Provisioning

Queensland has an established and highly competitive turf grass production industry. Industry estimates in 2006 indicated that there were 152 producers throughout Queensland, in the tropical north, the Toowoomba and Darling Downs area, and South East Queensland. In Australia, 72% of product is sold within a 100 km radius of the farm (Aldous et al., 2007).

The economic value of the industry at the farm gate in Queensland is forecast to be $105 million in 2009-10, a slight (5%) downturn from the previous year’s forecast. In the first half of 2009, the global financial crisis saw a moderate level of demand maintained in the residential, renovation and infrastructure market segments, but a noticeable drop off in demand in the commercial, subdivision and development segments.

Opportunities

The relaxation of permanent water restrictions has improved the ability of consumers to care for turf grass. This provides an opportunity for the turf grass market to expand because of improved customer confidence in their ability to successfully maintain and renovate lawns.

When considering moving into turf production, it is vital to consider what the likely demand might be for your product and what your competitive edge is (e.g. service, varietal choices, locality). As circumstances change, review your situation as you may need to shift to something new.

Risks

Like other rural industries, producers battle rising input costs such as petrol, fertiliser and labour. Selling under cost to gain a short-term competitive advantage is a problem within the industry. A tightening of water restrictions could undermine consumer confidence in their ability to care for turf grass and reduce demand for product.

Unlike many other farming enterprises, many turf farms are vertically integrated. That is, they not only grow sod, but also often deliver, install and sometimes even maintain it. These enterprises face additional layers of complexity and require a diversified set of skills to do the job well. The turf itself is often reasonably easy to grow, but new entrants need to break into a relatively limited market niche, in which existing producers have well-established networks.

Glossary

Sod: grass and part of the soil held together by grass roots; harvested product from turf farms, seen as rolls or mats

References

These are only a small selection of the publications available.

Aldous, DE, Haydu, JJ and Satterthwaite, LN 2007, ‘Economic analysis of the Australian turfgrass industry’, Project TU06004, Horticulture Australia Limited.

Department of Employment, Economic Development and Innovation 2009, ‘Prospects for Queensland’s primary industries 2009-2010‘, Queensland Government, Brisbane.

Beard, JB 1973, ‘Turfgrass: Science and culture’, Prentice Hall, New Jersey, USA.

Handreck, KA and Black, ND 2002, ‘Growing media for ornamental plants and turf’, University of New South Wales Press, Sydney.

Spencer, J 2002, ‘The definitive guide to Australian turfgrass pesticide management’, Glenvale Publications, Melbourne.

Turgeon, AJ 2008, ‘Turfgrass management’, Pearson Prentice Hall, New Jersey, USA.

Other organisations

• Turf Queensland (formerly Queensland Turf Producers Association)
• Turf Australia (formerly Turf Producers Australia (TPA) Limited)
• Australian Golf Course Superintendents Association Ltd (AGCSA)
• Lifestyle horticulture contacts directory

Infrastructure

Buying the infrastructure and equipment to undertake turf production can be costly. Some activities, such as sprigging, can be contracted out; however, significant efficiencies are achieved in larger-scale, well-capitalised operations with specialised equipment. This can make it difficult for smaller producers to compete. The capital items and variable expenses indicate what might be needed for a smaller enterprise.

• Capital items (equipment list)
• Variable expenses

Labour

The average turf farm in Queensland employs the equivalent of two full time staff, plus casuals. Many farmers supply a turf laying service, which involves either employing and managing your own team of labourers, or hiring a contractor. In a competitive labour market, sourcing and retaining skilled labour is a concern for some producers.

Some areas of farm operation are expensive if they are inefficient. One such area is the manual stacking pallets at harvest, which is the single greatest use of labour. Poor farm layout can also increase costs by increasing the travel time between tasks.

Marketing and finances

Input costs, such as labour, fuel, fertiliser, insurance and equipment, are rising at a faster rate than the returns achieved for turf. Many people in the industry are not aware of what their real costs are. In some areas, there is over-production relative to the local demand. This is frequently followed by price cutting to move product and undercut the competition. In this scenario everyone loses.

Within the turf industry, it is common for producers to sell directly to customers. A common strategy is to bundle services such as site preparation, installation and after-care into the sales mix. Discounts are offered where add-on services are purchased.

In an Australia wide survey, 65.5% of variable costs were tied to production, 27.5% to administration/sales/marketing and 7.2% of costs to landscape services (Aldous et al. 2007). Businesses that sell direct need to invest in advertising and use other marketing techniques. Bigger operations will employ a sales manager. An accounts officer is needed to issue invoices, collect money and follow up on overdue accounts.

35% of turf sales are direct to homeowners. These sales attract a higher price as they are targeted at retail level; however, these sales are time consuming and incur more transaction costs. Other sales are to:

• landscapers (20%)
• developers (18%)
• retail garden centres (11%)
• other turf farms (7%)
• golf and sports surfaces (5%)
• brokers (3%).

