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Compost analysis report yesterday

Posted by daguvanuh (My Page) on
Wed, Mar 9, 11 at 10:06

Ground black CompostPile material;texture of potting soil.
HM% .66
W/V .60
CEC 26.3
BS% 99
Ac 0.3
pH 7.1
P-I 145
K-I 323
Ca% 73.0
Mg% 19.0
Mn-I 357
Mn-AI(1) 214
Zn-I 1199
Zn-AI 1199
Cu-I 198
S-I 83
Na 0.3

Only recommendation on N P K for flower and veg rooting soil was 50 on N...... (I guess that is for 50 lb per 1000 sq feet, need to check on this) .

My garden soil was tested also and its reccommendation was 20 lbs of 5/10/5 per 1000 sq ft. It is about 40% compost mix and 50% clay soil and 10% fine river sand. Ph on it was 6.8. It tills good and grows super but this is the first time I had it tested....
Soil test is free in NC.....
I still do not know where the perfect parameters are.... this is just 4 to 7 year old leaf compost ground back to black dirt for me.

Comments are welcomed as I can learn from specifics in this report that are good or bad.

Follow-Up Postings:

RE: Compost analysis report yesterday

I'm a novice in regard to compost, but from some reading a good measure of the effectiveness of compost as fertilizer is the Carbon:Nitrogen ratio, but I don't see a reading for either in your test results. Are those called something else in the report, or are they no measured? Are they relevant?

RE: Compost analysis report yesterday

From my point of view compost as an amendment is not fertilizer in itself.
It helps the nutrients, the micro-nutrients, the tilth, the moisture, the compaction, the oxygen supply and overall soil conditions that let the roots of a plant work passively and effectively with soil.
As for N, finished leaf compost yields about 2% dry weight organic Nitrogen in most of the analysis that I have looked at.
This being over 4 years old and older and been so compacted should be pretty low C/N and has shown no tie up or immobilizing of N. Low C/N ratios (appx < 20) will mineralize or break down Organic N to inorganic N which is plant usuable reasonably quickly.
Again for me its not fertilizer and if its compost it needs to be finished or it will create a nitrogen sink.

RE: Compost analysis report yesterday

There are no "perfect" parameters for soil, but for most all plants you do want a soil with a pH in the 6.0 to 7.0 range because most all nutrients are most readily available to plants in that range. You also want your major (NPK, Ca, Mg) nutrients in balance and a humus (residual organic matter) level of between 6 and 8 percent.
Compost is a soil amendment and not a fertilizer, no one needs an opinion about that. However, compost, as well as other organic matter, feeds the Soil Food Web that feeds the plants you are growing and converts, from compost and organic matter, the nutrients plants need, when they need them.

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