Jeremy Hreben said: Ronald Conard, CGCS said: Scot Dey said: Anyone pulled a double aerification on Poa greens? I'm looking to touch base with any super's who have done it-along with hearing any positive and or negatives they expereinced from it...I recently did a double aerification on a 2 X 2 setting with 1/2" inner diameter using the 648's. I estimate that I pulled around 10% organic out and was able to get in apprx 124 tons of sand over 100,000 sq feet. My ISTRC numbers on average over the last 1.5 years is at 2.5% in the top 0-1". I felt the event was a success from my perspective over the short and long term. If you've pulled 2X punch on Bermuda or Bent I'd be interested in hearing from you as well.
Does the practice of pulling a core and backfilling with sand, in and of itself, reduce organic matter?
Where are you headed with that thought? It sounds like you are waiting for answers then have another idea?
Isn't organic matter old dead, tissue, thatch, roots, etc. etc.? So I would say yes.
Well, to make a long story long for years I was an aggressive pull a core and backfill the holes with sand guy. It was certainly beneficial as 20 years ago the greens here were clay based so the process over time has converted them to about 10" of 100% sand. Eventually, I started to question why were we pulling out sand just to put it back in. At that point, based on research out of the University of Nebraska by Dr. Gaussoin, Dr. Rossi's thoughts on a "hole is a hole" and the "no till" theory out of the U.K., I decided to try a less intrusive, more bentgrass friendly approach. Of course I was leery as I knew the tried and true core aerification/sand topdressing program worked. It was just a pain in the ass and very intrusive to play.
So after some discussion with Dr. Gaussion about what he was finding out in the field, I decided to take a gamble and go with a soley solid needle tine with frequent light topdressing program to dilute any thatch build-up. Upon starting this program I committed to running o.m. tests in 1" layers to a depth of 4" on an annua basis. I'm not saying this program is the end all for all locations and situations but after 6 years our o.m. levels throughout the profile are lower than when I was pulling a core. In addition I don't verticut but rather brush regularly. If someone told me they were doing this 10 years ago I would have laughed and thought they were destined for failure. But with regards to verticutting I was always questioning why we were mangling the bent and cutting off its most competitive feature. Throw in a number of other cultural practices (i.e rolling, lean nutrition, moderately high iron rates, Trimmit use and keeping it dry) and the real upside has been in the increase in bentgrass percentage. A major factor in all of this is that by not pulling a core I am not creating a void for Poa to invade.
Take from all this what you will as I know some guys think it's not worth the risk. But the greens perform better now, including green speed then they ever have before. In our area it is critical to have a high percentage of bentgrass going into the winter otherwise we run a greater risk of the Poa checking out before spring. My program has always been based on maximizing bent populations and they are now at a level to where I feel semi-comfortable heading into a winter that may be open, frigid, and windy.
Here are a couple of links I found you can look at. To be honest I haven't had time to fully look at these but the information is in there. I also attached a pdf of Dr. Rossi's article entitled "Any hole will do.." If nothing else it is pretty interesting information.
[u">http://www.gcsaa.org/uploadedfiles/education/conference-sessions/2014/dilution-is-the-solution.pdf[/u">
[u">http://www.turfnet.com/blog/4/entry-1274-dr-roch-gaussoin-soil-organic-matter-percentages-topdressing-coringnot-coring/[/u">