Period 1

aeration and Topdressing (1)

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LHAP 106 Turfgrass & Ext Softscape Presentation turf

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Slide 1 LHAP 106 - Aeration & Topdressing Slide 2 What is the problem? Compaction or Thatch? Or is it just spring debris? Many interventions are “just because it’s what we do” BEGIN with analysis: What NEEDS to be done? Options: Debris Rake - freshens the lawn Power Rake - thatch control Slicing - thatch / light aeration Aeration Core Solid Tine Tilling and overhaul What measures will you take to ensure this doesn’t happen again? Slide 3 Mechanical Raking Slide 4 Dethatch Vs Rake: Objective of thatch removal, vs breaking up dead leaves and debris from winter. Words: Verticutter & Power-Rake are used interchangeably. Top left: Verticutter used to slice stolons and relieve minor compaction. Top right - rake blade (puts strain on engines) Bottom - Stihl Yard Boss Rake Slide 5 This feels so cathartic - like you’re cleaning the lawn and purging the long hard winter blues. The problem is that it may end up removing the entire thatch profile. If you really had so much thatch to begin with, evaluate the three legged maintenance “stool”. Slide 6 Two main options: Solid Tine or Hollow Core Slide 7 Solid Tine Aeration: Advantages May be done on entire surface or selected areas Minimal disruption to play, can be done anytime Quick solution to compaction, air and water infiltration Several options for varying depths. Disadvantages Only provides temporary relief Tool not available for rent (usually) Slide 8 Spiking Minimal disruption, quick recovery, temporary fix. May be done several times a month if needed. Normally tines vary in depth from “Spiking” depth (2.5 cm) to 30 cm depth Slide 9 Deep Tine Aeration: Advantages Break through soil profiles / disrupt layering Amend soil profiles deeper Gas exchange throughout entire soil profile Water penetration and increased sub-surface drainage Increased rooting depth Disadvantages Disruption to play Must top dress afterwards Need healthy turf to perform Slide 10 Core Aeration Removal of soil cores leaving holes in the turf Benefits All the same benefits of Solid Tine PLUS: Stimulates root growth within the holes Increased shoot growth Rental machines more available Disadvantages Disruption of turf surface Longer recovery time compared to solid tine Increased weed development (ie. Poa annua) Slide 11 Slide 12 Coring: hollow tine Two types of equipment: Piston - linking vertical and forward motion (drive carefully or you’ll overdrive the speed of the pistons) - Expensive machine, usually on sports turf Drum Rollers Tines on a drum, mounted on a rotating shaft Quicker but can tear the grass out May not be heavy enough to drive into the grass effectively Slide 13 Slide 14 Core Aeration Option 1: Leave the Cores Advantage - CHEAP! Disadvantages - Cannot be left on playing surface. Self defeating on lawn turf (no amendment, adds to thatch). If you ARE going to do it though, suggest doing in the Fall so they break down over winter and any remainder is collected in spring rake up. Slide 15 Core Aeration Option 2: Core Dispersal Instead of waiting for mother nature… cores are broken up, core cavities filled in by former cores Roots move in quickly, disruption of play minimized Disadvantage - still can add to thatch, no amendment, added cost. Slide 16 Core Aeration Core Removal and Topdressing Allows soil amendments through topdressing holes Recovery is fairly quick (holes close up quickly) Slow release N added Disadvantages: More labour Disposal Cost Amendment Cost Possible Layer disease Slide 17 Core Collection Slide 18 Core Aeration for texture amendment In actual fact, there’s only about 3% disruption, so it will take multiple treatments to create real change. Slide 19 Topdressing Slide 20 What is TOPDRESSING? ‘The practise by which a thin layer of soil (or other material) is applied to an established turf or a new turfgrass planting.’ Slide 21 Selecting Topdressing Material If existing soil is favourable, choose something as close to what is there as possible May consider stockpiling soil during construction If existing soil is unfavourable Compost, aged manure, peat moss (sphagnum), zeolites, calcined clay particles, diatomaceous earth materials Check particle size before you buy (greens / sand soils) Reminder: will take many applications to affect texture Slide 22 Layering: Occurs in soil profile through the use of different top dressing materials over time Perched water tables Drainage problems Black Layer disease Watch for layering when top dressing after core aeration - make sure new material is well worked in. H2S Slide 23 Reasons to TOPDRESS Post aeration (surface disruption) Provide crown protection from winter injury/eliminate ice Add Organic Matter!!! Most clay based soils will benefit from OM, especially if compaction prone Improve CEC & Microbial activity in Sand Root Zones New products claim to boost CEC without affecting drainage or porosity Improved quality putting surface Preventative measure for thatch development on greens Post sod - may help if there has been desiccation of edges Slide 24 How Often?? Slide 25 Topdressing Rate and Frequency Never cover more than 60% of leaf blade 0.05 -0.1 cubic yards 100m sq. = 5 – 10 mm in depth Mowing Height of 50 mm (5 cm) on KB Lawn. 30 mm (3 cm) MAX coverage Aeration displacement will have a major effect on topdressing volumes Like Mowing, Frequency is based on plant recovery and shoot growth rates. Slide 26 Light, Frequent Topdressing Usually on golf greens for thatch 1-3 week intervals Requires minimal brushing or matting depending on consistency of throw Minimal disruption Slide 27 Considerations: Topdress after Aeration is the usual Watering is a good complement vs. over-matting or brushing too much (crown abrasion) Topdressing PRIOR to aeration on new greens will reduce ‘tire rutting’ Fertilize PRIOR to topdressing, not after! (fertilizer will be closer to rootzone that way) Slide 28 Slide 29 At some point, it may be worth it to just start again… consider sod or faster germinating seed?! Slide 30 Machinery Used: Often performed with manual, centrifugal spreader or by hand with shovel Powered mechanical top-dresser Large capacity to reduce time spent refilling

