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feeding high potassium soil

Posted by Galasoneth 8 (My Page) on
Tue, Feb 26, 13 at 8:54

Hello All,

I did a soil test yesterday and ended up with PH of 7.0
nitrogen very low
phosphorous very low
potassium very high

Ive have a few fertilizers that are high in nitrogen but none that are say 10-10-0. most have at least 10% potassium. Is that a problem having so much potassium? Thoughts suggestions?



Follow-Up Postings:

RE: feeding high potassium soil

First I'd recommend contacting your local county extension office for a $10-12 professional soil test. The home do-it-yourself kits are notorious for inaccuracy and should not be used for purpose of "fixing" soil.

Second, it is quite rare to find soil that is either low in phosphorous or high in potassium. It can exist but is rare so that is another reason for questioning the results of your tester kit. The pH is another - what the kit actually tests is your water and they almost always give a reading of 7+.

IF it turns out that your soil is truly high in potassium then nitrogen is all you need to focus on and there are many fertilizers available that are N only.

Plus there are numerous organic supplements that are simple N - alfalfa meal, cottonseed meal, blood meal, etc. There are also supplements that are straight phos - bone meal is the most common.

Hope this helps.


RE: feeding high potassium soil

  • Posted by glib 5.5 (My Page) on
    Tue, Feb 26, 13 at 13:41

In the unlikely chance that you tested your soil right, chicken manure is perfect for contributing N and P while contributing less K, compared to other manures. Anything that has to do with grains, such as cornmeal, will do the same.

RE: feeding high potassium soil

awesome thanks all

RE: feeding high potassium soil

The suggestions Dave gave were good and I'd support them except for the last few paragraphs. All of the meals mentioned may contain significant N but they are also sources of many other nutrients; Alfalfa meal might be expected to contain 3.5% N and also 1.8%K, .5% P, etc. The same for bone meal which is high in Calcium as well as Phosphorus.

A soil test will reveal your soil status on other important nutrients, most notably Calcium and Magnesium. I would be more concerned about the ratio of Potassium (K) to Calcium (Ca)+ Magnesium (Mg) than just K alone.

Surprisingly to some, few soil test labs will routinely test for nitrogen(N). They will usually just make a blanket recommendation based on the crop you intend to grow. A test for N midway through the growing season might be of some benefit. But what the Lab. will usually do is a regular pH reading and a buffered pH reading. between the 2 a specialist can better determine if limestone, dolomitic limestone, or some other nutrients might be applied and in what rates. From your test Sulfur (S) would be suggested to lower pH, but as Dave said get a reliable test first.

If you are looking to purchase straight fertilizer ingredients you should look past the box stores to a farm supply store. There you could ask for P sources: Diammonium phosphate (DAP)(16%N, 48%P2O5), Monammonium phosphate(MAP)(12%N, 61%P2O5). For N sources the more common are: Urea (46%N), Ammonium Nitrate (34%N) and Calcium Nitrate (15.5%N, 19% Ca).

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