The Effect of Winter Covers on Autumn Established Kentucky Bluegrass
David D. Minner, Deying Li, and Federico Valverde
Objectives
The objective of this study was to determine if winter covering of autumn seeded Kentucky bluegrass had any effect on turf establishment by the following spring. Various tarp colors and cover materials were evaluated.
Background
The specific color of vinyl-coated polyester tarps used to protect baseball fields from rain has been shown to have a dramatic effect on turf color and growth when used for the entire winter as a protective cover on Kentucky bluegrass in Iowa (Minner et. al. 2001). The effect of tarp color on turf performance follows the general ranking from best to worst; red, yellow, orange > white, purple, light-blue, blue > gray/white, light-green, dark-green, white/black, black/white. There was a strong correlation (r = 0.78 to 0.99) between turf color and photosynthetic photon flux density for both the vinyl and polyethylene materials. Winter covering produced less injury than spring covering, especially for the light-green, dark-green, black/white, and white/black tarps. More investigation is needed to determine if tarp color has any effect on turf performance when covered for shorter intervals and under warmer conditions during the summer. The research mentioned above was conducted on mature stands of Kentucky bluegrass. Seedling turf is often present in late autumn as the result of overseeding after the autumn football season. This study was initiated to evaluate the effect of covering materials placed over seedling turf in the autumn and then removed in the spring.
Materials and Methods
Thirteen cover materials were used in this study (Table 1.) The experimental design was a randomized complete block with three replications. Individual covered plots were 5 ft by 5 ft. ‘Unique’ Kentucky bluegrass was planted in September 2000 at 3 lbs/1000 sq.ft. Turf covers were placed on 7 December 2000, approximately 70 days after seedling emergence. On 4 April 2001, all cover materials were shifted 2.5 ft so that half of the originally covered plot was uncovered and the remainder of the plot continued to be covered. Turf color was visually rated on a scale of 1 to 10, 10 = darkest green and 1 = no green color (white or brown tissue) and 6 = lowest acceptable color. Turf leaf growth was rated on a scale of 1 to 10, 10 = most vertical leaf growth and 1 = no vertical leaf growth. Turf cover was visually estimated as the percent of the plot area with living turf. Turf evaluations were made on 4 and 19 April, and 3 May 2001.
Data were analyzed using ANOVA and the results are listed in Tables 2, 3, and 4.
Results
On 4 April 2001 the yellow and orange tarps provided the best color when covered in the winter. When covered for a longer period of time (winter/spring) yellow, orange, and red tarps showed poor color and elongated growth on 19 April 2001. Even with this less desirable growth, the yellow and orange tarps had the highest amount of turf cover, 82% and 72% cover, respectively. On 19 April the winter covered grass had significantly more cover under the Typar black, Turf Defender, Evergreen, white, and red tarps when compared to the non-covered control plot. Enka Plus, light-green, purple, and the control had inferior turf cover on 19 April 2001 in the winter/spring covered plots.
