Best Technical Merit Answers- February 2003
Following the success of the Technical Merit Award 2003, sponsored by Tillers Turf. Pitchcare are going to publish some of the best answers submitted to the monthly scenario questions. Starting with last February's answers. Followed by all of the monthly winning answers over the coming weeks.
Issue: At this time of year, an alga 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?
: 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.
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.
Management - Long- term control of squidge can only be rectified by removing the conditions that favourits 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. Re-occurring 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 causelocalisedflooding 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.
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.