Manage sports turf areas

Transcription

1 Manage sports turf areas Note: This section is in three parts Plan and ensure the maintenance of sports turf areas CONTENTS Part 1...Page Number Why plan?...2 Steps in planning...2 Finance how much will the job cost? Selecting machinery for sports turf surfaces Soil type and condition and its effect on maintenance operations...7 Factors affecting turf maintenance regimes How often should mowing take place?...9 The time of year and its effect on the mowing height of cut...10 Weeds, pests, disease and physiological disorders on sports turf Moss in turf Selection of and application of fertilisers Methods of monitoring and assessing the effects of sports turf maintenance...22 Waste and environmental impact that might arise from maintenance operations and how to deal with them...22 Reducing environmental impact...23 Typical problems that might occur when maintaining turf and how to deal with them...23 Statutory requirements for the application of pesticides...24 The principles of risk assessment...24 Scarification, verticutting and vertigrooming Top dressing Aeration of sports turf Rolling...33 Switching or brushing...34 Irrigation The main difference between Level 2 and Level 3 is the requirement to plan operations with regard to turf maintenance. Therefore a brief introduction to planning is included in the following section. You should get a good insight into the steps involved in planning in the chapter that deals with Estimate resource requirements and programme work.

2 PART 1 Plan and ensure the maintenance of sports turf areas Why plan? Have you ever worked at a place where no one really seemed to know what they were supposed to do? People would finish a job then wait for instructions on what to do next. The manager was always running around trying to get jobs completed on time. Work sometimes did not happen because someone had forgotten to order the material required. The members were always moaning because the greens were being aerated the week before their annual club tournament. If you have worked at a place like this, it is likely that the manager was not good at planning. Most poor managers will tell you that planning takes too long and they are too busy to do it. However, the truth is, planning frees up much more time than it consumes, it avoids wasted effort and maximizes efficiency. Steps in planning Planning is not difficult and should not take a great deal of time. There is no set system to planning. Some managers write out plans in longhand, others use bar charts. All that is important is that you understand exactly what is required, list the jobs in a logical order and then put a time scale against each job. If you do not know how long a job will take you could ask more experienced staff, use published data e.g. Spon s Landscape Handbook or estimate it based on experience of similar work. In planning, you should consider the following factors: Labour Equipment Materials How many staff do you need? And for how many hours? For example to complete a job you could use two people for four hours or one person for eight hours. The man-hours are the same but which option is chosen will depend on its importance and urgency. You should also consider specific expertise; e.g. will you need someone who can drive a digger or someone who is qualified to apply pesticides etc.? What tools and/or machines do you need to complete the job? What type and how much material will you need etc.? Page 2

3 Finance how much will the job cost? In day to day maintenance, most managers will use a simple bar chart (some times called a Gantt chart). These are quick to design and allow the manager and workers to see instantly what is happening each day, the equipment and materials required and how long each job should take. To follow is an example of a simple plan for maintaining 18 golf greens for one week in June. Note the plan is for demonstration purposes only. Tasks Monday Tuesday Wednesday Thursday Friday Saturday Sunday Mow greens (5mm) Change hole Mow collars (10mm) Rake greenside bunkers Hand water dry spots 2 2 Apply NPK at 35 grams per m 2 Sunday evening 4 Equipment required Greens mower Triplex mower Fertiliser distributor Materials required 17 bags of NPK fertiliser Total man hours The benefits of such a plan are the ability to see instantly what work is to be done each day, how many man hours it will take and what machines and materials are required. The manager can also see when materials will be needed. This will help him/her ensure they are available when required. The purpose and function of sports turf surfaces and the effects of maintenance operations The main purpose and function of any sports turf surface is to allow the sport in question to be played by the players to the highest standards possible. This of course will depend on factors such as weather, soil type, budget etc. For example, if we take a golf green as an example, its purpose would be to provide an area of turf that allows the golfer to strike a ball onto its surface and then putt the ball into the cup. This will require a clearly defined area (so the golfer can see it from a distance). The surface would be closely cut and very smooth to allow the ball to run across the surface without deviation. The grass types should be fine in texture and upright in growth habit. To allow the player to stop a ball on the green, it should not be over firm, nor should the surface be over soft, as this would result in a slow surface prone to pitch marking. Page 3

4 However a golf tee need only be level enough for golfers to take up a firm stance and not too firm that wrist injuries could occur. The actual quality of the turf surface (i.e. mowing stripes etc.) is in effect irrelevant for the game being played, but of course the player would perceive such a surface as being unacceptable on aesthetic grounds. This aesthetic factor has become more important in sports turf in the last decade and is seriously affecting the maintenance schedules in all sports. The increased quality of surfaces in Premier League football stadiums is one obvious example where improved construction and maintenance techniques have resulted in a quality of surface impossible 20 years ago. One other major driving factor of today s maintenance regimes has been the televising of sporting events which has led the playing public to expect the levels of quality seen at major sporting venues at their own sporting location. Page 4

5 Selecting machinery for sports turf surfaces The choice of machinery that can be used to maintain sports turf surfaces is almost limitless. However the turfgrass manager should be able to select suitable equipment for his or her surfaces. In order to do this efficiently he/she should take into account the following factors: - Size of the area Large areas such as golf rough will require ride-on machines with a wide width of cut. However manoeuvrability of large equipment around trees and banked areas must be taken into consideration. Quality of the playing surface The use of very expensive high quality cylinder mowers with 8 to 12 blades may be required for areas such as putting greens. Where as areas such as golf tees (with large amounts of divot debris etc.) may only require cheaper mowers with a lower number of blades of heavier construction. Number of staff (man hours) The number of staff will dictate the type of machinery used, i.e. clubs with large teams may be able to use pedestrian mowers to mow greens all year round. Operating budget This will of course affect staff numbers and overtime as well as machinery type. Surrounding environment The type of surface (tee, green) will affect the amount of debris encountered by machinery. Football fields on council land may contain a wide range of debris and so machines used must have strong cutting mechanisms resistant to damage. Health and safety The amount, and degree, of slopes and banks will also affect machines used. Steep slopes will require low centre of gravity and good roll-over protection systems. The soil type will also influence selection as the use of very heavy machinery on wet clay soils may cause compaction problems. Examples of selection criteria for sports turf mowers Ransomes Super Certes 51. The blades on this machine spin very quickly against a fixed bottom blade. The grass is pulled between the cylinder blades and the bottom blade and is then cut in a scissor like action. It should be noted that the higher the number of cylinder blades the better the quality of cut. Most fine turf mowers are fitted with between six and 10 blades. Image courtesy of the Textron company Page 5

6 Ransomes Hydraulic 7. This Ransomes Hydraulic 7 is a good example of a cylinder gang mower. It is designed for cutting large areas such as golf fairways and sports fields. Page 6

