high concentrations
in times of environmental stress.

30

• ---------- --------- *

C O N T R O L

D - ------ ------ □

P P D

1

m----------

P P D

2

A ----------

M G

Clipping weight (gram)

Quality rating

Burn rating

INHIBITORS

JUNE
Fig. 1.

JULY

AUGUST

SEPT.

The effects of inhibitors on foliar burn, quality and clipping
weight (fresh) of Kentucky bluegrass turf treated with surface
applied urea.
Liquid urea was applied at 0 (NO), 1 lb N/J000 ft^ (Nl), and
2 lb N/1000 ft2 (N2).

31

Evaluation of Different Granular
Nitrogen Sources for Fertilization
of Kentucky Bluegrass Turf
M. L. Agnew and N. E. Christians

In this study, eight granular nitrogen (N) sources are being evaluated
for maintenance fertilization. The turf is Glade Kentucky bluegrass which was
established in September 1984 and is maintained at a cutting height of 2
inches. A randomized complete block design with three replications is being
used. Plot size is 3.5 x 7 feet.
The treatments include seven slow-release N sources applied at 4 lb
N/1000 ft^/year split into two equal applications of N. In addition, one urea
treatment was applied at 4 lb N/ 1000 ft^/year split into four equal
applications.
The dates of fertilizer applications are May 1 and August 15.
treatments were applied on June 1 and September 15.

The urea

Measurements to be taken include visual quality every 2 weeks.
Particular attention will be given to disease development, density of turf,
and color of turf.

32

Table 15.

List of treatments

lb N per
1000 ft2

Fertilizer
Source

Date of N
Application

1

Urea

May 1
June 1
August 15
September 15

1
1
1
1

2

IBDU (Estech)
(31-0-0)

May 1
August 15

2
2

3

SCU (Andersons)
(32-0-0)

May 1
August 15

2
2

4

SCU (Lesco)
(37-0-0)

May 1
August 15

2
2

5

Methylene Urea (OMS)
(41-0-0)

May 1
August 15

2
2

6

UF (Blue Chip)

May 1
August 15

2
2

7

PCU (Estech)
(100 day release-rate)

May 1
August 15

2
2

8

Azolone (Noram)
(38-0-0)

May 1
August 15

2
2

Treatment
Number

Evaluation of Liquid Fertilizer
Programs on Three Kentucky
Bluegrass Cultivars
R. W. Moore, M. L. Agnew, and N. E. Christians

The purpose of this study is to compare programming concepts and goals of
12 liquid fertilizer programs on three Kentucky bluegrass cultivars.
Treatments (Table 16) were initiated in the spring of 1985 and will be
continued for several years. The turf is maintained at a cutting height of 2
inches, with all clippings removed.
The treatments include a comparison of a balanced, heavy May, and latefall liquid program. A nonfertilized control and heavy spring fertilizer have
been added for comparison purposes only. Each treatment is replicated 3 times
for Park, Vantage, and Majestic Kentucky bluegrass in 5' x 10' plots.
Measurements to be taken include visual quality, carbohydrate reserves,
clippings, root density, and thatch development.

Table 16.

Treatment
Number

List of treatments.

Program
Name

Date of N
Application

1

Balanced

April
May
August
September

1
1
1
1

Urea
Urea
Urea
Urea

2

Balanced

April
May
August
September

1
1
1
1

Powder
Powder
Powder
Powder

3

Balanced

April
May
August
September

1
1
1
1

FLUF
FLUF
FLUF
FLUF

4

Balanced

April
May
August
September

1
1
1
1

Formolene
Formolene
Formolene
Formolene

(Continued on next page)
34

lb N per
1000 ft^

N
Carrier

Blue
Blue
Blue
Blue

Table 16.

Treatment
Number

(Continued)

Program
Name

Date of N
Application

lb N per
1000 ft2

N
Carrier

5

Heavy May

April
May
August
September

1/2
1 1/2
1
1

Urea
Urea
Urea
Urea

6

Heavy May

April
May
August
September

1/2
1 1/2
1
1

Powder
Powder
Powder
Powder

7

Heavy May

April
May
August
September

1/2
1 1/2
1
1

FLUF
FLUF
FLUF
FLUF

8

Heavy May

April
May
August
September

1/2
1 1/2
1
1

Formolene
Formolene
Formolene
Formolene

9

Late Fall

April
May
August
September
November

1/2
1
1/2
1
1

Urea
Urea
Urea
Urea
Urea

10

Late Fall

April
May
August
September
November

1/2
1
1/2
1
1

Powder
Powder
Powder
Powder
Powder

11

Late Fall

April
May
August
September
November

1/2
1
1/2
1
1

FLUF
FLUF
FLUF
FLUF
FLUF

12

Late Fall

April
May
August
September
November

1/2
1
1/2
1
1

Formolene
Formolene
Formolene
Formolene
Formolene

35

Blue
Blue
Blue
Blue

Blue
Blue
Blue
Blue
Blue

Figure 2

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1984 Preemergence Annual Grass
Control Study
N. E. Christians

The treatments for the 1984 preemergenee annual grass control study were
applied on April 27, 1984, with follow-up applications applied on May 30. The
area chosen for the study was a lawn area on the ISU campus which is heavily
infested with crabgrass. Goosegrass (Eluisine indica) was also seeded into
the area prior to treatment at a rate of 1 lb seed/1000 ft^. Individual plots
measured 5 X 5 feet. The study was conducted with four replications. On
April 29, 2.2 inches of rainfall were recorded near the study sight. This was
followed by unusually wet conditions with more than 15 inches of rain recorded
in May and June.
The materials used in the study included Dowco 356, an experimental from
Dow Chemical; Devrinol, an experimental from Stauffer Chemical; plus Dacthal,
Betasan, Benefin, and Oxadiazon which are labeled preemergence materials for
turf (see Table 17 for rates and treatment combinations).
Phytotoxicity ratings, based on a scale of 9 - 1, where 9 = no damage, 6
= acceptable, and 1 = dead turf, were made 18 days after treatment
(observations of the study area prior to the 18th day indicated that no
ratings were warranted). At this time, only the plots treated with Devrinol
showed signs of damage. Of the three formulations, the wettable powder
appeared to damage the turf most. Only plots treated with the 3 lb a.i./acre
rate of the Devrinol wettable powder were judged to be unacceptable. The
damage had recovered by the 25th day following treatment and no further damage
was observed during the summer.
First crabgrass seedlings were observed in protected areas of ISU campus
on May 3. It was not until May 10 that crabgrass began to appear on the study
area. The Dowco 356 material was not effective in controlling crabgrass in
this investigation (Table 17).
The single application of Dacthal
significantly reduced crabgrass, although some crabgrass plants remained in
these plots. A follow-up application of Dacthal at 7.5 lb a.i./acre was
required for complete control.
The Devrinol WP significantly reduced crabgrass at all rates; however,
the material could not be judged to be entirely effective. The DF and G
Devrinol material were effective only at the 3.0-lb rate and again, even at
that rate, control was not satisfactory. Where Devrinol was combined with
Betasan (treatments 7, 8, 12, and 13) crabgrass numbers were significantly
reduced, but control was not as complete as where Betasan was applied alone at
the 10 lb a.i./acre rate.
Oxadiazon was an effective crabgrass control in 1984 at both the 3- and
4-lb a.i./acre rate and there was no apparent phytotoxicity associated with
this product.
The Benefin combined with a 23-3-5 fertilizer (a commercially available
material from U.S. Steel Agri-Chemicals) was not effective where single
37

applications at the 2-lb rate were used. However, this material was effective
when followed up by a 1.5 lb a.i./acre application 33 days after initial
treatment.

The germination of goosegrass was quite poor in the 1984 season and no
consistent results on goosegrass control were obtained.

Table 17.

Phytotoxicity ratings and crabgrass counts for the 1984
preemergence herbicide trials.

Treatment
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.