Some growers act as satellite sites for big turf farmers. Turf is sold under contract, normally at a discount, to larger growers for distribution by them. This gives the larger turf producers the option of tendering for very big contracts and allows the small grower to focus on the production side of the business.

Larger turf farms are able to implement economies of scale and have better access to improved varieties. Their greater capitalisation and improved logistics allows them to transport product over greater distances and even to gain entry into specialised export markets.

Water issues

Access to water for growing turf has been a major concern for South East Queensland producers. Water restrictions have compounded the problem by impacting the ability of customers to establish and maintain turf. This caused a depression in demand in affected areas, until permanent water restrictions were recently eased.

Land use 

Check with your local council’s planning department to see if a material change of use approval is required before entering into turf production. Depending on the circumstances, this can prove expensive if, for example, an environmental impact statement is required.

References

These are only a small selection of the publications available.

Aldous, DE, Haydu, JJ and Satterthwaite, LN 2007, ‘Economic analysis of the Australian turfgrass industry’, Project TU06004, Horticulture Australia Limited.

Department of Employment, Economic Development and Innovation 2009, ‘Prospects for Queensland’s primary industries 2009-2010‘, Queensland Government, Brisbane.

Beard, JB 1973, ‘Turfgrass: Science and culture’, Prentice Hall, New Jersey, USA.

Handreck, KA and Black, ND 2002, ‘Growing media for ornamental plants and turf’, University of New South Wales Press, Sydney.

Spencer, J 2002, ‘The definitive guide to Australian turfgrass pesticide management’, Glenvale Publications, Melbourne.

Turgeon, AJ 2008, ‘Turfgrass management’, Pearson Prentice Hall, New Jersey, USA.

Other organisations

• Turf Queensland (formerly Queensland Turf Producers Association)
• Turf Australia (formerly Turf Producers Australia (TPA) Limited)
• Australian Golf Course Superintendents Association Ltd (AGCSA)
• Lifestyle horticulture contacts directory

The site and soil

Farm sizes vary from a few hectares to hundreds of hectares. The average turf farm size in Queensland is 16-17 hectares. Small farms Australia-wide average 9.6 hectares and medium-sized farms 37.7 hectares (Aldous et al., 2007).

The land must be able to be levelled to create a plane surface for harvesting equipment. Flat or gently rolling land is suitable, particularly when it has deep sandy loam or clay loam soils. Heavy clay and stony soils are unsuitable. Sandy soils may be suitable if organic amendments are added to improve water-holding capacity and sod strength at harvest. The optimum soil pH is 6.0-6.5.

Good soil depth is essential for sustainable production. At each harvest, a small amount of soil and organic material (about 1 cm) is taken.

Turf is often grown on river flats; however, most turf will not survive anything other than transitory flooding. Weeds on such sites (e.g. nutgrass and giant rat’s tail grass) are a potential problem and must be eradicated completely before the first crop is planted. Left untreated, such weeds are not only a production problem, but also spread to the customer as well.

Climate

While many turf cultivars can tolerate ground frosts, the tolerances need to be checked for each cultivar. Sites subject to frosts and colder hollows will have slower growth, increasing the turnaround time and reducing profitability, even with cold-tolerant cultivars.

Irrigation

Turf grass has a very limited root zone, so accurate and timely soil moisture management is critical. Multiple irrigation applications per day may be needed, especially when establishing turf. Access to a reliable supply of good-quality water is critical for most turf varieties. The average amount of water applied in Australia is 6.5 ML per hectare per annum, but actual figures will vary depending on the species used, crop stage, incident rainfall and evaporation rates. Efficiencies can be achieved with good irrigation design and by tailoring watering to the soil conditions and crop requirements. The water requirement is highest during grow-in phases of the crop and during hot, dry periods.

Community

Turf farms are often located in semi-urban areas, adjacent to residential areas or areas that may be earmarked for residential development. Farmers have to contend with issues raised by neighbours, such as noise made by pumping equipment and machinery operation, and dust and odour control (e.g. where composted manures are in use). This can cause significant disruption to business. Factor in a buffer zone around the farm to separate the business from the neighbours.

Environmental issues

Turf farms are often located adjacent to watercourses. Provision must be made for a vegetative buffer zone between the farm and these waterways.

Production needs to be managed to prevent fertiliser and chemicals from entering surface and subsurface water. Composted animal litter is commonly used to provide nutrients and to bulk up the soil following harvest. Ideally, litter piles need to be stored on bunded concrete slabs to prevent the contamination of run-off water, following rainfall. A sequence of containment dams may be required to prevent run-off into environmentally sensitive waterways and riparian areas.

A Turf Accreditation Process (TAP) has been developed for turf producers. The process is voluntary and independently audited, with a focus on best management practices for business and environmental sustainability.

