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strip till fertilizer savings??
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NE Ridger
Posted 12/25/2015 22:50 (#4987206 - in reply to #4987156)
Subject: RE: strip till fertilizer savings??


EC Nebraska
Norstman - 12/25/2015 22:08

NE Ridger - 12/25/2015 21:54

Norstman - 12/25/2015 21:37

NE Ridger - 12/25/2015 21:25

In the first place, I've gotten my best corn yield ever off ground that had phosphorus tests like that. Mehlich-3 phosphorus tested 8-10 ppm. 100 lbs of MAP banded in a rough 2X2. 280 bpa on 40 acres.

I'm not talking about zero applied, I'm talking about a specific situation where at least 1/2 of crop removal is being banded near the row. AND where a healthy soil microbial community is being maintained.

If the ground is being worked multiple times per year, no covers, and very little fertilizer applied, then of course the soil tests are probably going to drop and crop yields will suffer. You've wiped out the fungal networks and there's no one to sell P to the corn roots.

Those are two different situations.



So if your applying a half rate the remainder is being pulled out of the "bank" so to speak. It will deplete over time and my bet is it wont take too long. Can we agree on that? Healthy soil microbials is a whole nother deal and wasent what i was referring to in my original post or any that followed.


Plant available phosphorus (at least for corn) can't be discussed apart from the soil microbial community. Corn roots are terrible at picking up phosphorus on their own. "Fallow corn syndrome" is a case where the microbial community is so poor that it starves the corn for phosphorus no matter what the soil test. I've had corn nearly die from phosphorus deficiency on soil that tested nearly 100 ppm P (lots of swine slurry on PP).

The soil microbial community is what really determines the size of the bank. Traditionally, soil was managed for a minimal microbe community that needed lots of water soluble phosphorus in order to supply the crop needs. If the soil is managed for a healthy community that can extract mineral-bound phosphorus from the soil then your "bank" is huge. If you work the soil to death and starve the microbes, then yes, your crops can't access the bank and need artificially acidified phosphorus to survive.

If you insist on separating the two, then you're right.

Im not disagreeing with any of your assessments. But how does the method of applying fertilizer have anything to with your findings on soil microbials? Also must be a difference in areas because i have never seen fallow corn syndrome.


The only time I ever had fallow corn syndrome was on a field that was prevent plant the prior year. I controlled the weeds completely on part of the field, but part of it was always too wet to drive on. The next year it all came up, looked great until V3, and then the part that was weed free the year before turned purple and started shrinking. It was the start of my study of soil microbes and how they interact with crops.

The method of application matters because microbe are lazy. If you broadcast 200 lbs MAP across the field, the entire soil profile is flooded with water soluble P. The microbes are going to gorge them selves on that P, and stop spending energy to extract mineral P. What they can't hold binds to calcium or iron or aluminum, depending on pH. If you band 100 lbs MAP in a three inch wide strip, then only the microbes near that strip are going to be lazy. They'll trade that phosphorus around a bit, but 75% of the profile is still a little hungry for P. Those microbes will continue to scavenge for insoluble phosphorus as long as they have enough carbon fuel to work.
In addition, that little strip will have saturated all the Ca, Fe, or Al and still have soluble P floating in the solution and on the exchange sites. The young corn roots going into that band of soluble P are going to take some up directly and more from the gorged microbes. It's plenty to get the plant structure going and set up the photosynthesis factory so the roots have a sugar supply to trade for nutrients. As the corn moves toward R stages, the roots spread throughout the profile, suck up all excess available P, plug into the soil network, and start buying phosphorus from the real soil bank.

If you broadcast you need to supply enough for the entire community's needs and you discourage that community from extracting it's own P. Banding gets more to the corn directly and encourages the microbes to keep mining.
Sure, the microbes may eventually run out of parent material to mine. It's going to be 1,000 years on my soils before that happens. It'll never happen on some of the best ILL soils. And it's a pretty poor shallow or sandy soil where it won't take 100 years.



Edited by NE Ridger 12/25/2015 23:01
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