Advances in mowing equipment has certainly had an impact on green speeds over the past forty years, but it’s only one of many factors.
To start with, mower reel grinding machines are a dream compared the the old days when mower reels had to be disassembled and ground by hand. Usually, because of the down time involve, this could be done only in the off-season. With modern equipment, the set up and operation are simple and automatic. We can tune up the blades as often as necessary even through the season. Without sharp and adjusted mower blades, nothing else you do will help green speeds.
Improved turfgrass varieties have played an important role. The close cutting mowing equipment would be useless on the old mixes of creeping, velvet, and colonial bentgrasses that you couldn’t mow below 3/16 inch. In the ‘70’s, Penncross bentgrass was state of the art, and even that won’t do well below 1/8 inch, and I don’t think anybody is sowing greens with that stuff anymore. Today there are hundreds of varieties to choose from according to the particular situation. The “A” series bents, for example, are finer, denser, and tolerate close mowing.
The impact of improved turfgrass species is doubly true for warm season locales. In the ‘70’s, the best green surface we had was 328 bermudagrass, which might be okay for a tee today. First came Tifdwarf, then the ultra-dwarfs, and bermuda greens today are easily twice the speed of forty years ago. Seashore Paspalum, not available ten years ago, can also be mowed tight and speedy as anything.
As for equipment, besides the mowers there are new verticutting units, groomers, brushes, spikers, aerators, and topdressers, all of which help control thatch and keep the surface true, smooth, and fast. Certain cultural practices evolved with the new machines. For example, light frequent sand topdressing came into vogue in the ‘80’s, and has made a huge difference in firmness and putting quality. Up until then everybody pretty much topdressed twice a year after the aeration and that was it.
The development of lightweight greens rollers alone has added considerably to green speeds. No such thing existed until I think the ‘90’s.
Growth regulators also contribute. These have only appeared for turfgrass use in the past fifteen years, but now most greens are on some type of regulation. In the old days, greens might be noticeably slower as the day wore on. Products like Primo slow growth so there is less of a difference between morning and afternoon. If there isn’t much leaf growth, then daily mowing accumulates speed, like double cutting might in the past. Regulators can also help the turf tolerate a lower height of cut.
Fertilizer regimes have evolved. Back in the ‘70’s, conventional wisdom held that you fertilized bentgrass greens with one pound of nitrogen per thousand square feet per growing month, or 6-8 pounds per year in the northern U.S. Today, it’s more like 2 pounds per year. An overfed bentgrass leaf grows fat and lush, increasing resistance to the ball roll. Leaner greens roll faster, and lots of us are applying the absolute minimum of nitrogen. Bermudagrasses still need to be fed more, but the other factors listed here more than compensate for it.
I’m sure there are other practices I can’t think of right now, but the point is that green speed is a complex issue that has evolved in more ways than one.