Glossary

Sod: grass and part of the soil held together by grass roots; harvested product from turf farms, seen as rolls or mats

References

These are only a small selection of the publications available.

Aldous, DE, Haydu, JJ and Satterthwaite LN 2007, ‘Economic analysis of the Australian turfgrass industry’, Project TU06004, Horticulture Australia Limited.

Department of Employment, Economic Development and Innovation 2009, Prospects for Queensland’s Primary Industries 2009-2010, Queensland Government, Brisbane.

Beard, JB 1973, ‘Turfgrass: Science and culture’, Prentice Hall, New Jersey, USA.

Handreck, KA and Black, ND 2002, ‘Growing media for ornamental plants and turf’, University of New South Wales Press, Sydney.

Spencer, J 2002, ‘The definitive guide to Australian turfgrass pesticide management’, Glenvale Publications, Melbourne.

Turgeon, AJ 2008, ‘Turfgrass management’, Pearson Prentice Hall, New Jersey, USA.

Other organisations

• Turf Queensland (formerly Queensland Turf Producers Association)
• Turf Australia (formerly Turf Producers Australia (TPA) Limited)
• Australian Golf Course Superintendents Association Ltd (AGCSA)
• Lifestyle horticulture contacts directory

Turf farming is an intensive and highly specialised horticultural endeavour. Turf production may look deceptively like broad acre cropping; however, it has high management inputs and production costs, and product wastage is expensive for growers. Quality turf production requires well managed nutrient, pesticide and water inputs.

On this page:

• Establishment
• Species
• Access to improved varieties
• Certification
• Knowledge requirements
• Harvesting
• Quality
• Glossary

Establishment

Turf is normally established from sprigs and meticulous attention to weed control, pest and disease control, irrigation and nutrition is essential to grow the crop successfully. Occasionally naturalised stands of Queensland blue couch are managed to eradicate non-grass species and to encourage the development of harvestable (but low value) sod. Pests and diseases can severely affect all types of turf and some are very difficult to control.

To replenish the small amount of soil (1 cm) shaved away at harvest time, turf producers normally add organic matter, such as well composted chicken or feedlot litter or vermicompost, prior to planting and again after harvest as a topdressing to stimulate regrowth.

Irrigation is essential (see Commercial turf production – farm requirements).

Species

There are nine species of turf grass commonly grown in southern Queensland. These are:

• green couch (Cynodon dactylon)
• hybrid couch (Cynodon dactylon x Cynodon transvaalensis)
• Queensland blue couch (Digitaria didactyla)
• soft leaf buffalo grass (Stenotaphrum secundatum)
• zoysia (Zoysia japonica and Z. matrella)
• kikuyu (Pennisetum clandestinum)
• sweet smother (Dactyloctenium australe)
• seashore paspalum (Paspalum vaginatum)

Each of these species has differing cultural requirements and most of these species have numerous cultivars that may need particular management practices. Most turf producers specialise in a few cultivars that suit their own growing conditions and their client base. When a new cultivar comes onto the market, its performance characteristics may not be fully known for different environments (yours and your customers), making the decision to grow it or not more difficult.

Access to improved varieties

The Plant Breeders Rights (PBR) system has encouraged the importation and Australian breeding and selection of new turf grass varieties. Selection criteria include characteristics such as:

• cold tolerance
• shade tolerance
• improved density
• disease resistance.

PBR cultivars are often supported by marketing campaigns and attract premium market prices and profits. Smaller growers and new entrants to the industry may find the up-front licensing fees and the ongoing contractual obligations difficult to meet. This often forces new growers to use ‘commodity’ unlicensed cultivars. These are not as profitable because of their lower price.

Certification

Unlike many other horticultural industries, the Australian turf industry does not have an independent certification scheme for planting stock or seed. For PBR protected varieties, the Australian licensees take responsibility for ensuring that their stock is as described. Imported varieties are sourced from certified stock (usually from the USA). In Australia, PBR protected varieties are often delivered with certification documents. However, with repeated propagation, common ‘commodity’ cultivars with the same name can mutate into clearly different forms. For a new grower, this may mean that the farm is established with forms that are not true-to-type and that may perform differently to expectations.

Knowledge requirements

Turf farmers require not only skills and knowledge in growing and marketing the crop and running a business, but they are asked by clients to supply varieties to suit the specifications of particular sites.

Grassed areas are used for residential, commercial, school, sports and recreational activities. Turf farmers need to have a good understanding of turf varieties and the uses and conditions they are best suited for. Be prepared for customers who ask for advice before and after they buy. Expect to answer questions on:

• specific varietal characteristics (density, texture and colour)
• shade and sun tolerance
• drought tolerance
• wear resistance
• soil type
• cold weather tolerance
• establishment advice
• herbicide tolerance
• long-term turf care (fertilising, weed control, watering and mowing).