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Slide 1

LHAP 106 - Aeration & Topdressing

Speaker Notes

Very basic but okay video…
http://www.youtube.com/watch?v=tD_bzith8SA&feature=related

Slide 2

What is the problem?

Compaction or Thatch? Or is it just spring debris?

Many interventions are “just because it’s what we do”

BEGIN with analysis: What NEEDS to be done?

Options:

Debris Rake - freshens the lawn

Power Rake - thatch control

Slicing - thatch / light aeration

Aeration

Core

Solid Tine

Tilling and overhaul

What measures will you take to ensure this doesn’t happen again?

Slide 3

Mechanical Raking

Speaker Notes

When the thatch problem is too advanced for a verticutter, aeration can be employed.
Solid tine will punch holes for immediate, short term solutions (VERY much so)
Core aeration would be the better to physically remove it.
BEWARE of tearing out plants with drum rollers. Remember that severing stolons and rhizomes will promote more growth.

Slide 4

Dethatch Vs Rake:

Objective of thatch removal, vs breaking up dead leaves and debris from winter.

Words: Verticutter & Power-Rake are used interchangeably.

Top left: Verticutter used to slice stolons and relieve minor compaction.

Top right - rake blade (puts strain on engines)

Bottom - Stihl Yard Boss Rake

Speaker Notes

Dethatching in the spring is so cathartic - so much debris is lifted every year… but does your non irrigated, rarely fertilized, non stoloniferous home lawn NEED such an aggressive treatment?
Is it really good to beat the tar out of it first thing in the spring?

Slide 5

This feels so cathartic - like you’re cleaning the lawn and purging the long hard winter blues. The problem is that it may end up removing the entire thatch profile. If you really had so much thatch to begin with, evaluate the three legged maintenance “stool”.

Speaker Notes

photo e kawahara 2021 - dethatching!

Slide 6

Two main options: Solid Tine or Hollow Core

Speaker Notes

1) To expose to the action of air or to cause air to circulate through. 2) To change or treat with air or gas."
All results in improved plant health, vigor and hardiness
Aeration is recommended where soil has been compacted, particularly lawn areas heavily used by pedestrians and heavy machinery and lawns on clay soil.
The purpose of aeration is to loosen and add air to the soil under the turf without disturbing the turf.
Aeration makes the soil porous, allows air, moisture and fertilizer to reach the root zones, and thus encourages rapid growth.
Aeration is best accomplished by coring the lawn when the soil has adequate moisture.

