I heard on the PermaculturePodcast with Scott Man that hugelkultur beds are usually not used in more tropical climates because, in part, for fungal issues. My bigger concern would be termites, which can be counted on to consume any nontreated wood in contact with the ground here in Florida. Not actually sure if that would even be a problem or if there are other possible problems. I've considered doing trench biochar instead which would have the added benefit of killing the invasive sword grass(not sure what it's really called but the tips of this grass can draw blood as well as any thorn). The goal is to increase the soils water retention, and more important, the ability to retain the nutrients that literally gets drained away in this sandy soil. Any advise is appreciated.
Looking at the end grain of a piece of charcoal one sees cells or pockets that have been shown to trap air and water nutrients within their structures,
very much like the cell walls noted within the center of Bones and Corals
Having said that there is a large difference between the pore structure created in Charcoal and the pore structure created in bio-char !
Also recent excavations near Williamsburg Va. and Ogdensburg New York have shown large fragments of the palisade walls of pre- revolutionary
forts in these quite different locations !
From these sites it can be clearly determined that whether or not most wood rots faster in more tropic locations all forms of charcoal appear to
last longer than the wood mass they are made from !!!
This, and pre-historic use of Terra Peta, or dark earth , seems to show that the use of charcoal /Bio-char will extend the useful range of hugelkulture
into much more tropical climates !
For the good of the Crafts ! Big AL
Success has a Thousand Fathers , Failure is an Orphan
I've used a combination of charred wood, fresh cut trees, and partially rotten material to make several hugels and as the core of my raised beds in the greenhouse. This is purely anecdotal, but I've noticed the areas with more of the charred wood have not rotted down and settled as much as the areas of predominately fresh and rotten wood. This seems to indicate that the charred wood will last longer in the soil. I scavenged all of this wood from slash piles on the property. It seems like you could get the best of both worlds in your situation by utilizing a combination of charred wood, bio-char proper, and inoculating the whole mess with plenty of compost/tea. You could do raised or sunken beds like this, and create all sorts of beneficial micro-climates to play around with!
Making char is pretty contraption intensive. Best case scenario, gasifier byproduct. But if you could just get it when its being discarded...
Lots of people here in rural michigan heat their houses with outdoor boilers. Lots of you use hi efficiency woodstoves. These things generate char and ash.
Char is carbon, (but not for purposes of C/N ratio) water absorbent, microbiota apartment house. Ash is potash (carbon and potassium). Now if only you could add Nitrogen, Phosphorus, Humus, some micronturients and huge mess of active microbiota, you'd have the perfect product.
We collect charcoal from a local restaurant/brewery where they make wood fired pizza (we originally began that relationship to pickup spent brewing grains for animal feeds). We then use it in bedding (most of it gets saved for winter, but the poultry use it year round)
Its the perfect match! The char is a veritable sponge at grabbing ammonia. I swear it can pull it out the air itself. A layer of that between the carbon diaper layers, and there will be a lot less wasted nutrients and a more pleasant barn. The char, sitting in contact with nutrients and bacteria is now biochar. Its layered in between manure, straw, sawdust, anything else I can throw in there. It will be slow composted, then dug up and spread on the fields: a complete soil meal.
As an aside, I prefer higher carbon bedding with higher nitrogen poopers. Cows and sheep hardly ever merit biochar. They are bedded with rained on Hay, wood chips, and things in the 40-100 C/N range. Bulking/air accessibility is important. Poultry need very-high-carbon: sawdust, shavings, cardboard, straw and CHAR! Pigs are in between, and they get good use out of straw.
Anyway, its my guess that char is best value as a byproduct on the inflow, and I'm confident its many times worthwhile as a bedding agent on the outflow.