If these ammonia rich soils catch on amongst our formites I am sure methods to deal with the new tank start up will develop too.
As Ceg has already said the dry start method is well tested & using an already mature filter will help no end too.
Trickle filters are very effective & fast at reducing ammonia levels & are extremely easy to build even if they are just a temporary (unsightly) method to employ while the tank settles in.
In my humble opinion soil substrate is in itself a method for tank start up.
I can only speak from personal observation but I have always find that the ammonia given off during mineralisation is more than adequate to cycle a filter. I suppose this is in effect fishless cycling. I also add water conditioner that contains beneficial bacteria in the hope that it will speed the process up; but I suppose this is controversial. Either way it can't hurt and the product I use only costs a few quid.
I have found that levels of ammonia stabilize within acceptable levels quite quickly, often within a few weeks, which is borne out by others experience. So although it can take up to 2 months before mineralisation is complete - and therefore for the soil to stabilise as "aquatic sediment" - it is not usually necessary to wait anywhere near that long before adding fish etc. In this respect it probably helps to think of mineralisation and tank cycling as two separate but mutually inclusive processes.
Usually I have gradually built livestock levels to full capacity over the period of a month or so without any problems.
I am convinced that planting heavily from the outset also helps. The use of macrophytes as water purifiers is well documented and they help to reduce ammonia and other chemical compounds to non-toxic levels.
Also planting heavily from the outset probably helps to reduce the length of time it takes for the submerged soil to stop giving off ammonia since macrophytes release O2 and organic compounds through their roots which will greatly increase microbial activity, and therefore nitrification and denitrification, in the forming sediment. The existing bacteria on plant roots will perhaps also help seed the sediment, speeding the process on its way.
Eventually an equilibrium is reached and the soil substrate will actually start to absorb ammonia/ammonium from the water column where it will undergo nitrification. A substantial water change at this point is usually all that is needed to make the tank habitable to fish etc. This combined with dense planting and even a partially cycled filter probably prevents ammonia reaching toxic levels, even when gradually adding critters and increasing the bioload.
I think there is often a tendency to overcomplicate matters when it comes to soil substrates, I am sure it has something to do with ideological barriers. But as I have said before it’s relatively easy to get the best from them.