Slide 7

Solid Tine Aeration:

Advantages

May be done on entire surface or selected areas

Minimal disruption to play, can be done anytime

Quick solution to compaction, air and water infiltration

Several options for varying depths.

Disadvantages

Only provides temporary relief

Tool not available for rent (usually)

Speaker Notes

Does not remove soil cores; potential for more compaction at the base of the holes…
Watch your speed so you don’t tear the sod…
Soil may be uplifted and fractured as the tines move thru the soil profile – direct increase in soil aeration – this is more likely to occur under lower soil moisture levels – in wet soil compaction is more likely

Slide 8

Spiking

Minimal disruption, quick recovery, temporary fix.

May be done several times a month if needed.

Normally tines vary in depth from “Spiking” depth (2.5 cm) to 30 cm depth

Slide 9

Deep Tine Aeration:

Advantages

Break through soil profiles / disrupt layering

Amend soil profiles deeper

Gas exchange throughout entire soil profile

Water penetration and increased sub-surface drainage

Increased rooting depth

Disadvantages

Disruption to play

Must top dress afterwards

Need healthy turf to perform

Speaker Notes

jist of it is that there’s all the same advantages to solid tine except it’s DEEPER.
You can puncture through to the next profile in the case of perched water tables.
Uses solid or hollow tines
Requires approx 40HP, 3pt, PTO
Breaks through the 10 – 12.5 cm (4-5”) compacted layer
Can fracture soil profile up to 30 – 40 cm (12-16”) deep (fracturing extends beyond penetration)
Greatly improves percolation through the profile

Slide 10

Core Aeration

Removal of soil cores leaving holes in the turf

Benefits

All the same benefits of Solid Tine PLUS:

Stimulates root growth within the holes

Increased shoot growth

Rental machines more available

Disadvantages

Disruption of turf surface

Longer recovery time compared to solid tine

Increased weed development (ie. Poa annua)

Speaker Notes

Cavities are very porous : allows for better oxygen exchange, improves water infiltration
Physically removes thatch, Remove or break-up unfavorable soil layers
Provides opportunity to modify rootzone (topdressing with desired material), add amendments, microorganisms to rootzone
Best performed when soil is moist – penetration of tines or spoons is quite limited in dry, compacted soil; some may water heavily a day before aerating to get better penetration – the deeper the cores are removed, the better the aeration possibliti

Slide 11

Speaker Notes

Cores image: e kawahara spring 2016
Hollow times – removal of core with hollow tines or a spoon. Variety of types available.
Vertical depth of the cores depends on the strength of the soil and the capacity of the equipment
Depths of 7.5 cm are possible in good moisture conditions and can be deeper with high-powered machinery
Core sizes from (0.5 cm - 2.5 cm) 0.25 to 1 inch. (solid tine is usually 0.5 cm)
Length of cores varies with soil strength, penetration capacity of the coring apparatus, although increasing soil moisture facilitates deeper penetration ((7.5 cm) 3 inches not uncommon)
Timing – when turfgrass is growing vigorously and is not subjected to severe stress from atmospheric conditions. - topdressing and irrigation immediately afterwards can help So do it in June, not early spring!
leaving the cores is good for mid-low maintenance turf, you want to match the soil profiles and not take away organic matter… BUT is there any point in doing it if you just leave them - see the dips above in the 8-10 weeks shot these dips will affect playability.
Once-a-year aeration situations - aeration done late in the season (fall) and the cores break down over the winter via the freeze/thaw cycle (low maintenance parks, school yards) ; doesn’t usually affect the playing surface as the mowing heights are fairly high. Good in theory but most people do it in spring… and it assumes no amendment necessary! Just amend it anyway and add these to the compost pile!