Harvesting

Once harvested, most producers send the sod to market on the day it is cut to prevent the turf from drying out. It is common for turf producers to harvest on-demand for clients. For example, a client will ring in the morning and ask that five pallet-loads of turf be delivered that afternoon. For small operations, this responsiveness means that it is more difficult for the producer to leave the farm for any length of time.

Whilst harvesting can be highly automated, this machinery is very expensive (approximately $120,000) and is generally used on very large scale enterprises. With a small hand cutter, harvesting is usually a two person operation, with cut sod being stacked onto pallets for trucking. Rolling and stacking sod is physically demanding work, requiring a good level of fitness.

Harvesting is an acquired skill. The machinery needs to be driven in straight rows at the correct depth. Sod harvested too early or cut too shallow will break up. Rhizomatous species, such as green couch, are clear harvested, whereas stoloniferous forms, such as blue couch, are left with green ribbon strips to enable regrowth. Harvesting aims to retain as much soil on the property as possible whilst making provision for the rapid reestablishment of cut sod.

Once the sod is cut, it should be delivered and installed as soon as possible. The harvesting process shaves off the majority of the grasses root system and it immediately begins to dry out. An additional danger is that core temperatures can build up within the pallet load and the product can stew.

On average, each turf block would be harvested one and a half times per year. Grown-in rates vary with environmental conditions, the species used and cultivar. Slower growing species have a longer period of care prior to harvest and are generally more costly to grow (and purchase).

Quality

The turf grass industry is in the process of developing quality standards for cut sod and recommended installation practices. Premium quality turf should be the cultivar or variety specified, have no weeds present, be dense and green and have no evidence of disease or pest problems. For lower grade turf, offered at a price discount, some weed grasses are permissible (e.g. blue couch contaminating a green couch sward). In some instances, special turf grass sod blends are marketed. In these cases the presence of more than one specified species/cultivar would not prevent the turf from being of premium quality if all other quality attributes are present.

Glossary

Sod: grass and part of the soil held together by grass roots; harvested product from turf farms, seen as rolls or mats

Vermicompost: nutrient-rich compost consisting of earthworm castings

Further information

• About the commercial turf grass industry
• Farm requirements
• Infrastructure and management
• Capital items
• Variable expenses

Our services

• Biosecurity Queensland
• Customer Service Centre
• Queensland Government Bookshop

References

These are only a small selection of the publications available.

Aldous, DE, Haydu, JJ and Satterthwaite, LN 2007, ‘Economic analysis of the Australian turfgrass industry’, Project TU06004, Horticulture Australia Limited.

Department of Employment, Economic Development and Innovation 2009, ‘Prospects for Queensland’s primary industries 2009-2010‘, Queensland Government, Brisbane.

Beard, JB 1973, ‘Turfgrass: Science and culture’, Prentice Hall, New Jersey, USA.

Handreck, KA and Black, ND 2002, ‘Growing media for ornamental plants and turf’, University of New South Wales Press, Sydney.

Spencer, J 2002, ‘The definitive guide to Australian turfgrass pesticide management’, Glenvale Publications, Melbourne.

Turgeon, AJ 2008, ‘Turfgrass management’, Pearson Prentice Hall, New Jersey, USA.

Other organisations

• Turf Queensland (formerly Queensland Turf Producers Association)
• Turf Australia (formerly Turf Producers Australia (TPA) Limited)
• Australian Golf Course Superintendents Association Ltd (AGCSA)
• Lifestyle horticulture contacts directory

Moisture

Water is necessary for the microbes in organic material to work efficiently, as it acts as a medium for chemical reactions, the transport of nutrients and the movement of the micro-organisms. The moisture content of the composting material should be maintained between 40% and 50% (wet basis). Too much moisture will cause conditions to become anaerobic (lack of oxygen) and unpleasant odour may result. The compost is too wet if water can be squeezed out by hand, or too dry if it is not moist to the touch. The composting material generally dries out with time. In turned systems, water should be added regularly. In no-turn systems, moisture can be prevented from escaping using a thick layer of finished compost or bulking agent.

Carbon to nitrogen ratio (C:N)

Micro-organisms require a balance of carbon and nitrogen for healthy cell growth. It is important to provide carbon and nitrogen in the right proportions to encourage microbial activity. A carbon to nitrogen ratio (C:N) between 15:1 (15 parts carbon to 1 part nitrogen) and 30:1 is required for good composting results. While the C:N largely determines the blend of materials to be used, the rate at which carbon compounds decompose should also be considered.

Table 1 shows a variety of agricultural materials that are used for composting, and their suitability for composting. Virtually any plant or animal product can be used.

Table 1. Characteristics of some organic material used for composting

Aeration (oxygen addition)

The composting pile should contain sufficient oxygen to maintain adequate microbial activity. While the initial mixing of the materials will introduce oxygen into the pile, this small supply of oxygen will be rapidly exhausted. To maintain sufficient oxygen levels, some form of aeration will be required.

