Northern Guys - what are you using for your late fall app?

Discussion in 'Fertilizer Application' started by DA Quality Lawn & YS, Sep 18, 2012.

  1. unit28

    unit28 LawnSite Bronze Member
    Messages: 1,554

    Late-season N:
    Recent research on bermudagrass found that late-season N applications prior to frost promote fall color retention and do not have a negative effect on bermudagrass winter hardiness. Late-season fertilization is highly recommended for athletic fields and some newly established lawns. The only downside to this practice is that it will increase winter annual weed pressure and may predispose bermudagrass to more injury from spring dead spot and zoysiagrass and bermudagrass to more large patch.


    I know the OP addressed Northern climate, but someone tried to make the issue obligatory to Southern grasses somewhere. Another thing we did in TX was overseeding with annual/winter rye. Except St Aug.
  2. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    That's where most of the "Ol' Wives Tales" and "Lawncare Mythology" got started, IMO...

    You just can't even try to relate the life facts of cool-season grasses with warm season grasses,,, without completely messing up any hope of botanical understanding ofwise cultural practices of either...

    Leave it alone southern man,,, the grassy weeds you call turf have no part of this conversation... that is a joke... :)
  3. lazyike

    lazyike LawnSite Senior Member
    Messages: 302

    DA we use urea... We spray it on at about.75# per 1000... Strong green untill the snow covers it up, and our yards are the first to green back up in the spring. Started using it 5 years ago and never looked back.
  4. FYS777

    FYS777 LawnSite Silver Member
    Messages: 2,305

    it only makes sense that if you fertilize at the right time here in fall that when the ground freezes, what asn't been used up by the grass will hold in soil until thaw when the grass is ready to start growing again.
  5. DA Quality Lawn & YS

    DA Quality Lawn & YS LawnSite Fanatic
    Messages: 9,286

    I believe you...BUT what about this year. Its so bone dry, is it not risky to throw down straight urea.
  6. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    Actually it makes sense that when dealing with such a volatile element as N(in most any form) that the likelyhood of it remaining stable through a typical winter is almost nill...

    Let's say the ground freezes solid about 6" - a foot down, before snow cover hits... We get a huge storms with one or two feet of snow that stays the rest of the winter...

    What happens under the snow??? What happens when the snow melts in the Spring???

    Once you think about the dynamics of the living world, you don't look at N being 'preserved through the winter' the way hamburger is preserved in the freezer...

    I really would like an answer to those 2 questions... :)
  7. unit28

    unit28 LawnSite Bronze Member
    Messages: 1,554

  8. Skipster

    Skipster LawnSite Bronze Member
    Messages: 1,086

    Studies have shown over and over that soil N content is usually very stable in frozen soils.

    In the fall, nitrates tend to move down in the soil profile with increased rainfall, then move up with the freeze/thaw of late fall, stay stable in mid-winter, then move up with spring freeze/thaw cycles, and back down with rain and snow melt. Nitrate really follows the water.

    Denitrification reactions are inhibited by cold temperatures in fall/winter/spring, do very little nitrate is lost.

    Ammonium tends to hang around on CE sites and very little is converted to nitrate in cold weather because the weather is too cold for amped activity of those microbes. This is partially the reason that anhydrous ammonia can be used as an ag fertilizer and is applied in the cooler weather.

    Once you look at the dynamics of the living world, you better understand why applications are done in a particular manner.
  9. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    That is interestting that N moves upwards through the soil profile after moving down for a while... back to that in a minute... right now I would like to discuss with you on the subject,,, snow...

    It does make sense, that frozen ground would stabilize the elements within it... but my point is that one may have frozen ground in Nov.,,, but thawing completely under a foot of snow,,, by December... now,,, the snow melts underneath and soaks into the ground, going down, down, down, replenishing the water table over the course of the Winter...
    Now your saying that 'because it is colder than Summer' that N no longer leaches down when it's under the snow, but actually rises to the surface???
    You see,,, I've always assumed that because water is percolating downward through the soil,,, that N would leach downward along with the water, regardless of the temperature... That is incorrect???
  10. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I'm glad to hear people talk about CE sites... it promotes the idea that fertilizer doesn't do much once all the CE sites are filled... it also demonstrates the difference between the nitrates attached to CE sites that the stuff that is leaching away and/or volatizing away...

    You see I also believe that good tilth and humus will hold N,,, not just during the winter, but also during the growing season...

    I think the concept, that the article was putting forth is that excessive N floating about in the soil profile doesn't do much for the plant, during Winter... the next followup point is that a fresh supply of N as soon as the grass starts growing "burns out" the carbohydrate reserves and forces top growth,,, at the expense of the normal root development,,, that would have occurred if left to it natural life cycle...

    This could be a good discussion if we can keep all the pieces of the big picture together... :)

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