February Scenario answers.
By Dave Saltman
The February Technical Merit Award in association with Tillers Turf attracted 77 entries to the topical question. The question was:
At this time of year, algae is a problem on many sports grass surfaces. There may be a number of contributory factors for this. What, in your opinion, are the likely reasons for algal growth and what remedial action or actions would you take?
The best ten answers are below. The Judges have now made their decision for the best topical answer from these entries and so one lucky member is in the pot for the £2000 All-inclusive holiday. Remember that the judges are looking for the answer that best responds to the question set. This may not necessarily be a text book answer.
Each month a new set of multiple choice questions are posed, with each correct answer going into the monthly draw. In addition to these eight questions, a topical question, requiring a little thought will gain every entree the chance to win the Grand Prize.
The purpose of the Technical Merit Award is to share knowledge and help explain some of the many topical questions that we encounter in our profession. Our philosophy has and always will be ' A problem shared is a problem solved'.
Good luck with March, there is now just over a week to get your entries in.
The answers below are not in any order of excellence, it's just how I picked them out of the database to be viewed by the judges. Feel free to e-mail me your best first, second and third answers at firstname.lastname@example.org. The answers are not necessarily completely correct in their assessments, particularly in chemical suggestion and expert advice should be considered prior to application of any chemicals.
1) The problem of algal growth faces my grounds managers and greenkeepers during the winter months when there is insufficient heat to dry the surface of the soil. Surfaces are much easier to "seal up" during this time of year to allow algae and moss to develop on any damp compacted areas.
The two maincontributoryfactors for algal invasion are therefore SURFACE compaction and excess moisture.
To remedy the algae problem we must first change the growing environment of the sward. Spiking should be done all year, but too much disturbance during the winter months in my opinion can be detrimental to the sward during periods of dormancy. Therefore I would advocate that Sarrel rolling the turf during the winter months is an absolute must. This helps to dry the surface and keep the surface aerated.
Another method that I would recommend is to use a push rake over the turf, just to lightly score the surface; this could be used on tufted swards such as on cricket squares. This practice keeps the sward open and therefore easier to dry, and moves the surface collecting any thatch and prevents moss and algae getting a "foot hold." Cricket is not played on thick swards!
Evidently air movement and shade could be a problem and these have to be addressed if possible as a way for controlling the turfgrass environment. There are no textbook answers to the problems associated with turfgrass but it is vital that turfgrass managers are fully aware of all of their control options. Sound cultural turfgrass management is what we should be inspired to do.
2) Factors: Profile compaction, poor drainage, holding surface water, shade. Timing: Spring/ Autumn. Aeration methods, either with a hollow/ solid tine/ slit or by hand, and Top-dressed with a quality 80/ 20 dressing aiding to keep the profile open, compaction will be alleviated and drainage improved. Aeration is best carried out when the soil is moist with a few days of dry weather forecast ahead to obtain the maximum affect from products applied.
Areas of algae can be controlled using a moss killer, containing dichlorophen. A med/ course particle sized lawn sand containing ferrous sulphate, used to kill moss on turf surfaces, will also be effective in controlling algae. When the algae has dried to a crusty texture, you must rake or scarify it out (boxed off/ collected) to alleviate spreading the spores and the problem reoccurring. If necessary, when weather conditions arefavourably, lightly spike the surface, top dress and overseed.
3) I believe chemical (e.g. copper Sulphate) or physical remedial action to be only a temporary cure. The underlying problems of drainage, light and pH need ultimately to be addressed. The problem is basically one of competition between the grass species and the encroaching algae, and conditions should be improved to favourgrass growth. Grass roots require a well-aerated root zone so a program of winter aeration may be beneficial.
Their light requirement is also higher than that of non-vascular plants and their growth and competitive ability can be improved by removing shade inducing overhanging branches and dead leaf matter on the grass surface. Optimum algal growth occurs at low pH whereas that of grass is at a pH of 6 or above. If a low pH is indicated by a simple test kit, applications of lime at a rate of about 8-tonnes/hectare (depending on soil type) per 1 unit increase in pH required.
4): Mechanical stress. Ware from play, excessive mowing or general maintenance.
: Poor management in general
: Poor drainage due to soil structure.
: Low- mowing heights
: Over watering
: Poor fertilizer program
: Sparse turf due to disease activity.
Algae are basically caused by the turf being put under stress, resulting in the thinning of the turf surface and allowing space for this pest to flourish. In my opinion Algae is always present, it is just a question of how well you manage your turf as to how bad the problem appears to be. The correction of any one of the above- mentioned causes usually would not be an enough alone to solve algae problems, as it is usually a combination of these things.
Simply raising the height of cut or the introduction of gypsum could improve the turf quality, whilst reducing the problem to a manageable level. The Combination of several cultural practices would be the best answer. The problem should be ascertained and then a program of curative actions should be put into the maintenance plan. Results could be seen in a relative short space of time
But it should be noted unless the problem is continually addressed, or in the case of poor drainage permanently improved, the problem will return.
5) Algae is a symptom of poor grass growth that thrives in compacted waterlogged soils under humid conditions. cultural (scarifying) or chemical (dichlorophen) action will aid in the temporary removal of algae but for a more permanent solution, growing conditions will have to be improved.
A good place to start would be to have the soil tested for ph (algae likes acid soil) and nutrient levels (important for strong healthy grass). regular aeration will help to keep the surface dry and also relieve compaction. Scarifying, the removal of thatch, will also help to improve surface drainage. Some surfaces/ soils will also benefit from a dressing of sand to help improve soil structure and drainage.
If a more serious problem exists then artificial drainage may need to be installed. Last but by no means least, regular brushing of the sward will help greatly by removing dew/ water off the plant and keep the leaf upright allowing air to flow more freely across the surface.