Literature Cited
Minner, D.D., D. Li, V. Patterozzi, and J.J. Salmond. 2001. The effect of tarp color and material on Poa pratensis growth. International Turfgrass Society Research Journal, Canada, 2001.
Table 1.
Cover materials placed over autumn-established Kentucky bluegrass.|
Cover Material |
Description |
|
1. Typar white |
Nonwoven fabric composed of thermally bonded, continuous polypropylene |
|
2. Typar black |
Nonwoven fabric composed of thermally bonded, continuous polypropylene |
|
3. Enkamat Plus |
Enkamat Plusâ is Enkamat with a geotextile fabric attached to one surface. Used primarily to protect field from traffic. |
|
4. Enkamat Flat Back |
Enkamatâ is a bulky black mat made from nylon threads which are fused together where they cross. Although Enkamat is primarily used to physically protect turf or prevent erosion, the black color of Enkamat also may enhance turf greenup during the spring. |
|
5. Turf Defender |
Woven polypropylene |
|
6. Covermaster Evergreen |
Evergreenâ turf enhancement cover high density, translucent polyethylene by Covermaster, Inc. |
|
7. VCP Yellow |
7 oz./sq.yd. vinyl-coated polyester (274 gms/sq. meter). |
|
8. VCP Dark blue |
7 oz./sq.yd. vinyl-coated polyester (274 gms/sq. meter). |
|
9. VCP Light green |
7 oz./sq.yd. vinyl-coated polyester (274 gms/sq. meter). |
|
10. VCP White |
7 oz./sq.yd. vinyl-coated polyester (274 gms/sq. meter). |
|
11. VCP Orange |
7 oz./sq.yd. vinyl-coated polyester (274 gms/sq. meter). |
|
12. VCP Red |
7 oz./sq.yd. vinyl-coated polyester (274 gms/sq. meter). |
|
13. Control |
No cover material |
|
14. VCP Purple |
7 oz./sq.yd. vinyl-coated polyester (274 gms/sq. meter). |
|
Table 2. Turf color, growth, and % cover rated on 4 and 19 April 2001 for autumn established Kentucky bluegrass that was covered for various durations during the winter and/or spring. |
||||||||||||||
|
Winter Cover |
Winter Cover |
Winter/Spring cover |
Spring Cover |
|||||||||||
|
Covered 12-8-00 to 4-4-01 |
Covered 12-8-00 to 4-4-01 |
Covered 12-8-00 to 5-3-01 |
Covered 4-4-01 to 5-3-01 |
|||||||||||
|
Rated 4-4-01 |
Rated 4-19-01 |
Rated 4-19-01 |
Rated 4-19-01 |
|||||||||||
|
Treatment |
Color |
Growth |
Color |
Growth |
% Cover |
Color |
Growth |
% Cover |
Color |
Growth |
% Cover |
|||
|
1 |
6 |
3 |
4 |
1 |
41.7 |
6 |
3 |
73.3 |
6 |
3 |
73.3 |
|||
|
2 |
4 |
2 |
4 |
1 |
86.7 |
5 |
4 |
68.3 |
7 |
3 |
86.7 |
|||
|
3 |
4 |
3 |
5 |
1 |
21.7 |
2 |
1 |
11.7 |
3 |
1 |
23.3 |
|||
|
4 |
5 |
2 |
5 |
1 |
43.3 |
6 |
4 |
63.3 |
7 |
3 |
71.7 |
|||
|
5 |
5 |
2 |
4 |
1 |
75.0 |
6 |
2 |
68.3 |
6 |
3 |
88.3 |
|||
|
6 |
5 |
3 |
4 |
1 |
71.7 |
6 |
2 |
63.3 |
7 |
3 |
81.7 |
|||
|
7 |
7 |
7 |
4 |
3 |
48.3 |
4 |
8 |
81.7 |
4 |
7 |
78.3 |
|||
|
8 |
5 |
4 |
4 |
1 |
58.3 |
4 |
3 |
65.0 |
5 |
3 |
68.3 |
|||
|
9 |
5 |
6 |
3 |
1 |
35.0 |
2 |
3 |
11.7 |
3 |
2 |
33.3 |
|||
|
10 |
5 |
3 |
4 |
2 |
76.7 |
6 |
5 |
73.3 |
6 |
4 |
80.0 |
|||
|
11 |
7 |
7 |
3 |
3 |
56.7 |
4 |
7 |
71.7 |
6 |
5 |
75.0 |
|||
|
12 |
6 |
6 |
4 |
2 |
76.7 |
4 |
6 |
63.3 |
5 |
5 |
76.7 |
|||
|
13 |
3 |
1 |
5 |
1 |
21.7 |
5 |
1 |
21.7 |
5 |
1 |
23.3 |
|||
|
14 |
6 |
8 |
3 |
2 |
15.0 |
2 |
4 |
26.7 |
2 |
4 |
30.0 |
|||
|
LSD 0.05 |
1.4 |
2.3 |
NS |
0.9 |
35.0 |
1.4 |
1.8 |
20.3 |
1.5 |
1.3 |
24.5 |
|||
|