7 Soil type and condition and its effect on maintenance operations Soil types are classified by their texture (the amount of large or small particles within them). Sandy soils contain large particles that drain well and resist compaction. This makes them ideal for games that are played all year round and require good winter drainage (i.e. golf, football etc.). Soils that contain a high percentage of clay (very small particles) do not drain very well and compact easily. This makes them suitable for games such as tennis and cricket, which are played during the summer and require compaction to get the bounce required by the sport. Of course we do not live in an ideal world and often we must provide sports surfaces on soils that are totally unsuitable (i.e. many football fields and golf greens are growing on heavy clay). This means the manager must adjust his/her maintenance regimes to take this into account. There is not sufficient space to cover all the relevant details but some basic principles might be as follows: - Clay soils These are slow to warm in the spring (due to the water they hold) and so grass growth occurs later than on sand based surfaces. This will affect such maintenance tasks as weed control, applications of fertiliser, overseeding operations etc. Clay soils will also be slow to cool in the autumn resulting in grass growth continuing later into the year than on sandy soils. This will affect operations such as mowing and increase the risk of fungal diseases such as fusarium. Clay soils drain slower than sandy soils so we require more aeration to keep them draining and relieve compaction. Sandy soils These are quick to warm in the spring (due to their good drainage) and so grass growth occurs earlier than on clay based surface. This will mean such maintenance tasks as mowing, weed control, application of fertiliser, overseeding operations can be done earlier. Sandy soils are less affected by compaction and so may require less aeration to keep them draining and prevent compaction. Factors affecting turf maintenance regimes Turf maintenance is affected by a large number of factors; deciding what to do and when to do it often presents the turf manager with difficult decisions. One of the main problems is the conflict between the need for maintenance and the need of the players. Some of the main factors are as follows: - Weather conditions Heavy rainfall can make operations such as mowing difficult and messy (the wet grass tends to collect in unsightly clumps on the playing surface). High winds can affect operations such as the application of fertilisers and pesticides. Very hot weather can cause fertiliser to scorch the turf surface. Page 7

8 Soil temperature Soil temperature affects grass growth, the warmer the soil the faster the turf growth. Operations such as mowing are adjusted to reflect the changes in growth rate caused by the cooling and warming of the soil over the seasons. Soil moisture Wet soils compact more easily as the water in the soil acts as a lubricant allowing the particles to slide closer together. Use of heavy machinery on wet soils may result in surface ridging and damage from sliding wheels. Length of daylight The total hours of daylight have a big impact on turf growth, increased daylight resulting in increased grass growth. This is most noticeable in spring when increasing daylight is combined with warming soil temperatures and maximum grass growth is achieved. These factors have made spring the prime period for major maintenance and renovation operations. Playing season Many sports have closed playing seasons and most of the major operations such as aeration, top dressing etc. are carried out during these periods. Golf course managers are faced with the problem of all year round play and the need to fit in maintenance between the busiest periods of play. Soil type The ability of a soil to drain, resist compaction and warm up/cool down is dictated by its texture See Soil type and condition and its effect on maintenance operations on page 7. Grass type Grasses such as perennial ryegrass have very rapid rates of growth and therefore requires increased mowing and feeding regimes. Grasses such as fescues are very slow growing and require less nutrition, mowing and irrigation. Page 8

9 Soil, weather and usuage conditions and their effects on mowing operations Mowing should not take place when the soil is waterlogged, as this may compact the soil structure, and weaken the sward. If the soil contains a lot of clay you may also find that ruts are produced, which ruin surface levels. When you must mow during wet soil/weather conditions, slow down the mower and take extra care when you turn at the end of a mowing run, as this will help prevent damage to the turf surface. Mowing turfgrass during frosty weather should be avoided, as it will cause the grass to turn black, which is unsightly and may encourage attack, by Fusarium patch disease. The mowing of turf when having only just thawed after being frozen should also be avoided as the soft, newly thawed upper layer of soil may slide over the frozen soil below breaking the grass roots. This process is known as root shearing and will badly damage a playing surface. During very hot weather and periods of drought it will be worthwhile raising the cut slightly as this will help reduce the stress on the grass sward. Golf courses are under constant use by players and if possible, areas such as the greens and tees should be cut early in the morning to avoid interrupting players. Failure to do this will mean mowing operations will take longer and players will become annoyed with the greens staff, leading to poor customer relations. How often should mowing take place? As a general rule, the more often a surface is mown, the better the playing surface will be. The frequency of mowing will depend on the time of year (day light and soil temperature changes), grass growth and the sport being played. As a rough guide the mowing regime on a golf course during the main growth periods of spring and summer might be as follows: - Golf greens Surrounds and approaches Golf tees and green surrounds Fairways each day. 1 to 2 times per week. 2 to 3 times per week. 2 to 3 times per week. Page 9

10 The time of year and its effect on the mowing height of cut Generally speaking, the height of cut is dependent on grass growth, which is of course dependent on the soil temperature and length of day. During the winter, grass growth is slow and therefore recovers slowly from the wear caused by players. Therefore during the winter the height of cut is raised slightly to help the grass withstand this wear. The same applies to periods of drought when cutting height is often raised to help reduce the heat stress on the grass surface. We must remember that this does not apply to all sports e.g. a football field may have its height of cut lowered in the winter as it is the playing season for this sport. Typical heights of cut for sports turf areas (these are guidelines only) Golf Summer Winter Green 4.5 to 6 mm 5 to 7.5mm Tee 6 to 13 mm 12 to 15 mm Fairway 13 to 16 mm 15 to 20 mm Surrounds and approaches 8 to 12 mm 12 to 15 mm Semi rough 35 to 60 mm 35 to 60 mm Rough 50 to 100mm and above 50 to 100mm and above Other sports Playing season Out of season Football 20 to 40mm 25 to 40mm Rugby 25 to 55mm 25 to 50 mm Hockey 15 to 20 mm 25 to 30 mm Cricket Outfield 12 to 18 mm 20 to 25 mm Square 10 to 15 mm 15 to 20 mm Wicket 3 to 5 mm As above Tennis 6 to 10 mm 12 to 18 mm Bowling green 5 to 7 mm 8 to 10mm Page 10

11 Weeds, pests, disease and physiological (drought/compaction etc.) disorders on sports turf Reasons for the control of weeds 1. They are unsightly on fine turf surfaces. 2. They interfere with play (e.g. when putting on golf greens or cricket balls being deflected off line). 3. Weeds with coloured flowers can slow up play (e.g. white flowered weeds can look like golf balls and make ball location difficult in the rough). 4. Weeds compete with turf for food, water, light and space and this weakens grass growth. 5. Weeds can break up path surfaces etc. Weed roots are very strong and they can damage tarmac car parks and other hard surface areas. Controlling weeds in turf Remember the best way of avoiding weeds is to keep the grass healthy, as a thick cover of grass will resist weed invasion. Weed control can be achieved in three ways: Physical This is to physically attack the weed, for example, by cutting the weed out with a knife or by scarifying the turf surface to cut up the weed. Cultural This means changing the environment that the weed is growing in. For example, the broad-leaved plantain thrives in compact soils. By aerating the turf we can reduce compaction improving grass health and reducing the number of plantains. Chemical this is done using a selective herbicide. Selective herbicides will kill the weeds but leave the grass unharmed (if used correctly). Selective herbicides work in one of two ways: 1. Contact selectives These burn off the weed leaves and are mainly used on young turf areas to kill off competing annual weeds. 2. Translocated selective weedkillers These are absorbed into the plant and kill it down to the roots.they are used on established turf to control annual and perennial weeds. They do not kill the grass due to differences in leaf size and shape and other physiological differences. For best control of weeds when spraying: Do not mow for three days before spraying and then three days after, this will ensure you have a good target weed and that the chemical will have time to be translocated through the entire weed. Do not spray if the turf is suffering from heat stress, drought, frost or if the soil is water logged. Page 11

