What is micro-topdressing for?

Micro topdressing of sand on greens is a very common practice that provides important agronomic and playable benefits to the surface.

It achieves important benefits such as more firmness, less organic matter accumulation problems or more oxygenation of the soil profile by carrying out a good micro-irrigation programme.

Why is a frequent micro-topdressing programme important?

Sand is an excellent medium for turf growth, allows excellent gas exchange with the atmosphere and allows water to circulate freely avoiding waterlogged areas. In large areas such as golf courses, combining sand with organic matter improves the tandem by adding qualities such as nutrient retention, improved firmness and moisture uniformity.

Grass is a great fixer of organic matter in the soil, faster than its natural degradation, so micro top-dressing is applied to prevent it from accumulating in excess in the same stratum. The fine layer of sand provided generates another new area where organic matter can accumulate, diluting its concentration.

What happens if we don’t schedule micro topdressing often enough?

Not frequent light topdressing may not have an immediate negative impact, but in the long term the thatch will accumulate more densely causing disastrous problems of low infiltration and low oxygenation. It will also greatly reduce the firmness of the surface causing major problems with tyre marks, ball pitting and user footprints.

The measurement of agronomic variables such as infiltration and depth of thatch helps us to estimate the evolution of the micro topdressing programme. A well topdressed soil is able to increase its infiltration and the thach will be much less compact and more distributed throughout the profile.

Measurements of mechanical surface variables such as firmness, speed, rolling or reliability are also affected by micro topdressing. The tools that allow these variables to be monitored are:

• Clegg’s hammer or trufirm for firmness.

• The stimpmeter for speed

• The parrymeter for rolling and putting reliability.

Not all sands are the same.

The sands selected for the fields and also for the top dressing are key. They can be calcareous, feldspathic, siliceous, and rounded or more angular in shape. The use of calcareous sands is not recommended because of their basic reaction and their great buffering capacity which will not allow the pH to be modified downwards.

Regarding its granulometry, sands with D50=230 micrometres are recommended for football pitches and with D50=330 micrometres for greens. In both cases, uniformity values lower than 3.3 are recommended.

At Tiloom we offer accurate sand analysis to choose the best sand for your course.

The most important advice on the use of silica sand is that the texture of the sand should resemble as closely as possible the fine fraction of sand that was used for the construction of the green.