6) Algae are small, green filamentous plants that form a green scum over a moist soil surface. The green scum produced by algae forms a tough, black crust when dry on the surface. The conditions at this time of year are ideal for the growth and development of the species, as they prefer areas with a wet soil surface in full sunlight.
This is commonplace throughout the winter due to increased surface moisture present, which should be removed using cultural practices such as switching. Compaction is a common problem during the winter and this isfavourablefor the development of algae, so any practice that will reduce compaction, such as verti- draining should be practiced. Open, thin turf swards are also susceptible as they allow the growth of the algae on the bare exposed surfaces.
The spraying of an algaecide onto the surface will kill any algae present at the recommended rate. Copper sulphate applied at a rate of 90- 150 grams in 12 litres of water on 100 sq. metres.
7) Algae are green to very dark green gelatinous mass on the surface of the turf. It is a very primitive plant with no true structure and forms a slime commonly called "squidge".
Occasionally small spheres of green jelly 5mm in diameter form on the turf foliage these algae are called Nostoc, although surface algae are the more common on the golf course. Squidge is not harmful to grass but my cause chlorosis due to its smothering nature.
Long- term control of squidge can only be rectified by removing the conditions thatfavourits development. If the infestation is due to a particularly wet prolonged period of bad weather the infestation will subside when drier weather prevails. In any case the squidge can be removed with the back of a rake or some flat object; the affected area can then be dried through aeration, i.e. spiking or slitting or even hand forking the area; a suitable top dressing may also be helpful.
Squidge also needs a space to live in, this can be through disease scars or mower damage so careful mowing and early disease diagnosis can be useful. Reoccurring squidge often indicates that some other underlying drainage problem has occurred. Check or install drainage on affected areas, alleviate compaction and aerate the surface so as to aid water movement, increase air movement and sunlight penetration by removing shading trees or shrubs. Monitor soil ph and nutrient levels, as acid soil is prone to
infestation as is infertile soil, also monitor irrigation times and patterns as this can cause localisedflooding and further problems. Should chemical control be deemed necessary because of the severity of the infestation, calcined sulphate of iron has been used successfully in the past along with copper sulphate.
Great care should be taken with the later as it is poisonous to plants and repeat applications can cause problems.
8) Algae are small filamentous plants that form a green scum over a waterlogged surface, and this green "scum" forms a tough, black crust when dry.
Major contributing factors include compacted soils, high pH and open, thin turf.
It is important to recognisethat algae occurs only when the turf is particularly weak, due to deficiencies in the soil, and once the soil has been affected by the algae the condition will worsen due to the exposed soil becoming infected with slime. So the turf manager needs to address the local site conditions that are contributing to poor quality turf.
Firstly this must mean addressing the lack of soil structure, and incorporating sufficient air space in the soil profile to allow for root growth and improved nutrient uptake. Significant aeration treatments such as the verti- drain, as many passes as the sports use will allow, to a depth indicated by a closer look at where compaction in the root zone is occurring. Alternatively repeated slit tining to a range of depths over a short period has produced sufficient improvement to support further treatments.
These would include appropriatefertilisertreatments to improve turf density and recuperative potential from wear and tear. Because of the high pH levels associated with algae, a sulphate dressing of ammonium and iron would produce a denser, tougher sward capable of preventing further attack, as well as healing any immediate symptoms. A careful look at the longer-term nutrition requirements of the turfgrass species in question would then be needed to ensure a balanced program is in place.
Finally, the specific location problems that have led to the soil and surface conditions need to be investigated. These may include removing shade problems, preventing traffic in waterlogged conditions, and avoiding over use of the irrigation system. These final measures rely very much on the sport in question and the relationship the turf manager has built up with the end user. Their understanding is essential with any successful turf maintenance program.
9) On our pitch, algae have started to appear on areas that are short on grass cover and also hold more water than areas of the pitch. To combat this, we 'board off' the area when cutting in damp conditions so that we do not smear the surface and suffocate what grass is there by making it flat and causing it to stick to the algae.
Once this is done, the area affected by algae will be cut using a light pedestrian rotary mower without a roller on it meaning less compaction. The algae area is also 'opened up' using a multicore or vertidrain every 4 weeks approximately, again only when the conditions are dry and the surface will not smear. When we do get dry spells, we also clean the algae off using a springbok rake to pull the algae off the exposed root zone and this helps to keep the surface as dry and as non- slippy as possible.
When getting into the warmer months- march onwards- the area is cleaned with the springbok after opening up the surface and once the algae is removed, the area is then seeded and germination sheets are put down to try to promote new growth which will lesser the chance once growing of more algae coming in once more.
10) Algae are almost entirely reliant on moisture for survival. Therefore, removal of the moisture source should control and eventually eradicate algae problems. Surface drainage or lack of it is generally the problem, so identification of the reasons for the drainage problem is paramount.
An overview of the area surrounding the algae infested turf will tell you whether there is a problem with water running off banks or slopes and waterlogging the turf. Poor underground drainage will lead to poor surface drainage so check your drainage system, i.e. pipes, outfall etc. If these are all ok then the problem is likely to be cultural. There are algaecides that will work but they will only kill the algae and not the problem that is causing it.
Too much thatch will hold moisture at the surface. Once in to the growing season, a regular thatch removal program will certainly lead to a reduction in surface moisture. Regular aeration throughout the year (in suitable conditions) will also allow water to pass from the surface in to the root zone.
Hollow tining combined with an application of a carefully selected free draining topsoil will again help to avoid the conditions in which algae thrive. Just as with moss, algae need water. Take away the water and the algae will not survive so drainage, drainage, drainage is the answer.