Does anyone know of any sources for nutrient facts on Hugelkultur? I'm looking for things like grams of nitrogen/potassium released per year per kg of Hugel matter. All I can seem to find is anecdotal evidence such as it provides long term fertility. The reason for wanting to know some hard facts is I'm designing a closed food growing space for a contaminated site and want to close the fertility loop as much as possible. Knowing how much a given amount of Hugel matter will contribute would be very helpful when calculating the nutrient budget.

Howdy Marcus, welcome to Permies!

Interesting question.

I have not seen a detailed analysis yet but that does not mean it is not out there somewhere.

Here is a nice article that talks about some of what happens in a hugel bed.

http://permaculturenews.org/2012/01/04/hugelkultur-composting-whole-trees-with-ease/

One of the things to think about is how the mycellium, that builds into a hugel, gathers and distributes nutrients within the hugel.
So not only does the wood add nutrients but the other ,living, components do too!

Welcome to Permies, Marcus!

Like Miles, I have also looked for this type of information and found it to be lacking. You can usually find lots of scientific research on any given topic at Google Scholar, but on the topic of hugelkultur, it is noticeably sparse, and half of what does show up brings you right here to Permies.

I have two hypotheses why this is the case: (1) there is no research funding because it does not help big Ag sell more fertilizers, pesticides, fungicides, herbicides and other high dollar inputs and (2) how is someone going to write a proposal to do research on hugelkultur? Which of the variables are they going to study and which will they control for? Type of biomass buried? amount? fungi used to inoculate? crops grown on it? soil fauna? After you figure all those variables out, then you have the matter of time frame -- a study with big logs could take decades. And then, after you plan your study and take data for several years, then there is the matter of 2-, 3-, 4-, and up to n-factor interactions. Not an easy puzzle to untangle.

But you're welcome to give it a shot.

Thanks for your replies chaps. Quite a challenge. I wonder if the benefits of knowing this type of information justify the effort?

Marcus Draper wrote:I wonder if the benefits of knowing this type of information justify the effort?

In the long view, doing this kind of research and collecting this type of information will be worth the effort, but as with a lot of biological knowledge, it takes a long time doing painstaking research before results you can use start to show up.

When I was constructing one set of hugelbeds, I used a bunch of pine logs that were teeming with bess beetles. That could be a research project in itself, having a control with no beetles, and having hugelbeds with differing numbers of them, all chomping up the wood and converting it to insect frass. And that would be a different research effort from just collecting the frass and chemically analyzing it and using it as a fertilizer. So many research ideas, so little funding to carry them out.

My own research is thus --- Pile up unwanted wood and other organic stuff --- See what grows. This was not the original plan. My tenants were supposed to plant the beds and failed to do so for 2 years. On the beds, wild thistles grew 6 ft. high, unaided. The natural landscape beside the beds grew skinny thistles 3 ft. tall. They are extremely averse to any type of work. Nothing was watered, weeded etc. A pretty pure test.

My first test started 14.5 years before I learned the term hugelkultur. I burried 17 fir stumps to make a berm. Things grew well on "Jasmine Mountain" which was named for my 2 year old who was the first to reach the summit. It took more than 10 years for the stumps to rot an inch deep. Bark broke down in about 5 years. Many bushes survived droughts that killed stuff on unimproved ground. I'll return for a look this summer. It will be 17 years in July.

Dale Hodgins wrote:My own research is thus --- Pile up unwanted wood and other organic stuff --- See what grows. This was not the original plan. My tenants were supposed to plant the beds and failed to do so for 2 years. On the beds, wild thistles grew 6 ft. high, unaided. The natural landscape beside the beds grew skinny thistles 3 ft. tall. They are extremely averse to any type of work. Nothing was watered, weeded etc. A pretty pure test.

The problem is the solution .

I can't quite envisage an experiment that could control for the many variables, both intended and incidental such as introduced fungal inoculants vs. random arrivals, much like others have mentioned.
On one's own property however good record keeping including rainfall stats etc together with regular photos over an extended period would likely give you significant data for future endeavours at least in a similar environment. IMHO memory is far too fallible. Although I've done many courses over the years (including a PDC in early 2001) some of the most significant 'take home messages' have been from field trips and walking the land with knowledgeable people which is one of the reasons I give much more credence than many on this forum to Biodynamics and their practitioners.
I've viewed wonderful examples in Queensland Australia, various sites around New Zealand, but know that much of what I witnessed there would not be applicable here in coastal British Columbia--still many of the underlying principles are applicable.
Another good source I've found is old time farmers, gardeners or horticulturists in your area, especially if they are prepared to share their failures as well as their successes!

Just my 2 cents,
Edith

Perhaps the term Hugelkulture will not result in a plethore of scientific papers and data sources but if you search for "cellulose decomposition in soil" or "water retention by decomposing cellulose in the soil" you might find some. i.e.

http://nora.nerc.ac.uk/5033/1/N005033CP.pdf

http://www.fao.org/docrep/009/a0100e/a0100e05.htm

http://www.landfood.ubc.ca/biomet/geog317/Lecture8-SoilOrganicMatter.pdf

From such sources you can make inferences of what the Hugel bio-processes are and how they impact plant life.

Wood core raised beds or growing beds seem like terms that could be agreed upon.

Due to the stratified layers of the beds, the long time frame of decomposition, fungal activity etc. they will be hard to measure and analyze - however, comparing the nutrients in a crop grown in a hugelbed to the same crop in a control bed might be practical, no?

Marcus Draper wrote:Thanks for your replies chaps. Quite a challenge. I wonder if the benefits of knowing this type of information justify the effort?

Well, a reaserch based on scientific methodology and presentation of results based on statistical significancy would be the answer to those who consider permacuture to be a pseudoscience. In many cases we are able to say that something "works" for us, but one thing is to know that, and another one is to make it proven in terms of science. Moreover, a scientifical approach would tell us under exactly which condition something works, and prevent many disappointments for people new to permaculture with using particular pattern in circumstances that are absolutely not suitable for it.

I think a good approach would be to estimate the % of carbon/mineral bearing material put into the original mound, try to factor in what the wood will require for decomposition, and mulch with more or less of specific types of things. Sugar maple for example has around 5% mineral composition in its leaves, being higher in nitrogen then most other trees. Pine needles have 2.5 percent of their weight in calcium, magnesium, nitrogen and phosphorus, plus other trace elements according to research. Certain woods are going to have different properties, other then containing mostly cellulose/lignin binder, I believe the most notable difference will be in the bark where we see some utilized for winter foods by animals. This is a very complex situation, one that I would very much like to see works published on. Good luck on the build.