Turning the piles regularly (weekly) provides good aeration, as the pores created allow air to move easily through the pile. However, this is known to increase methane emissions into the atmosphere.

No-turn systems introduce air into the material via passive or forced aeration of windrows. A bulking agent such as sawdust or woodchips can be used to increase the air pockets within the composting material. Such systems need to be carefully constructed and require additional monitoring to ensure their success.

Particle size

A small particle size will ensure the microbes have ready access to the organic material to help speed up the composting process. Smaller particles also allow oxygen to penetrate through the pile more evenly and be available to the microbes. If the material is clumped into large particles, the material will be compacted, allowing less oxygen into the pore spaces.

Temperature

The natural composting processes produce heat, and the micro-organisms grow best within a temperature range between 55°C and 65°C. Operation at this temperature also assists the destruction of pathogens and weed seeds. However, if the temperature exceeds 65°C, the composting organisms will die and the process will slow down substantially. Provided the oxygen and water supplies are within the optimum ranges, the composting material should maintain suitable operating temperatures. In Queensland, composting can be successfully achieved throughout the year. However due to the higher temperatures during summer, more moisture addition may be necessary in drier areas.

Time required for composting

The length of time required to transform manure into compost depends on moisture, temperature, aeration, C:N, and the physical structure of the raw materials. If optimal conditions are maintained, the composting process can be completed in around 8 weeks, with 4 weeks additional curing time following the active composting stage. Curing involves the further aerobic decomposition of some compounds, organic acids and large particles that remain after composting. Less oxygen and water are required during curing than during active composting. However, compost that has had insufficient curing may damage some horticultural crops. The test of completion of the compost process is if the temperature of the material does not rise after turning and watering.

References

• Misra, RV, Roy, RN & Hiraoka, H 2003, ‘Large scale composting’ in On-farm Composting Methods, FAO, Rome, p:21-28.
• Potts, J & Casey, KD 1999, Co-Composting Timber Residues and Feedlot Manure Project – Final Report, Department of Primary Industries and Fisheries, Toowoomba.
• Rynk R. (ed) 1992, On-Farm Composting Handbook, Northeast Regional Agricultural Engineering Service, New York.

Introduction

Tufted grassy weeds are from the Poaceae family. Unlike problem grasses that creep into the lawn, clumping and tufted grasses have a restricted horizontal spread. After mowing they leave an obvious stub behind. In coarser species, such as crowsfoot, this can create a trip hazard.

Early identification and swift action can prevent a serious problem developing. In small numbers, these grasses are relatively easy to dig out. However, clumping or tufted grass weeds usually spread freely from seed and quickly multiply. For this reason, it is particularly important to maintain a regular mowing schedule to prevent these grasses from heading. If a headed tufted grass is to be removed or mowed, and if plant numbers are small, clip the head and seal it in a bag to avoid inadvertently re-seeding the area.

Compacted sites

Three grass weeds, elastic grass, dwarf Parramattta grass and crowsfoot, establish commonly in areas subjected to wear. Their growth is favoured by a tolerance of compacted soil and a lack of competition from other species. The stalks of these grasses are resistant to cutting with mower blades and remain on the plant after the pass of the mower. Once hardened off, they also cope with trampling.

Shade areas

Winter grass is a problem grass of both shady and sunny areas. Its seed germination is favoured by exposure to light. However, the mechanism of germination in winter grass is complex, so that long duration exposure to low light intensities has the same effect as a short exposure to high light intensity. This enables the plant to succeed over a wide range of light levels.

Lawns are often subjected to additional shading in winter, arising from the sun’s lower angle in the sky and shorter day lengths. Turfgrass species with a relatively low shade tolerance, such as blue couch and green couch, may thrive in a location in summer, but thin markedly in winter, allowing winter grass to become dominant.

Prime conditions

The presence of common paspalum in a lawn can be a sign of good growing conditions – for both the turf grass and the weed. Common paspalum is a clumping grass and will slowly spread laterally and via seed if not controlled.

More on tufted grass weeds

Growing in compacted areas:

• elastic grass or wire grass (Eragrostis tenuifolia)
• Parramatta grass (dwarf) or rat’s tail grass (Sporobolus africanus)
• crowsfoot or goosegrass (Eleusine indica)

Growing in shaded areas (and sun):

• winter grass (Poa annua)

Growing in prime conditions:

• paspalum or common paspalum (Paspalum dilatatum)

Introduction

Leguminous weeds are broadleaf plants from the Fabaceae (bean) family. In tropical and subtropical lawns, these weeds typically grow beneath the height of the mower blade and are mat-forming. Although distinct patches can form, initially they tend to move through the turfgrass assisted by horizontal stems which peg roots from their nodes into the soil.

Some Benefits

In some societies clover lawns are highly valued, staying green when the grass dies back due to drought, and adding stable forms of nitrogen to the soil via a unique symbiosis between the plant and rhizobial bacteria (rhizobia).

