I decided to write about manures since I have lately been answering questions about the different types and their best uses by some of the local farmers.
Manures are good additions to soil and to compost heaps and even some worm farm operations.
Manures are generally thought of as high in nitrogen (hotness) but the actual content of N is generally lower than usually thought by the layman.
For instance Chicken manure is thought of as very hot but it contains only around 3%N when fresh.
Now this means we might, if using the chicken manure as our only source of N for the compost heap build, not add enough to get the results we desire.
It is however fairly useful to have an idea of approximately how "hot" any source of manure really is.
This is so we can build our compost heaps as close to the "ideal" as possible at the start so we get the heat up we want and so get the quality of compost we expect.
To that end, here is my list of manures, set up in the order of hottest to coolest and %N normally found through chemical testing.
The calculated average N % was done on fresh droppings (or as fresh as I could gather), a minimum of 30 samples were tested and averaged.
Bat Guano (usually will test to 4.0 to 4.5 N)
Sheep manure (usually will test to 4.0 N)
Goat manure (usually will test to 3.8 N)
Donkey manure (usually will test to 3.5 N, the mean was 3.1)
Hog (Pig) manure (usually will test to 3.3 N)
Horse manure (usually will test to 3.0 N)
Alpaca and Lama manure (usually will test to 3.0 N)
Chicken manure (usually will test to 3.0 N)
Rabbit manure (usually will test to 2.5 N but the median range in general is closer to 2.1 N)
Note: animals that are given some alfalfa as part of their daily feed tend to produce "flyers" (above the average of the test samples)
Note 2: this post is not part of the soil series and will not be listed as such.
Is duck manure higher or lower than chicken? I think I recall it being lower, but it's been a while since I found the info. Since they're not as common an animal as chickens, it's harder to find their stats.
I did not have access to a duck population but I would think that they would be in the 2.0-2.5 range just like geese.(I am using results from one of my students here)
There is an acidification factor for duck and goose manures, it is evident if you look close at their droppings on grass lawn.
It turns brown within a day and Bermuda (the one grass plant I was able to make the observations on) doesn't make as quick a comeback as it does from chicken droppings.
hau Lukas, yes this is apparently the first time this sort of list has been compiled (I talked with many professors and some extension service personnel and none had heard of such a list, so I took that as a cue to make the attempt).
While I have to say my sample set is horribly lacking (I would have preferred to use around 1K samples but time is currently at a premium, so no such luck at this time), I do believe that the numbers are fairly representative of what further testing would provide.
I have heard alpaca manure can be applied to plants as there is less risk of it burning them. Personally I didnt see the point of risking it... However I have not heard the same of horse which appears to have a similar N level. Persumably they both eat the same sort of things e.g grasses etc. So I am intrigued how the horses digestion affects this ability.
Very good question Henry, perhaps a Vet. could give some insight or outright answer. It is rather out of my realm of expertise.
I can tell you that donkey manure is very different than horse manure in particle size and acidity and it does depend (in the donkey) on what makes up their diet.
I have a friend that raises Alpaca and he uses the manure to compost with. Dr. Dorband has done quite a lot of research with his herd of alpaca but we haven't discussed how it would compare with other animal manures.
Next time we talk, I'll ask about that.
If it isn't the nitrogen, why do some manures tend to burn plants (like chicken manure) if applied fresh, while others are less risky. Could it be an acidity problem, like Bryant mentioned with ducks? (Or maybe too base, I can surely smell the ammonia when I drive by a feedlot).
Thank you for sharing this list.
Rabbit manure is one of my favorite compost/fertilizer components. I raise show rabbits (around 100 head), so always have plenty of fresh & aged manure to work with.
Strangely, I've had plants burned by fresh rabbit manure, and it has even killed grass around the piles where I dump the wheelbarrow on barn-cleaning days. I suspect, however, this is due more to the urine than the manure. My rabbits are kept in stackable cages with catch-pans under each cage so, when I empty them each week I have a week's worth of manure, urine, spilled feed, and a small handful of compressed pine pellets used to soak up urine. Since rabbit urine is so high in ammonia, I assume that is what's too "hot" for direct application. Furthermore, after it's dumped out in the sun for a couple of days it's usually okay to apply, which is probably due to the urine drying out and bacteria breaking down the ammonia.
I recently built my first real compost bin and learned that dumping the trays as a few layers is a great way to heat up the pile. I generally apply it over a layer of "browns" and top with a layer of forest soil & shredded wood/leaves, which releases steam on cooler days. I've also been layering it & filling spaces in my buried hugel beds, which I hope will be beneficial in the decaying process of the logs.