—
Control
Dowco 356
0.38
Dowco 356
0.50
Dowco 356
1.00
Dacthal
10.5
Dacthal
10.5 + 7.5
Betasan 4E/
Devrinol WP 5.0/1.0
Betasan 4E/
Devrinol WPa 5.0/1.5
Devrinol WP
1.5
Devrinol WP
2.0
Devrinol WP
3.0
Betasan 4E/
Devrinol DF 5.0/1.0
Betasan 4E/
Devrinol DF 5.0/15
Devrinol DF
1.5
Devrinol DF
2.0
Devrinol DF
3.0
Devrinol G
1.5
2.0
Devrinol G
Devrinol G
3.0
Betasan 4E
10.0
Benefin
2.0
(23-3-5)
Benefin
2.0 + 1.5
(23-3-5)
Oxadiazon
3.0
Oxadiazon
4.0
LSD

a
k

lb a.i./acre

Phytotoxicity
18 days
After Application

9.0b
9.0
9.0
9.0
9.0
9.0

0.05

Number of
Crabgrass Plants
Per Plot

161
86
184
130
37
1

9.0

32

9.0
8.8
7.3
5.5

12
56
22
48

9.0

55

9.0
8.8
8.3
7.6
9.0
6.8
7.8
8.8

28
129
87
66
85
127
11
6

9.0

56

9.0
9.0
9.0

11
8
2

1.2

84

WP, D F , and G indicate wettable powder, dry flowable, and granular,
respectively.
Based on a scale of 9 - 1, where 9 = no damage, 6 = acceptable, and 1 =
dead turf.
38

1984 Postemergence Annual Grass
Control Study
J. Webb and N. E. Christians

Crabgrass has long been a problem in the turfgrass i n dustry.
Traditionally, turfgrass experts have used preemergence herbicides to control
annual grasses, but they often face the problem of missed application
deadlines. Once an application deadline is passed, turf specialists are faced
with the task of finding an effective postemergence herbicide. Until
recently, no postemergence material has proven to be truly effective for
annual grass control. One of the most commonly used postemergents is MSMA,
but when used alone, it has not proven to be completely effective. A new
product, Acclaim (Hoe-A25 01), being tested by the American Hoechst
Corporation is proving to be effective in postemergent crabgrass control and
an experimental from Dow Chemical (Dowco 356) has also shown potential for use
as a postem e r g e n c e . The purpose of this study was to compare various
postemergence treatments in annual grass control. Acclaim and Dowco 356 were
compared to more tradional treatments of MSMA and other postemergence
materials.
Application dates of June 15, July 2, July 12, and July 20, represented
four different seasonal stages of postemergent crabgrass growth (Table 18).
June 15 was the two- to four-leaf crabgrass stage, July 2, the three-leaf to
two-tiller stage; July 12, the one-to four-tiller stage, and July 20, the
mature stage. Chemicals were applied at recommended rates to 5 X 5 foot plots
in three replications. Liquid solutions were dispersed through a hand-held
boom. The area used was a lawn area heavily infested with crabgrass.
Goosegrass (Eluisine indica) was seeded into the area on April 27 at a rate of
1 lb seed/1000 ft2 .
Crabgrass percentage cover was estimated on August 8. The counting of
the crabgrass plants on the plots was completed on August 24. Crabgrass
percentage cover was again estimated on September 19.
Phytoxicity
observations were performed on each area 2 and 4 weeks after each application.
The germination of goosegrass was insufficient for data collection;
however, there was very good germination of crabgrass.
No phytotoxicity was
observed on the Kentucky bluegrass at any time during the study. Some plots
contained creeping bentgrass. The Dowco 356 appeared to damage the bentgrass
where it was present in the Dowco 356 plots.
Based on the August 8 ratings, the Hoe-A25 01 (Acclaim) was very
effective in controlling crabgrass at the 0.12- and 0.18-lb a.i./acre rate
when applied on July 2 (the three-leaf to one-tiller stage) and on July 12
(the one- to four-tiller stage) The 0.08 rate was not sufficient to control
crabgrass at any of the application dates. The June 15 two- to four-leaf
stage) was too early and the plots were reinfested by late germinating
crabgrass.

39

The MSMA alone was not effective in controlling crabgrass; however, when
it was combined with the preemergence materials Betasan and Dacthal, control
was complete. This would indicate the crabgrass in the plots treated with
MSMA alone was the result of late season germination.
The Dowco 356 was effective in controlling crabgrass at the 1.5-lb
a.i./acre rate at the June 15 application date only. It was not effective on
crabgrass at the July 2 or the July 20 application dates, although crabgrass
cover was reduced at the 2- and 3-lb application rates following the July 20
application.
The Hoe-A25 01 (Acclaim) material appears to be a very effective
postemergence crabgrass control. Further tests combining this material with
preemergence materials should be conducted next year. The Dowco 356 material
was less effective in this test; however, 1984 was a very wet year and this
material may prove effective under more normal conditions.

40

Table 18.

Results of the 1984 postemergence crabgrass control study

Material
lb a.i./
acre

Treatment

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.

Control
0.08
Hoe-A25 0la
0.12
Hoe-A25 01
0.18
Hoe-A25 01
0.08
Hoe-A25 01
0.12
Hoe-A25 01
0.18
Hoe-A25 01
0.08
Hoe-A25 01
0.12
Hoe-A25 01
0.18
Hoe-A25 01
MSMA
2.0
Dowco 356
1.0
Dowco 356
1.5
Dowco 356
1.0
Dowco 356
1.5
Betasan/MSMA
5/2
Dacthal/MSMA 10.5/2.0
Dowco 356
1.0
Dowco 356
2.0
Dowco 356
3.0
LSD

N.S.
a

Perb
Plot

.17 ml
.26 ml
.38 ml
.17 ml
.26 ml
.38 ml
.17 ml
.26 ml
.38 ml
.75 ml
1.1 ml
1.6 ml
1.1 ml
1.6 ml
2.7/.72
3.65g/.72
1.1 ml
2.2 ml
3.3 ml

0.05

Crabgrass
Percent
Cover
August 8

Crabgrass
Count
August 24

Crabgrass
Percent
Cover
Sept 19

20
23
8
3
12
0
0
7
0
2
13
10
3
5
8
0
0
22
5
5

67b
98
22
7
43
1
0
54
1
2
75
15
5
8
13
0
0
63
43
30

33
40
10
10
30
0
10
13
3
20
18
20
17
5
20
8
2
42
18
18

15

N.S.

27

Not significant.

Hoe-A25 01 = 1.00 lb a.i./gal.
Data represent counts done in 5 X 5 foot plots.

Treatments
Treatments
Treatments
Treatments

—
—
—
—

2, 3,
11, 12,, 13, 16, 17 —
—
5, 6, 7, 14, 15
—
8, 9, 10
18, 19, 20
—

applied
applied
applied
applied

June 15
July 2
July 12
July 20

treatments were applied in the equivalent of 4 gal distilled water/1000

41

1984 Broadleaf Weed Control
and Postemergence Crabgrass
Control Study
N. E. Christians

The 1984 postemergence annual grass and broadleaf weed control study was
conducted at the North Dakota Avenue Cemetery in west Ames. The Kentucky
bluegrass on this area was established more than 40 years ago and no
herbicides have been used on the site. There is a uniform stand of bluegrass
which is heavily infested with crabgrass and dandelions.
The treatments included 1) EH 795 and EH 805 (Quadmec) which are
experimental materials from PBI/Gordon containing 2,4-D, MCPP, and Dicamba for
broadleaf weed control + MSMA for crabgrass control;
2) EH 765, an
experimental trimec material from PBI/Gordon containing 2,4-D, MCPP, and
Dicamba;
3) EH 791 (Trimec ester) an ester formulation of PBI/Gordon's
trimec;
4) Trimec, the commercially available form;
5) XRM-4755, an
experimental material from Dow Chemical which contains triclopyr and 2,4-D;
and 6) Formula 40, a 2,4-D material commercially available from Dow. Only
the EH 795 and EH 805 would be expected to provide satisfactory postemergence
control of crabgrass. Plot areas measured 5 x 10 feet and the study was
conducted in four replications.
The materials were applied on April 27, 1984, a clear day with wind
speeds below 5 mph. The temperature at application was 82° F.
Phytotoxicity ratings were made on July 1, 1984 (Table 19). The Quadmec
materials discolored the Kentucky bluegrass at this initial observation date.
By July 10, the bluegrass had completely recovered. The EH 765 also initially
discolored the bluegrass, which was surprising, but a recheck of the data
indicated this was a real effect. These plots too had recovered by July 10.
None of the materials produced an unacceptable phytoxicity.
Crabgrass control ratings were performed on July 21.
Because of
variability among the replications, no significant differences in crabgrass
control were found among treatments. The crabgrass was in the one- to twoleaf stage at application and many of the materials provided some slight
reduction in crabgrass cover. The EH 795 (Quadmec) at 5.02-lb a.i./acre,
reduced crabgrass infestations by 50$; however, none of the MSMA containing
compounds were truly effective in controlling crabgrass.
This was an area
with a very heavy infestion of crabgrass and rainfall was especially heavy
during the spring and early summer months which may have contributed to the
poor control.
All of the materials were effective in reducing dandelions and white
clover. The Quadmec materials were not as effective in controlling dandelions
as the trimec materials, although both were effective in controlling clover.
The XRM-4755 provided poor control at the 0.5-lb a.i./acre rate. The 1.0-lb
rate was more effective, but only the 1.5-lb rate was truly effective against
both species. The Formula 40 was effective against both dandelions and
clover, although sufficient clover remained in the Formula 40 plots to
indicate it may not be as effective against this species.
42

Table 19.

