Scientific GOAL of AERATION

Discussion in 'Lawn Mowing' started by MOW ED, Sep 21, 2001.

  1. MOW ED

    MOW ED LawnSite Fanatic
    Posts: 5,028

    There is plenty written on the benefits of aeration but there seem to be a few different schools of thought when it comes to exactly what procedure is used.
    Core pulling seems to be most popular and there is quite a bit of techincal info on the benefits of pulling a core to aerate.

    On the other hand there is not much written on the other types of aeration and I would like to know your opinions and experiences with all of them as well as some questions about traditional Plugging. What is the Scientific Goal of the procedure that you use ?

    Is the "Hook" type of aeration. (JRCO) good or bad in comparison to the standard?

    Solid tines or hollow spoons?

    Break the cores or leave them?

    Pick the cores up?

    What size cores and how deep is the best?

    Is "Spiking" beneficial?

    Is "Slicing" beneficial?

    Disk mounted coring?

    Drum mounted coring?

    How does "Aeravation" compare?

    Does anyone do WIC (water injected cultivation)? If so what are the pros and cons?

    What is your first hand experiences with these and whay do they work or don't work? Tell us all about it.
    Do you notice improvment and is the procedure used a benefit to the lawn?

    Does one lend itself to other procedures? IE Topdressing after coring or overseeding after aeravating?

    I want to know why you use the procedure, be honest. Are you doing it because everyone else is, or the predominant procedure in your community is this or do you do it different from most of the others.
     
  2. GroundKprs

    GroundKprs LawnSite Bronze Member
    Posts: 1,969

    "Scientific GOAL of AERATION"
    - These comments are from working in cool season ornamental turf (northern Indiana). Some of my ideas may not apply at all to southern, warm season ornamental turf.
    - Also realize that most of ornamental turf management ideas were extrapolated originally from agricultural grasses, like corn, wheat, oats, barley, etc. This is because the agricultural plants were a cash crop, so consequently there was funding for research in that field. In the mid-20th century, golf turf rapidly became a profitable crop, and research was funded in that area; results of golf turf research were then applied in many cases to ornamental turf. The advent of the big LCO's in the late 1960's and 70's made ornamental turf somewhat into a cash crop, and successful companies began to fund their own and university research in the 80's. So current management of ornamental turf is based on wheat fields and golf greens, with a touch of real ornamental reality thrown in. Therefore, it is important to attend seminars and other trade events to learn the current scientific principles of ornamental turf. Our state turf association used to have seminars 10-12 years ago with varoius topics for everyone. Today, you go to a seminar, and choose between the golf turf agenda, the sports turf agenda, or the general (ornamental) turf topics. Yep, grass ain't just grass anymore.

    "There is plenty written on the benefits of aeration but there seem to be a few different schools of thought when it comes to exactly what procedure is used. Core pulling seems to be most popular and there is quite a bit of techincal info on the benefits of pulling a core to aerate."

    "On the other hand there is not much written on the other types of aeration and I would like to know your opinions and experiences with all of them as well as some questions about traditional Plugging. What is the Scientific Goal of the procedure that you use ?"
    - Main goal of aeration is to loosen the soil for better root and overall plant growth. Grass and all other plants need to absorb oxygen through roots to grow healthy (oxygen is used in a chemical process that is a catalyst for photosynthesis; without this oxygen plants will slowly die). Heavy soils, or highly trafficed soils like sport fields, will surely benefit from aeration. In ornamental turf, you may notice grass weakens on tire track of mowers, even 21" push mowers, along borders like beds, buildings & fences where you must run the same track each mowing.
    - Many different machines are made for aeration, but you need to pick what is most useful for soils in your area. Spikes and solid tines don't usually help in relieving compaction, but increase it. I once heard the comment that aeration with regular hole puncing machines can cause subsurface compaction (at the bottom of the tine plunge) over the long term, but have not seen any definitive research reports on this. I have seen aerators that actually bounce off clay soils (not heavy enough), and big, expensive cam type machines that bog down even in sandy soils with 3/4" tines. Manufacturers and dealers will tell you anything to make a sale. If you are in the market for a machine, go to trade shows with outdoor demo areas, get a demo unit or rent the machine you are thinking about.
    - Most common university recommendations are to penetrate 10% of surface area to a depth of 4". Not too many machines will get you that, in all honesty. The very best aerator is the Verti-Drain. Their biggest does 24" cores (obviously only for an engineered sports field), down to the pedestrian (walk behind) that does 6"; Their machines give a kick backwards at the bottom of the plunge, really loosening the soil. Of course the cost is way up there for these.