12 Turf pests 1. They may eat grass roots causing unsightly damage as the turf dies or becomes stressed. 2. They may interfere with play (worm casts can deflect the roll of golf balls etc.). 3. They interfere with turf maintenance e.g. worm casts sticking to mower rollers can alter the height of cut. This will affect the quality of the playing surface. 4. They may weaken the grass cover allowing weeds to invade the playing surface. 5. They may encourage predators who do great damage to the turf while feeding on the pest (e.g. moles, which tunnel through sports turf looking for worms). The main turf pests in the UK are: - 1. Leatherjackets. 2. Earthworms. 3. Cutworms. 4. Chafer grubs. 5. Moles. 6. Rabbits. 7. Wire worms. 8. Frit flies. Pest control can be achieved in three ways: Physical This is to physically attack the pest, for example, by trapping moles or shooting rabbits. Cultural This means changing the environment that the pest is living in. For example, the earthworm thrives in soils that have a high (alkaline) ph and deep thatch layer. By slightly acidifying the turf and reducing thatch we can reduce the activity of earthworms. Chemical For insect pests, control is achieved using chemicals known as insecticides. These are normally sprayed onto the soil and then enter the soil killing the pest on contact. How to identify pests We need to identify pests correctly to ensure we apply the correct treatment.this is easy in the case of pests such as moles and earthworms. However some pests live underground and cause damage to turf by eating the roots of grass. This type of damage is often mistaken for turf disease. In order to correctly identify a turf pest you should ask the following questions: 1. Does the damage match the description of the damage caused by the pest found in books? Look at the size of the area affected etc. 2. Is it the right time of year for the pest to be active? 3. Can the pest be found if you peel back the turf and look under the surface? Life cycles of turf pests Knowing how a turf pest life cycle operates can be useful, as if you understand the life cycle you will be able to better identify pest damage and deal with it. You will also know when to expect the pest and be able to keep an eye out for early signs that the pest is active. Example of an insect s life cycle the cranefly: Autumn Eggs laid and hatch, larvae feed Winter Young rest in soil feeding on roots in warm periods Summer At the end of summer young pupate and emerge as flying adult Spring Young larvae feed on grass roots and leaves Page 12

13 Turf diseases 1. Diseases may cause unsightly damage to the playing surface. 2. Diseases may kill or damage turf. 3. The damage to the turf may interfere with play. 4. Diseases leave bare areas of turf and this may encourage the invasion of weeds and moss. Disease control can be achieved in three ways: - Physical This is to physically attack the disease. For most diseases this is not practical. However some greenkeepers have tried to remove fairy rings by digging out the area affected by the fairy ring and replacing with clean soil. Cultural This means changing the environment that the fungi are growing in. For example the disease red thread thrives in conditions of low nitrogen. By feeding the turf with a nitrogen fertiliser we can improve grass health and reduce the amount of red thread damage. Another example of cultural control is switching early morning dew, which dries the turf surface making it more difficult for the fungi to spread. Chemical This is done using a systemic or contact fungicide. Important A systemic fungicide can only be used when the grass is actively growing, as it must be absorbed into the grass plant. A contact fungicide can be used all year round. Remember the best way of avoiding diseases is to keep the grass healthy. Understanding fungal diseases Fungi are diverse groups of either single-celled or multicellular organisms that obtain food by direct absorption of nutrients. The food is dissolved by enzymes that the fungi excrete and is then absorbed through the thin cell walls of the fungi. Some fungi are parasitic (feed on living matter) and cause serious plant diseases. Fungi were traditionally classified as a division in the plant kingdom. They were thought of as plants that had no stems or leaves and that in the course of becoming food absorbers lost the pigment chlorophyll, which is needed for conducting photosynthesis. Most scientists today however, view them as an entirely separate group. Most fungi reproduce by microscopic spores, for example, the common mushroom may form 12 billion or more spores on its fruiting body; the giant puffball may produce several trillion. Page 13

14 Structure of a fungus Fungi are made of filamentous tubes called hyphae. In many species, perforated walls, or septa, divide the hyphae into cells containing one or two nuclei. Cell fluids or protoplasm flows through the opening in the septa to provide the cells with nutrients, which are stored in the hyphal walls as glycogen. Hyphae elongate from the tip. The entire mass of hyphae is collectively called the mycelium, primary below ground and secondary above. The most common fungal diseases that attack in the UK are as follows: 1. Fusarium patch. 2. Red thread. 3. Brown patch. 4. Fairy rings. 5. Take-all patch. 6. Grey snow mould. 7. Anthracnose basal rot. How to identify fungal diseases We need to identify diseases correctly to ensure we apply the correct treatment. This is often in the form of a chemical known as a fungicide (remember the word -cide comes from the Greek word that means to kill). It is often hard to correctly identify turf diseases and great care should be taken as often what appears to be a turf disease can be caused by other things like fertiliser scorch etc. In order to correctly identify a turf disease you should ask the following questions. 1. Does the damage match the description of the disease found in books? Look at the size of the area affected, the shape of the affected area etc. 2. Are the weather conditions right for the disease to strike? (Some diseases usually only strike at certain times of the year when the weather is warm and others when it is cool and moist). 3. Is the type of grass affected susceptible to the disease? (Some diseases will only attack certain types of grass). Turf disorders What is a turf disorder? A turf disorder is a problem affecting sports turf growth or quality but not actually attacking the grass plant. Examples are: - 1. Dry patch. 2. Drought. 3. Soil compaction. 4. Thatch. 5. Slime moulds. 6. Algae. 7. Lack of fertiliser. 8. Poor drainage. 9. Shade. Page 14

15 Reasons for dealing with disorders (compaction, algae, slime moulds, etc.) 1. They may interfere with play (compaction may cause excessive bounce). 2. They may affect turf and playing surface quality. 3. They may affect turf health (weaken grass). Dealing with disorders in turf Disorders can be dealt with in three ways: - Physical this is to physically change the conditions causing the disorder, for example by scarifying the turf surface to remove thatch from the turf surface. Cultural this means changing the environment that is causing the disorder. For example by aerating the turf we can improve drainage and reduce compaction. Chemical for example using a wetting agent to deal with dry patch on turf. Moss in turf Reasons for controlling moss 1. Moss competes with grass, crowding the grass out. 2. Moss, as it dies, helps cause rapid thatch build up. 3. Moss can make a playing surface slippery (e.g. on tennis courts). How to identify moss Moss on turf is normally one of three types: 1. Cushion mosses (the moss grows in cushion shaped clumps on the turf surface). 2. Trailing moss (feather-like moss). 3. Upright moss (moss grows upright with bottlebrush shaped bundles of leaves). Controlling moss in turf Moss control can be achieved in three ways: Physical this is to physically attack the moss for example by raking the moss out with a rake or by scarifying the turf surface to cut up the weed. Cultural this means changing the environment that the moss is growing in. For example, most types of moss thrive in damp, compact soils. By aerating the turf we can reduce compaction and improve drainage. This will improve grass health and reduce the amount of moss. Chemical this is done using a moss killer such as dichclorophen or chemicals that burn the moss such as iron sulphate or ammonium sulphate. Page 15