Weed control in the 1983 broadleaf herbicide study.

Treatment

Phyto­
toxicity

Crabgrass

Dande­
lion

White
Clover

lb a.i./acre
1.

EH 795 'Quadmec'

4.69

6a

14b

5°

0

2.

EH 795 'Quadmec'

5.02

7

50

36

0

3.

EH 805 'Quadmec'

4.69

6

30

5

0

4.

EH 805 'Quadmec'

5.02

8

23

10

0

5.

EH 765 'Trimec'

1.13

7

20

1

0

6.

EH 765 'Trimec'

2.25

6

23

1

0

7.

EH 791 'Trimec
ester'

1.20

9

10

2

0

EH 791 'Trimec
ester'

1.60

9

20

1

0

Trimec

0.83

9

15

6

3

10.

XRM-4755

0.5

9

0

80

74

11.

XRM-4755

1.0

9

23

7

12

12.

XRM-4755

1.5

9

18

4

1

13.

Formula 40

3.0

9

28

3

14

14.

Control

—

9

0

258

203

2

N.S.d

40

34

8.

9.

LSD
a

b

0.05

Rating of phytotoxicity on Kentucky bluegrass, where 9 = no damage, 1 =
dead turf, and 6 = acceptable.
Crabgrass control is based on a rating scale with 100 = complete control
and 0 = no control.
Dandelion and white clover data represent counts of the number of plants in
the 5 x 10 foot plots.
N.S. = not significant at the 0.05 level.
43

Rubigan Field Study— 1984
M. C. Gaul and N. E. Christians

Annual bluegrass (Poa annua) has presented turf managers with serious
problems for many years. Research has ranged from complete eradication to
seedhead suppression, to the development of programs to manage Poa annua as a
turf species.
Rubigan, produced by the Elanco Company, is a systemic
fungicide labeled for controlling many common turfgrass diseases. It has also
been labeled for the gradual reduction of annual bluegrass (Poa annua). At
Iowa State University, research is being conducted using Rubigan to control
Poa annua in creeping bentgrass and Kentucky bluegrass.
Objectives of this
study include determining appropriate rates of Rubigan for controlling Poa
annua and observing any phytotoxic effects which may occur on the desired
turfgrass species.
The field study was initiated on June 13, 1984, at two locations in Ames,
Iowa. The first location was at the Iowa State University Golf Course on the
east end of the practice putting green. The second location was on a Kentucky
bluegrass fairway on Homewood Golf Course. Both sites contained healthy
populations of Poa annua.
Treatments included rates of 0.05, 0.10, 0.15, 0.20, and 0.25 oz
a.i./lOOO ft^. Each treatment was applied to a 5 X 5 foot plot and replicated
three times. The treatments were applied in 326 ml of water (equivalent to
150 gal/acre) at 20 psi using a hand-held boom operated in four different
directions to ensure uniform coverage. Each treatment was applied eight times
over a period of 3 months until cumulative amounts ranging from 0.40 to 2.0 oz
a.i./lOOO ft^ were reached.
Data were taken at periodic intervals during the study and included only
quality ratings. The quality ratings were determined on a scale from 9 - 1 ,
with 9 = best quality, 6 = acceptable, and 1 = dead turf. Clipping weights
were not taken because species were so dispersed throughout the plots that
separation would have been impossible.
Responses in this study varied with species and treatment rates. In the
bentgrass study, both creeping bentgrass and Poa annua showed increasing
phytotoxicity (decreased quality ratings) with increasing rates of Rubigan
(Table 20). Overall mean quality ratings ranged from 7.9 to 5.4 for bentgrass
while Poa annua ratings ranged from 7.7 to 6.3. Phytotoxicity developed on
the bentgrass which appeared as an aqua-green wilted condition. This condition
was very minor at the lower rates but increased significantly at higher rates.
Phytotoxicity was not as severe on Poa annua and generally included a slight
chlorotic condition. In terms of recovery, the Poa annua was quick to recover
while the bentgrass still showed some phytotoxicity up to two months after the
last application.
On the Kentucky bluegrass site, phytotoxic results were not nearly as
severe as on the bentgrass site (Table 21). Overall mean quality ratings on
the Kentucky bluegrass ranged from 8.8 to 9.0 while for Poa annua the ratings
44

ranged from 3»2 to 2.5. In trying to explain the low ratings for the Poa
annua it must be noted that this study was located on a nonirrigated fairway.
The summer heat stress period was in full swing approximately 1 month after
the initial application and as a result the Poa annua population was greatly
weakened. By August the Poa annua population was dead while the Kentucky
bluegrass remained reasonably healthy at all treatment levels. Discoloration
of the Kentucky bluegrass was very minimal and what stress did appear on the
turf was probably due to heat and lack of water. Poa annua disappearance
could be attributed to many factors — heat, lack of water, or Rubigan. With
the onset of the cool, wet temperatures of late September, favorable for
annual bluegrass germination, the amount of Poa annua to germinate appeared
less than that present at the beginning of the study and was very slow to
germinate compared with control plots. This suggests that possibly Rubigan
was creating a preemergent growth effect on the Poa annua♦
Poa annua is a very diverse plant species. As stated in the Rubigan
Product Information Bulletin, Poa annua is capable of producing regionally
adapted biotypes which differ both morphologically and physiologically.
Central Iowa is known for its unpredictable weather. Fast moving weather
fronts are capable of producing a variety of conditions including very hot
summers, freezing winters, and varying amounts of precipitation.
It is
logical, therefore, to expect Poa annua biotypes to have developed in response
to local climatic conditions.
In this study, especially on the bentgrass
putting green where low mowing and daily irrigation favors Poa annua, we
believe we are dealing with some very stubborn Poa annua biotypes — possibly
biotypes which have developed a somewhat perennial lifecycle, in which case,
Rubigan would be ineffective.
With the warm weather of spring, we will be examining our plots to
observe how the Poa annua has survived the cold winter months. We believe
that perhaps the Rubigan may have weakened the Poa annua population enough to
decrease winter survival. We also plan on using infrared film to detect any
changes in the Poa annua populations. This study will be repeated in 1985 on
turfgrass stands composed primarily of Poa annua with better data expected.
Currently we are conducting a greenhouse study using Rubigan on two different
Poa annua biotypes and creeping bentgrass cv. 'Penncross'. One biotype was
obtained from the bentgrass field study and the other from the Kentucky
bluegrass field study. Morphological differences can be observed between the
two.
Data being taken includes quality ratings, clipping weights, and
seedhead counts.

45

Table 20.

Rubigan field study at the practice putting green, Iowa State University Golf
Course, Ames, Iowa. The first application was June 13, 1984, the final application
was September 19, 1984.

_______________ ___________ Turf Quality3
Treatment
(oz/
1000 ft2
a.i. )

Total
a. i.

Control
0.05
0.10
0.15
0.20
0.25

0.0
0.40
0.80
1.20
1.60
2.00

a

Total
Rubigan

0.0
0.80
1.60
2.110
3.20
4.00

July
bd

8.0
7.3
7.6
7.6
7.6
6.0

7.6
7.6
7.6
7.6
7.0
6.0

Turf quality ratings as follows:
Creeping bentgrass.
Poa annua.

Table 21.