In poor fertility situations, some of these weeds have the capacity to develop root nodules that fix atmospheric nitrogen into a form available to the plant. This organic nitrogen source is in slow release form, less likely to leach away or to cause excess soil acidity. The process is activated by rhizobia and needs specific conditions. Hence, not all leguminous weeds have nodules and only nodules with a red interior are actively working.

It is estimated that a 5% clover lawn with active nitrogen fixing nodules produces enough nitrogen to supply half the lawn’s annual nitrogen requirement.

Undesirable Qualities

Despite the benefits of (sometimes) adding soil nitrogen, most dedicated gardeners scowl when leguminous weeds break the visual continuity of their grassy lawn.

Legumes in lawns can be painful, and for some individuals create the potential for a medical emergency. Clovers, in particular, attract bees which are readily trodden on, with severe consequences for those allergic to their stings. Lesser, but still painful and annoying, injuries are caused by burr medic, which has spiny fruits and sensitive weed, which has short curved prickles.

Reading your site

The presence of leguminous weeds in the lawn can be an indicator of low levels of nitrogen relative to phosphorus.  Early weed identification, followed by hand weeding or spot treatments with glyphosate or a desiccant herbicide (such as a solution of vinegar and salt) can prevent a small problem becoming greater.

Shifting the balance

As the weeds listed below are all nitrogen-fixing to varying degrees, fertilizing the lawn with a nitrogen-rich N:P:K formulation or a N:0:0 fertilizer will assist the turfgrass to out-compete the weed. Suitable nitrogen forms include: ammonium sulphate (rapid release) or slower release sulphur-coated urea, resin-coated urea or natural organics. At a pH < 6.5 grasses are more efficient at taking up nitrogen, giving them an advantage relative to the leguminous weed. Try to avoid adding unnecessary phosphorus, as this element is known to favour the leguminous weed over turfgrass.

Ferrous (iron) sulphate is registered as a herbicide for clover control.  Use strictly according to the directions on the label, and not on already acid soils. As an added advantage it kills other broadleaf weeds and will correct iron deficiency, which is endemic in tropical and subtropical lawns through the wetter months.

A range of registered herbicides are available for clover control, and are freely available at nurseries and hardware stores. These mostly contain MCPA (a phenoxy herbicide) in combination with one or two other herbicides.

A demonstration site on a Gold Coast Hinterland turf farm clearly showed the value of turf grass in retaining sediment on slopes and reducing nutrient movement into waterways.

The project monitored soil losses during an eight week period in January and February 2011 including a time of extensive flooding in South East Queensland. Sediment movement was captured in three monitoring troughs from adjacent slopes that were either fully covered with turf mats, left bare or sprigged. Estimates of phosphorous and potassium losses in off-site soil movement were calculated from a spot test in late January.

Full sod – what a difference

• Turf mats protected exposed slopes almost instantly, even prior to rooting.
• Sod was 100 times more effective at keeping soil in place than exposed soil during two high rainfall periods (100 mm and 90 mm) and for the term of the monitoring period (see table).
• Sod retained around 19 tonnes/hectare of soil for each rainfall event.
• Where break-through erosion occurred, the sod trapped sediment minimising its travel down slope.

What we found

Soil Loss

Soil loss 52 days after 427 mm of summer rainfall (6 January 2011 to 28 February 2011).

Sediment trapping

In late January, a breakthrough area was found on the low earth mound designed to deflect water and sediment movement from the bare area upslope of the demonstration area. Water and sediment entered the fully turfed area. The ability of turf grass to trap sediment was well illustrated, as the wash area tapered away at 6.5 metres (see Plate 1). As a result, the soil was retained on the slope, and the sediment levels in the monitoring trough remained low.

Implications

The work demonstrated the vulnerability of bare slopes to erosion during the summer rainfall period. It highlighted:

• The need to minimise the time that steeper slopes are left unprotected through high intensity rainfall periods (October to March in South East Queensland).
• The effectiveness of turf grass cover as a means of preventing soil and nutrient losses from slopes, and thereby protecting nearby waterways.
• That although the best results are achieved with 100% turf cover, some level of slope protection is afforded by lesser amounts of cover such as turf buffer strips laid on the contour, sprigs or plugs. Planting of sprigs or plugs prior to high rainfall periods will afford full slope protection in around eight weeks.

More Information

For copies of the fact sheets “Monitoring Sediment Loss in Turfgrass Production” and “Improving Soil Retention in Turfgrass Production: The Benefits of Turfgrass Cover” contact: cynthia.carson@deedi.qld.gov.au.

Acknowledgements

This Department of Employment, Economic Development and Innovation project was run in conjunction with Turf Queensland and John Keleher, Principal of Australian Lawn Concepts. It was funded under the Queensland Government Healthy Country programme.

