# Low in calcium magnesium and potassium



## Greyleafspot (Oct 16, 2018)

SoIl year said I need to add potassium, calcium and magnesium. What should I use?


----------



## Greyleafspot (Oct 16, 2018)

Soil test showed ph at 6.3


----------



## Mightyquinn (Jan 31, 2017)

@Greyleafspot

I moved this thread over here as it will get you more detailed answers.


----------



## Virginiagal (Apr 24, 2017)

What did the lab recommend? How many lb/1000 sq ft for each?


----------



## Greyleafspot (Oct 16, 2018)

They didn't recommend anything.


----------



## Greyleafspot (Oct 16, 2018)




----------



## Greyleafspot (Oct 16, 2018)




----------



## Greyleafspot (Oct 16, 2018)




----------



## Virginiagal (Apr 24, 2017)

This looks like something for @Ridgerunner. Why is the ppm high in potassium but the paste extraction low? I would call the lab and ask for recommendations. Dolomitic lime would give you calcium and magnesium and there is some room for lime (not much but some at pH 6.3), but they should give you a lime recommendation based on a buffer test, which I don't see. To raise calcium and magnesium without raising pH, there is gypsum and Epsom salts.


----------



## Ridgerunner (May 16, 2017)

@Virginiagal There is no obvious explanation for those results. This is one for an agronomist, an expert in the field of soil science. 
Sampling error? Always possible, but not likely. I can't think of any single amendment application that would have such across the board effect on all nutrients. Although some would result in chemical reactions making a nutrient unavailable (insoluble), many detriments occur due to an imbalance between nutrients, not due to a lack of presence. 
@Greyleafspot This isn't a potting medium, correct?
Soil Science?
pH and soil texture (clay) and OM can have a broader effect on nutrient availability/solubility, but highly unlikely that it could ever be this drastic, at least not across the board. This (and the chemical interactions mentioned above) is where a soil scientist's input would really be helpful as there are always exceptions and unique situations, but unique situations are just that, unique. The odds are against this being unique.
Testing error?
Based on the consistent across the board differences between chemical extracted results and paste extraction results, my guess is that this is most likely an error in the paste extract testing.
Regardless, based on the chemical extraction, the K:Mg ratio is high. Combined with the relatively low Mg levels, Mg deficiency is a likely possibility. Otherwise, nutrient levels are pretty good.


----------



## dwaugh (Aug 25, 2020)

Ridgerunner said:


> Based on the consistent across the board differences between chemical extracted results and paste extraction results, my guess is that this is most likely an error in the paste extract testing.


@Ridgerunner I realize the extraction method is different, but do the results look so different because the Chemical Extraction is in soil PPM and the paste extract is in solution ppm?

I had never heard to the paste extract, but I did find this link with was useful for me http://www.earthworksturf.com/pdf/paste_extract.pdf


----------



## Ridgerunner (May 16, 2017)

> Based on the consistent across the board differences between chemical extracted results and *expected* paste extraction results, my guess is that this is most likely an error in the paste extract testing.


Edited


----------



## Greyleafspot (Oct 16, 2018)

Ridgerunner said:


> @Virginiagal There is no obvious explanation for those results. This is one for an agronomist, an expert in the field of soil science.
> Sampling error? Always possible, but not likely. I can't think of any single amendment application that would have such across the board effect on all nutrients. Although some would result in chemical reactions making a nutrient unavailable (insoluble), many detriments occur due to an imbalance between nutrients, not due to a lack of presence.
> @Greyleafspot This isn't a potting medium, correct?
> Soil Science?
> ...


This is not potting mix.


----------



## Greyleafspot (Oct 16, 2018)

So I was told the chemical extraction tells what's in the soil and the soluble paste extraction tells what's available to be taken up.


----------



## Ridgerunner (May 16, 2017)

@Greyleafspot 
My apologies, I just noticed you are near Houston. (a Texan w/acidic soil   )
Were you subject to much of the rain/flooding from the recent hurricanes and tropical storms?
If so, did you take your soil samples afterward or before?
Paste tests are intended to measure the "readily" available nutrients in soil solution, akin to the spot residue left on a hard surface after a drop of water evaporates. If the soil had been "washed" by a recent heavy rain period, that might account for low paste levels across the board in a well drained or sandier soil.
What's your soil texture (sandy, clay)? Does water percolate easily?


----------



## Greyleafspot (Oct 16, 2018)

Conroe is more piney woods. Than houston. The natural soil is Sandy loam.


----------



## Greyleafspot (Oct 16, 2018)

We got 5 inches from the tropical storm but this test was before the storm


----------