Table 3. Turf color, growth, and % cover on 3 May 2001 for autumn established Kentucky bluegrass that was covered for various durations during the winter and/or spring. |
||||||||||||
|
Dec. 8, 2000 to Apr. 4, 2001 |
Dec. 8, 2001 to May 3, 2001 |
Apr. 4, 2001 to May 3, 2001 |
||||||||||
|
Treatment |
Color |
Growth |
% Cover |
Color |
Growth |
% Cover |
Color |
Growth |
% Cover |
|||
|
1 |
5 |
6 |
46 |
6 |
9 |
57 |
6 |
9 |
57 |
|||
|
2 |
5 |
6 |
38 |
7 |
5 |
55 |
7 |
5 |
62 |
|||
|
3 |
4 |
6 |
25 |
1 |
1 |
12 |
2 |
5 |
12 |
|||
|
4 |
5 |
6 |
52 |
7 |
7 |
60 |
7 |
8 |
58 |
|||
|
5 |
5 |
6 |
40 |
5 |
8 |
53 |
6 |
8 |
63 |
|||
|
6 |
5 |
6 |
50 |
6 |
8 |
83 |
6 |
9 |
85 |
|||
|
7 |
5 |
6 |
37 |
9 |
6 |
73 |
8 |
6 |
65 |
|||
|
8 |
5 |
5 |
35 |
3 |
2 |
25 |
3 |
2 |
17 |
|||
|
9 |
5 |
7 |
18 |
1 |
1 |
0 |
1 |
1 |
0 |
|||
|
10 |
5 |
6 |
37 |
8 |
6 |
53 |
7 |
7 |
52 |
|||
|
11 |
5 |
6 |
38 |
7 |
5 |
55 |
7 |
5 |
60 |
|||
|
12 |
5 |
6 |
55 |
7 |
5 |
55 |
7 |
6 |
57 |
|||
|
13 |
5 |
7 |
43 |
5 |
7 |
45 |
5 |
7 |
45 |
|||
|
14 |
4 |
6 |
40 |
2 |
1 |
32 |
2 |
1 |
32 |
|||
|
LSD 0.05 |
||||||||||||
|
Table 4. Temperature under the cover materials. |
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|
29-Mar |
30-Mar |
31-Mar |
1-Apr |
5-Apr |
6-Apr |
||||||||||||||||||
|
Treatment |
Max. |
Min. |
Avg. |
Max. |
Min. |
Avg. |
Max. |
Min. |
Avg. |
Max. |
Min. |
Avg. |
Max. |
Min. |
Avg. |
Max. |
Min. |
Avg. |
|||||
|
Typar white |
12.8 |
1.8 |
5.8 |
23.5 |
2.0 |
9.1 |
19.2 |
-0.2 |
7.3 |
26.8 |
-0.6 |
9.5 |
21.1 |
8.6 |
13.6 |
15.8 |
1.8 |
11.0 |
|||||
|
Typar black |
10.1 |
0.3 |
3.8 |
23.1 |
0.9 |
7.5 |
16.4 |
-0.7 |
5.1 |
20.6 |
-1.1 |
6.4 |
18.8 |
7.4 |
12.0 |
14.3 |
0.0 |
9.8 |
|||||
|
Enkamat Plus |
7.0 |
0.6 |
3.0 |
12.8 |
0.5 |
4.4 |
10.4 |
-0.3 |
3.8 |
14.7 |
-0.4 |
4.6 |
13.0 |
6.1 |
8.8 |
11.8 |
-2.3 |
7.5 |
|||||
|
Enkamat Flat Back |
10.8 |
0.1 |
4.9 |
21.1 |
0.5 |
7.7 |
15.7 |
-1.6 |
5.6 |
23.2 |
-1.9 |
7.3 |
18.8 |
7.8 |
12.3 |
15.6 |
1.9 |
10.0 |
|||||
|
Turf Defender |
11.1 |
0.3 |
4.7 |
22.4 |
0.3 |
7.6 |
18.1 |
-2.0 |
5.9 |
23.7 |
-2.5 |
7.3 |
20.9 |
8.3 |
13.3 |
15.8 |
2.0 |
9.9 |
|||||
|
Covermaster |
14.3 |
0.2 |
5.3 |
25.6 |
0.4 |
8.7 |
19.2 |
-1.2 |
6.3 |
28.7 |
-1.5 |
8.4 |
21.4 |
8.1 |
13.0 |
15.7 |
1.8 |
10.0 |
|||||
|
Yellow |
10.0 |
1.0 |
4.6 |
20.4 |
1.3 |
7.3 |
17.5 |
-0.7 |
6.4 |
20.5 |
-1.0 |
7.3 |
19.0 |
8.7 |
12.9 |
15.4 |
1.9 |
10.4 |
|||||
|
Dark blue |
10.4 |
1.5 |
4.7 |
20.8 |
1.4 |
7.8 |
18.2 |
-0.6 |
6.6 |
26.3 |
-1.2 |
8.3 |
24.2 |
8.7 |
13.8 |
17.0 |
2.6 |
10.7 |
|||||
|
Light green |
10.1 |
1.4 |
4.9 |
20.3 |
1.5 |
8.1 |
17.8 |
-0.3 |
6.7 |
22.5 |
-0.7 |
8.2 |
24.8 |
8.3 |
13.8 |
16.1 |
1.6 |
10.0 |
|||||
|
White |
6.6 |
-0.5 |
3.1 |
14.8 |
0.6 |
5.1 |
13.9 |
-0.8 |
5.0 |
16.9 |
-1.3 |
5.7 |
15.6 |
7.8 |
11.3 |
14.2 |
0.7 |
9.3 |
|||||
|
Orange |
11.0 |
0.5 |
4.7 |
22.2 |
0.7 |
7.4 |
19.5 |
-1.2 |
6.4 |
22.2 |
-1.5 |
7.2 |
21.5 |
8.5 |
13.0 |
15.3 |
1.2 |
9.7 |
|||||
|
Red |
12.2 |
0.5 |
5.0 |
26.3 |
0.5 |
8.5 |
19.0 |
0.5 |
7.0 |
23.5 |
-0.2 |
8.6 |
18.3 |
8.4 |
12.1 |
14.7 |
-0.4 |
9.4 |
|||||
|
Control |
15.1 |
0.2 |
5.2 |
19.0 |
1.0 |
7.6 |
16.1 |
-1.3 |
5.9 |
22.0 |
-1.9 |
7.1 |
20.6 |
9.0 |
13.5 |
17.2 |
3.7 |
10.6 |
|||||
|
LSD0.05 |
3.6 |
1.1 |
0.8 |
6.3 |
NS |
1.0 |
NS |
NS |
1.0 |
6.0 |
NS |
1.3 |
2.7 |
0.9 |
1.0 |
1.5 |
1.5 |
1.4 |
|||||