Terracing and Hugulkultur

I am interested in trying to terrace a south facing slope (of perhaps 30 degrees) where the outer side of the terrace is composed of Hugulkultur beds, as it appears you do sometimes. How much slope is considered too steep to try this, and what happens as the beds begin to break down? Would there be a need to plan to rebuild those Hugulkultur beds in a few years time to keep the terracing intact?
Thanks for getting your book translated into English! Barbara

The question of how steep is too steep is a good one. I believe that the answer is that the steeper the hill, the more narrow the terraces must be, and more steep the "bank" must be between the terraces, so I imagine the answer is in the type of soil you have, so if it's stable enough, and you can get the terraces wide enough for access, then go for it, and be sure to seed it out right away!

As for hugels at the bottom edge of terraces, I have also been thinking about this. It seems slightly conflicting with the importance Sepp seems to put (as I understand it) in having the terrace surface ever so slightly sloped down the hill, keeping water flowing on the surface from forming streams, helping it sink slowly... if the terrace is like that, angled slightly downhill in both the length and width directions, then having a hugel at the downhill side might slightly interfere with the water flowing down and off the terrace, and causing (depending on the soil type I imagine) a bit of a stream to form above the hugel. This, I think you would want to be avoided.

Thoughts everyone?
--Joshua

Questions for Sepp, On average, what ratio of wood to soil do you use in you hugulkultur? I know it depends on what you have on site, etc, etc, but whats you recommendations as others want to know as well. Also, are there problems with planting fruit trees on the top of the hugulkultur. I have been planting bare-root trees on the hugul, here in Montana, as I am high on a mountain of decomposed (and not so decomposed) granite. I have observed the trees on the hugulkultur outgrow the trees in the field by at least 100% if not 200%. These huguls were made with minimum trees and lots of hay/straw bales on contour. I have since started using dead aspen for the hugulswales as I refer to them. So again so we can all know is there many problems with planting on the hugul. Thanks for being great.

We are in the process of terracing 2 acres of pure sand on our property to try to build some living soil, as when the Florida rains come to our sloped property, they simply strip away any topsoil that has accumulated. We are incorporating hugelkultur beds as our terraces, for several reasons. First, the dense thicket of branches and brambles that form the "bones" of the beds help resist water washout. Second, they create a bit of a "backwash," which allows most of the soil to settle out uphill, rather than washing away. We are fundamentally lazy, and would rather let mother nature grade it out as she sees fit. We angle the beds slightly downstream as Sepp recommends, but make a concerted effort to slow down the water to allow it to be absorbed. We have a lot of downed trees on our property that we can harvest, which is very helpful. The hugelkultur beds will certainly erode in time, but we hope to use this technique to help build soil and to buy us time, and eventually back up these terraces with stone or black locust trees (which we are currently fostering in our nursery). If we still have issues with Florida deluges undoing our soil efforts, we will likely implement some keyholing ponds to help control it. We don't know exactly what we are going to do with this acreage, but whatever it is, it will certainly require living soil. It will evolve as it evolves.

Just another perspective on hugelkultur and terracing, for what it's worth...

BTW, our slope is, at greatest, about 15 - 20 degrees.

IIRC, in Sepp's three older videos, most of the hugel beds were in the open, on slightly sloping fields.
These beds were pretty small by current hugel tech standards, probably about 3-4 feet tall.
As I understand, Sepp builds them much bigger now.

@Dave: That's good info on the increased growth rate. Do you think it's because of the increased water-holding capacity, or nutrients, or something else?

@Barbara: Like Joshua said, keep the terraces (with or without hugel beds) sloping slightly downlhill so you don't get water undercutting your terrace.
And it really does seem to depend on soil type and stabilizing factors (underlying soil strata, trees & herbaceous plants roots holding ability, etc).

The Krameterhof is pretty steep in places, so you can go quite far. I would say if mountain goats like it, it's too steep.

Cam : I believe the trees and shrubs grew better as a result of the edge effect and loosened soil compared to the compacted granite. I also added a lot more supporting species on the hugulswale. The trees in the field did have supporting plants as well but not connected to as big of a support system. Also it seemed as if the mycorrhizal network was more prevalent which means more sharing of the nutrient that are already there. Water holding capacity was super increased as well Im sure. I am currently increasing the crescent shaped mounds of woody material around the guilds in the "field" to stop and sink more water and create more edge effect. I am on a steep south facing slope with little precip. at 6300'

Thanks for the great discussion and good ideas about "Hugulkultur type swales" and terraces. I do have fairly good soil a sort of sandy loam mixed with a healthy share of rocks and I was planning to use mostly brush and the dead aspens we have lying about here. The idea of waste straw bales seem good too. Yes, you all are right that getting the slope within the terraces might cause some undermining of the Hugul swales, I will have to work on that to avoid catastrophic failure of the bank.... well I will try experimenting. Also, if its possible, it would be so great to see a photo or two of what you all are doing or have done! Sometimes a picture really helps to clarify what you are explaining. Thanks again.

It is important not to confuse terraces and hugelkultur. Building a terrace is a very different situation than building hugelbeds. Terraces are for steep slopes and are a very tricky matter. If the terrace is not built properly it can cause big landslides. If the slope is steep it is important to seek professional help. It is also important to remember that hugelbeds break down and shrink over time. You don't want your terraces to be degrading over time!

Building terraces depends upon the geology, biology, and climate of a region. It is VERY important to take all of these factors into account. Furthermore proper terraces take many years to develop. Good terraces take 8 years to build up to the right conditions. Terraces also must be done in steps, building just one terrace first. Then it is planted and stabilized, thinned and then the next terrace can be built. Step by step is important to remember as terraces are a very tricky matter. Steep slopes have great potential for Catastrophe! It is best to consult a professional.

Dave: Your question on wood to soil ratio is a good one, the answer varies considerably. Sepp is only using what he has available on site, so this determines the ratio to a large extent. Different hugelkultur material provides different benefits and as always the more mixed the better. If you are using smaller material it will break down quicker, whole logs take about 8 years to decompose in a hugelbed. The question of trees on hugelbeds and highbeds is also a good one. Basically the less wood in a hugelkultur the more appropriate it is for trees. If you have lots of wood mass in a hugelkulur it will break down more over time, destabilizing the tree. If your hugelbed does not have much wood, or you have a high bed with no wood, then it is most appropriate for trees. Great to hear that you have had such great success! The hugelbed provides several bennefits for trees, the only concern is that as the material breaks down it may destabilize the tree. Because you don't have much wood in your hugelswales I don't think you will have much trouble with destabilizing over time.

Judith, Johnny, Zach and Team Holzer AgroEcology