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Soil testing

 
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Location: Zone 9b
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I am a bit of a chemistry nerd and was wondering if anyone here has attempted to do their own soil tests. Sure, we can all buy the kits off of Amazon or take a sample to the county or examine our plants for lack of npk, but I'm curious to know if anyone has tried to make their own npk tests from scratch. A pH test is easy enough but the npk is a more involved.
 
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I am no chemistry nerd, and I'm sure this is WAY too reductionist to work, but am I right in thinking you would:
Step 1 add reactant to break down the common N,P, & K-containing compounds into a simpler or pure elemental form,
Step 2: add a known catalyst for each;
Step 3: document the resulting compounds using sensory cues(changes in color, texture, smell, etc).

Edit: this would only indicate presence of such, and not ratio, so, now that I think of it, sorry for wasting everyone's time.
 
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hau Steven,

You will want to download and perhaps print off this book  Soil Chemical Analysis So you get things right.

Don't forget, these tests are only going to give you partial results since the N test is going to be reporting ammonia as nitrogen. (industry standard method)
P and K are also not going to be for total but for water soluble P and K. (also industry standard)

Have fun

Redhawk
 
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Dustin's method sounds viable, but I think it would be easier to quantify things that exhibit a colour change, like a pH test, rather than a smell or texture.

With a colour change, you can have a colour swatch that transitions across the whole visible spectrum. You can then record what known values' colours are, and compare them against test samples. I think you could even get a number of different readings of known quantities, record the colours, and then do the math as to how the amount in the sample changes for each measured shift in colour.

But I agree, without the ability to grade the amounts present, we're essentially just testing for the presence or absence of NPK.

I wish I had a list of different plants that could be employed to tell us, based on their growth characteristics, what the soil conditions are. I know farmers have been doing so for ages in their fields, like if there's lots of clover in the field, that indicates the presence of, what, limestone underneath (I think, I might be wrong)? I would sow the soil testing guild in new beds, or on the perimeter of existing ones, giving me a constant, real-time feedback on what is actually bioavailable for my plants.

-CK
 
Bryant RedHawk
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Chris Kott wrote:I wish I had a list of different plants that could be employed to tell us, based on their growth characteristics, what the soil conditions are. I know farmers have been doing so for ages in their fields, like if there's lots of clover in the field, that indicates the presence of, what, limestone underneath (I think, I might be wrong)? I would sow the soil testing guild in new beds, or on the perimeter of existing ones, giving me a constant, real-time feedback on what is actually bioavailable for my plants.



Usually it is the leaves that give the most information, stems come along in second place. There are quite a few web sites with good photography so you can do pretty accurate comparisons
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