    "Is the "Hook" type of aeration. (JRCO) good or bad in comparison to the standard?"
    - Haven't look closely at them, can't honestly comment.

    "Solid tines or hollow spoons?"
    - Solid tines will give more compaction at the bottom of the hole, and will not have the benefit of introducing soil into a thatch layer for aid in decomposition. I definetely would go with hollow.

    "Break the cores or leave them?"
    - No need to break up cores on ornamental turf; irrigation or rainfall will soon dissolve them (2-3 weeks max usually). But I do usually run a "dethatcher" over a spring aeration a few days later (when cores have dried); flails are set to not hit ground, just to pulverize the cores sitting on the grass. I do this because in spring everyone is looking for all plants to look nice.

    "Pick the cores up?"
    - only on a golf course, and maybe other sports turf, so they can't interfere with immediate play.

    "What size cores and how deep is the best?"
    - On ornamental turf, usually the larger the better, most are 3/4"; but on sports turf, a small as 3/8" is used to lessen interference with immediate play.

    "Is "Spiking" beneficial?"
    - It is generally considered that, at least in northern soils, spiking just increases soil compaction. I have seen this stated in a number of university bulletins.

    "Is "Slicing" beneficial?"
    - Slicing (vertical mowing), as done with fixed vertical blades on a reel, is usually done to stimulate stoloniferous grasses (e.g., creeping bentgrass) to grow in after a stress period. It can be done to remove excess thatch (sliced in 2-3 directions), but this procedure is EXTREMELY destructive to turf.

    "Disk mounted coring?"

    "Drum mounted coring?"
    - I assume these two are referring to disks or drums, with coring spoons or tines attached, that roll across the turf surface. The main problem with a rolling action to aerate is that you cannot penetrate very deeply without tearing the turf. Most of the machines that roll, including mine, only get penetration to 2-1/2" to 2-3/4". Of course that is with new tines; I have seen production companies aerating with tines so worn that they just dent the soil surface, LOL, but they still charge for a real aeration.

    "How does "Aeravation" compare?"
    - Aeravation is great for overseeding (right, Ray? ;)), but will not pull up soil to be trapped in a thatch layer as well as coring. I have not seen any university studies, but I expect that subsurface compaction would be less with aeravator compared to coring.

    "Does anyone do WIC (water injected cultivation)? If so what are the pros and cons?"
    - Pros: not messy or destructive, less machine wear (not digging in soil). Con: $$$$ for machine. Long term data non-existent, machines have only been out for general use a few years. Mostly geared to golf turf now.

    "What is your first hand experiences with these and why do they work or don't work? Tell us all about it. Do you notice improvement and is the procedure used a benefit to the lawn?"
    - The choice here MUST BE SITE SPECIFIC. In our area of glacial till soils, half of a site can be sand based and the rest clay. Some lawns can benefit from 2 to 4 aerations a year, others may only benefit from biennial aeration, and some are just fine without aeration. I have one 17K site that needs aeration each fall on 60% of the turf area, or it will dramatically thin out next year (heavy soil); the rest of the site is the same soil and more shady, but has filled in with poa trivialis over the years (these parts are beautiful, and no coring for last 7 years; poa triv does well in compacted, shaded soils). If you really want to know if aeration is a benefit on a particular lawn, do test areas on the site over a number of years, and compare the test plots with the uncultivated areas. I have done test areas for no charge in the past, then let the client make the choice based on the different appearance. I once had a big back yard to play with, and set up 9 adjoining plots to be done once or twice a year at 1x, 2x, 3x and 4x. (9th was control with none.) Unfortunately got too busy to follow through next couple of years, but you could see that any aeration was a benefit to this site.
    - In Fort Wayne, Indiana, soil is all clay. No sense in trying to bring in decent topsoil, so premium lawns in that area are aerated 3-4 times a year to maintain turf vigor. This is one area where you can make a general rule like this about aeration.

