The re-construction of greens is a major decision for any golf club to make. The greens are the heart and soul of the course and generally make or break a club in terms of reputation. If greens are not performing or not meeting club expectations, reconstruction may be the best solution.
Before reconstruction begins, it is essential that a thorough investigation of the existing greens is carried out. It is vital to understand what the problems are and issues that have led to the decision to reconstruct. Failure to carry out this process could result in the same problems occurring in the newly-constructed green(s).
When reconstructing golf greens there are a number of important issues that need to be understood to ensure the project is successful. Many of these issues are relevant to golf courses world-wide. However, there are also issues that are specific to the wet tropics region and Malaysia. These include climatic characteristics, available materials for construction and turf grass selection.
There are several reasons why a golf club in Malaysia may wish to reconstruct its greens. These include:
• The original design or construction was poor and the greens do not perform
• The greens are contaminated with common Bermuda grass or other weeds
• Member pressure for higher quality greens
An independent consultant, carrying out a detailed feasibility study, should be able to identify any current limitations to guide the club in the best way forward.
Common problems associated with poorly-performing greens in Malaysia include:
• Poor construction, in particular wrong rootzone depth
• Incorrect selection of rootzone materials
• Poor amendment selection and mixing
• Incorrect fumigation procedure
• Inappropriate fertiliser program
• Incorrect pesticide selection and application (in particular fungicide use)
• Poor turf grass species selection and management
• Inadequate grow-in period
• Poor irrigation management
Adding to any deficiencies in construction method, or turf management practice, in the region are player pressure and climatic challenges of South-East Asia.
All of the above issues can present problems during and after the grow-in stage and restrict the potential of the turf surface. A number of these points are discussed in more detail below.
Poor construction/rootzone depth
Although USGA golf green construction specifications advise rootzone depths should be approximately 300mm, it must be noted that this is a guideline only. Depth will need to be adjusted in accordance with the sand type used.
Finding greens construction materials that meet USGA standards in Malaysia can be difficult for golf courses, as supply companies do not consider the sports turf market significant (i.e. most of the material produced is for road construction or building material).
Materials are often used that contain a high proportion of particles outside the USGA guidelines, often with coarse material (small stones) and fine material (silt) making up the majority of the particle size distribution. This component is a key factor in determining the optimal depth of the rootzone. Recently, the NZ Sports Turf Institute completed laboratory testing of a rootzone material for a client in Malaysia. The results of the laboratory testing indicated the ideal depth for their particular greens construction should be 250mm to 275mm; any deeper than this would have made it more difficult to manage during establishment. Conversely, if the rootzone was constructed at a depth less than 250mm, aeration problems, such as algal slime, fungal infections and possible weed infestation would be likely.
Instead of complete rootzone reconstruction clubs can opt to simply re-surface their greens in an effort to provide improved putting surfaces for their members. Re-surfacing is an option in many situations. Before this is carried out a few questions should be answered.
1. Why is the current turf on the greens surface not performing?
2. Is the construction material (selected for topdressing) the same as the original green rootzone material?
Re-surfacing normally includes removing the existing turf to depth, so that all vegetative material is removed along with any identified troublesome layers. New sand is placed on the existing sand to an approved depth and stolons of a selected turf species are planted. This practice is normally acceptable if the greens drainage system is performing satisfactory and there are no internal rootzone problems such as black layer.
Where the old turf cover is to be removed, care must be taken to collect all of the vegetative material and thatch. Common Bermuda grass stolons, and other plant species, can remain viable in the soil for many months and it is important to remove this material to avoid contamination of the new surface. It is strongly recommend that the old turf is sprayed with a non-selective, systemic herbicide such as Glyphosate before blading off.
Another reason for thoroughly removing all material is to prevent layering that may occur once the new rootzone material is imported on to the existing surface. Any layering, or resulting moisture break, will only create future problems with the new green(s).
It is common practice for superintendents to mix rootzone sands with an amendment to aid management (such as nutrient and moisture retention).
So why do sands require amendment addition?
Referring to the previous example of sand sent to the Institute for testing. The sand selected fell within the USGA particle size analysis range. However, it did not pass the moisture release test (a test that indicates the ability of the sand to hold moisture - so the selected turf grass will not dry out). For this sand to be used the rootzone would have to be constructed at a depth of only 200mm. This is not practical, given golf green flag holes are installed to this depth and any disturbance to the gravel raft below will result in contamination. Therefore, the sand was re-analysed with a peat-moss amendment. With the amendment, we found that the green was able to be built to 275mm, as the amendment retained adequate moisture for the turf.