16 Selection and application of turf fertilisers In order for grass plants to grow well they need the correct nutrients which they obtain from the soil. Correct feeding of turf will be less likely to suffer from diseases and problems such as drought stress in hot weather. Correct feeding will also help ensure a good cover of grass that will resist the invasion of weeds, added to this is the ability of healthy turf to stand up to the wear and tear caused by players and maintenance operations such as mowing. Also to be considered is that fine turf is mown on a regular basis and the clippings removed. These clippings contain nutrients that are lost from the soil. On areas where clippings are not removed e.g. fairways and golf rough, it is unlikely that fertiliser will need to be applied at all. It must also be remembered that over feeding turf is more harmful than under feeding it. Too much fertiliser will result in excessive grass growth leading to increased build up of thatch and the encouragement of weed grasses (such as Poa annua) and turf diseases such as Fusarium patch. How much fertiliser should be applied per year? There is no answer to this question, as it will depend on soil type, the grass type and the sport being played. Fertiliser should not be used to produce colour in turf and should be applied in amounts that keep the turf healthy and able to resist the wear and tear of play. The more fertiliser you apply the more time you will spend mowing. If you are always removing large amounts of grass clippings and your turf is always bright green you are most likely applying far too much! Fertiliser terms explained There are many types of fertiliser available to the greenkeeper and groundsperson and the choice can become very confusing. The next section will try to explain some of the terms used by producers of fertilisers. Slow release fertilisers are designed to feed the plant for a long period normally 4 8 weeks but some types can last a complete season. The benefit of slow release fertilisers is that less labour is involved as they only need to be applied a couple of times a year. However, they do have one drawback that once applied the greenkeeper is dependent upon them acting as designed and must not be tempted to apply more fertiliser if the effect is not quick enough or does not generate the required effect. Quick release fertilisers release their nutrients in a short period of time (e.g. 1 2 weeks); they are useful for kick starting growth in the spring. However, they do have to be applied more often meaning more labour time and more expense. Quick release fertilisers offer the manager much greater control on the rate of grass growth and applications can be timed to offer maximum benefit with regard to weather conditions etc. The above fertilisers may come in a granular form, liquid or as a powder. Granular fertilisers are easy to handle and apply, but can take a while to work into the turf surface (risk of boxing off when mowing). Page 16

17 Powdered fertilisers are messy to handle and are easily blown around in the wind (often covering the operator) however they work into the turf surface quickly. Liquid fertilisers are fertilisers applied to the turf in a liquid form; they are absorbed quickly by the roots or in some cases through the grass leaves (note fertilisers designed to act in this way are known as foliar feeds). Liquid feeds are quick and easy to apply (provided you have a sprayer) also there is less risk of scorching the turf surface. Organic fertilisers are made from plants or animals that once lived (or have passed through something that lived) examples hoof and horn, bone meal, refined chicken manure. Inorganic fertilisers are man-made from mineral or chemical sources e.g. iron sulphate, ammonium sulphate, ammonium phosphate etc. Straight fertilisers are fertilisers that have only one nutrient in them. Compound fertilisers contain a number of nutrients e.g. nitrogen, phosphorus and potassium (NPK). Note: A fertiliser may fit several of the descriptions mentioned for example a fertiliser might be described as follows: a slow release, compound fertiliser in a granular form. What fertilisers do plants need to grow well? The three most important nutrients for grass growth are as follows: - Nutrient Chemical Effect on grass growth symbol Nitrogen N Used by grass plant to grow green tissue (leaves, stems etc.). Phosphorus P Needed only in very small amounts that are normally available from the soil. It is sometimes used in small amounts prior to seeding or laying turf as it is used by the grass plant to promote root growth. Potassium K Used by grass plant to help the grass control water loss, resist cold, disease and wear. It is these three elements that are often shown on the front of fertiliser bags as three numbers N P K e.g These numbers refer to the percentage of the nutrient in the bag (in this bag the amount of nitrogen is 10%). Page 17

18 Grass also needs many other nutrients for growth and these include: sulphur copper zinc molybdenum magnesium boron calcium iron manganese However these are only required in very small amounts and are normally available from the soil the grass is growing in. They are not normally applied by the greenkeeper other than on pure sand greens. Applying fertilisers the time of year and its effects on feeding Most fertiliser is applied to turf when it is actively growing, this being in the spring and summer. Fertilisers designed to be used at this time of year will have a high nitrogen content to promote grass growth. Some fertilisers are designed to be applied in the autumn, these are known as autumn feeds and will have a low nitrogen content. Do not use a high nitrogen fertiliser on fine sports areas (such as golf greens) in the autumn or winter as it may cause soft lush growth leaving the turf open to attack from the fungal disease fusarium patch. How should I apply fertiliser? Fertiliser needs to be applied carefully and evenly, if damage to the turf surface is to be avoided. Following the steps listed below will help ensure you do not damage the grass and just as importantly you get even growth and colour. 1. Always read the label and obey the instructions on the fertiliser bag, wear any personal protective equipment required. 2. Do not apply the fertiliser if there is a strong wind blowing or heavy rain is expected. 3. Always ensure that if you are using a machine to apply the fertiliser, you calibrate it first. 4. Sweep up any spills of fertiliser from the turf quickly and water the area to prevent burning of the surface. 5. Try to avoid getting fertiliser onto surrounding plants or into water (e.g. ponds etc.). 6. Never fill the distributor on the sports surface (more chance of spilling fertiliser onto the turf). 7. Apply the fertiliser evenly by using some kind of markers. Many greenkeepers apply it in 2 directions (half the amount each way). A trick often used is to apply in the morning so you can see your wheel marks in the early morning dew. 8. Always wash any equipment after use as fertilisers are corrosive and may damage machinery if not removed. 9. Wash your hands, any exposed areas of skin and any personal protective equipment that was worn during the work. Page 18

19 10. Put any fertiliser safely back into storage (a dry place away from heat and petrol). 11. Make a record of what you used and where you used it. Calibration of distributors and applying fertiliser It is vital that fertiliser is applied evenly to turf surfaces at the rate recommended by the manufacturer. Failure to do this can result in: a Burning of the turf sward by applying too much fertiliser. b. Inconsistent colour to the turf sward. c. Inconsistent growth rate of grass on the treated area, the result will be a poor looking surface. d. Increased costs as more fertiliser than is needed may be applied. Calibration of a spinning disc (cyclone type) fertiliser distributor The information below is a guide only and you will need to experiment with each type of machine you use. 1. Look at the fertiliser bag and find the application rate (for this example 35 grams per square metre (35g/m 2 ). 2. Lay out three 1 metre square sheets of cloth on a clean workshop floor (do not use plastic as the fertiliser will slide off the slippery surface). 3. Set the distributor to the halfway mark and run it over the sheets walking at the same speed you use when you actually apply the fertiliser to the turf. 4. Weigh the material on the centre mat and continue trial runs until the correct amount (35g/m 2 in this case) is thrown onto the mat. Do not forget to clean off the mats after each trial run! Once the required amount is laid on the centre mat, you must weigh the material produced on the outer mats. In a perfect world it would be half the amount of the centre mat and for this example we will assume that this is the case. Note if the machine throws wider than 3m use more mats. For the following example we will assume a spread of 3m and an application rate of 35 grams per m 2. 1st run on green 17g 35g 17g 17g 35g 17g Note most of the fertiliser has fallen on the centre mat. Page 19 17g 35g 17g Return run on green with overlap ensuring even application.

