This is why I get confused...below is what the "Understanding Soil Test" says. How do I know if I have enough organic matter that just hasn't decomposed yet?

The relative humic matter content may or may
not represent the total organic matter content of
a soil. For example, sandy soils have a very low
organic matter content and a correspondingly low
HM%. In contrast, organic soils may have in excess
of 50% organic matter with a HM% of less than 10.
This implies that most of the organic matter in ORG
soils has not been decomposed to the humic and
fulvic acid fractions. In a general sense, HM% is
related to the weight/volume ratio (W/V): that is, as
the W/V increases, the HM% usually decreases.

Optimum levels of organic matter in soils is in the 6 to 8 percent range and if what you put in really did have 50 percent compost those levels should be much higher. These simple soil tests may be of some help sorting out what you have.

1) Soil test for organic
material. From that soil sample put enough of the rest to make a 4 inch level in a clear 1-quart jar, with a tight fitting
lid. Fill that jar with water and replace the lid, tightly. Shake the jar
vigorously and then let it stand for 24 hours. Your soil will settle out
according to soil particle size and weight. For example, a good loam will have
about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of
silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%)
of organic matter on the top.

2) Drainage. Dig a hole 1-foot square and 1 foot deep and fill that
with water. After that water drains away refill the hole with more water and
time how long it takes that to drain away. Anything less than 2 hours and your
soil drains’ too quickly and needs more organic matter to slow that drainage
down. Anything over 6 hours and the soil drains too slowly and needs lots of
organic matter to speed it up.

3) Tilth. Take a handful
of your slightly damp soil and squeeze it tightly. When the pressure is
released the soil should hold together in that clump, but when poked with a
finger that clump should fall apart.

4) Smell. What does your
soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant
odor? The more organic matter in your soil the more active the soil bacteria
will be and the nicer your soil will smell, to a point. Too much organic matter
can be bad as well.

5) Life. How many
earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5,
according to the Natural Resources Conservation Service, indicates a soil that
is not healthy.

I haven't seen a test with only humic material analyzed. Total organic matter is a much more useful parameter.

Humic acids and fulvic acids are not individual compounds but weight ranges of complex organic matter that is extractable from the soil with base. Essentially the permanent soil organic matter because it can't break down any further by microbial action.

The compost you recently put into the soil mostly wasn't counted in the analysis.

Kinmq, thanks for that info. I don't have a quart jar, but those tests do sound interesting. It definitely passes tests 3 and 4. No earthworms yet since so new (that I know of), but I am going to pick up a few nightcrawlers over the next few weeks and let them multiply. I will try the others and keep an eye out for a quart jar. :)

Tox, is there a test that actually analyzes the organic matter? What you said is basically what the lady said when I called today...though, I think your explanation makes more sense. Thanks!

The lady also said since the potassium is so high, no rabbit manure. Whoops. I added it to my compost bin. :)

You need a test for total organic matter. It's normally what is run when you get a soil test for garden soil. Not sure how you ended up with this more advanced test.

My statement that the compost you just added wasn't counted is not strictly correct. There may be some fraction of fresh compost that would be extracted in a humic-fulvic test. Total OM analysis however would count ALL of the recently added, partially decomposed OM, PLUS the humic/fulvic. Ideally it should be 5-10%.

It’s the NC state soil test. Any recommendations on how/where I get one for total organic matter, if NC doesn’t do it? (I will check.) That sounds like a great test. Thx!!

NC does not test for total organic matter. Rats.

If your bed is half compost - on top of the organic component of the soil that makes up the other half - you have way too much already. And will have some serious settling as it breaks down.

https://s3.wp.wsu.edu/uploads/sites/403/2015/03/soil-amendments-3.pdf

Hmmm Good point. I am not sure if it’s really 50/50....I should call to ask to see if my memory is right. I do know it hasn’t hardly settled at all in 3 months. Hope that’s a good sign! It was mixed in evenly with the topsoil, so I assume it was at least partially decomposed. Thanks!

Embo, that link was super helpful. Thx! I am still trying to figure out how to get the organic matter tested. I am also going to try kim’s method.

True, if it was 50/50 compost/soil you probably have plenty of OM, and any test you do within a few months or a year of mixing in that much compost will show high results anyway. But it will not be 50% even at the outset.

Interesting facts: Most compost is about 50% water. It can vary a lot but generally a reasonably dry (not dripping wet) sifted compost is 50% plus or minus as a rule of thumb. Of that 50% that is dry matter, a certain percentage is minerals (aka ash) rather than organic matter. Some cheap bagged composts can have as little as 10% organic matter if they sneak in soil, sand etc. Let's say it was half organic matter.

The analysis is based on dry weight, so a result of 50% OM is actually 25% based on original wet weight.

And that's going to continue to decompose. Some of it becomes 'permanent' or at least long lasting soil OM, and some goes off as CO2 and water.

And that's how adding 50% compost does not result in a soil test showing 50% organic matter.

I wouldn't get too worried about OM, it would be nice to know but it's not going to be low at this point and you can't remove it if it's high, so just go with it. Better to focus on the other results, such as keeping K fertilizers out. Is your soil clay? After adding compost to my clay for 25 years I ended up with excessive K and P. They stick.

