Tom,
I saw the greens just prior to the over-seeding program two years ago.
We could see the soil and it appeared black to me.
Is the base a silty sand, is that black a layer of organic, or was I fooled by what I thought I saw.
Hi Ian,
Much of the soil underneath is quite a dark colour - just as you see in the bunkers of some of the other Sandbelt courses, such as Commonwealth & Yarra Yarra - but the dark colour of RM's greens this week is just the iron sulphate. This is rarely applied, and this blackish appearance of the greens is not something you'd ordinarily see.
Matt,
To my eye, the greens haven't looked stressed at all, which is a bit surprising. The main practice putting green looks as if it is stressed (some light surface cracking over a spare grass coverage) but the competition greens don't look like this. I would add that the look of that practice putting green is how RM's greens frequently look in summer, and the greens can be maintained like that for extended periods. It's surprised me how quick the green have been, while not not appearing to be stressed.
The iron sulphate does two things: it firms up the texture of the leaves, and alters the colour. The former impact increases the speed of the greens. The latter impact hides any colour variation on the greens, so any patchiness gets disguised.