Aug
B

24
pC

8.6
8.3
8.0
7.3
7.0
6.3

Sept. 3
B
P

25
P

8.0
7.3
7.6
7.6
7.3
6.0

8.6
8.3
8.3
7.6
8.0
6.3

8.0
7.6
7.0
7.6
7.0
7.0

Sept. 14
B
P

8.6
7.3
7.3
6.0
6.0
4.0

9.0
7.6
7.6
7.3
7.6
6.3

Oct
B

9.0
8.3
7.3
6.6
6.3
4.6

Mean
B
P

5
P

8.6
7.6
7.6
7.6
8.0
6.3

8.6
7.9
7.7
7.0
7.0
5.4

8.2
7.6
7.7
7.6
7.6
6.1

9 = best quality, 6 = acceptable, 1 = dead turf.

Rubigan field study at the Kentucky bluegrass fairway, Homewood Golf
Course, Ames, Iowa.
The first application was June 13, 1984, the final
application was September 20, 1984.

____________________ Turf Quality5
Treatment
(oz/
1000 ft2
a.i.)

Total
a. i•

Control
0.05
0.10
0.15
0.20
0.25

0.0
0.40
0.80
1.20
1.60
2.00

a
b
c

Total
Rubigan

0.0
0.80
1.60
2.40
3.20
4.00

July
K6

9.0
9.0
9.0
9.0
9.0
9.0

11
pO

7.6
7.6
7.6
6.3
7.0
7.0

Turf quality ratings are as follows:
turf.
Kentucky bluegrass.
Poa annua.

Aug.
K

9.0
9.0
9.0
9.0
9.0
9.0

13
P

1.0
1.0
1.0
1.0
2.6
1.0

Sept . 20
K
P

8.3
8.3
9.0
9.0
9.0
8.0

1.0
1.0
1.0
1.0
2.0
1.0

Oct.
K

P

9.0
9.0
9.0
9.0
9.0
9.0

1.0
1.0
1.0
1.0
1.0
1.0

5

Mean
K
P

8.8
8.8
9.0
9.0
9.0
8.8

2.6
2.6
2.6
2.3
3.2
2.5

9 = best quality, 6 = acceptable, 1 = dead

46

Selective Control o f Tall Fescue
in Kentucky Bluegrass Turf
with Chlorsulfuron
B. M. Maloy and N. E. Christians

In the present study, a chemical, called chlorsulfuron, which has shown
some potential as a selective control of tall fescue in Kentucky bluegrass
turf, was tested in field studies. The purpose of the field experiments was
1) to determine the effects of the chlorsulfuron on tall fescue and Kentucky
bluegrass, 2) to establish the tolerance levels for both species to the
chemical under field conditions, 3) to test single vs split applications of
chlorsulfuron, and 4) to study the effects of chlorsulfuron on Kentucky
bluegrass seed germination.
Kentucky bluegrass is the most important and widely utilized cool-season
turfgrass of the midwest. Due to its medium to fine leaf texture and
rhizomatous growth habit, it forms a turf of high shoot density. Tall fescue,
another cool-season turfgrass common to the transition zone, has a wider leaf
texture and bunch-type growth habit which forms a turf of low-shoot density.
In the cooler regions, however, because of its low-temperature hardiness, tall
fescue plants will thin out until only coarse textured plants that eventually
become weeds remain within a Kentucky bluegrass area. Therefore, tall fescue
often disrupts the uniformity of a bluegrass turf. This disruption may occur
when a poor-quality seed mix is used which is contaminated with fescue seed.
The only current methods for controlling tall fescue in Kentucky bluegrass
turf are mechanically digging the tall fescue plants or using nonselective
herbicides. Glyphosate is the best nonselective choice because of its short
residual activity. However, these herbicides are all nonselective, killing
all growing tissues including surrounding desirable grasses. To date, there
are no selective controls of perennial grass weeds in Kentucky bluegrass turf.
The field experiments were initiated on June 28, 1983, at the Iowa State
University turf research plots north of Ames, Iowa. Two studies were
established. One in tall fescue (Kentucky 31) and the second in a premium sod
blend of Kentucky bluegrass. The studies consist of twelve 5 X 5 foot plots
replicated three times. In both studies, each 5 X 5 foot plot was divided in
the middle with bluegrass on one side and tall fescue on the other. The plots
were established by interchanging strips of sod (2 1/2 X 5 feet) between the
two areas.
The study was arranged as a split-plot with chlorsulfuron
treatments as main plots and species as subplots (Fig. 3)*
Treatments included single rates of 0.25, 0.50, 1, 2, 3, and 4 oz/acre
and split rates of 0.25 + 0.25, 0.50 + 0.50, 1 + 1, 2 + 2, and 3 + 3 oz/acre.
Each treatment was applied in 326 ml of water at 20 psi with a hand-held boom
operated in four different directions to ensure uniform coverage. The single
application and first of the split application rates was applied July 11,
1983, while the second application of the split rates was applied July 25,
1983.

47

The Kentucky bluegrass was maintained at a height of 2 inchs while the
tall fescue was cut at
At quarterly intervals throughout the growing
season, 1 lb N/1000 ft (sulfer-coated urea) was applied to the experiments.
Water was applied by the sprinkler irrigation system as needed to prevent
moisture stress.
Data taken weekly during the experiment included fresh clipping weights
and quality ratings. The quality ratings were determined on a scale from 9 to
1; with 9 = best quality and 1 = dead turf.
After all of the data had been collected from the summer experiment,
glyphosate was sprayed over the entire study 1 year from the date that the
chlorsulfuron treatments had been applied. Two weeks later all the above
ground tissue was mowed to 1-inch in height. A Jacobson overseed^r was used
to reseed Kentucky bluegrass seed at the rate of 1 1/2 lb/1000 ft into the
chlorsulfuron residual plots. The experiment was irrigated daily for 2 weeks
until germination was observed and then irrigated regularly to prevent
moisture stress.
The second experiment that had been initiated on June 28, 1983, in a
Kentucky bluegrass premium sod blend area was allowed to establish for 3
months. On October 1, 1983, the same single application and first of the
split application rates was made. On October 15, 1983, the second application
of the split rates was applied. The management practices and data collection
were uniform throughout both experiments.
The responses varied with species and treatment rates. The Kentucky
bluegrass showed a much higher tolerance to the chemical with no decrease in
quality at the highest single and split application rates in both experiments.
However, as the chlorsulfuron rate increased the clipping weight significantly
decreased (Fig. 4). This observation suggests that chlorsulfuron has some
growth retarding effects on Kentucky bluegrass. The tall fescue showed a very
low tolerance to the chemical and both quality and clipping weights were
severely affected at single rates of 141 g/ha and split rates of 141 + 141
g/ha and greater. Growth inhibition and above ground burn occurred at the
lower rates, however, the tall fescue recovered from damage at 71 g/ha single
rate and 71 + 71 g/ha split rate.
Chlorsulfuron effects on turfgrass quality appeared within 2-3 weeks of
application in Experiments 1, whereas in Experiment 2, death of the tall
fescue plants was slow (within 4-5 weeks) and was preceded by chlorosis,
necrosis, growth inhibition, and terminal bud death.
The heaviest
chlorsulfuron treatments affected plants sooner than the lighter rates. The
differences observed between Experiment 1 and 2 are probably due to
differences in environmental conditions. The lethal effect on tall fescue at
higher rates of chlorsulfuron was not reflected in the quality or clipping
weight data because of the progressive nature of the damage after application.
In the tall fescue plots where the heaviest rates of chlorsulfuron were
applied, it was noted that some plants were withstanding the treatments.
These plants were later identified as orchardgrass. The seed used to
establish the tall fescue sod area at the Iowa State University research farm
was foundation seed of Kentucky 31 Tall Fescue which has been contaminated
with orchardgrass. The amount of orchardgrass in the tall fescue plots was
48

significant, affecting quality and clipping weight data. Kentucky bluegrass
was also noted to exist as a contaminant in the tall fescue sod which was not
controlled in the tall fescue plots at the heavier chlorsulfuron rates. These
two species did not make up a large percentage of the tall fescue plots,
however, after death of the tall fescue plants, counts of these two species
seem to expand quickly without competition from the fescue.
Kentucky bluegrass seed germinated 10-14 days after planting it into the
chlorsulfuron treated plots 1 year from the application date for both
experiments. Kentucky bluegrass visually covered 90$ of all plots regardless
of rate. It would be interesting to further evaluate Kentucky bluegrass
germination in chlorsulfuron residual much sooner than these experiments took
into account.
The data from these experiments indicate that chlorsulfuron has the
potential for being a selective control for tall fescue in Kentucky bluegrass.

