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View Full Version : Why no phosphorus?


Kenny Snyder
03-11-2006, 09:54 AM
Why are there so many preemergent/fertilizer combo products with 0 phosphorus? I've been asking around and gotten an assortment of opinions.....from "the state just put out new recommendations for no P in spring app" (which I researched and couldn't verify) to "hurricane Katrina affected phosphorus production to the point that it has become cost-prohibitive for companies to try to sell it until production is back to normal". So, I wonder what's the truth? Anybody know?

jkkalbers
03-11-2006, 10:08 AM
It's illegal for general use in MN, but I don't know how many other states are like that. Maybe that is part of why you are seeing more of it with 0 phosphurus.

lilmarvin4064
03-11-2006, 10:15 AM
I wouldn't consider myself an expert on this but here is the way I understand it. First off, many regions have enough P already in the soil and do not require any extra. Applying excess P can cause pollution in watershed areas. Do a soil test to determine if the soil needs P amendments. I have gotten soil test reports back on completely neglected lawns, and the P levels were off the chart! Once you put a decent amount of P down it will stay there longer than most of the other nutrients, so you don't need to apply it everytime you fertilize. Why apply it when you don't need it; it will just cost you more money. Excessive applications of P in the spring will also enhance the growth of weeds, so what I would recommend is to focus your apps of P in the fall; Sept, Oct, Nov. (for turf)

Prolawnservice
03-11-2006, 10:34 AM
If your using a pre emergent herbicide, it dosen't make sense to have phosphorus in the mix as almost all pre emergents are root pruners and the P would be wasted. It would change into an unavailable form or run off before the plant could use it.
You were right about the excess all over the county, when P is in the wrong form it becomes locked up in the soil. There may be alot of P there, however some plants can still be deficient. :dizzy:

kyles974
03-11-2006, 12:26 PM
It's illegal for general use in MN, but I don't know how many other states are like that. Maybe that is part of why you are seeing more of it with 0 phosphurus.


I am from Michigan and it has been banned in some counties there. Myself along with some other Great companies & a GREAT local supplier got together a fews yrs back to educate ourself & along with the industry AND public on this matter. MSU research shows that 1lb of phos. can pruduce up to 750 lbs of algae in a stading body of water! Also many of the soil in MI is high in phos. so it is not needed unless you are putting seed down. The seed is not anle to pull the phos. from the soil! With all of the water in MI this is a huge concern! The water shed is or was trying to blame lawn care companies for high phos. going threw. Which in fact it was est.imated that this matter made up less than 2% of the problem..... but you know how that goes.... we are easy targets! SO.... we were beating them to it by using a NO phos. programs before they banned it! This industry requires ALL of us to be leaders!:usflag: