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Rolla, ND | He could be generally correct but wrong on this individual field. Somehow I think the stronger acid of the Bray II is giving you a false high reading for plant availability.
I'd sure run a Bray I, Bray II and Olsen probably throw in a Mehlich while at it too, on the same sample to see if they are anywhere near.
You sound as though you've taken more than a few soil and tissue tests and this patter is repeating. In a matter like this, I'm going to go with the tissue tests. Not if there was just one, but if that's been a continuing pattern.
The other thing that could happen is some sort of contamination in your soil tests.
I've seen some weird ones over the years. Actually saw an example where a company was drying samples set out on trays in the fertilizer plant. Let me tell you that didn't sell much fertilizer because a little dust goes a long way.
I mention it but it seems unlikely to me that there is contamination if it's been happening over a period of time. But I'd probably pay someone else to run a few samples and see if the results are similar.
Other than that, it comes down to plant absorption.
That can get disrupted too. Root problems for instance. Most common would be Mycorhizzae problems resulting in nutrient deficiency even when nutrient levels are adequate. Or compaction. Or too stinking wet. Or a lot of things.
But to disrupt P to that extent over a period of time seems kind of to be unlikely.
So I kind of go back to you might have some form of P in your field that is testing available with Bray II that isn't really. That's why I asked if someone had spread rock phosphorus. It might be your parent material. Maybe you are sitting on a P mine. Just don't know your geology so I'm not much help but that's what it might come down to. The Bray test might just not work for you no matter what anyone said. It's not correlating with what is happening in crop.
It would be really, really interesting to use the resin sticks on your land. See what they take up. | |
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Phosphorus Uptake ?