Turf managers may add amendments to sand in an effort to increase the ability of the rootzone to store plant available nutrients. Sphagnum peat moss has traditionally been used for this purpose (particularly in dry climates). The ability of the peat moss to store moisture in the ground is undoubtedly good. However, recent studies completed by NZ Sports Turf Institute have indicated peat moss has minimal plant nutrient value as both a retainer and a supplier. Another issue that must be mentioned is the acidic nature of many peat mosses. Low pH values in golf greens can restrict the availability of nutrients.
Rootzone amendment selection should be based on the following points:
• Increasing the CEC value of the rootzone to retain nutrients
• Retaining drainage to remove high levels of rainfall in Malaysia
• Providing moisture retention (particularly dry season periods)
What other rootzone amendments are available?
Other amendments commonly used in golf green construction include chicken manure and a naturally occurring mined product called zeolite.
Chicken manure offers an added value to young Bermuda grass greens as it has nutritional value and it does not affect the pH of the rootzone.
Many turf specialists have called zeolite a 'designer sand'. It is internally porous, comes in sand sized and shaped particles and offers nutrient retention.
Different amendments are available to golf courses in Malaysia. However, they do not differ in mixing requirements.
Amendment mixing requirements
For a successful blend of sand and amendment the key is off-site mixing.
The following steps should be adhered to for a successful sand/amendment mix.
• Have both the sand and selected amendment tested in a laboratory to assess the ideal mixing ratio and depth of the rootzone.
• Once this has been achieved it will be relatively easy to calculate the quantities of the materials required and purchases can take place in bulk.
• Mix materials off site. Use a semi-large concrete pad, a front-end loader (such as a bobcat) and, if available, a concrete mixer.
Note: Materials such as peat moss are often sold in measured quantities (per volume basis). Once the material is dried slightly for mixing with sand, volume decreases. This can lead to miscalculations when making a purchase. It is recommended the decrease in volume be assessed before bulk material is ordered.
Figure 1. Photograph of sand and peat moss being mixed off site on a golf course for greens construction.
Mixing on site
Amendment mixing on-site affords no guarantee of mixing quality. If the amendment is not at the correct moisture content, or the sand is wet during the mixing process, the amendment can effectively "ball up" under the surface and form a layer. This is especially so with peat moss.
The mixing of amendments on site should only be done as a 'final solution' to improve the current rootzone of existing greens.
An example of this would be to intensively hollow-tyne an established green and topdress with a mixture of sand and zeolite. Although this is generally not recommended, it can improve the CEC value of a green and may give a club a 'few more years' before full reconstruction has to take place.
Photograph of a green that had an amendment mixed on site. The poor mixing contributed to poor plant health and reconstruction after only three (3) years.
Many course superintendents insist fumigation must be carried out to eliminate any potential turf -damaging organisms, such as nematodes and fungal pathogens, before the stolons are planted.
Others suggest fumigation destroys any naturally-occurring beneficial organisms that help protect turf by attacking plant pathogenic organisms. Both of the above groups have legitimate cases and are discussed below.
Malaysia still has access to soil sterilents, such as methyl bromide and Basimid (990g/kg dazomet).
Effects of fumigation
Many Superintendents fumigate purely to remove any plant parasitic nematodes that may have been brought in with the rootzone material. In general, it must be pointed out that it is unlikely nematodes are imported with new rootzone material. Nematode populations are generally restricted to the top 75mm of rootzone. Construction sands are usually mined at greater depths than this (or taken from rivers), thus the nematodes are more likely to be imported into the new greens via sand amendments, or with the vegetative material to be used for stolonising (which is after fumigation).
It is important to note that most developed rootzones have populations of nematodes. Nematode damage is often not seen or noticed until the turf is placed under some external stress. Commonly in Malaysia this stress is brought on by low light, excessive watering or wear (or a combination of all). Once the turf is in a weakened state it is unable to cope with combined stresses and damage becomes apparent.
Sports turf advisors around the world have differing views and opinions on soil fumigation. Some believe there are more risks involved with fumigation than without. Cases are cited where sterilised greens are more prone to attack from fungal diseases, such as Take-all patch and Rhizoctonia spp, as a result of the beneficial micro-organisms (that naturally protect the turf from these diseases) being removed during fumigation.
In contrast, other findings have indicated micro-organism levels after fumigation were restored to the same or greater level than pre-fumigation within a month of treatment. This work suggests fumigation does not kill all the beneficial micro-organisms, and that there are billions of microbes lying dormant in the soil that are not awakened until an actively growing plant root provides them a home.