49

C LIP P IN G WEIGHTS (GRAMS)

Figure 3

50

C L IP P IN G WEIGHTS (GRAMS)

Figure 4

51

Chlorsulfuron Experiments
B. M. Maloy and N. E. Christians

The purpose of these greenhouse experiments was to determine the effects
of chlorsulfuron at the rates of 141 and 282 g/ha on seven different grass
species often found in a Kentucky bluegrass turf.
Annual bluegrass,
bentgrass, fine fescue, tall fescue, quackgrass, bromegrass, and perennial
ryegrass are a few of the grass species which may occur as weeds in a Kentucky
bluegrass turf. Kentucky bluegrass turf has shown no phytotoxicity when in
preceding field experiments chlorsulfuron has been applied at the same rates.
Fifteen sod plugs of the seven grass species (3-inch diameter) were
removed from the Iowa State University turf research plots. All soil was
washed from the roots and the plants were reestablished in 3 x 3-inch plastic
pots filled with a Nicollet soil having a pH of 7.2.
Greenhouse temperature regimes were maintained at 16 to 18° C (night)/21
to 23° C (day). The pots were uniformly surface-irrigated three times weekly
with 50 ml of distilled water per pot. Chlorsulfuron was applied on September
30, 1983, at single application rates of 0, 141, and 282 g/ha. On October 3,
1984, the experiment was repeated using the same procedure. Each treatment
was applied with a spray-mist atomizer attached to an air pressure pump in 2
ml of distilled water.
The experimental design was a split-plot with the seven species as main
plots and the three chlorsulfuron treatments as subplots in five replications.
Data was collected three times throughout the experiments. Clipping weights
were obtained from each pot 1-inch above the soil surface.
An analysis of variance (ANOVA) was performed on the data and the means
of the three chlorsulfuron treatments of each of the seven grass species are
denoted in (Fig. 5).
The responses varied among the grass species. The bentgrass, annual
bluegrass, fine fescue, quackgrass, and bromegrass were more tolerant of the
141 and 282 g/ha chlorsulfuron rates. However, the tall fescue and perennial
ryegrass were extremely sensitive to the two chlorsulfuron rates.
Initial chlorsulfuron effects on turfgrass quality appeared on all
species within 3 weeks of application. The treated species appeared darker
green in color and shorter in height than the controls in both experiments.
Death of the tall fescue and perennial ryegrass was slow (within 4-5 weeks) in
both experiments.
Tall fescue and perennial ryegrass clipping weights
decreased when either 141 or 282 g/ha was applied to these species. Figure 2
denotes averages of three clipping sessions obtained throughout the course of
the experiment. The species weights at both chlorsulfuron rates did not
average to zero, because the initial clipping session of these two species
contributed to the averages presented in the figure.
Tall fescue is shown to have a higher clipping weight at the 282 g/ha as

52

compared to the 141 g/ha, however, this can be attributed to Kentucky
bluegrass which was a contaminant in two of the five replications for tall
fescue. Since Kentucky bluegrass is not controlled by chlorsulfuron, its
weight contributed to the overall means for tall fescue.
Bentgrass clipping weight actually increased with applications of
chlorsulfuron. At the beginning of both experiments, the treated plants were
shorter in height and darker green in color as compared to the controls.

53

5

EXPERIMENT 1
CLIPPING WEIGHTS
CHLORSULFURON
RATES

LSD=.47 at .01%

SPECIES
1. A n n u a l B lu e g ra s s
2. B e n tg r a s s
3. F in e Fescue

(g a . i . / h a )

4. T a ll Fescue

00

5. Q u a c k g r a s s

2.

6.

7. P e re n n ia l R y e g r a s s

2.

1.

1.

.5

4.

B ro m e g ra s s

EXPERIMENT 2

3.

3.

2

2

1

1

S P E C IE S

54

Effects o f Five Growth Retardants
on the Vegetative Growth
o f Kentucky Bluegrass— 1983-1984
K. L. Diesburg and N. E. Christians

Two field experiments were combined to compare the effects of Ethrel (4.0
lb a.i./A), EL 500 (1.0), Embark (0.4), PP-333 (0.4), and Limit (2.5)
(Monsanto 4621) on leaf and stem growth of Kentucky bluegrass at three
different seasonal stages of growth. Effects were studied on Baron in 1983
and Premium Sod Blend in 1984. The experiments were conducted on a silty clay
loam soil. Fertilizer was applied as urea at 4 lb N/1000 ft^/year. Water
irrigation was used to prevent drought stress. In both years, chemicals were
applied around May 10, June 17, and September 22, representing spring
reproductive, summer, and fall vegetative stages, respectively.
Liquid
solutions were applied to 5 X 5 foot plots through a hand-held boom with three
nozzles passing 3 feet above the ground with pressurized C0£ in a tank
strapped to the operator's back.
A split-split-plot design was used with years as whole plots, application
dates as subplots, and chemicals a sub-sub-plots replicated three times within
each year. Plots were mowed immediately prior to application and once more 1
week afterward.
Canopy heights were measured from the soil surface 4 weeks
after treatment. Leaf length, leaf number, and internode number and length
were measured and counted from nine representative shoots per plot and then
averaged. Subjective ratings of toxicity were based on turf color with 9 =
best color and 1 = brown. Ratings of seedhead formation were also subjective
with 1 = most heading and 9 = no heads.
Canopy heights averaged over all treatments and seasons, differed between
the 2 years (1983: 7.2 cm vs 1984: 7.5 cm). Among seasons averaged over both
years they were highest in spring (8.7 cm), lower in summer (7.4 cm), and
lowest in fall (6.8 cm). Canopy heights were lower in summer 1984 (6.5 cm)
than in summer 1983 (8.3 cm) while the reverse occurred in fall of those years
(1983: 6.1 cm. vs 1984: 7.4 cm). This juxtaposition could be due to the
difference in response of Baron and Premium Sod Blend to leaf growth
inhibition or it may have been due to differences in environmental conditions
between the 2 years.
All chemically treated plots exhibited lower canopy heights than that of
the control (Table 23). Embark was most effective followed by Ethrel. EL
500, PP-333, and Limit were least effective. In both years, Embark caused
cessation of growth within a week after application with resumption of growth
within 5 weeks (Fig. 1). The effects of Ethrel were not apparent until about
the third week after application. From that point until more than 10 weeks
after application, it produced the lowest canopy heights of all treatments.
Effects of EL 500 and PP-333 were delayed even further than Ethrel's, becoming
evident between only the third to fourth week after application. Limit
appeared to have a long range effect, causing canopy heights nearly the same
as those of Ethrel 10 weeks after treatment. In seasonal performance over
both years, Embark and Limit performed best in spring with Ethrel being
slightly less effective and EL 500 and PP-333 least effective (Table 23). In
55

summer and fall, Embark and Ethrel were most effective while Limit,
and PP-333 were least effective.

