Improving my composting of Horse Manure?

I've had horses for years, and I've always made piles of their manure, turned them occasionally, and after a couple of years I have some very nice compost.

Now I'm reading Paul's "Backyard" book (it's great). The book has me questioning whether my approach is really eco-friendly or not. Something about releasing greenhouse gasses I think?

I've done a little experimenting layering cut pasture grass into the manure, seems okay but not earth shattering.

So any ideas? Can I do composting "better" ?

Hi Bert,
Thank you for your input!
I have one horse. I've had him for two months now (he's friends with the neighbors' donkey).
In his stable I'm using sawdust as bedding material.
Every day I'm taking out one wheelbarrowload of pee-wet and manured sawdust and put in fresh sawdust to 'top up' the bedding again.
Until now I've been emptying the used stable bedding material into
- the compost piles (there are 2)
- onto hugel beds
- on flowerbeds
I honestly am not sure if I'm doing things "right" or not. Any input / feedback from everyone reading is welcome!

Not a suggestion, but a warning.

We got well rotted horse manure from our friends, who are organic gardeners from way back.  Also have laying hens, in addition to the horse, and extensive raised beds.

Both we and they had an "off" year with our gardens following that - very poor growth of most things, though peas and beans did OK.  Last summer, similar results.  Both years were pretty good weather, plenty warm and a long growing season.  The only stuff that did well was the stuff in buckets and pots.

The common denominator was the manure.

Putting our collective heads together, we suspect that the straw which they used for bedding for the horse and chickens had been sprayed with some sort of herbicide.  I dug out all of the soil from our raised beds and put it into a compost pile.  Then I put in mixed fresh compost, peat moss and vermiculite, with some cardboard as sheet mulch in the hopes of slowing down the sub-soil rhizomal grass invasion.  I'll let the old soil age for a few seasons, then test with tomatoes or cukes in buckets as coal mine canaries to see if the toxic gick has broken down sufficiently.  Hopefully it will eventually break down (5 years? 7?).

Anyway, straight manure is probably safe, but be careful about bedding materials.  Sawdust should generally be fine, I'd think, but straw may be dicey, unless you know its pedigree.

Maybe reduce the length of time you are composting the manure.

Also you can try using aerobic processes of composting, and preventing anaerobic conditions.

Here is a thread that will explain those conditions:

https://permies.com/t/83299/Jadam-aerobic-anaerobic-bacteria

Thank you Kevin, for the warning.
So sorry to hear you had that bad experience with the straw bedding! And good that you found out the cause of the issue.
We're getting our sawdust from the local sawmill, they're making pallets from treetrunks, so it should be just raw sawdust, no chemicals there.
Wishing you the best of luck and a great gardening season with container gardening, until your soil has healed. Maybe get some wood chips to mulch with to make the soil nice and cozy for helpful soil bugs to move in?

According to soil scientists Dr. Ingham, Dr. Johnson, the best composts are made with 10% or less manure, and over 25% gets to be detrimental in going anaerobic, excessive salt content, lack of biodiversity, off gassing and related lower yield of compost. This seems to be true in my own experience, with microscopy and results being my indicators. Horse manure will also be high in Nitrogen (good for green growth, can suppress flowering and fruting) and relatively low in P, K, and Ca nutrients needed for flowering and fruiting stages. This leads to 20ft lush tomato vines with 2 sickly fruits.

I would add as much carbon rich unsprayed material as I could, ideally wood chips, to encourage fungi coming into balance with the bacteria flourishing in the horse manure. Unsprayed straw would be my next choice, and a mix of both is best. Instead of laborious turning, I would use the Johnson-Su method of passive aerated composting that produces the most biodiverse result. This uses chimneys of perforated pipe to ensure no part of the pile is more than 1ft from air. Worms are added once the temp is below 90F. It does take a year, but ends up being extremely good compost. I have found it does not need to be in a tower or on top of a pallet (i use sticks and a perforated pipe at the base), as long as the basic principals of air with 12” everywhere and a diverse, carbon rich feed stock is used with 10-25% manure max.

Our horses generate a lot of manure

The other thing we have a lot of is "bad" hay. Hay that is somewhat disintegrated. We don't have much in the way of other materials. I guess we can add water

So with only those ingredients, what might a better approach be?  (I've tried making manure / disintegrated hay lasagna, so far the results are "meh")

Horse manure by itself has a pretty decent green/brown ration in itself from what I have read. If you have bedding included in your manure pile you might want to consider something on the nitrogen side of things to balance out the excessive carbon. (I am a fan of "when in doubt, pee on it" when it comes to compost.)

Seeds can remain viable after passing through a horse's digestive tract so I would recommend a hot composting process if you are worried about transferring surprise volunteers into your garden areas.

We use very, very little bedding.

I really like the suggestion to pee on the composting manure.

In the fall leaves are usually abundant on street curbs.

Tree trimming, garden chop and drop or any organic matter would help.

https://permies.com/t/5072/human-pee-horse-manure

Anne Miller wrote:I really like the suggestion to pee on the composting manure.

In the fall leaves are usually abundant on street curbs.

Tree trimming, garden chop and drop or any organic matter would help.

https://permies.com/t/5072/human-pee-horse-manure

We're fortunate that our horses are NEVER in stalls. They are always outside, unless it's too sunny, then they can choose to go in a shady shed. (As an aside, they don't go in the shed when it's cold or rainy or windy, only when it's sunny

So they pee wherever they want to. I could capture our household pee I guess, but honestly it would be the proverbial "drop in the bucket". My gut is that we'd need 100 times the pee to impact our big manure piles. Same with our household compost pile, it also would be a drop in the bucket.

Hi Bert,
Have you thought about using the manure in the way farmers have been doing since the beginning of agriculture?

Spreading it/just throwing forkfulls?
You'd be emulating the way grazing herds fertilized the prairies. Without chickens to scratch it up, and spread it, I've used a mower to do that.
You also get a good layer of clippings over the manure to help reduce nitrogen loss to the atmosphere.

I did create a very good compost by making a five ft. diameter circle of old 4' fencing. I just layered on a few forkfulls of horse manure for each 8 or 10 inches of woodchips. Downside is it takes a year or more to break down the chips, but it came out rich, black, and crumbly.