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| One way of looking at the results is a DRIS analysis, sometimes you can pick up which nutrients to look at first even when everything is withing the critical levels. Basically it comes down to are there any that though within critical ranges are towards the lower end while others are higher.
If you did a whole plant analysis, it might be worth doing a most recent mature leaf. Whole plant might be within critical range but that might be because the low nutrient keeps getting stored whereas it is too low in the new tissue.
Is there any unaffected corn? Best of course is the same field, but if not, I'd try some of similar age from an ajoining field. Take a look at a soils map to take it where its most similar to where you took this one. Sometimes you can pick up differences that don't show with just the sick plant sample.
Here's one thing I do when I just haven't got much of a clue. I go to my local harware store and buy some Miracid fertilizer, now it has low levels of just about every nutrient known to mankind in plant available forms. I take some and water it in next to a section of row, say ten or twenty plants and I use enough water that I don't need a rain, it's in the root zone. My experience is that if nothing happens, you can pretty well forget nutrients as your problem. It's kind of a down and dirty way to figure things out, but it's worked pretty well for me. If the plants that you give the Miracid to pop out of it you at least know it's a nutrient.
A couple of more specific fertilizers you can try that same way are ammonium sulfate which is used for spraying chemicals is a quick sorce to test for sulfer (I do it all the time on canola which is very sensitive), and on corn another that comes to mind is zinc. Just a little zinc chelate or even some zinc oxide watered in would let you know pretty quickly, Note that it's pretty easy to get to levels of zinc that are plant toxic if you throw a handful in. With the chelates a quart an acre is usually all that's applied or just a few lbs of oxide so be a bit careful with that one.
That's some ideas.
Marv | |
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Tissue Sample Iron Levels