Slide 12

Coring: hollow tine

Two types of equipment:

Piston - linking vertical and forward motion

(drive carefully or you’ll overdrive the speed of the pistons)

- Expensive machine, usually on sports turf

Drum Rollers

Tines on a drum, mounted on a rotating shaft

Quicker but can tear the grass out

May not be heavy enough to drive into the grass effectively

Speaker Notes

Vertical motion with hollow tines
Quite slow (linking vertical and forward operations) MUST be aware of PTO speed and RPMs - can do a lot of damage to the machine if you drive too fast.
by far the superior machine in that it pulls them STRAIGHT up and out, no circular tearing (think of giving someone a needle!).
Pictured here: Toro Procore. Power Take Off Unit, hydraulic operations, 6” Piston Depth, a LOT of tines - rocks will damage this guy. Minimum requirement is 34 horsepower tractor with 3 point hitch (Residential useages?? not so much).
Drum roller action showed in previous slide - be careful not to tear the plants up (again, watch your speed!!)

Slide 13

Speaker Notes

is this really helping? (In this specific example, aerating for thatch...Is it deep enough to be relieving compaction?)
This is a roller drum, essentially we’re just rolling a big heavy piece of walk-behind machinery (remember compaction concerns?) over the lawn...

Slide 14

Core Aeration

Option 1: Leave the Cores

Advantage - CHEAP!

Disadvantages - Cannot be left on playing surface. Self defeating on lawn turf (no amendment, adds to thatch).

If you ARE going to do it though, suggest doing in the Fall so they break down over winter and any remainder is collected in spring rake up.

Speaker Notes

If you’re going to do it though,

Slide 15

Core Aeration

Option 2: Core Dispersal

Instead of waiting for mother nature… cores are broken up, core cavities filled in by former cores

Roots move in quickly, disruption of play minimized

Disadvantage - still can add to thatch, no amendment, added cost.

Speaker Notes

Aeration and core dispersal – better than just leaving them
Dispersal – pulling a drag mat (harrows) behind the aerator; dragging a weighted chain link fence behind the tractor etc.
– assures the holes are filled up with soil which is usually changed from its compacted state to a loose open soil and should fill the cavity right back up to grade; This does not change the texture and is more expensive than just leaving them.
these cavitiies will then have better porosity and water infiltration characteristics; the disturbed root and rhizome system will spread very rapidly into this new loose open soil.; disruption of playing surface is reduced; healing over of the holes is much quicker; new root and rhizome tips will increase water and nutrient update in the plant; loose open soil in the cavity promotes better oxygen/gas exchange in the soil, better infiltration rates

Slide 16

Core Aeration

Core Removal and Topdressing

Allows soil amendments through topdressing holes

Recovery is fairly quick (holes close up quickly)

Slow release N added

Disadvantages:

More labour

Disposal Cost

Amendment Cost

Possible Layer disease

Speaker Notes

Remove the cores completely – bring in new topsoil or growing media, topdressed into the turf and matted into the cavitiies; allows the turf manager to amend the soil via topdressing mix used – very common on soil based golf and bowling greens
Use often with bentgrass – mown low and has a rapid healing ability
Playing surface disturbed but holes close up quickly;
avoid seed head production of Poa in late June/July to avoid invasion
With topdressing soil profile is amended, cavities refilled and over repeat topdressings the soil profile will change. Sand is often used as it resists compaction
**very important to maintain same top dressing mix or you will be creating layers (perching, drainage problems) – caused by layering materials of different porosities - more in topdressing. Once you start, you are committed.

Slide 17

Core Collection

Speaker Notes

Must be pretty drastic to do that on a fairway - SO labour intensive. SO Expensive. 3% rule… is it worth it??

Slide 18

Core Aeration for texture amendment

In actual fact, there’s only about 3% disruption, so it will take multiple treatments to create real change.

Speaker Notes

Consider a golf green with a massive thatch problem - by the time you’ve aerated it, there’s only 3% disruption. So on a 100ft square area with a 6” thatch problem, you’ve removed 3 ft square. in Order to remove 100% of the issue, you need to do this 30x!! how labour intensive is that? What are you material costs on that?
As a golf course super, is it not cheaper to just rip up the whole thing, amend the soil and re-do it?!
Bear in mind, when aerating for thatch, at some point you need to weigh the cost of the process.
Core aeration is required once a year on heavily used lawn areas and every three to four years on all other areas.
Minimum required depth of cores is 5 cm with a spacing of 9 cm. The best time to aerate is in early spring or late summer.
Generally, fall aeration is considered best for cool-season turf, because grass plants are developing more roots in preparation for winter. Opening up the root zone with aeration provides an enhanced growth zone for new roots. Plus, you can combine aeration with an early fall application of slow-release fertilizer to get grass in shape for winter and charged-up for new growth next spring. Turf management schedules may be a little more flexible in the fall, too.
The key factor is to allow plenty of time for turf to “heal” after a fall aeration treatment. “Lawns need about three weeks to recover from core aeration, so don't schedule aeration much later than early to mid-September in northern areas,” says Roch Gaussoin, extension turf specialist at the University of Nebraska.
On the other hand, spring aeration can be beneficial, as well. Gaussoin says spring aeration is sometimes more effective where winter freeze-thaw action has loosened soil already. Mechanical aerators can do a better job before the ground gets too hard and dry.

Slide 19

Topdressing

Speaker Notes

Sand is $45/Tonne - 1000 square feet - 3% = 30 square feet x 6” = 15 cubic feet divided by 27 = 0.55 yards needed.

Slide 20

What is TOPDRESSING?

‘The practise by which a thin layer of soil (or other material) is applied to an established turf or a new turfgrass planting.’

Speaker Notes

The topical addition of material to a growing media
Material may be spread over the surface or spread and then incorporated into the growing media

Slide 21

Selecting Topdressing Material

If existing soil is favourable, choose something as close to what is there as possible

May consider stockpiling soil during construction

If existing soil is unfavourable

Compost, aged manure, peat moss (sphagnum), zeolites, calcined clay particles, diatomaceous earth materials

Check particle size before you buy (greens / sand soils)

Reminder: will take many applications to affect texture

Speaker Notes

May choose to add organic matter to the soil before topdressing (but turfgrass usually generates enough of its own organic material)
Sand can be very abrasive and injure weak turf when it experiences traffic - make sure it is well brushed in!!
Once you start, you are committed to a constant program until it’s pretty well entirely done.
Requirement depends on the type of turfgrass, natural environmental conditions, culture, turf purpose: Why am i top dressing?
Am I adding Micro-organisms or Organic Matter?
Am I filling in Cores?
Am I trying to level out an uneven surface (do not smother)
Am I just settling in the sod?
Am I essentially doing an organic fertilizer?
Am I fixing a problem I caused? (Compaction, damage to grass during construction).
Increasing the C:N ratio for decomposition of thatch?
How much is too much?

Slide 22

Layering:

Occurs in soil profile through the use of different top dressing materials over time

Perched water tables

Drainage problems

Black Layer disease

Watch for layering when top dressing after core aeration - make sure new material is well worked in.

H2S

Speaker Notes

https://www.flickr.com/photos/quasarkitten/9230605263/ (photo source)
fine texture over coarse - water cannot percolate, fine soil in upper layer can stay wet, (and it settles down into the coarse and causes cementing)
Black layer only occurs in anaerobic soil conditions. - It is caused by a physical condition of the soil. -
If soil drainage is insufficient it is likely that anaerobic conditions will develop and encourage Black Layer.
- Anaerobic bacteria produce Hydrogen sulphide gas, which has a characteristic ‘rotten egg’ smell.
- Hydrogen sulphide is poisonous to grass plant roots & reacts chemically with metal elements such as Iron (Fe), creating black deposits, which form layers within the soil.
Authentic black layer is a continuous layer or pockets of metal sulphides accumulated as a result of anaembic respiration by sulphur-reducing bacteria, Desulfovibrio spp. (heterotrophic gram-negative bacteria), under severe reducing conditions brought about by prolonged anaerobic (lack of oxygen) soil conditions. Sulphur-reducing bacteria metabolise soil organic matter and use sulphate or elemental sulphur as a terminal electron acceptor instead of oxygen in the respiration process, resulting in the production of hydrogen sulphide gas. The chemical reaction between hydrogen sulphide (HzS)and ferrous iron (Fe2+) results in the formation of the black precipitate FeS, which is often associated with organic matter and fine pore systems.