EL 500,

Toxicity levels averaged over all treatments and seasons did not differ
between the 2 years (1983: 6.6 vs 1984:7.4). Toxicity levels among seasons
averaged over both years were lower in the fall (6.5) with spring and summer
being similar at 7.6 and 7.4, respectively. EL 500 was the only chemical to
show no toxicity over all seasons and years (Table 24). PP-333 caused only
slight discoloration while Ethrel and Limit showed a little more, but nothing
objectionable.
Embark severely damaged the leaves and apical meristems
causing the turf to turn brown. Toxicity from Limit and Embark were seen 1
week after application and remained through the fourth week after which the
turf began to recover. Recovery from Embark was through growth of lateral
meristems. Toxic effects from Ethrel were not evident until 3 weeks after
application and remained until the sixth week.
The only chemical to perform differently between years averaged across
seasons was Embark. In 1983, it was significantly more toxic than in 1984.
Likewise, Embark caused unacceptable turf quality in all seasons averaged over
years. It showed higher quality in spring compared to summer and fall. Limit
lowered spring turf quality close to the level of Embark. The damage was less
in summer and fall. Ethrel allowed top quality turf in spring with slightly
lower quality in summer and noticeably lower quality in fall. EL 500 and PP333 allowed top quality turf in spring and summer with only slight damage in
fall.
In 1983, Embark did not cause variable toxicity levels across seasons
while in 1984, it was least toxic in spring, more toxic in summer, and even
more toxic in fall. Limit's effects were also nonvariable in 1983, and
variable in 1984, giving lowest quality turf in spring, slightly better turf
in fall, and good quality turf in summer. Ethrel, EL 500, and PP-333
performed similarly across seasons in both years.
Carryover effects through winter, of chemicals applied in fall 1983, were
studied in spring 1984 (Table 25). Embark eliminated spring heading in this
case, while all other chemicals were ineffective. Spring green-up of these
plots showed that the toxic effects of Embark, PP-333, and Limit were still
apparent.
Ethrel was the only chemical to remain active in leaf growth
inhibition.
Leaf lengths and numbers were determined by averaging samples taken 28
and 45 days after summer treatments in both years. Over all chemical
treatments there were similar numbers of leaves absent between 1983 and 1984
but shorter leaves were observed in 1984, compared to 1983 (Table 26). Each
chemical affected leaf growth differently. With EL 500, PP-333, and Limit the
accumulated length of all five leaves was not drastically reduced compared to
the control, rather Leaf 1 and Leaf 2 were significantly shorter, Leaf 3 was
similar, and with the exception of Limit, Leaf 4 was longer. Leaf 5 was
usually absent. There seems to have been a slight redistribution of leaf area
away from newly produced leaves toward older leaves with EL 500 and PP-333 but
not with Limit. This redistribution phenomenon appears to have been very
strong with Ethrel where lengths of Leaf 1 - 5 were similar averaging 3*2 cm.
Embark was also unique in that Leaf 1 - 3 were short while Leaf 4 and 5 were
usually absent.
56

The data indicating number of leaves absent show that EL 500, PP-333» and
Limit were similar to the control in usually having Leaf 1 - 3 present with
Leaf 4 absent about half the time and Leaf 5 absent most of the time. With
Embark, Leaf 1 - 3 were absent one third of the time while Leaf 4 and 5 were
absent most of the time. With Ethrel a few leaves were missing only in 1984,
at Leaf 4 and 5.
There were a few isolated differences of chemical effects on leaf length
between the two years. At Leaf 1, EL 500, PP-333, and Limit caused shorter
leaves than that of the control in 1983, but there was no difference in 1984.
At Leaf 4, Ethrel and EL 500 resulted in similar leaf lengths in 1983, at
around 3.0 cm while in 1984, all treatments with the exception of Embark had
leaves of that length. The number of leaves absent at Leaf 1 - 4 did not vary
much between the two years for any treatment with the exception of Embark. It
caused fewer leaves to be absent at Leaf 1 and 2 and more leaves to be absent
at Leaf 3 and 4 in 1984, compared to 1983.
Shoot elongation beyond that observed in control plants occurred in both
years with Ethrel treatments, only (Table 25).
Data over two growing seasons indicate that all chemicals, with the
exception of Limit, were fairly stable across the three dates of application
in the inhibition of leaf growth of Kentucky bluegrass. Limit was very
effective in spring and less so in summer and fall. Ethrel and Embark were
consistently very effective while EL 500 and PP-333 were not. All chemicals
were sensitive, however, to environmental variation in terms of toxicity.
Those chemicals with a higher degree of toxicity (i.e. Embark, Limit, and
Ethrel) appeared to be the most sensitive. For instance, during summer 1983,
plants suffered from more heat stress than in summer 1984. Embark was most
toxic during summer and fall of 1983. Limit and Ethrel were unique in that
they were most toxic in spring and fall, respectively, in both years.
Regardless of their sensitivity, the chemicals that were most toxic were the
ones most effective in inhibiting leaf growth. Ethrel was unique, also, in
that it caused the highest level of growth inhibition over a ten week period
while allowing very good turf quality. Since it was also the only chemical to
cause stem elongation in the shoot, perhaps it acts by shifting growth away
from the leaves in favor of the stem. This could be beneficial in terms of
allowing healthy, dense turf while inhibiting leaf elongation. A potential
advantage provided by Embark and Ethrel was shown in their ability to inhibit
spring heading and early spring leaf growth, respectively, when applied the
previous fall. Both could be a great help to turf managers who lack time for
intensive spring mowing.

57

Table 23.

Growth
Retardant

Mean canopy heights of Kentucky bluegrass four weeks after growth
retardant treatments in 1983 and 1984 at three dates of application.

Rate
(lb a.i
acre)

Spring
May 10

Summer
Jun 18

Fall
Sep 22

Yearly
Average

Grand
Mean
83-84

--- o.m
Ethrel

4.0

1983
1984

7.3
5.3

8.0

5.0
6.3

6.2
6.6
6.4

EL 500

1.0

1983
1984

9.3

9.3
7.0

7.0
7.0

8.2
7.8

6.7

5.7
5.0

5.0
5.3

5.3
5.7

9.0

8.3
6.7

6.7
7.7

7.5
7.8

7.7

8.7
7.7

6.3
8.0

7.5
7.8

11.3

10.7
7.7

6.7
10.0

8.7
9.7

7.9
Embark

0.4

1983
1984

5.5
PP-333

0.4

1983
1984

7.7
Limit

2.5

1983
1984

7.7
Control

—

1983
1984

9.3

LSD
LSD
LSD
LSD

(•(,=
(06 =
(Û6=
(°C =

1.1
1.9
2.4

0.05) within a year
0.05) between dates
0.05) between years
0.05)

0.8
1.7 (NS)
0.5

58

Table 24.

Growth
Retardant

Ethrel

Mean toxicity ratings3 of Kentucky bluegrass four weeks after growth
retardant treatments in 1983 and 1984 at three dates of application.

Rate
(lb a.i./
acre)

4.0

Year

1983
1984

Summer
Jun 18

Fall
Sep 22

Yearly
Average

8.0

8.0
7.0

5.0
6.3

6.5
7.1

9.0

9.0
8.3

7.6
7.3

8.3
8.2

5.3

2.0
4.7

2.0
4.0

2.0
4.7

8.3
8.7

7.3
7.3

7.8
8.3

6.3

7.3
8.3

6.7
7.3

7.0
7.3

8.3

8.3
9.0

7.7
9.0

8.0
8.8

Spring
May 10

Grand
Mean
83-84

6.9
EL 500

1.0

1983
1984

8.3
Embark

1.4

1983
1984

3.6
PP-333

1.4

1983
1984

9.0

8.1
Limit

2.5

1983
1984

7.2
Control

—

1983
1984

8.5

LSD (c*= 0.05) within a year
LSD (0C= 0.05) between dates
LSD (ac = 0.05) between years
LSD
= 0.05)

0.8
0.9
1.2

0.6
0.9 (NS)
0.4

Ratings based on color; 9 = best, 6 = acceptable, 1 = brown.

59

Table 25.

Growth
Retardant

Means of 1983-1984 heading ratings of Kentucky bluegrass in response
to spring-applied growth retardants.
Mean heading ratings, toxicity ratings, and canopy heights during
spring 1984 in response to carry over effects from 1983 fall-applied
growth retardants.
Mean internode lengths and numbers in Kentucky bluegrass shoots
averaged over samples taken 28 and 45 days after June 12, 1983
treatment with growth retardants.

Rate
lb a.i./
acre)

1983-1984
Heading3

Carryover
Turf
Color*3
Heading3

Internode
Canopy
Height

Length

Number

------ cm
Ethrel

4.0

2.5

1.3

7.3

7.0

0.5

3.3

EL 500

1.0

1.8

1.7

6.0

11.0

0.1

0.2

Embark

0.4

8.7

8.0

4.3

10.7

0.1

0.6

PP-333

0.4

2.5

1.0

5.0

10.7

0.1

0.2

Limit

2.5

7.5

3.0

5.0

9.0

0.1

0.4

Control

—

2.8

1.0

6.0

9.3

0.0

0.0

LSD (01=0 .05)

1.7

2.0

1.5

3.2

0.1

0.4

a

Ratings with 9 = no heads and 1 = full heading.
Ratings based on color; 9 = best, 6 = acceptable, 1 = brown.