    "Does one lend itself to other procedures? IE Topdressing after coring or overseeding after aeravating?"
    - Topdressing is intense work, mainly done only on sports turf. It could be beneficial on ornamental turf only to introduce good soil into a poor growing medium or to aid in thatch decomposition.
    - Can't beat the aeravation process for overseeding preparation. But I have good success in overseeding with core aeration (2-4 passes), then slitseeding a few days later when cores are dry. Proper maintenance in our cool season grasses usually negates any need for overseeding, but transition zones like Kirby's N.C. area requires it regularly.

    "I want to know why you use the procedure, be honest. Are you doing it because everyone else is, or the predominant procedure in your community is this or do you do it different from most of the others."
    - I use a Lawnaire IV core aerator. It is hard labor, shoulders & back will tell you a few days after running one all day. But I feel that a self propelled machine, pulling itself through the soil, is giving the best result in aeration. As you are coring, you are actually fracturing the whole soil profile by the activity of the machine pulling itself through the soil. Only machine better is the Verti-Drain mentioned above. I have cored soils so heavy that the machine only penetrated 1/2" on first pass, even with bar weight installed and water drum filled; but the second pass penetrated to full depth. I also never make just one pass, except in very weakly rooted turf that will be damaged excessively by more than one. A single pass with most aerators only penetrates 1% to 3% of soil surface, and most university recommendation is to penetrate 10% of surface.
     
  3. Eric ELM

    Eric ELM Husband, Father, Friend, Angel
    Posts: 4,831

    Great Post Jim, as usual. :)

    You covered that topic from one end to the other. Thanks ;)
     
  4. KirbysLawn

    KirbysLawn Millenium Member
    Posts: 3,486

    WOW Jim, don't hold back! Very good post.
     
  5. NC Big Daddy

    NC Big Daddy LawnSite Senior Member
    Posts: 267

    Outstanding Post......This is why I visit this site most everyday.
    Brovo Jim :blob4:
     
  6. hubb

    hubb LawnSite Member
    Posts: 192

    Excellent post. Thanks. Ive been wondering about aeration and the actual benefits of it also.
     
  7. David Gretzmier

    David Gretzmier LawnSite Gold Member
    Posts: 3,645

    here here. we aeravate and love it. I have looked at the water injectors and they are high dollar. great post

    Dave g
     
  8. GroundKprs

    GroundKprs LawnSite Bronze Member
    Posts: 1,969

    Anyone in cool season areas using an aerator with a water drum for extra weight:

    If you find that you are always using the water drum filled, forget the water and use sand. You get the same weight, and don't have to worry about water drum freezing or water leaking out.
     
  9. GroundKprs

    GroundKprs LawnSite Bronze Member
    Posts: 1,969

    Anyone notice it took me 9 days to respond - lot of work for 2 finger keyboard idiot, with sore arms and back from aerator. Let's get some more input to Ed's serious questions. Surely I'm not the only one who has concrete ideas and experiences. SHARE
     
  10. KirbysLawn

    KirbysLawn Millenium Member
    Posts: 3,486

    My $0.02 worth. I use the aeravator about 80% of the time here and the Classen Split the other half. As Jim said each area has it's problems, here it's hard clay soil.

    This week I had many jobs to do, several involved having top soil brought in. I ran the aeravator prior to delivery to break the ground open, which was easily done. Then the top soil was delivered and spread across the lawn, and finally I ran the aeravator again to help mix the clay and top soil together, worked great!

    With the topic of aeration anyone with hard soil soil consider the following. When you take your plugger across the ground and small plugs are pulled up and the are what 4" apart, what about the compaction of the rest of the ground? You throw see out and it lays on hard ground, first rain and it washed into the plug holes. What's next? A lawn that looks like it was installed by "The Hair Club for Men".

    If take an aeravator and run it across the same ground you will find that most of the soil, not just plugs have been loostened and aerafied. Check out this photo of how it broke open this hard ground.

    Most of my first aeravation jobs are coming in, I will post after photos soon!

    RAy

    [​IMG]
     

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