20 Operator with machine Drop spreaders 3m width of spread Note: Some modern disk type spreaders can be adjusted to throw the fertiliser evenly across the entire width of spread. This may remove the need to overlap. In the above example the amount of overlap required will be 1m. In real life you will need to experiment with the machine you are using and try to get the most even application of fertiliser possible. Often it will be impossible to get it perfect but you will get close. Once you have calibrated a machine, record the details so you do not have to do it all over again when you next use the same fertiliser. These machines are easy to calibrate as they apply fertiliser evenly along the length of spread. Therefore all that is required is the laying out of a 1m square sheet and then run the machine over the sheet ensuring the whole sheet is evenly covered. Weigh the amount on the sheet and repeat the process adjusting the spreader until the correct amount of fertiliser is applied to the sheet. How to apply the fertiliser to the turf surface Drop spreader type Spinning disc type Start Start point End Drop spreaders are easy to use as they drop fertiliser evenly along the length of the machine. There is no risk of the fertiliser being thrown onto plants or into ponds. However it must be noted that any overlap is a 100% over-application and will most likely scorch the grass. Note: The diagram shows a drop spreader being used on a bowling green with 1 pass being made. Note some turf managers make 2 passes to avoid missing areas. If this is done then it is vital to remember to calibrate the machine to apply half of the required application rate on the fertiliser bag. The above diagram shows a spinning disc type spreader being used on a golf green. Marker posts are being used to help avoid missing areas. In some cases the posts are replaced by a fellow worker who acts as a marker taking a set number of steps after each run. As with the drop spreader, often two runs are made at right angles to ensure no missed areas are left. If you choose to apply from two directions, remember to calibrate the machine to apply half of the required application rate on the fertiliser bag. Page 20

21 Types of equipment for applying fertiliser Mounted on a Toro workhorse, this large pendulum type spreader is designed for large areas. The hopper holds large amounts of fertiliser that flows to the large pendulum that moves rapidly from side to side throwing fertiliser evenly onto turf surface. Image courtesy of Modern Amtec Spinning disc distributor. Fertiliser falls from the hopper onto a flat disc that spins when the machine is pushed forward. This spinning motion throws the fertiliser onto the surrounding turf. These types of machines require careful calibration as they often require the operator to slightly overlap each run. Image courtesy of Sisis Drop spreader in use on a fine turf area. On the underside of the hopper can be seen two small metal hooks which make a line on the turf to show the operator where he/she has been. These lines are used as markers to ensure each run is evenly applied. Image courtesy of Page 21

22 Methods of monitoring and assessing the effects of sports turf maintenance Good managers will take an interest in the effects of their work. The ability to understand how a turf surface reacts to maintenance operations is important as it will improve your management ability and avoid repeating expensive mistakes. Making notes or records of what happens after operations will help improve future performance and help the manager justify his/her actions to their senior managers. This monitoring can be in the from of written records, photographic records etc. An example of such records might be Stimpmeter readings taken on a golf green. Over time these records will build up a picture of how the playing surface reacts to such tasks as top dressing, verticutting and fertiliser applications etc. Waste and environmental impact that might arise from maintenance operations and how to deal with them The disposal of waste off site (e.g. having it removed by contractors) is and will become more so an expensive option. Turfgrass managers should try to reduce waste and look at ways of disposing of it on site, if possible. There are two main types of waste that arise from turf maintenance operations, these are: Organic waste This might be grass clippings, aeration cores etc., and is best recycled if possible by the process of composting. Correct composting relies on material being piled up and turned regularly to allow good aeration. Bacteria within the waste will break down the organic matter producing rich humus that can be used in top dressings or planting operations. Note that large rotting piles of grass clippings can produce a toxic liquid that is poisonous to aquatic life and so should be placed well away from any streams, ponds etc. Chemical waste from applications of pesticides This is more difficult to dispose of and should be minimised by careful calibration of spraying equipment. However even if the manager is careful, there will always be a small amount of chemical waste after a spraying operation. There are several ways of dealing with this waste. Among these are: a. Using up excess materials on non-target areas such as golf rough. b. Spraying the waste onto waste ground. c. Collection of the waste for disposal via an approved contractor. The laws relating to disposal of chemical waste are complicated and for more detailed information it is suggested you refer to the chapter Prepare and apply pesticides. Page 22

23 Reducing environmental impact It is the duty of the sports turf industry to reduce environmental impact to an absolute minimum. The sports turf manager can do this in many ways, examples might be: a. Reducing drift of pesticides by correct nozzle selection, spraying in low wind conditions, selecting the lowest effective application rate for the pesticide being used. Ensuring spraying operations keep well away from water bodies (ponds, streams etc.). b. Using fertilisers that are formulated from materials that are not prone to easy leaching. c. Avoid using fertilisers near water or areas of wild flowers such as golf rough where they may create artificially high nutrient conditions leading to the loss of important habitat. Typical problems that might occur when maintaining turf and how to deal with them The types of problems that might occur are limitless, with this in mind it was felt that two of the most common should be looked at in detail: Spills of fertiliser Sweep up any spills of fertiliser from the turf quickly and water the area to prevent burning of the surface. Avoid spills by filling the machine in areas away from important turf. Hydraulic oil leaks If these occur near to the edge of important playing surfaces such as a golf green, attempt to drive off in the shortest distance. Stop the machine as soon as possible and attempt to apply an absorbent material such as sand to the area of spill. This will help soak up the oil and prevent soil contamination. Special absorbent packs are available for this purpose and some organisations have them fitted behind the driver s seat ready for instant use. After the main body of oil has been absorbed remove the absorbent. Then if possible wash the affected area with copious amounts of water and non toxic (to the grass) detergent. Maximum damage will show some 48 hours later and a decision can be taken on whether to remove the turf from the affected area and replace it or allow the grass to re-establish naturally. Page 23

24 Statutory requirements for the application of pesticides There are many statutory requirements relating to pesticide use and you are advised to read the chapter Prepare and apply pesticides for further information. However two of the most important pieces of legislation are: Control of Pesticides Regulations (COPR) These regulations cover the use of pesticides and state that: Pesticides (weedkillers, fungicides etc.) can only be used for the purpose stated on the label. Pesticides must not be used at a higher rate than that stated on the label. Pesticides must not be mixed together unless it says this is allowed on the label. Food and Environmental Protection Act (FEPA) This act deals with the use of pesticides and states that those using pesticides must take reasonable care to: Protect the health of humans when spraying. Protect the health of animals and plants when spraying. Take particular care to avoid polluting water courses (streams, ponds etc.) when spraying. Ensure safe storage, use and disposal of pesticides. The Act also requires that people are trained before they use can use pesticides. The principles of risk assessment It is a legal requirement for organisations to consider the risks of workplace operations to the staff and members of the public (players included). This is achieved by a process known as Risk Assessment. There are 5 steps involved in the process, these being: 1. Look for the hazards (possible causes of harm). 2. Decide who might be harmed. 3. Evaluate the degree of risk and decide how to remove or reduce the risk. 4. Record your findings. 5. Review your assessments of the risk on a regular basis. You are advised to see the chapter Promote, monitor and maintain health, safety and security for further details on risk assessment. Additional information It is felt that candidates on a level 3 sports turf management course will already be aware of the reasons and timings for the major maintenance operations. However the following pages may serve as useful reminders. Page 24

