When I was at Keya GC last month for the Japan Amateur Championship, it rained a lot. From June 29 to July 8, there was precipitation every day, and the total was 446 mm, or 17.
When I saw this photo captioned “a little potassium replenishment being applied,” I asked “replenishment from what loss?” As I found out, the potassium (K) was being applied after a heavy rain event.