Thanks, tox! I have been going nuts looking for somewhere to send it in for a another test. Glad I may not need to. I am going to buy some pickles or something in a 32 oz jar to do kim’s.l test.....but, that is tons easier and cheaper. :)

I appreciate all that info. It doesn’t look like what I consider typical clay because it is fairly dark and slightly...looser? But, it can still clump up nicely. It just isn’t the hard brick clay I am used to. However, the lady at the NC soil division said it is classified as clay.

She said same thing about no potassium (such as the rabbit manure). Is it too late to mix in any shredded leaves, since I will be planting flowers in a month? I think better to wait until fall so much of the nitrogen tie-up will happen over winter? Though, I may add some nitrogen as recommended from the soil test, anyway.

I appreciate all the feedback so I can learn!!

In addition to tox's very good comments, let me add this. We tend to think of stuff like compost, composted manures, chopped leaves, grass clippings, etc. as organic matter when they should really be considered as organic material. There is a significant difference. The organic 'materials' will continue to break down and decompose over time and shrink as much as 90% in volume before they actually become organic 'matter'. Organic material is very temporary and changeable - organic matter is pretty stable in the soil. It is the relatively permanent and stable levels of organic matter that soil labs test for (if they do that type of testing). So a 50-50 mix of soil and compost is unlikely to be an excessive amount of OM......once it fully breaks down - which will happen quite rapidly, usually within a single growing season - it should put you somewhere in the 5-8% range that is most desirable. Based on how this process actually works, I would argue that it is pretty near impossible to have too much organic matter!!

I wrote about this in another thread and included this LINK that you might find useful and explains this concept very well.

btw, I would not be concerned about adding any rabbit manure - the level of potassium it contains is negligible.

Ohhh! I had no idea there was a difference. Thanks for explaining the math behind it, too (I love math). I am definitely starting to feel better. :) I will definitely read that link here in a bit.

I was wondering that about rabbit manure..thought it was only 1 or 2 in potassium. I am guessing that would be better than adding shredded leaves right now?

Thanks!

Given the amount of compost in the mix that you put down, there is plenty of organic material in the soil so you almost don't need anything at this point. You might want to use those leaves as mulch when it gets hot in the summer. By fall they will break down enough to till in if you want. As for the rabbit poo, your nutrients are already high so no immediate need...you could actually build a compost pile of rabbit poo (if it is not already composted) and those leaves. Add kitchen scraps to it all summer. By fall you'll have a whole batch you can use somewhere. Just a thought.

You’ve gotten some great explanations regarding organic material, matter and humic matter. To my knowledge NC is the only region where HM% is regularly done. I believe it is because of the climate and the high rate of decay. You could call the testing service again and ask if they have recommended, optimal or desired ranges for HM%. If so, please report back FMI.

FYI: w/v (weight to volume ratio) is an indicator of soil texture. >1.6=Sand, 1..6-1.3=Silt, <1.3=Clay. Below 1 indicates an organic soil (high OM%).

Your w/v is .97. Hmmm :)

A FIV of 786 for Mn is high. Keep pH above 6 to avoid toxicity.

Tox, thanks for pointing it out. I was so awful at adding organic matter before redoing the boxes (had to redo them for other reasons) that I guess I am swinging too wildly this way now. Lol Not sure about the mulch...I should, but I will have to see how seedlings are doing at that point. Of course, they will hopefully grie faster now. It would be nice to use less water. :) Thanks for that reminder and combining leaves with rabbit manure. Getting a good system going for the over-abundance of leaves in my yard is my next project. :)

Whass...I will have to ask them that. Wonder why we have such a high rate of decay? Hmm on the W/V. Lady told me it is clay, but it sure doesn’t feel like clay to me. Guess it’s nearly clay, but not quite. ;) Thanks for those ranges. I hope to keep it on the organic side of that range. :)

I refined my early post hoping it will help. It doesn’t appear that you had a soil texture (soil particle measurement) test done. So the lady was probably just going by the w/v scale I cited. That is not always an accurate method for determining soil texture (sand,silt or clay) in the presence of OM. It works well if the soil is void of OM and a ratio that is below 1 is always going to reflect the presence OM but when OM is present the ratio scale may not accurately reflect soil texture. For example: a pure sand with a w/v of 1.6 could be mixed with enough OM with a w/v of 0.6 to result in a soil w/v of 1.1. Per the w/v scale that would be a pure clay even though it is really a sand and OM mix. The only thing we can say about your soil for sure is that it contains OM. Otherwise it’s w/v would have to be above 1. The more sand in your soil, the higher the % of OM there would be for a resulting .97 w/v value. Make sense?

That makes perfect sense. We were talking about w/v when she said clay. Thanks!

If you have tons of leaves, you might want to make a leaf corral in an out of the way spot. Just a circle of fencing, any kind, as tall and as big in diameter as you like. Pile it with leaves, smash down, pile in more. By spring they shrink down quite a bit. At this point I usually turn them once and make a smaller pile. You can use them in the compost too (add some greens) but they will slowly break down by themselves. By fall you should have a nice layer of leaf mould under there. It's extremely fluffy compost and a great soil texture improver.

Thanks! I was trying to figure out why people fenced/walled it in instead of a big pile. I can see how it would be easier to crush this way.