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Discussion in 'Fertilizer Application' started by DA Quality Lawn & YS, Sep 18, 2012.
So you have fert being released from now, until when???
You obviously do not belong to the Wisconsin Turf Association. The latest research from the UW Turf Department has totally debunked the idea of late season fertilization in cool season lawns such as Wisconsin has. They recommend being done with fertilizer no later than Oct. 10m preferably Oct. 1. I have seen the research and talked to the professor who did it. Ant fertilizer applied to late in the season is mostly wasted. The grass cannot uptake that much nitrogen in that short of time.
Thank-you , thank-you and thank-you...
You and your association just confirmed what I noticed years ago... misunderstandings abound, but once the misunderstandings are cleared away, people can actually learn from one another on this forum...
How does your association feel/think about the common practice of Fert/Pre-m for Early Spring Apps???
Nitrogen is not normally needed until May 15 at the earliest and Pre-emergents should be applied when needed.
Do you have a link you could paste to this particular research? I would like to see it as I'm always interested in new findings. When you throw out dates like October 1 and October 10 (yes, I know thikngs vary from year to year), what part of Wisconsin are you talking about as Northern Wisconsin has a much different growing season that the southern counties.
Maybe you've misunderstood Dr. Soldat's work. The actual research conclusions were that more N is taken up in warmer temperatures, so most of the fall application should be done before the first frost. This doesn't mean that none should be done later -- just that most of it should be done earlier. His work actually showed that spoonfeeding turf at 0.1 to 0.2# N/M every week for 6 wks beginning at the first frost was more beneficial than applying most of your fall N in a soluble form before the first frost. Also, don't forget that some N is still needed after the first frost, since photosynthesis will still be occurring through much of the fall.
This really confirms what many of have been doing for years -- using most of our fall N in Sept or early Oct, then using less afterward.
I will see if it is online somewhere. I read in the Wisconsin Turfgrass News, went to the presentation at Field Days and spoke to the professor and student who did the research. It was done in the field and in the lab to simulate different weather patterns.
I don't think I misunderstood it at all. For years it was common practice to apply 1 lb of water soluble nitrogen in October to early November in the theory that the roots would use it to build carbohydrate stores. He went looking for research to prover this theory and he couldn't find much. Many of those ideas came from the central part of the country such as Ohio which has a much different growing season. He stated to me in person that if applying 1 lb of water soluble N it should be done no later than Oct. 1. He said you could apply a 1/2 lb up to Oct. 10th. Any N applied after those dates will result in 1/2 to 3/4 of the N volatilizing or leaching away before the roots can uptake it. You are correct that the plants still need N up until the ground freezes but I use at least a 50% controlled release product so the N is available until the ground does freeze. I believe his research was done using ammonium sulfate. Since I can't be on my customers lawn every week I asked if my idea of using a controlled release earlier in the fall would work and he said yes, it should.
I've known Doug for quite a while. His major professor was my college roomate. Anyhow, these recommendations aren't much different from Wayne Kussow's recommendations in the 1970s. They differ a little from other research sites only in timing, such that it gets cold earlier in Madison than it does in Columbus.
But, you'll have to read their research paper. I don't agree with the controlled release source, though, because all controlled release sources are tied back to temperature -- either microbially degraded (the speed of which depends in part on temperature) or is totally temperature dependent. So, you put this fertilizer product in the environment without release, so it is subject to all sorts of different fates, including runoff loss. Since none of your fert will release from controlled release sources in the winter and could be lost ro runoff, I would just save that fert until spring.
Also, fall fert doesn't create carbohydrates in roots directly. Fall applied N allows chlorophyll to be regenerated at higher rates than no N, and it is the chlorophyll that makes the carbohydrates through the photosynthesis process. Remember, grasses in the upper midwest (WI, MN) are typically photosynthetically active until covered with snow.
Again, Soldat found that 70% of your fall N should be applied before the first frost, with the rest to come not long after.
When people talk about N being applied and then considering it all used up, like a dog licking his bowl clean, I consider that the concept of soil fertility gets lost...
Right now, the surfaces of the lawns turn solid every nite and some shaded areas stay solid, but the grass is still green, though not very britely colored green...
Let's say that the time release prills were applied at the beginning of October but becuz it was so dry, the prills were still in visible form 2 weeks ago when frosts were becoming common, but no freezeups...
How much of that N likely got used in this scenario??? My personal opinion is that since there was very little greenup after the rains started, that the N never really did get used much and now that the ground is frozen, there is very little chance that the 1 pound of N will even be used...
How does that line up with the threory???