Causes

Lawn can be considered a form of horticultural flooring. This green carpet, like the coverings we lay within our homes, is subject to wear by a variety of sources, such as foot traffic, cars, pets and equipment. Both human and animal behaviour follows patterns resulting in tracks or patches through the lawn. Common examples are motorbike tracks near the letterbox, a path from the back door to the clothes line, or a bare area where the dog runs up and down the front fence line. Lawn subject to breaking, turning and standing fares the worst.

Traffic: the problem

What we see in lawns is ´traffic stress´ – a combination of deteriorating turf quality (including browning and thinning) and reduced growth, accompanied by an increased percentage of bare ground.

At a plant level the lawn is being crushed, torn, scuffed, abraded and dug out. Some grasses are known to have the ability to resist wear due to attributes such as their mechanical strength at a cellular level, high shoot density and/or strongly rooted mat of dense stolons. The chemical analysis of various grasses has shown that grasses, such as zoysias with higher levels of fibre and lignin, have an improved ability to resist applied forces.

Direct damage is worst on sandy soils where tearing and abrasion can be caused by the movement of sharp particles. Coarse topdressings can sometimes inadvertently exacerbate the problem.

A further impact of traffic on lawns is to increase compaction in the trafficked area, which in turn reduces turf grass growth. In particular, wear can increase in wet weather on higher clay content soils.

Observed wear

Unfortunately, simply planting a species with tougher or denser shoots and stems will not solve the problem of traffic stress in lawns. Whilst some species have a tolerance to damage, there is a second factor involved as turf grass can repair itself. Some species are readily damaged, but grow so vigorously that they recover rapidly. Others such as the zoysia, whilst being resistant to damage, can take some time to recover.

Observed wear = damage – recovery.

Contributing factors

On all soil types, sand through to clay, water deficits will reduce recovery rates and increase the percentage of bare ground during periods of water shortage and drought. Compaction on higher clay content soils can reduce the growth rate of an otherwise vigorous species.

Observed wear varies with any factor which impacts on the growth rate of the turf grass. These include seasonal changes in rainfall and temperature, the age of the turf, planting sod quality, soil physical and chemical factors and stresses such as waterlogging, pests and diseases. A well watered lawn with a very high rate of nitrogen fertilisation can develop softer leaves and not wear as well as the same lawn when it is moderately fertilized.

Species selection

Agri-Science Queensland, part of the Department of Employment, Economic Development and Innovation (DEEDI), has been looking at the observed wear of turf grasses under stimulated wear testing in separate experiments in both sun and shade (see Table 1). The extent of damage varies with the intensity of the treatment, the type of damage, the species (and in some cases cultivar used within the species), and the how the turf is managed.

Table 1: The relative resistance to wear (crushing, abrasion, scuffing and tearing) of various warm-season turf grasses in two separate trials (full sun and 50% shade), along with the relative rates of recovery from wear in full sun and shade, when not subjected to other growth limitations (such as water or nutrient shortage)

¹  Individual cultivars vary widely in their resistance to wear
²  Minor differences occur between individual new generation cultivars, however one very old cultivar wore poorly
³  Named cultivars perform better than common blue couch.

Results from trials in full sun indicate that green couch (Cynodon dactylon) cultivars performed better under stimulated wear testing than kikuyu (Pennisetum clandestinum) ´Whittet´, which in turn was better than blue couch (Digitaria didactyla) cultivars ´Aussiblue´ and ´Tropika´. Cultivar differences existed within the green couches tested, with Oz Tuff^TM, and ´Grand Prix´ and the hybrid couch (Cynodon tranvaalensis x C. dactylon) TifSport^TM being the most wear tolerant in 2009 tests.

Wear trials in 50% shade were undertaken as part of an evaluation of soft leaf buffalo (Stenotaphrum secundatum) cultivars. In particular, newer cultivars of buffalo grass such as ´King´s Pride´, ´Sir Walter´, ´Sir James´, ´Matilda´, ´Jabiru´ and ´Shademaster´ performed well in simulated wear testing. All of the newer cultivars of buffalo grass tested out-performed kikuyu, sweet smother and green couch in the shade. Sweet smother is known for its high level of shade tolerance; however these results confirm why it is not recommended for high traffic areas. Green couch requires high light levels to flourish, so the results in 50% shade, where it would be under stress and thinning, are to be expected.

Without careful management, soft leaf buffalo grasses can develop luxuriant growth in full sun. They are not recommended for heavy traffic areas as they need time to recover from damage by growing new runners.

The differing performance of green couch in full sun experiments, compared with the shade experiment, highlights the importance of choosing the right species for all the conditions of the site.

Managing wear

• select species vigorous in the conditions afforded by your site
• fork to loosen soil and improve soil aeration in the worn areas
• provide adequate water when possible, fertilise and monitor for pests and diseases
• divert people, animals and machinery to other areas (including roping off) to encourage lawn recovery
• avoid topdressings with sharp particles
• manage to minimise thatch and luxuriant soft growth.