25 Scarification, verticutting and vertigrooming The best way to understand the difference between scarification and verticutting/vertigrooming is to think of the operations in terms of cutting (or raking depth) and the number and thickness of the blades used, for example: 1. Scarifying (sometimes called thatch removal) refers to the operation of vigorously raking/slicing the turf surface with the intention of removing thatch, dead grasses etc. When scarifying with a machine we would tend to set the blades to cut slits in the turf surface and thatch layer (note blades must not be set so deep as to engage the underlying soil as this will blunt the blades of the machine very quickly). The blades on a scarifying unit would be quite thick (to withstand the high wear) and set wide apart to avoid causing too much damage to the surface. 2. Verticutting (sometimes called thatch control) is a lighter operation, which is carried out more often and it is designed to prevent thatch build up on the sports surface rather than remove it. Blades on verticut units are thinner and closer together. The blades are normally set to just touch the base of the grass leaving very thin lines on the turf surface. Most modern golf green machines have verticut units which can be fitted instead of the normal mowing units. Light verticutting can be carried out during most of the year (once every 1 to 2 weeks) with the exception of extremely hot dry weather and during the winter months. 3. Vertigrooming is a very light operation that is carried out regularly (c. 3 times a week during the growing season) and it is designed to prevent lateral grass growth. This produces a grass surface with upward growing grasses which hold the ball up and therefore produce a faster, truer putting surface. Vertigroom units have a very high number of blades that are very thin and set very close together. The blades are normally set a couple of millimeters below the mowing height. Most modern golf green machines have vertigroom units which are fitted in place of the normal mowing units. What are the advantages of scarifying? 1. By raking the surface we can remove and help prevent thatch. Thatch is a layer of organic material made of dead grass leaves and roots. This layer causes many problems such as a slow, soft surface with a resulting poor bounce in games like cricket. 2. Scarifying often is carried out prior to overseeding and fertilising operations as it helps thin the grass cover and create grooves into which the fertiliser or seed can be worked and for the same reason it is often done prior to top dressing. 3. The reduction in thatch and improved airflow around the base of the plant also helps prevent fungal diseases such as Take-all patch and Fusarium patch. 4. The slicing of the grass surface helps encourage the finer grasses which are less damaged by the cutting blades. Page 25

26 5. Finer grasses create an upright sward and this results in a fast surface (balls roll across the surface easier) and this helps the ball stand on top of the grass, providing a better club to ball contact in games such as golf and hockey. 6. As only fine grasses can pass through scarifying and verticut undamaged, the coarser grasses and weeds are sliced up and their growth is discouraged. This also applies to moss as long as it is killed before scarifying (raking living moss will help spread it across the grass surface). When should we scarify turf surfaces? In general terms, we scarify turf when it is actively growing as this allows the grass to recover from the scarification. This means that most scarification is carried out in the spring, early summer and the early autumn. Scarification is not normally carried out in the winter as the grass is not growing and the thinned grass that would result, might become invaded by moss and other weeds. Also the playing surface would be badly affected in terms of quality. Scarification is also best avoided in conditions of extreme heat as the turf could become severely stressed leading to a poor playing surface. Scarification or verticutting is best done gently and often, as this will encourage fine grasses as they adapt to the constant raking. Some greenkeepers will scarify lightly once per month in the growing season and others perhaps only 1 or 2 times per year. There is no correct amount of scarification, as it will depend on the amount of thatch you have, the type of grass, how much you feed your turf and the sport being played as well as many other factors. Page 26

27 Top dressing Why top dress sports turf? 1. Top dressing is an important part of sports turf maintenance and is carried out on all sports surfaces. Because the top-dressing fills in any divots, pitch marks and other types of damage it helps to create a smooth surface. 2. Smooth sports surfaces allow a ball to roll faster and truer thus improving the game for players. Top dressing is very often carried out after aeration and one of the reasons for this is to fill in the aeration holes (improving drainage and aeration) and return the surface to a suitable playing condition. 3. Depending on the material used to top dress, improvements to the soil structure of the area can be made. This may help improve drainage or depending on material used help improve moisture retention. This is most often done using a process called soil exchanging where the sports surface is hollow tined and the cores of original soil removed, top dressing is then applied and rubbed into the holes to replace the soil with a better material. 4. The potential improvements in drainage may raise oxygen levels in the soil, which will increase soil bacteria levels thus increasing the breakdown of any thatch present. 5. Top dressing with soil based materials may help supply nutrients (plant food) to the turf. 6. Some top dressing materials such as sand may have a high/low ph and therefore help to slowly change the soil ph over a long period of time. Note: Generally, mixtures of sand:soil are used in ratios of 80:20 or 70:30 (the sand being the dominant fraction). Using sand-only top dressings Sand-only dressings should be used when the rootzone is comprised of sand. Using sand-only dressings on soil based or soil sand-based rootzones can cause problems as the sand will build up and create layering problems. This may result in increased dry patch problems, lack of surface firmness in winter and root breaks in the rootzone profile. The effects of weather conditions and the time of year on top dressing operations Before applying top dressings, always check that the grass surface is dry as this will ensure that applying, spreading and working in the dressing is easier. Always try to obtain a weather forecast before starting the job as rainfall will make it very difficult to continue the operation. Do not apply heavy dressings in the late autumn or winter as grass growth is slow and the damp dressing will lie around the base of the grass plants leading to a high risk of the disease Fusarium patch. Page 27

28 When and how often to apply dressings Top dressing should be applied when the grass is actively growing during the spring, summer and early autumn months. How often will depend on the quality required the amount of play etc. Golf greens might be done lightly on a monthly basis or twice a year with a fairly heavy application. Materials for various sports surfaces Top dressing materials must be suitable for the sports surface being top dressed, for example cricket and tennis require heavy loams and should never be dressed with peat or sand which would cause the playing surface to break up and ruin surface bounce. Golf greens built from sand should not be dressed with heavy soils that would impair the drainage of the green. Top dressings for golf areas should be of a sand and soil mix with less than 3% by weight of organic matter and lime free. The majority of the particles in the sand should be between 0.25 and 0.75mm with a fines content of less than 10%. NB Fines refers to very fine sand, silt and clay particles. How much to use This will depend on the sport; any surface damage and if aeration has taken place. Rough guidelines are 0.5 to 1kg per m 2 for light regular dressings to 3kg per m 2 after aeration. Weights given are for dry materials. Page 28

