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Central Mass

My level of phosphorus in my soil was reported at 290 ppm last fall. I want to apply mycohrizza this growing season. Will I be wasting my time and money with the phosphorus level being so high?

3/24/2008 8:28:49 PM

Kevinstinindians@yahoo.com

Thats one of the million dollar questions right now. I have high P as well, about the same as yours. I'm going to try mycor on some of the plants but not on others to see if there is a noticable difference at the end of the season.

Different mycor experts will give you different answers about the toxicity of P to mycor. I've been wondering if the toxicity of P is determined by the availability of the P and not the total amount. If its unavailable to the plants does that means its unavailable to be toxic to the mycor?

Free Ca is available to interact with other nutrients. Soluble P is an anion, meaning it has a negative charge. Any free Ca reacts with P to form insoluble Ca-P compounds that are not readily available to plants. Since there is typically much more available Ca in the soil than P, this interactions nearly always results in less P availability. The higher the pH the greater the reactivity of the Ca. Most AG growers patches have a pH of around 7 and alot of available Ca. This is my current theory and may be pure BS, but then again maybe its not.

Hopefully I will find out this season if mycor will do my patch any good or not. I don't really want to spend the money if its not. But if it is then I'm willing to buy the product. In this case it seems the only way to find out is to try the product yourself and see if it works in your patch.

3/29/2008 4:38:15 PM

Ctpumpkin@optonline.net

Rhizobacteria will help liberate bound Phosphorus but probably won't do anything to save mycorrhyzae. I plan to try multiple mycorrhizal inoculant treatments this year to (hopefully) keep the P toxicity at bay.

3/29/2008 9:10:04 PM

Colorado

you may be ok.the myco fungi doent do well in high available phosphorous.If the phosphorous is tied up youll be fine.a alkaline Ph(above 7) helps keep the phos. bound.

3/30/2008 2:24:01 AM

Long Island,New York

ok...at what point will we have to be concerned with the constant grow-kill off-reinoculate-kill-off as it applies to penetrations in the roots cells? I mean, some people run around with bleach in a sprayer when they prune tertiaries...then wait a day for the wounds to heal. By growing and killing are we promoting open porosity/wounds to nasties in the roots? Voids of decay in root cells cannot be good....openings to diseases etc....

3/30/2008 9:21:03 AM

Kevinstinindians@yahoo.com

Steve, my understanding was the P was unbound at a very slow rate. Do you have any idea at what rate that is? I don't think I've ever found info on that. It maybe related to just how much rhizobacteria is in the soil.

What products and how often do you plan on reinoculating?

Glenn, I've wondered the same things. I don't believe most growers treat open wounds. That of course is a major no-no in most horticultural practices. I've wondered what diseases can enter through open wounds. And if systemic fungicides, at least for the most part, prevent diseases from entering the plants via open wounds.

I don't treat the open wounds on my plants and don't have a plan to. I leave the wounds open and uncovered until they've dried up and healed over, then I cover them. I have had a couple plants get what I think was gummy stem blight however. I don't know for sure thats what it was. The plants that have got it have all been in areas where I put composted wood chips into the soil. I also haven't used fungicides in the past, other than daconil. I don't believe I've ever seen a case involving the typical nasties of pumpkin growing( fusarium, pythium, phytophtora, etc...)in my patch either.

3/30/2008 11:46:52 AM

Ctpumpkin@optonline.net

I've never seen anything published about actual amounts of liberated Phosphorus. I know that a lot of the research is done around mines where Phosphorus liberating microorganisms are collected, ID'ed & quantified. I presume the cloak of secrecy is there to offer investment security to commercial stake holders.

The data I have seen does indicate that the larger the rhizobaterial population the greater the release especially in rock phosphate soils.

We're using PHC's Flower Saver Plus.

http://www.planthealthcare.com/HT/Mycorrhizal/PHCFlowerSaverPlus

I'd say that contact fugicides would be better for wound treatment than systemics. Contacts start & remain fungistatic. Most systemics need to encounter active disease hyphae within plant cells to work.

3/30/2008 8:28:34 PM