Case Study 1
Large grassed areas (over 1 hectare) are brown or dead following an event. There has been considerable compaction on the site due to machinery and the public.
Question a) What turf species would be suitable for the site?
Festuca arundinacea
(known as Tall fescue)
Will withstand heavy wear once established.
Lolium perenne
(known as Perennial ryegrass)
Wide usage where tolerance to wear and strong colour are required.
Poa pratensis
(Kentucky bluegrass or Smooth stemmed meadow grass)
Very durable and attractive turf, appears to need cool night temperatures.
Question b) How would you relieve the compaction?
Firstly, I need to ask myself, what is soil compaction?
Soil compaction is the process in which a stress applied to a soil causes densification as air is displaced from the pores between the soil grains. Heavy traffic over the soil is the major contributor to soil compaction, and prevention is better than cure, however there are ways to increase the aeration of the soil.
To reduce soil compaction:
1/ Add/ cultivate organic soil amendments into the top six to eight inches of the soil. In compacted/clayey soils, anything less can lead to a shallow rooting system with reduced plant growth, lower vigor, and lower stress tolerance.
2/ Manage traffic flow
3/ Mulch
4/ Aerate the soil
5/ De-thatch the soil.
Dethatching, Or Scarifying?
Both aerating and de-thatch the soil will bring air into the soil.
De-thatching
Thatch is dead grass and plant material that nature has not been able to break down. Instead, it has formed an impenetrable layer below the grass.
When the thatch layer exceeds .2 inches, the water permeability of the soil decreases, the grass roots grow closer to the surface and the root mass and the oxygen exchange decreases.
As a result, the grass becomes less durable and can no longer withstand the foot traffic it once could. In addition, the risk of disease increases dramatically and some grass varieties cannot survive.
Aerating
Aerating your lawn breaks through a thatch layer, enables the roots to breathe, and improves water and nutrient penetration. If that’s not enough, aerating helps break down thatch by providing a better habitat for the microorganisms that do those sorts of things. Aerating annually is one of the best things you can do for your lawn, thatch or no thatch.
Aerating is the process of punching small holes all over your lawn. The most effective type of aerating is with a gas-powered machine called a core aerator that pulls out small cores of grass and soil. Other aerators use short spikes to punch holes in the turf. Spiking is not nearly as effective as core aerating, but it’s better than nothing.
An Aerator
Question c) Describe the checks that need to be made at the site before commencing work and how you would proceed (eg. irrigation, drainage)
1/ Access for machinery needs to be checked.
2/ Irrigation plans, water mains plans, fire mains, sewerage or waste water mains need to be obtained from council or land owners before any works are done.
3/ Overhead (height of machinery), and underground power services need to be checked with relevant authorities.
Question d) Describe any topdressing/oversowing that may be required?
Firstly, what is topdressing?
Top dressing is an application of a thin layer of soil over a turf grass area and is used to smooth and level the surface or to modify the soil condition, usually no more than ¼ to ½ inch.
Examples of top dressing machines.
Why Topdress?
The main reason for topdressing is to level the lawn or build it up to the desired level. Topdressing fills holes or low spots and encourages the grass to spread by giving it a medium to grow in.
Top dress lawns in Autumn or Spring as this is the active growing time. Don't top dress dormant grass. You will damage it, if not kill it.
Top dressing of lawns in summer and winter is not recommended.
Fertilize a couple of weeks before topdressing, this will help the grass push through the soil quickly. Also, mow the lawn the day before you do the job. Long grass takes more soil to cover properly and the thicker the soil layer, the harder it is for the grass to emerge.
Top dress maximum of over existing grass, and use soil that has a similar profile to the existing one. Do not use topdressing soil that contains organic matter, as it may contain foreign and unwanted weed seeds, and you can add nutrients separately later.
You have been asked to provide advice for a prestigious city bowls club that is in poor condition.
Question a) What options does the client have for restoring the playing surface?
It really depends on whether the surface is natural or synthetic.
This scenario talks about restoring a playing surface that is natural.
A quality green will be due to a number of factors:
The cost of re-surfacing a natural turf green (planning and re-grassing) is estimated to range from $7,000 to $21,000, availability of voluntary labour being the main variance;
Restoring the playing surface depends on the problem.
It may have one of the following:
- Surface undulations are too severe to correct by standard renovation and soiling;
- A severe thatch or layering problem;
- An undesirable turf species, variation in turf type (e.g. different types of couch) or a high weed content;
- A playing surface that is too high or banks that are too low in relation to standard guidelines.
- A bad outbreak of nematodes.
The recipe for a quality green.
When planning a re-surfacing operation it is important to get a full understanding of the make-up of the green and the resources available to carry out the work. The planning process should evaluate the following:
1/ The existing greens levels/contours.
2/ The soil profile.
3/ Labour requirements.
4/ Equipment needs.
5/ Soils and supply
6/ Ditches/plinth boards
7/ Timing of works
8/ Soil moisture
9/ Plant material
10/ Soil testing
b) What turf species or cultivars may be suitable for the work?
The best grass types for a natural turf bowls green are ones that produces a tight, fine, robust cover that can tolerate low mowing height.
The main grass species used in Australia are generally of either Agrostis (bent grass) spp. or Cynodon (couch) spp. Bent grass is generally preferred in cooler climatic regions, whereas couch is favoured in the warmer climatic regions.
Within each of the main species, there are various types of grass cultivars.
For Tasmania I would suggest:
1/ Agrostis capillaris
(known as Browntop bentgrass or Colonial bentgrass)
or
2/ Agrostis stolonifera (Creeping bentgrass or Carpet bentgrass)
Both species can tolerate very low mowing.
Bentgrass
Question c) What ground preparation will be required?
A series of deep core samples need to be taken across the green in order to identify key properties, including:
• The thatch depth (and how much material must be removed);
• The depth of topsoil remaining and quality of this topsoil;
• Any impeding layers in the soil profile.
If there is a pan or layering it may be necessary to carry out additional soil physical treatment;
- Drainage status and root zone health.
Question d) What fertilisers/top dressing will be required including application rates?
Scotts ‘SierrablenPlus’ by Everris
USEAGE: Ideal for new sowings with high phosphate content. Improved green-up, a more even colour and an extended longevity. 3 month longevity.
RATE PER 100 sq.Metres: 25 – 35 gr/m2. (250-350 kg per Hectare)
PACK SIZE: 25 kg
‘Blade Runner’ by Neutrog - premium lawn fertiliser.
USEAGE: Granular/Crumble form of poultry manure for use in turf & horticulture to build up organic matter in soils.
RATE PER 100 sq.Metres: 5 – 40 Kg
PACK SIZE: 40 Kg
Question e) Suggest ongoing turf maintenance activities that will be required after the renovation.
Regular assessment of the turf by a reputable Agronomist is a great help in improving the quality of your turf, and will normally include soil sampling followed by analysis by a specialist laboratory. The agronomist should then provide an individual interpretation of the results with recommendations for an appropriate fertiliser, nutrient and management programme.
Student: Luisa Pollard
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