0 Seed to Play in 4 Weeks!

Article provided by Pamela Sherratt, Dr. John R. Street & Arly Drake
The Ohio State University

One of the goals of our Sports Turf Extension Program is to find ways to help sports turf managers get their fields ready for play in the shortest time possible, because many schools and parks and rec fields in Ohio are used 24/7 with little or no down time.

The ideal time to do any kind of renovation is in the fall (August 15-September 15), when soils are warm, there is a good chance of rain, and weed pressure is low, but there are other times when renovation can be done. For example, some fields are used February through May and then there is some down-time in June and July before fall sports resume in August.

Renovating fields in June and July is far from ideal! Unfavorable weather conditions and tremendous pressure from weeds like crabgrass, goosegrass and nutsedge make it almost impossible to get cool-season grasses established, especially slow growing species like Kentucky bluegrass. One option of course is to use sod, not only because sod gives instant turf cover, but also because it offers field managers a great way to get Kentucky bluegrass back onto the playing surface, after perhaps years of over-seeding with rye.

Seed to Play Study 2008-2009

If there is time to seed and, more importantly, someone available to nurture the newly established seed, then it is possible to seed successfully in June & July in Ohio. A study was conducted at the OTF Research & Education Facility in both 2008 and 2009 whereby cool-season grasses were seeded in June or early July to determine the best practices to achieve 100% grass cover in the shortest period of time, with little or no interference from weeds. The study area was native soil (silt clay loam) and there was supplemental irrigation via an in-ground system.

Seedbed Preparation

In June 2008, the seedbed area was prepared with minimal soil disturbance: the existing ground cover was killed with a non-selective herbicide then mowed short to remove as much ground cover as possible. Prior to seeding, a heavy-duty scarifier was used to create shallow slits and grooves on the soil surface, so that seed:soil contact would be achieved.

he end result of this particular seedbed preparation was minimal soil disturbance, and therefore minimal weed competition, with less than 30% weed cover that was easily controlled with a postemergence herbicide (Drive/quinclorac) once the new grass seedlings were a month old. In 2009, the seedbed was prepared the textbook way - it was tilled to a depth of 4-inches and raked to produce a tilth suitable for seeds.

Two seedbeds were prepared this way: one seedbed was sprayed with Tenacity (mesotrione) herbicide the day of seeding, and one was not. The seedbed that was sprayed with Tenacity resulted in a clean, weed-free seedbed. The seedbed without Tenacity resulted in >90% weed cover, namely crabgrass, yellow nutsedge and goosegrass (Figure 1). The conclusion here is two-fold: try not to disturb the soil and bring weed seeds to the surface, and if the soil is disturbed, used Tenacity herbicide at the time of seeding to prevent weed seed germination.

pam pics.jpgFigure 1: Seedbed infested with weeds (L), and clean seedbed (R) treated with Tenacity (mesotrione) at time of seeding


The Fungicide Effect?

During previous studies there has been some evidence to suggest that fungicides could have a beneficial, non-target effect on turf health, particularly during the establishment period. In 2008, newly seeded perennial ryegrass turf that had been treated with granular Subdue Maxx (mefenoxam) fungicide at the time of seeding showed improved color, density, biomass, sward height, and overall establishment quality, compared to perennial ryegrass that had had no Subdue applied.

The Subdue treated turf also contained greater (0.5%) tissue nitrogen compared to the non-treated. Neither of the grasses showed symptoms of disease, so the fungicide appeared to have a non-target effect on turf health (Figure 2). In 2009, both granular Heritage (azoxystrobin) and granular Subdue Maxx were applied at time of seeding. Results were similar to those seen in 2008, in that fungicide treated turf provided better quality and quicker establishment. Mid-way through the study however, the untreated and Subdue treated turf got infected with rust (Puccinia) and so the non-target effect was lost. The Heritage treated turf was not affected by rust.

pam plots.jpgFigure 2: The effects of granular Subdue fungicide on the establishment quality of perennial ryegrass

Cultural Practices & Seeding Rates

Seeding rates were slightly higher than normal to expedite rapid establishment. Cultivars were selected for quick establishment and were as follows:

• Kentucky bluegrass - 50:50 blend of Barari and Barimpala seeded at 4 lbs per 1,000 sq.ft.
• Perennial ryegrass - 50:50 blend of Barlennium and Bar LP 7613 seeded at 10 lbs per 1,000 sq.ft
• Tall fescue - 50:50 blend of Barrobusto and Barvado seeded at 8 lbs/1,000 sq.ft.