60

Result of 1984 Turfgrass Disease
Control Trials
L . E . Sweets

Selected fungicides were tested in field trials for efficacy of control
of Bipolaris leaf spot (Bipolaris sorokinianum) on bluegrass and dollar spot
(Sclerotinia homeocarpa) on bentgrass. Trials were conducted on the Turfgrass
Research Plots at the Horticulture Research Station, Ames, Iowa.
Fungicides were applied to Penneagle bentgrass maintained at a 5/32-inch
cutting height and Park bluegrass maintained at 2-inch cutting height.
Fungicides were applied with a modified bicycle sprayer at 30 lb psi and a
dilution rate of 5 gal/1000 ft2 . The experimental design was a randomized
block plan with four replicates. The plots were 4 X 5 feet. Fungicides were
applied on a 7, 14, 21, or 30-day schedule. Applications began on June 6,
1984, and continued through September 26, 1984. Plots were evaluated for
percent diseased turf on July 18, and August 15, 1984.

Dollar Spot on Penneagle Bentgrass
The purpose of this study was to evaluate the relative efficacy of
standard and experimental fungicides in the control of dollar spot.
Fungicides included in the trial along with rates of application and spray
schedules are given in Table 26. The trial was conducted in an area with a
history of dollar spot and Rhizoctonia brown patch. Disease ratings for
dollar spot were made on July 18 and August 15. Ratings were made on the
basis of the percent of diseased turf per plot. Specific rating results are
presented in Table 26.

Bipolaris Leaf Spot on Park Bluegrass
The purpose of this trial was to compare the relative efficacy of
standard and experimental fungicides in the control of Bipolaris Leaf Spot.
Although the trial was located in an area with a history of leaf spot, little
leaf spot developed in the trial area during 1984. Ratings showed little
disease and no statistical differences between plots. None of the plots
showed symptoms of phytotoxicity from fungicides applied.

61

Table 26.

Treatment
Number

Rates, spray schedules and efficiency of fungicides tested in
dollar spot trial.

Product

Time Interval
Between Spray
(Days)

Rate of
Formulated Product
Disease Rating3
(oz/1000 ft2)
July 20
August 11

1

Daconil 2787

7-14

3.0

oz

2.5

2

Daconil 2787

7-14

6.0

oz

3.75 abc

3

Chipco 26019

14-21

1.5

oz

13.75 abc

37.50 ab

4

Chipco 26019

14-21

2.0

oz

5.00 abc

16.25 be

5

Bayleton 25DF

30

2.0

oz

7*5 abc

17.50 be

6

Bayleton 25DF

30

1.0

oz

12.50 abc

22.50 be

7

Bayleton 25DF

14

0.5

oz

8.75 abc

22.50 be

8

Bayleton 0.53&G

30

50.0

oz

2.50 be

26.25 abe

9

Bayleton 9.55&G

14

25.0

oz

6.25 abc

28.75 abc

10

Dyrene 4F

14

8.0

oz

11

Banner

21

1.0

oz

8.75 abc

15.00 be

12

Mancozeb 80W

21

8.0

oz

10.00 abc

20.00 be

13

Banner/Mancozeb

21

3.0

oz

5.00 abc

11.25 c

14

Banner/
Chlorothalonil

21

3.0

oz

6.25 abc

18.75 be

15

DPX H6573

14

.75 oz

10.00 abc

22.50 be

16

DPX H6573

14

1.25 oz

8.75 abc

17.50 be

17

Tersan 1991

14

1.0

oz

15.00 abc

28.75 abc

18

Duosan

14

3.0

oz

2.50 be

31.25 abc

19

Vorlan

14

2.0

oz

15.00 abc

46.25 a

20

Check

22.50 a

23.75 abc

be

21.25 ab

28.75 abc
12.50 c

22.50 be

£

a

Average of ratings from four replicated plots. Based on percentage of
diseased turf per plot. Means in a column followed by the same letter do
not differ significantly (DMRT, P = 0.05).
62

Sod Reestablishment Study
N. E. Christians

On September 19, 1980, a sod establishment study that included Glade,
Parade, Ram I, Rugby, and Touchdown Kentucky bluegrass was established at the
research station. Each cultivar planting measured 20 X 12 feet and the study
was arranged in a randomized complete block design with four replications.
Data were collected on this study until September 1982 when sod strength
measurements were taken, the investigation was terminated, and the results
were reported in an earlier research publication. The study area was
maintained with 4 lb N/1000 ft^/yr and mowed at a 2-inch mowing height during
the 1983 season.
All sod was removed uniformly from the study area on May 19, 1984, at a
cutting depth of 0.5 inches. The area was watered immediately after harvest
to prevent desiccation of the severed rhizomes. The entire study area was
fertilized with 1 lb N/1000 ft^ in May, August, and September of 1984 and the
area was irrigated to prevent drought stress. The objectives of this part of
the study are to observe the reestablishment of the five cultivars from
rhizomes and to determine if Kentucky bluegrass cultivars differ in their
reestablishment rate after harvest.
Parade and Ram I were the slowest to recover after harvest and Rugby was
intermediate (Fig. 6). Glade and Touchdown recovered most rapidly with plots
established to these cultivars showing 70% cover by October 13, 1984. The
data listed here are preliminary and more complete data, including sod
strength measurements, will be collected in 1985.

CD
CD

CD
CT>

CD
OO

CD

CD
<JD

CD
LO

j_______

J0AOQ %

64

CD

i_______ i

CD
OO

Figure 6t

cn

CD
OJ

rhizomes following harvest on May 19, 1984.

The regrowth of five Kentucky bluegrass cultivars from

REGROWTH FROM RHIZOMES

oo

Dormant Seeding Study
K. L. Diesburg

The optimum time to sow cool season turfgrasses in Iowa is from midAugust to mid-October.
Seedlings benefit from cool night temperatures,
adequate rainfall, and freedom from annual weed competition from September to
November.
Their roots can continue to grow at a very slow rate through the
winter if they have snow cover for insulation. The plants complete their
establishment in spring forming a mature turf capable of tolerating the heat
and drought stress of summer.
Even though 2 months in early fall seems like ample time in which to sow
turfgrass, the seasonal deadline is often missed, possibly because fall
directs our thinking toward harvest and preparation for winter rather than
planting and nursing a young crop. What is the next option if one finds that
early November has come and gone and the grass seed is still in the bag? The
usual course is to wait until next April or May to sow and accept the
consequences of summer heat and drought. Annual weeds are usually a problem
as well, even with the aid of Siduron preemergent herbicide.
In this experiment, another option was tested; planting seed when it is
too late for fall germination. This can be called dormant seeding, implying
that the seeds lie inactive in snow or soil as long as they are below 0°C.
They could have a low activity rate in 0 - 10°C, imbibing water and enlarging
the embryo in preparation for germination as soon as the soil becomes warm
enough.
Two Kentucky bluegrass cultivars (Rugby and Park) were tested at four
planting dates; the 6th of November, December, February, and March, at a
seeding rate of 0.6 lb seed/1000 ft^. A third cultivar (Parade) had been
previously planted on September 22. Establishment was excellent so it was
used for comparison to the experimental plots. Starter fertilizer (15-25-10)
was applied to the whole trial in November at a rate of 3.2 lbs material/1000
ft^. In November the seed was raked into bare soil, whereas in December,
February, and March it was worked into snow and ice.
Rugby and Park did not differ from one another in establishment at any
planting date treatment.
Their establishment was better in the November
seeding than in any other seeding date (Table 22).
The stand from the
September seeding of Parade, however, looked better than any treatment in the
experiment. When planted in November, the stands of Rugby and Park were
already covering the ground by April 26. This is about the time spring
seeding can first be done after the soil has dried enough to be worked.
Stands from the other three planting dates started out poorly but improved
gradually through the growing season. From June to September, annual weeds
were so thick, ratings could not be taken.
By October 17, stands from
February and March seeding dates were comparable to those of November.
Even though the soil was too cold in November for germination, the seed
could still be raked into it. Soil temperatures at a 2-inch depth ranged from
2 to 12°C through November, remained below 0°C from December to February 10,
65

and ranged between 0 and 12°C from February 11 through April. During the
times above 0°C, seed incorporated into the soil could imbibe moisture and
compl ete the early stages of g e r m i n a t i o n .
This can be called
"pregermination." As soon as the soil temperatures went above 10°C, the seeds
could quickly complete the final stages of germination and emerge from the
soil, thus avoiding the usual delays necessary in a spring seeding for working
the soil, imbibition, and release from dormancy. Stands in the December,
February, and March seedings were not good because most of their seeds were
trapped in the snow and ice, unable to take advantage of the above zero soil
temperatures.
The results from this experiment indicate that a dormant seeding in
November is preferable to the other dormant seeding dates tested, but it most
likely would not be as successful as an early fall planting.

