Dry Patch- Water Repellent Soils
Dry patch is defined as an area of turf that dries out and becomes difficult to rewet even when a high volume of water is applied. It is usually characterized by the presence of a water repellent soil, I.e. The soil repels water. This is visually characterized by irregularly shaped areas of dead or wilted turfgrass. These are a cause of concern to greenkeepers across the world due to reduced visual quality and surface performance.
The source of this water repellent soil has been linked to fairy ring activity and the breakdown of organic materials in the root zone as part of natural plant decomposition processes. This process leaves a waxy deposit on the soil and sand particles which is water repellent.
Drought stress is categorically different; there does not need to be water repellent soil present and the dryness is a consequence of another turf problem. In principle, a golf green may have both dry patch and drought stress.
The main reason is that poor irrigation coverage may lead to drought stressed patches. Simply the area is not receiving sufficient irrigation water.
Another issue which is often overlooked is poor rooting from a variety of causes, meaning the plant cannot take up the water which is available.
Lastly, frequent mowing at low cut heights has been found to reduce the resistance of amenity turf against drought.