29 Aeration of sports turf Aeration is one of the most important maintenance tasks carried out on turf. Aeration means to get air into something. In turf it is simply the production of holes through the turf surface into the underlying rootzone (soil) to allow gases (oxygen etc.) in and out of the soil and for water and grass roots to move down through the soil. How is it done? Traditionally, holes have been created in the turf surface using a range of metal implements known as tines. Below are the most commonly used of these metal tines. The right tine for the job The correct selection of aeration tine is critical if the desired results are to be obtained. Sports turf managers should ask themselves what it is they wish to achieve by way of aeration and then select the most logical choice of tine. In order to assist in such decisions the following information may be of assistance: Tine type hollow These are best suited to: a. Relief of soil compaction because a core is removed from the soil leaving space for plant roots to grow into. b. Soil exchanging the cores of soil removed can be replaced with an improved top dressing such as sand or a sand and soil mix. c. Aiding thatch control the ejected cores contain thatch, which is removed from the turf. Hollow tines should not to be used on: Stony or hard ground conditions as it is possible for the relatively thin walls of the tine to become bent and broken affecting the ability of the tine to eject a core cleanly leading to blockages and the need for expensive replacement tines. Tine type solid These are best suited to: a. Use on hard or stony ground this is due to the tines strong construction and resulting resistance to damage and wear. b. Allowing air into the soil during general aeration (as there are no cores to remove from the surface they are quicker to use than hollow tines). c. Enhancing the flow of irrigation water into dry turf during drought conditions. Solid tines create a round hole in the turf surface that will not open up as the surface dries. Solid tines are best not to be used: During wet conditions on heavy soils as the pushing of the tine into the soil can smear the edges of the tine holes making drainage worse. Page 29

30 Tine type slit These are best suited to: a. Root pruning as they slice though a large soil area (this operation is best done in the spring as the warming soil will stimulate the grass to produce new root growth). b. Improvement of drainage as the tine cuts through a large soil profile in the rootzone it can greatly improve drainage of the turf surface without too much interruption to play. c. General aeration as the tine creates less surface damage it is well suited to general use to allow air into the rootzone. Slit tines are best not to be used: During hot and dry conditions the slit left by the tine can open up. This is caused by the loss of water from the soil at the edge of the tine slit, resulting in the soil shrinking back from the edges. This is most likely on soils that have a high clay content. Tine type spoon These are best suited to: The same functions as the hollow tine, however their has the advantage of being stronger and less likely to become blocked during use. Tine type chisel These are best suited to: a. Hard ground conditions, due to their strong construction. b. General aeration of the soil due to the small effect on the playing surface. Other methods of aeration In recent years other methods of aeration have been developed these are: 1. Drills These use a power system, which turns a large number of drills mounted on a deck. These drills can penetrate deeply into extremely hard soils regardless of the moisture content or stone content. However, they are slow to use and expensive to buy. They are best suited to specialised areas and conditions. 2. Compressed air This system of aeration uses a metal tine, which is most often hydraulically driven into the turf surface. Once the tine has been driven into the turf surface, compressed air, which has been stored in a tank, is released down the tine emerging at great pressure into the surrounding soil. This pressurised air raises the soil and fractures it; this leaves a huge number of fissures in the soil for movement of air and water. The drawback of this system is the slow working speed and cost of machinery. It is not suited to regular use and is most often used to deal with specific compaction problems. Page 30

31 3. Compressed water A development of recent years no metal tine is used. Instead a number of jets of highly compressed water are fired at the soil surface in pulses. These jets of water cut into the turf surface and underlying material. The main advantage with this system is the lack of disruption to the soil surface (indeed it is often hard to tell that aeration has taken place). However there are several drawbacks to this system in that: a. The machines are expensive to purchase. b. The speed of operation is slow. c. The depth of penetration is affected by hard ground conditions. 4. Vibrating blades These machines use sharp blades that vibrate as they cut through the soil. This has an effect that is similar to a Verti-Drain (e.g. the soil is physically heaved creating fissures for root growth and drainage etc.). Ten reasons for aeration 1. It allows air into the soil (turfgrasses need oxygen for respiration). 2. To improve the drainage of the turf surface and underlying material. This improves the playing surface and helps avoid soil compaction (wet soils are more easily compacted). 3. To reduce the occurrence of some fungal turf diseases such as Fusarium which find it easy to spread from plant to plant in moist conditions. 4. To remove compaction from the soil; compaction reduces drainage, root growth and resistance to drought as well as creating a hard playing surface. Compaction is caused by compression of the soil by the movement of players and machines across the turf surface. 5. To encourage root growth. If done at the correct time of the year (spring being the best time), the slicing of the turf roots stimulates the turfgrass to produce new root material increasing its mass and depth. The holes left by aeration also offer an easy route for the turfgrass roots to progress downwards into the soil. 6. To increase oxygen levels in the soil. This in turn, stimulates soil bacteria, which are vital to soil health. Bacteria in the soil break down fertilisers for plant growth as well as breaking down organic matter (thatch). It is also thought that soil bacteria are beneficial in controlling some damaging fungi in the soil. 7. To aid the penetration of irrigation water. This is particularly important when compact dry soils occur on a sloped area, where run off of irrigation water is a problem. 8. To help in the control or reduction of thatch in the turf. The use of hollow tines is well suited to this role as a plug of thatch is physically removed during the aeration process. 9. To help in the process of rootzone improvement. After aeration, top dressings can be applied to the turf surface which can then be worked into the aeration holes to help improve drainage etc. Page 31

32 Fertilisers and chemicals (such as wetting agents in granular form) can also be worked into the rootzone in the same way. 10.To help maintain all round soil and turfgrass health! Thus reducing turfgrass problems such as fungal diseases and certain weeds and moss which thrive in the presence of high moisture levels. When to aerate The best time to aerate is when the grass is actively growing as this will allow for the quick infill of the holes by roots and cover of the holes by grass leaves. This means the main periods are the spring, summer and early autumn. Golf greenkeepers should always try to avoid aerating just prior to competitions as the aeration holes may affect the playing surface. Groundsmen looking after bowling greens and tennis courts etc. will carry out the main aeration at the end of the playing season so as not to affect the fine playing surfaces. The ground should be moist (avoid aerating very wet or dry soils). Page 32

33 Rolling It must be remembered that rolling can seriously damage turf health. The reason why grasses on cricket tables and tennis courts can withstand constant rolling is that they are only played on for part of the year and then they are extensively aerated at the end of the season and left to recover over the autumn and winter period. This is not a possibility on golf greens which are played on all year round. Rolling on golf courses should not form part of the greenkeeper s normal maintenance procedures. Bearing the above in mind, rolling turf is sometimes necessary, and good examples might be: a) A winter sports pitch (football, Rugby etc.) where turf cut up by players, needs re-firming or where frost has lifted the pitch. b) Cricket pitches; these require heavy rolling prior to and during the playing season to produce a surface that provides the bounce of ball required by the game. c) Tennis courts also require regular rolling before and during the playing season to provide a surface that gives the required bounce. d) Bowling greens may require light rolling in the spring to settle turf that has lifted over the winter as well a light rolling during the season to produce a surface on which bowls will roll smoothly. e) Golf greens may occasionally need rolling after operations such as aeration that unsettle surface smoothness or to speed up the surface prior to a competition. Under no circumstances should rolling take place on a soil that is very wet as this will result in serious damage to the soil structure by squashing the soil and expelling the soil air. This will result in a badly draining surface that prevents micro-organisms and plants from carrying out their normal metabolic processes. An increase in Poa annua, moss, disease, thatch and a reduction of fine grasses will then occur. Rolling will help produce a smooth surface but will not level an area. Rolling is often employed as a means of flattening bumps this will not work all that will happen is the tops of the bumps will become compacted and the grass cover will become thin and moss/weeds will invade the area. Humps must be cut out, some soil removed and then re-turfed. Hollows must be slowly raised by applications of top dressing, or in severe cases by removing turf and adding soil until level and then replacing the turf. Before rolling remember: 1) The soil must not be frozen or partially thawed as rolling in these conditions may shear frozen roots leading to serious surface damage. 2) The soil must not be over-wet as this will lead to compaction. 3) Must you use a roller? The same task can often be carried out using a cylinder mower with the blades turned off. Page 33

