does anyone have a Canadian source for calcium bentonite? I checked a local clay supplier, but they do not. The only thing I've found is Koi clay, but all the online suppliers are out.
Hmm. Redart is very plastic by itself which is why it makes a good pottery clay. Bentonite is a lot more slippery though so I could see it making it easier to push the mix through a mesh which I've never tried to do. The stuff is like axle grease when it is wet so one of the least pleasant substances I've worked with. In fact, one of its many uses is as a lubricant.Thanks for the detailed response Brent. I think the bentonite is used to give the clay more plasticity. To hold it together better.
I've considered that, but I think over time the clay would just was into the sand and fill the cavities. Then you'd have something more like concrete. In nature, fungi and bacteria secrete "glues" that bind small soil particles together into larger aggregates that lets the soil maintain an open texture. When I say 'pseudo sand' I'm talking about clay particles that are glued together into larger sand size aggregates. The soil is still clay and chemically behaves like clay, but the physical structure allows air and water to flow through it more like sand. The theory behind adding sugar and starch and then clumping or the media to force (temporarily) an open physical structure. We hoped the sugar and starch would supercharge growth of bacteria and fungi so they would 'glue' that hard-won physical structure in place so they didn't just dissolve into the voids over time.What would happen if you were to fill the space between the dried clay cubes with a coarse beach sand (or well washed construction sand)? Would the clay and sand blend long term, or would the sand maintain the drainage channels between the clay?
If it blends over time, would that give you the soil texture you are looking for?
Of course we should be careful about over generalizing what "tropical soil" does but it does both. Compared to the fluffy soils we typically find in temperate forests and grasslands, these tropical soils are compacted crap and infiltration rates are nothing compared to rich organic soils. But they are open enough that water does infiltrate the soil (and remember there is a LOT of water to go around in those forests (at least for now). Also, there is an abundance of ants, termites and other critters constantly tunneling through. With the help of those microbial glues, they stay open longer. That creates a LOT more volume for subterranean arthropods to occupy. That's where organic substrates like ABG have clay substrates beat hands down, but if we can solve the texture problem, we'll be adding a lot more function to our clay substrates.In the tropics, does water drain through the laterite soil or does it run along the surface? I always wondered about this last one.