Figure 3. Photograph of a new green being fumigated before planting.
Many different hybrid Bermuda grass varieties are found on courses throughout Malaysia. The most common Bermuda grass used in Malaysia is Tifdwarf, although even when certified stock is imported mutation tends to occur in greens after a period of five to ten years.
Mutation of the Tifdwarf leads to patchiness with turf that is coarse in nature, lower in density and grainy. Mutated turf also reacts differently to turf management regimes and this can affect putting quality.
There are three options available for the selection of Bermuda grass turf for a new green. They are:
1. Purchase certified Tifdwarf stolons from an overseas supplier.
2. Selection and isolation of a genetically mutated hybrid Bermuda grass from Malaysia.
3. Selection of a new certified Bermuda grass hybrid variety such as an ultra dwarf from an overseas supplier.
There appears to be a limited life span for greens established with Tifdwarf in Malaysia. We have no scientific explanation why Tifdwarf greens mutate so readily, although the low light, high rainfall environment may play a key role.
Isolating a 'mutant' Bermuda grass hybrid, establishing a nursery and using this turf grass for new greens establishment is risky. A plant that has spontaneously mutated may be better adapted to environmental conditions onsite than the original genotype (Tifdwarf). Mutation is a random process and the better strains will show up. The turf manager will be in the best position to isolate these grasses.
Currently Sports Turf NZ recommends looking beyond Tifdwarf and mutant hybrids in Malaysia. Some Bermuda grass hybrids have been developed using radiation. This has resulted in the production of 'ultra dwarfs' such as Tifeagle. Researchers are still trying to determine whether or not these grasses are more stable than the hybrids that were developed under spontaneous natural mutation (such as Tifdwarf). However, we do know that ultra dwarf Bermuda grass varieties do tolerate a lower mowing height. This allows the opportunity to maintain acceptable putting speeds during monsoonal periods without compromising plant health.
We can expect to see better cultivars of Bermuda grass (and other turf species) be introduced to Malaysia in due course. Research conducted at the Redlands Research Station in Queensland and elsewhere is producing promising results.
Although Bermuda grass generally copes well in dry conditions, irrigation is still required to supplement moisture levels. Problems often occur not due to the lack of water, but due to the application of too much water. Wet rootzones, humid conditions, cultural practices and high wear all contribute to fungal pathogen attack and, of course, algal slime infestations.
Before reconstructing a green, the irrigation system should be inspected to assess any major problems with water uniformity. If uniformity is found to be poor, corrective measures must be taken.
Once stolons are planted in a new green, the surface must not be allowed to dry for the first week. If the stolons become moisture stressed, viability of the plants is weakened and this may decrease the quality and speed of turf establishment.
Intense player traffic is typical of Malaysian golf clubs as the majority of clubs in this country are privately owned and exclusive to members. The members often play on other courses and comparisons (generally of the putting surface) are made. Golf club membership is a very competitive business. In this environment there is a conflict between offering members the 'best putting surface money can buy' and offering initiatives such as night golf. The need for reconstruction can often be avoided by limiting night golf to certain days of the week or resting sections (9 holes) of the course on occasions.
Newly constructed greens in Malaysia tend to be played on before they have fully established. In general clubs do not want to wait for more than 3-4 months from the time of construction before they 'try out the new green'.
Sports Turf NZ encourages clubs to extend the grow-in period (preferably up to 6-12 months after construction). If played on too soon, the turf will not cope with the requirements of producing food (carbohydrates) for healthy survival. The plant will be forced to use carbohydrate reserves to repair and sustain leaf matter at the expense of shoot and root growth. In an environment such as Malaysia this can have a devastating effect on the turf, eventually leading to a phenomenon called Bermuda decline.
Before greens construction is carried out, the club should identify all issues associated with the old greens.
Poor Bermuda grass performance on existing greens can generally be traced back to poor construction methods, Malaysian climatic conditions and inadequate turf management programs. We cannot manipulate the climatic characteristics of Malaysia and so must focus on those areas that we have some control over.
Make sure the green is built to the highest possible standard. Shortcuts such as on-site mixing will only lead to future problems and may even prevent the turf from establishing after construction.
It is also clear that the region is in dire need of further research on matters such as soil amendments and fumigation to use under Malaysian conditions.
Kenna, M. 2001. Nature will find a way: Common myths about soil microbiology. USGA Green Section Record, May/June 2001, pp. 10-11.
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