Difficult sites

Sometimes, it seems that no turf grass will work. For example, if you have a shaded area which is heavily trafficked, the solution might be to direct where people step with pavers and use a broadleaved ground cover such as Dichondra repens, Viola banksii or Viola hederacea to fill the remaining space. However, these are not particularly wear tolerant. Zoysia matrella is the most shade tolerant of the available turf grasses, handling heavy dappled tree shade (about 20% of full sunlight) and also very resistant to wear.

Landscaping choices make a difference

As more people move into urban areas and global warming increasingly threatens to affect our lives, can our landscaping choices help? The scientific literature reveals that the answer is a definite yes.

With increased pressure on urban water supplies, is irrigating such landscape elements really a waste of valuable water supplies? The literature shows that living landscape elements are an essential component in an urban environment and the benefits they provide outweigh the perceived disadvantages in maintaining them.

Review and research

A literature review of international research was conducted on the possible role of plants in alleviating high temperatures in our living spaces. The review was finalised in February 2008 by staff from the former Department of Primary Industries and Fisheries for a project between Landscapes Queensland and Horticulture Australia Limited. It identified work that has already been carried out in the area and highlighted the gaps to be filled by experimental research. A pilot study then investigated the thermal properties of six of the most common landscaping materials.

Benefits of greenlife

This project clearly showed that plants can play a significant role in modifying the thermal conditions of urban environments. Tall trees can shade nearby buildings and reduce cooling costs. As well as basic shading, the dispersal of heat via the plant´s natural transpiration stream has long been recognised as an important component of the urban energy balance. Urban temperatures can be up to 7°C higher than nearby rural areas, illustrating the effect of plants on their environment.

These benefits argue against removing plants from landscapes to save water in drought. Similarly, the idea of switching to artificial turf is questionable, as artificial turf still requires watering and can reach temperatures that far exceed the safe range for users.

While vegetation offers evaporative cooling, non-vegetative and impervious surfaces such as concrete do not. Therefore, they can cause greater surface and soil temperatures. In addition, the higher temperatures associated with these impervious surfaces can negatively affect the growth of plants in surrounding areas.

Permeable surfaces, such as mulches, have better insulating properties and can prevent excessive heating of the soil. However, they can also lead to an increase in reflected longwave radiation, causing the leaves of plants to close their water-conducting pores and reducing the beneficial cooling effects of transpiration. The results show that the energy balance of our surroundings is complicated and that all components of a landscape will affect thermal conditions.

Landscaping materials – thermal properties

The temperatures observed in the experimental phase of this study highlight the variability in thermal properties of landscape materials. The temperatures observed over non-vegetative surfaces were well above those considered safe for any form of activity in terms of recommendations from healthcare professionals.

Surfaces tested were:

• concrete
• clay pavers (light terracotta)
• moisture-stressed turf grass (green couch)
• gravel (10-25 mm angular multi-coloured)
• synthetic turf (third generation)
• pine bark mulch (25 mm ´nuggets´).

Temperature readings were averaged according to surface for both 24-hour minimum and maximum temperatures across all replicates and time, for the period between 9 November and 19 December 2007.

Concrete and paving had significantly higher minimum temperatures (22°C and 20°C respectively), suggesting the materials were able to store heat. Meanwhile, moisture-stressed turf grass (18°C), gravel (18°C) and artificial turf (19°C) could not be statistically separated with this parameter, but clearly stored more heat than mulch (17°C), which had significantly lower minimum temperatures.

Concrete (44°C) and paving (45°C), and moisture-stressed turf grass (50°C), had the lowest maximum temperatures. However, moisture-stressed turf grass could not be separated from paving, gravel (52°C) or mulch (53°C).

The experiment was conducted during a drought period. The turf grass was not irrigated and soil moisture levels were low. Cooling effects and lower temperature readings have been recorded in other experiments with actively transpiring irrigated turf grass. Artificial turf had significantly higher average maximum temperatures (61°C) than any other material. The requirement to use water to cool artificial sports surfaces negates the major selling point of such materials.

Implications

This study highlights the need for caution when choosing landscape materials. The time of day when the area is under greatest use and the types of activities to be carried out must be considered when planning any landscaping around residential properties, educational facilities, office buildings or sporting facilities.

A comprehensive database of thermal properties would allow landscape designers, architects and home owners to make informed decisions about the type and proportions of different materials for each landscaping project.

References

• Poulter, RE,  Holborn, S & Dahler, J 2008, ‘Collation, analysis and research of thermal benefits of green life in the urban landscapes’, Horticulture Australia Limited Project Report HG06133, p. 35.
• Steinke, K, Chalmers, DR, Thomas, JC & White, RH 2009, ‘Summer drought effects on warm-season turfgrass canopy temperatures‘. Applied Turfgrass Science doi:10.1094/ATS-2009-0303-01-RS.