Help me interpret my lab results

[skatefriday]

I had leaf and soil analysis done a couple of weeks ago and I've been staring at these results and the more I look the confuseder I get.



I have pretty severe chlorosis in the leaves that all the photos online suggest magnesium deficiency. So I was expecting low results there. Didn't at all expect that K value, nor the N either. Is nitrogen low because potassium is inhibiting uptake? See soil results below that also indicate low nitrogen, but note that I applied 15-15-15 in the spring, but sparingly and only at the vine. I took my soil sample from mid-row away from where I applied the fertilizer and I have a drip system that only applies water at the vine. Perhaps that distorts the soil results?

I applied soil drench liquid Iron/Zinc per label instructions on Wednesday, and foliar Epsom Salts yesterday at a rate of 1 tablespoon per gallon. Now how do I correct that Potassium/Nitrogen problem?





Thanks!

 

[Snafflebit]

I also had chlorosis in vines and lab results that showed primarily low N. You cannot really lower the value of P, but you can easily increase N, and that is really all I had to do the see dramatic improvement in greening of vines and increased fruit yield.

Your soil type shows clay loam and 6.56 pH. I have heavy clay loam soil. Clay is nutrient rich but also locks the nutrients. My soil is 7.2 pH and I chose to use ammonium nitrate broadcast (21-0-0) to acidify and fertilize. I calculated the needs of my plants which amounted to about 1/8 cup per plant per year in post harvest. I will need to run another soil test to see how this is performing because nitrogen is mobile and concentration will change over time.

 

[RonObvious]

Snafflebit is spot on. Grapes are nitrogen-hungry - some varieties more than others. I had chlorosis in my Marquette, but not in Petite Pearl or Seyval Blanc in adjacent rows. I used a conservative amount of ammonium nitrate for quick-acting effect and also organic nitrogen fertilizer for slow release, both applied prior to bud-break. They look much better this year. So just get some nitrogen on them and they'll be good. It looks to me like all the other numbers are OK, except calcium and magnesium are a little low. You could try spraying with CalMag, which is cheap and easy to do and at the very least won't hurt anything. I use CalMag occasionally, not only in the vineyard but also at home in the garden. Most plants seem to respond well to it.