34 Switching or brushing There are many reasons for this work, the most important being to remove early morning dew. This helps to prevent disease (fungal diseases such as Fusarium patch spread quickly on wet leaf surfaces) and improve the playing surface (a dew covered turf will slow down the roll of the ball). Brushing also helps to stand grass before mowing, therefore giving a better quality of cut. During the spring and autumn months when earthworms are most active switching or brushing will remove the casts prior to mowing and/or play. Often it is beneficial to brush sports surfaces after top dressing or fertiliser applications to help work the material into the grass surface. On golf green surfaces, it is important to pay careful attention to switching or brushing areas of the green near bunkers, as players can splash sand and small stones out of the bunker on to the green surface, and these materials could badly damage mower cutting units. Should trees surround the sports surface then leaf removal may be another important brushing task in autumn. Lastly switching and brushing allow the greenkeeper to inspect the turf surface before mowing, metal items such as studs, bolts from mowers etc. which can be spotted and removed reducing mower damage. Switching and brushing should be carried out as early in the morning as possible to ensure that the surface is in a suitable condition for the players. Note some golf clubs now use motorised blowers to remove leaves and dew from turf areas and these are often very effective in this role if used carefully. Page 34

35 Irrigation This section sets out the basics of irrigation. Irrigation is not a fixed subject as many variables (such as grass type, soil type and infiltration rate as well as the actual sport being played) will affect the operation of applying water to turf surfaces. Also many different opinions exist on what are correct practices. However it must be stressed that over watering is as detrimental to turf quality as under watering. Over watering is wasteful to the environment and will increase operating costs. Over watering leads to a soft playing surface more easily damaged by players and the impact of balls. It encourages the grass roots to become confined to the surface. It increases disease and moss problems and encourages weed grasses such as Poa annua to invade the surface. The constant filling of the air pores in the soil with water will also reduce soil bacteria leading to a potential build up of thatch and fungal diseases. A wet soil is also easily compacted as moisture allows soil particles to slide easily around each other. Why do we need to apply water? Water is an expensive and a valuable resource and it should be applied in amounts that are required to keep grass healthy and provide the playing surface requirements. These surface requirements will vary according to the sport being played. Golf greens require enough water to keep the grass healthy and ensure the surface is receptive to incoming golf balls. Not enough water will mean golf balls will bounce uncontrollably off the surface, too much water and the balls will stop immediately on hitting the soft green surface causing pitch mark problems. Cricket pitches are similar as too much water will mean a poor bounce and pace for the bowler and too little water may result in surface cracking. Cricket pitches require moisture during their preparation, as only moist soils will compact during rolling operations. Water is also used by the grass plant as a means of taking up of nutrients into the root system. The grass plant also uses water loss from the leaf as a system of cooling. Recognising drought stress When grasses have enough water they are in a condition known as turgid. As they obtain water from the soil via their roots they begin to use up the soil water. Unless rainfall or irrigation replaces this water the grass will start to suffer from drought stress. It is important to begin to water turf before signs of drought stress occur. To identify the early symptoms of drought stress on turf, the turf should be inspected for the following symptoms: 1. Colour change, the grass will turn a grey shade of green and the colour will become duller (note grass never turns yellow) for lack of water and only turns brown when the drought stress is quite advanced (a little bit too late!). 2. The grass leaves will wilt and lose their rigidity. This can be tested by a method known as the footprint test which involves walking on the grass and observing how quickly the grass takes Page 35

36 to stand upright. On turf suffering from lack of water, the grass in the footprints will not spring back upright very quickly. Experienced managers can assess the speed of response and therefore the degree of drought stress. 3. Surface firmness, as the soil dries it will become harder and this can be felt underfoot or assessed by the way a ball reacts with the surface (amount of bounce). 4. A reduction in grass growth will take place this will mean fewer clippings are removed when mowing. Applying irrigation water This may be done using a wide range of equipment ranging from special hoses covered in pin holes which are used to water cricket squares, hoses and travelling sprinklers used to water football fields and automatic pop up sprinklers that are often employed on golf courses. Whatever equipment is used, it is important that the water is used effectively. This will mostly apply to the timing of watering. The best time will be in the evening or very early in the morning which will avoid evaporation of the water (by the heat of the sun) from the surface before it has a chance to sink into the soil. In order to make best use of water, sports turf managers often lightly prick or spike the surface before watering to help the water get into the soil (a sarel roller is ideal for this task). Golf courses often water at night using automated pop up sprinklers, as this avoids problems of watering when players are on the course during the day. How often and how much? Note there are no hard and fast rules. The amount of water will depend on a number of factors and the information below is only a guide. Greenkeepers should rely on their manager s experience and their own observations to decide on whether or not to apply water. The average sward loses 25mm of water from the soil surface in an average summer week. Hot summer weather is normally from May to August (about 12 weeks long), therefore you may need to apply up to 25mm of water a week (subtract any rainfall from this amount). Most managers of turf areas feel this is best applied in several heavy applications of water every two to three days. This will mean the large amount of water will sink into the soil and the turf will dry out between waterings this will promote good rooting of the turf. Applying light amounts of water every day will encourage shallow rooting. The effects of soil type on irrigation When irrigating grass areas, the type of soil they are growing on makes a difference to the way in which they are watered. Sandy soils absorb water quickly and quite heavy applications can be applied before the water starts to flood the surface. However because sandy soils drain well they require constant topping up in dry weather. Page 36

37 Heavy soils (those with a lot of clay) will not absorb water very quickly due to the small particles in the soil fitting so closely together. Therefore these types of soils need to have water applied using sprinklers which produce a fine droplet size and often managers apply the water in small amounts and then allow the water to sink in before applying a second or even third application Reducing water usage The following, when done regularly, may help to reduce occurrences of drought stress and water usage and therefore costs. 1. Ensure the grass roots can grow deeply into the soil by dealing with any compacted areas on the sports surface by spiking. 2. If possible allow the grass to grow slightly longer in periods of extreme heat. This will help shade the soil reducing evaporation of water from the soil and reduce stress on the grass plant. 3. Ensure the turf is kept healthy by not under or over feeding with fertiliser. 4. Ensure the area is as well drained as possible (poor drainage will result in a shallow rooting grass sward). 5. Scarify the surface regularly to remove thatch as this prevents water from moving down into the soil 6. Ensure the area is kept free from excessive weed competition. Some examples of equipment for irrigation A wide range of equipment is available for irrigating turf surfaces. The type of equipment used will depend on the sport being played and the size of area to be watered. Some examples of irrigation equipment: Travelling sprinklers These are used to water large areas such as football fields or golf fairways. They usually pull themselves along by a series of gears that are driven by the pressure of the water as it leaves the nozzles. The sprinkler is connected to a hosepipe (not shown in this picture). Image courtesy of www,connectomatic.co.uk Automatic pop-up sprinklers. These are installed below the turf surface and "pop up" when activated to water the turf. See chapter Manage drainage and irrigation systems for more information on the subject of irrigation. Page 37