Slide 23

Reasons to TOPDRESS

Post aeration (surface disruption)

Provide crown protection from winter injury/eliminate ice

Add Organic Matter!!!

Most clay based soils will benefit from OM, especially if compaction prone

Improve CEC & Microbial activity in Sand Root Zones

New products claim to boost CEC without affecting drainage or porosity

Improved quality putting surface

Preventative measure for thatch development on greens

Post sod - may help if there has been desiccation of edges

Speaker Notes

Core Aeration: helps to fill in the holes created by cores, or allows amendments to be added while holes are open.
Surface irregularities: Caused by Aeration, but also over time on an uneven lawn.
Will not help with dew worms unless it is paired with a general deep core
aeration/amending the lower profile.
Provide truer putting surfaces, improves ball mark recuperation (golf)
Allows the opportunity to slowly change the lower levels of the profile.
Where the topdressing soil differs from that in the turf, the surface medium supporting the turfgrass is changed.
Ice (Freeze/Thaw)
Lawns with poor drainage are particularly susceptible to ice damage. When standing water + rapid drop in temperature, = damage to tender crowns and tissues. Damage is most severe in winters that have fluctuating cold and mild temperatures. A similar form of winter damage that can occur on a lawn results from foot traffic during wet slushy conditions, followed by a rapid freeze.
Ensuring the lawn has proper drainage prior to the onset of winter is a good way to minimize ice damage. This is accomplished by filling in low lying areas of the lawn where water has the potential to sit.

Slide 24

How Often??

Slide 25

Topdressing Rate and Frequency

Never cover more than 60% of leaf blade

0.05 -0.1 cubic yards 100m sq. = 5 – 10 mm in depth

Mowing Height of 50 mm (5 cm) on KB Lawn.

30 mm (3 cm) MAX coverage

Aeration displacement will have a major effect on topdressing volumes

Like Mowing, Frequency is based on plant recovery and shoot growth rates.

Speaker Notes

Awkward math because it’s Imperial (yards) and Metric (meters / cms), but it provides a starting point.
Aeration displacement - is the removal of a certain amount of material. You need to match your topdressing amount to the cubic yardage of cores you have removed. Remember that always doing ANYTHING (fertilizer, seeding, raking, mowing) it should be cross-directional. It helps avoid rutting, compaction, and repetition of the same area.
For many years, superintendents considered the standard to be applying 2 to 4 cubic feet of sand per 1,000 square feet every 3 to 4 weeks. However, when you consider variations in turf species, traffic, soil conditions, shade and climates, it becomes obvious that each course must make adjustments to fit local and seasonal situations.
Some superintendents find it best to use 1 to 1.5 cubic feet of sand per 1,000 square feet on a weekly basis when grass is actively growing. Applying 1 cubic foot is such a light rate (only 0.006 inch) it is impossible to measure this depth of application. For that reason, application-rate calculation and equipment calibration must be volume-based).

Slide 26

Light, Frequent Topdressing

Usually on golf greens for thatch

1-3 week intervals

Requires minimal brushing or matting depending on consistency of throw

Minimal disruption

Slide 27

Considerations:

Topdress after Aeration is the usual

Watering is a good complement vs. over-matting or brushing too much (crown abrasion)

Topdressing PRIOR to aeration on new greens will reduce ‘tire rutting’

Fertilize PRIOR to topdressing, not after! (fertilizer will be closer to rootzone that way)

Speaker Notes

New Greens are sand - when working on a sand based area, where rutting is a concern, topdressing first will help protect it.
Watering will help the new material settle in and blend.
Fertilizer should be in the rootzone. If you topdress heavily and THEN fertilize, it takes longer to get down to the base.