Doughnut pattern (Dry Spot)

Determining the main reason for a dry spell is not always an easy task, but the rings around sprinklers (doughnuts) is a pattern that usually has a concrete solution.

There are all kinds of dried fruits, among others these are very common:

• Points where the soil changes texture abruptly.
  A good example of this is a green that meets a natural terrain antegreen without being properly insulated, the green can dry out around the edges due to capillary action.
• Accumulation of thatch.
  The felt that lawns form over time consists of a water-repellent material that does not allow water to wet the entire profile. This problem can only be solved by scarifying and hollow pricking.

• Excessively dry ground.
  When the soil dries out excessively it can be really difficult to re-wet as thatch acts as a hydrophobic layer and a finger-flow pattern can appear in the profile. Only water flows into the points where a spike has entered or areas that are more easily wetted. The use of moisturisers is a highly recommended way to solve these dryness problems.

Ignorance during the choice of nozzles in a small irrigation retrofit at a particular time can cause many problems.

But when dryness is uniform around a sprinkler nozzles may be behind the problem. Each nozzle on a sprinkler is designed to have a specific range. During a minor renovation, the distance between sprinklers may have been changed, or the irrigation technician may have changed the long-range nozzle to have more overlap. But during the work, the mid-range or short-range nozzle may have been forgotten to be changed. Such errors create a very characteristic pattern, the doughnut pattern,

Due to the water pressure and other factors, sprinklers sink over time and in the order of one centimetre per year. They must therefore be checked frequently, raised and levelled. Their unevenness, as well as the choice of nozzle, results in poor water distribution. The part facing the sky will send water further away than it should and the part facing the ground will send it much closer.

The spray angle should be between 15º and 35º.