Table 22.

Mean establishment ratings and seedling counts of Kentucky
bluegrass cultivars at five planting dates.

Ratings5
Planting
Date

Cultivar

Sept 22
Nov

Apr 26

May 25

Parade

9.0

9.0

6

Rugby
Park

7.0
8.0

Dec

6

Rugby
Park

Feb

6

March 6

Experiment
Mean
LSD ( X= 0.05)
a

Oct

Oct 17

Mean

9.0

9.0

9.0

—

7.0
7.5

7.0
7.5

8.0
8.0

7.2
7.7

177
162

3.0
3.0

3.5
3.0

3.5
4.0

4.5
5.0

3.6
3.7

24
48

Rugby
Park

3.0
4.0

4.0
4.0

5.0
6.0

6.0
6.0

4.5
5.0

42
75

Rugby
Park

2.0
3.0

4.0
3.5

3.5
5.0

5.5
7.0

3.8
4.6

42
48

4.4
0.0

4.9
1.4

5.3
1.9

6.4
1.1

5.2
0.9

79
30

3

Stand5

Ratings based on a scale of 1 - 9; 9 = plot completely covered, 5 = plot
half covered, 1 = no plants.
Stand estimated by counting the number of seedlings in a random square foot
three times per plot.

66

Influence of Soil Compaction on
49 Kentucky Bluegrass Cultivare
M. L. Agnew

The 49 Kentucky bluegrass cultivars located in section two of the
turfgrass reaserch area were seeded in the fall of 1979« These plots were
fertilized at a rate of 4 lb N/1000 ft2/year (urea) in both the 1980 and 1981
seasons and with 4 lb N/1000 ft2/year (SCU) in 1982, 1983, and 1984. No
insecticides or fungicides have been used on the area. Irrigation was applied
as needed to prevent drought.
In 1985, this cultivar trial was used to evaluate the effects of soil
compaction on the growth and development of 49 Kentucky bluegrass cultivars.
Compaction was applied with a smooth power roller which exerted a static
pressure of 2.5 Kg cm-2 (35.5 in-2).
Measurements to be taken include thatch development, root density, shoot
density, clippings, and visual quality. With this information, we should be
able to give better cultivar recommendations for heavy traffic areas.

67

Introducing the Iowa State
University Personnel Affiliated
with the Turfgrass Research

DR. MICHAEL AGNEW

Assistant Professor, Turfgrass Extension.
Horticulture Department.

DR. NICK CHRISTIANS

Associate Professor, Turfgrass Science.
Research and Teaching. Horticulture Department.

MISS CHARLEEN CIACCIO

Turfgrass Graduate Student, Horticulture
Department M.S. (Hodges).

MR. KEN DIESBURG

Turfgrass Graduate Student and Research Associate,
Horticulture Department Ph.D. (Christians).

MR. MICHAEL GAUL

Turgrass Graduate Student, Horticulture
Department M.S. (Christians).

DR. CLINT HODGES

Professor, Turfgrass Science. Research and
Teaching. Horticulture Department.

MR. YOUNG JOO

Turfgrass Graduate Student, Horticulture
Department Ph.D. (Christians).

DR. DONALD LEWIS

Associate Professor, Extension Entomologist.
Entomology Department.

MR. BRIAN MALOY

Turfgrass Graduate Student, Horticulture
Department M.S. (Christians).
Graduated - Spring 1985

DR. JAMES MIDCAP

Associate Professor, Ornamental Horticulture
Extension. Horticulture Department.

MR. RICK MOORE

Field and Lab Technician.
Department.

MR. PAUL NORMAN

Irrigation Technician.

MR. MIKE NULL

Field Technician.

MR. ZACHARY REICHER

Field and Lab Technician.

MISS MEI-YU SU

Turfgrass Graduate Student.
Department M.S. (Hodges).

DR. LAURA SWEETS

Associate Professor, Extension Plant Pathologist.
Plant Pathology Department.

68

Horticulture

Horticulture Department.

Horticulture Department.
Horticulture Department
Horticulture

COM PANIES AND ORGANIZATIONS
that have m ade donations to the
Research Program
Special thanks is expressed to the Big Bear Turf Equipment Company and
Cushman Turf for providing a Cushman Truckster for use at the research area in
1985, to Tri-State Turf & Irrigation for providing a Greensmaster III Triplex
Greensmower for use on the research green this year, and to the Toro Company and
Tri-State Turf & Irrigation for providing a Toro 84 Triplex mower for use in
1985.

Eagle Green Corporation
Omaha, Nebraska 68103

American Hoechst Corporation
Agricultural Chemicals Department
Route 1 - Box 7
Brownsdale, Minnesota 55918

Elanco Products Company
5600 South 42nd Street
Post Office Box 3008
Omaha, Nebraska 68103

The Andersons
Post Office Box 119
Maumee, Ohio 43537

Eli Colby Company
Post Office Box 248
Lake Mills, Iowa 50450

Big Bear Turf Equipment Company
1840 Fuller Road
West Des Moines, Iowa 50265

GrassRoots Turf
6143 Southwest 63rd
Des Moines, Iowa 50321

Brayton Chemical Company
Post Office Box 437
West Burlington, Iowa 52655

Hawkeye Chemical Company
Post Office Box 899
Clinton, Iowa 52732

Britt Tech Corporation
Post Office Box 216
Britt, Iowa 50423
CIBA-Geigy Corporation
Agriculture Division
Greensboro, North Carolina
Cushman Turf
5232 Cushman
Lincoln, Nebraska

International Seeds
820 First Street
Post Office Box I68
Halsey, Oregon 97348

27049

Iowa Golf Course Superintendents
Association
68501
Iowa Professional Lawn Care
Association

W. A. Cleary Corporation
1049 Somerset Street
Somerset, New Jersey 08873
Dow Chemical
IO89O Benson
Shawnee Mission, Kansas
Dupont Incorporated
1007 Market Street
Wilmington, Delaware

Iowa Turfgrass Growers
Iowa Turfgrass Institute
Lebanon Chemical Corporation
Country Club Fertilizer Division
Post Office Box I80
Lebanon, Pennsylvania 17042

66210

19898
69

SDS BioTech Corporation
Agricultural Chemical Business
2015 Spring Road
Oak Brook, Illinois 60521

Lesco Inc.
300 South Abbe Road
Elyria, Ohio 44035
Loft-Kellogg Seed
Post Office Box 684
322 East Florida Street
Milwaukee, Wisconsin 53201

Spraying Systems Company
N Avenue at Schmale Road
Wheaton, Illinois 60187

M & A Enterprises
4346 South 90th
Omaha, Nebraska 68127

Stauffer Chemical Company
10250 Regency Circle
Omaha, Nebraska 68114

Mallinckrodt Incorporated
Post Office Box 5439
St. Louis, Missouri 63417

Par Ex
Swift Agricultural Products Corp.
518 Pauline Drive
Buffalo Grove, Illinois 60090

Monsanto Company
Agricultural Products Division
800 North Lindbergh Boulevard
St. Louis, Missouri 63166

3M Company
Agricultural Products Division
233-IN-05 3M Center
St. Paul, Minnesota 55101

Nor-Am Chemical Company
3509 Silverside Road
Post Office Box 7495
Wilmington, Delaware 19803

Terra Chemical Corporation
Box 218
Quimby, Iowa 51049

PBI/Gordon Corporation
1217 West 12th Street
Post Office Box 4090
Kansas City, Missouri 64101

The Toro Company
Irrigation Division
5825 Jasmine Street
Riverside, California

Pickseed West Incorporated
Post Office Box 888
Tangent, Oregon 97389

Tri State Turf & Irrigation Company
6125 Valley Drive
Bettendorf, Iowa 52722

Rhone-Poulenc Chemical Company
Black Horse Lane
Post Office Box 125
Monmouth Junction, New Jersey 08852

Union Carbide
Agricultural Products
Ambler, Pennsylvania 19002

92504

0. M. Scott & Sons
Marysville, Ohio 53040

*

In the rush to prepare this information for the field day report, some
companies may have inadvertently been missed. If your company has provided
financial or material support for the research program, and is not
mentioned above, please contact me so your company name can be added in
future reports.
Nick Christians

70