We were looking at the spell The Forgiving Earth (ArM5 p156) and... something seems wrong about this spell. Didn't see errata for it.
It's ReTe 20 (Voice, Sun, Part) and is using the Base 2 "Control or move dirt in a slightly unnatural fashion" guideline. But the effect weakens earth in a 15x15 pace area making it as loose as plowed earth.
The effect seems to want to be an application of Rego craft magic to duplicate the effects of Profesion Plowman or similar. But that shouldn't have Sun duration; it should be Momentary.
The written effect doesn't actually move or control the dirt; it changes it to another type of natural earth... which is the Base 2 Muto Terram guideline. And would need a Sun duration.
Am I missing something or does this need an erratum?
Yes, I recently pointed this out to David for the errata, as well as mentioning that the word "weakens" isn't really appropriate since this is plowing rather than PeTe weakening. And as ReTe craft magic, Momentary would be the Duration.
The Target also seems iffy. It's Part target... but that should reasonably be part of an Indivdual of dirt (10 cubic paces). Instead it's effect is described as 15 paces by 15 paces... which would be everything in Voice range and much more than part of an Individual.
I haven't used this spell in my saga yet, but I can see where "weaken" might be ambiguous. Perhaps use "loosen" instead.
My understanding is that the spell affects a part of the Earth by basically minutely shifting/shaking the packed soil so it is no longer so tightly packed.
Normally when ploughing only the turned soil is loosened, with it still tightly packed between the furrows. This spell produces no furrow but loosens the soil in the entire area.
Huh??? You seem to have made three math errors. First, there is +1 size, so you're looking at 100 cubic paces of dirt, not 10 cubic paces. Second, 15 paces by 15 paces is an area, so it is fine. It's just that the book has left figuring out the depth to you. 15 x 15 x depth = 100 paces. So depth = 4/9 paces = 4/3 foot, so just over a foot. When I look up the moldboard plow, I see it went to about 12 inches of depth at a maximum, so 4/3 foot is pretty close when using nice numbers for the area. Third, Voice range without shouting would extend out 15 paces from you, which is an area of 225pi square paces, rather than 225 square paces, so pi times as much area as this spell.
For the question of furrows, perhaps include a note about a variation of the spell which produces in lines? Though you would be looking at a 1 x 225 pace line with the depth of 4/3 foot.