Hi,
I have bad soil and want to turn it into good soil.
ReTe craft magic works if and only if there is a technological process suitable for ME by which this can be achieved. Otherwise, MuTe is required, since this soil is bad and not good, similar to the way transforming a white sheep into a spotted sheep is MuAn rather than something else. Alternatively, one could argue that CrTe is required, since this particular transformation is actually an improvement; vis can make this improvement instant and permanent. A magus does not need agriculture or any other skill to make the ReTe spell happen, in sagas where it is permitted to happen; knowledge of Terram and Finesse serve instead. Of course, the magus would need any raw materials needed to make the soil more fertile, and the ReTe spell might then be something like ReTe(Aq,An,He). I doubt that SotA in ME allows this application of ReTe.
Note that particular kinds of bad soil might do very well with ReTe or similar interventions. Is my soil too rocky? Destroy the pebbles or grind them to dust! Etc. I can use a peasant skill like agriculture to decide if this is true, but I can also use Intellego.
What about a Damascus sword?
Again, I don't need to be a swordsmith; ReTe is sufficient. But I do need raw materials. Note that I consider the text in Covenants (iirc, but it was somewhere) about needing carbon to be a botch, since carbon does not exist in Mythic Europe. /2 Mundane craftsmen need to heat, quench, fold, whatever, but magi do not worry about getting the right mix of oxygen, carbon, sulfur, vanadium, etc., and can skip these mundane processes through a magical one. OTOH, magi do need the right kind of high quality iron to start with, and do not know how to add oxygen, carbon, etc to ordinary iron to make just the right kind of alloy for their steel.
A magus might not even need to know that Damascus swords exist to create an equivalent sword or better, to the limit of what is possible. Terram covers intimate experience with iron, Rego covers manipluation of iron, and Finesse covers exquisite craftsmanship with ReTe.
I'm sure others disagree, but that's how I see it.
Anyway,
Ken