Our county offers compost. ($20 for 6 yards.) They've had it
analyzed,
https://ocrra.org/app/webroot/img/ga...-q2-071414.pdf

The reported nitrogen value seems quite high (2% by dry weight).
However, our retail soil tester, says the N is quite low.
Possibilities I can imagine:
(a) "organic nitrogen" is not really available, and we should add
something that is.
Or,
(b) Our soil tester is just looking for ammonium, and misses the
"organic"

If anyone knows more about this, I'd appreciate hearing.

G

wrote:
....
If anyone knows more about this, I'd appreciate hearing.


most compost is not particularly high in nitrogen.
over the longer term it is a very slow release
fertilizer, but mostly it is just for soil improvement
(to add organic matter, to improve water holding,
to help heavy soils break apart easier improving
water infiltration, etc).

inspect it visually before bringing it in. some
composting places don't remove trash from their
system and then it all gets ground up and sent
back out as little pieces of trash. looks rather
horrible in the gardens after a while...



songbird

wrote:
Our county offers compost. ($20 for 6 yards.) They've had it
analyzed,
https://ocrra.org/app/webroot/img/ga...-q2-071414.pdf

The reported nitrogen value seems quite high (2% by dry weight).
However, our retail soil tester, says the N is quite low.
Possibilities I can imagine:
(a) "organic nitrogen" is not really available, and we should add
something that is.
Or,
(b) Our soil tester is just looking for ammonium, and misses the
"organic"

If anyone knows more about this, I'd appreciate hearing.

G

Measuring nitrogen is one of the most problematic aspects of soil nutrition
because N comes in many different forms. Several of them are volatile so
that the concentration can change over time due to gas escaping. All are
soluble so N is leached out quite quickly unless the compounds are bound to
some substrate, so do not assume that having your N in a very available form
is necessarily better. These factors can change with pH and moisture
content. This compost has probably been limed to bring the pH to 7.4
Another complication is the compounds present may not be the ones that are
nominally measured for reporting by the lab.

Don't worry about it too much. If it is good compost and cheap then use it
and feed up gross N feeders with chicken manure as required.

--
David

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