Starter fertilizer 12-24-8 was applied at 1 lb N per 1,000 sq. ft. at time of seeding, then at 0.5 lb N per 1,000 sq. ft. at 14 and 28 days after seeding. Irrigation was set up on a syringing cycle for 5 minutes each cycle at 8am, 11am, 2pm, and 5pm each day until full germination, and then reduced to 2 x daily. Once grass was fully established, irrigation was used only to replenish ET.

critical part of seedling establishment is mowing. As soon as the seedlings reach 3" tall, they need to be mowed with a rotary mower, daily if possible. Regular mowing promotes tillers, thereby increasing turf density and percent ground cover. If daily mowing is out of the question, mowing at least 3 x week in the establishment phase is essential to the turf being ready for play. Mowing 1 x per week will not produce dense turf quickly enough.

Results

As expected, the first grass to germinate was perennial ryegrass (3 days), followed by tall fescue (5 days) and Kentucky bluegrass (6 days). Percent ground cover was determined by both visual rating and by point quadrant, whereby actual plants in a given area are counted. Just the kind of job a student likes to take on! At four weeks after seeding (WAS), perennial ryegrass with Heritage was at 98% ground cover, with Subdue at 94% cover and untreated at 88% cover. At six WAS, Kentucky bluegrass with Heritage was at 85% ground cover, with Subdue at 77% cover and untreated at 71% cover (Table 1). Note: At 6 WAS all treatments not treated with Heritage had rust.

Table 1: Establishment Rate (Percent Ground Cover) of Three Cool Season Grasses, Determined by Point Quadrant

Treatment

July 22

(5 DAS)

July 28

(11 DAS)

August 4

(18 DAS)

August 11

(4 WAS)

August 18

(5 WAS)

August 25

(6 WAS)

PRG + Subdue

60

71

83

94

90

92

KBG + Subdue

0

23

46

64

67

77

TF + Subdue

4

42

63

65

71

71

PRG + Heritage

54

60

94

98

98

100

KBG + Heritage

2

31

58

52

79

85

TF + Heritage

5

42

69

73

65

81

PRG

67

75

69

88

85

94

KBG

<1

27

48

50

58

71

TF

<1

44

52

60

65

81

LSD (0.05)

17

14

25

19

18

11



Measuring "Playing Quality"

There are several criteria for determining when turf is "playable", notably percent ground cover and shear strength. The shear strength component is typically measured by two pieces of equipment: (1) rotational shear equipment that mimics a foot rotating on turf, developed by Canaway in 1975 and (2) lateral shear equipment that mimics a foot digging into the turf and pushing out a divot, developed by Clegg (Figure 3).

At four WAS all perennial ryegrass treatments were determined to be playable, with shear strengths that exceeded recommendations and ground cover at or around 90%. At six WAS, all treatments displayed acceptable shear strengths. Kentucky bluegrass treated with Heritage at time of seeding was at 85% ground cover, with tall fescue at 81% ground cover (Table 2 and Figure 4). It should be noted that soil moisture was ~ 25% at time of testing. Saturated native soils may have given lower shear strength results.

pam traction.jpgFigure 3: Apparatus fro measuring turf shear strength: Rotational shear (L) and lateral shear (R)

Table 2: Playing Quality at Six WAS, Determined by % Ground Cover and Shear Strength

Treatment

Percent Cover

(Point Quadrant)

Rotational Shear*

Strength (Nm)

Lateral Shear**

Strength (Nm)

PRG + Subdue

92

64.6

117.7

KBG + Subdue

77

59.8

113.1

TF + Subdue

71

61.2

125.2

PRG + Heritage

100

69.8

115.7

KBG + Heritage

85

55.4

102.0

TF + Heritage

81

60.7

118.2

PRG

94

60.2

106.0

KBG

71

53.4

89.3

TF

81

56.8

115.3

LSD (0.05)

11

6.0

24.4

* STRI recommendation (Canaway, 1990, McClements and Baker, 1994b) is >25 Nm for soccer and >35Nm for rugby
** Mature, dense Kentucky bluegrass ~ 90Nm (Sherratt et.al, 2005)
pam pgr 4.jpg
Figure 4: Percent ground cover of perennial ryegrass at 4 WAS (L) and Kentucky bluegrass 6 WAS (R)

Conclusions from the Study

• A clean seedbed is possible by creating minimal soil disturbance or by applying Tenacity herbicide at time of seeding
• Perennial ryegrass was playable four weeks after seeding
• Kentucky bluegrass and tall fescue treated with Heritage were playable six weeks after seeding. Untreated tall fescue may also be playable in six weeks.
• Fungicides have a non-target effect on turfgrass health and could possibly be used to enhance establishment
• This is not a low-maintenance plan. For this program to work, there must be supplemental irrigation (syringing at first), applications of starter fertilizer, and frequent mowing as soon as possible.

Thanks to the study sponsors: Syngenta, Barenbrug & The Ohio Turfgrass Foundation.

Questions about this study can be directed to Pam Sherratt at Sherratt.1@osu.edu

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