After 10 days without any rain, I've been asked on 3 different occasions what the small brown spots are on fairways and several tees. That's a valid question and here are the contributing causes:
1. First of all, when we get a summer like this one where we receive large quantities of rain (over 75" YTD), the root system of the turf is compromised and shallow. When it goes from wet to extreme drought in a short period of time, the turf isn't deeply rooted enough to sustain healthy, drought tolerant turf.
2. Have you ever purchased a peat based potting soil mix and used it to plant flowers in window boxes or pots? You many recall the initial frustration trying to water it? When a soil gets dry, it can become hydrophobic and actually repel water. This is initially what happens when you water peat moss and it floats. On golf course turf, we use a lot of wetting agents- products that reduce water tension and allow dry soils to re-wet. These spots are random and better known as localized dry spots (LDS).
3. We try to walk a fine line with keeping the golf course playable and firm. Our irrigation system, designed and installed in the mid 1980's simply doesn't offer adequate coverage. To keep the course entirely green would mean we would have to constantly over-water. That would make golf less enjoyable. One day, a new irrigation system will allow us to target specific areas, using less water but with precision.
Here is a USGA piece that talks about LDS- Localized Dry Spots:
