It might even have an herbem requisite...
Of course according to some ancient pre-Christian cultures, fertility was restored to the soil through ritualized acts of excessive sexuality- a method I'm certain the church would frown upon...
... and ritualized murder. And other rituals, taboos, and so on.
I wasn't going to go to any of this, but since we're here, all this seems like Faerie magics of one kind or another, exchanging vitality for fertility in ceremonies or small actions performed at various boundaries, especially between one season and another, but also at the boundary between hearth and field, work and rest, etc.
I'd be comfortable with a generic Creo ritual to create fertility and it could certainly involve such elements. There might even be Mysteries that let one use sexuality or sacrifice to reduce the vis cost of it.
I'm going to go out on a limb here and say that improving, for example, soil makes the soil thick, rich, and productive, probably giving a small bonus to the appropriate Covenants table. I'll use the basic guidelines for creating Terram.
So,
Enriching the Field
Base 1
Range: Touch
Duration: +4 Year. This is a Ritual.
Target: +4 Boundary. This also bumps to Ritual. An individual amount of soil is about 10 cubic paces, per p. 152. Topsoil is 2-8"; 10 cubic paces is enough for a garden, but not fields.
Level 25, Ritual.
The fields are traced by the magus, who must walk the whole of the bounds of the fields affected. The soil improves to best natural quality possible, and a bumper crop is likely, assuming normal rain and no other detrimental circumstances. The soil degrades naturally in following years.
Similarly, improving metal makes the metal a high quality example of iron or copper or whatever. It does not make steel or alloys. I'd think making steel is at least +1 magnitude.
Keep in mind the Sacrifice mystery from the neo-Mercurians allowed them to substitute pristine animals for vis.
Yeah. And using fatigue as vis through sex magic is within the scope of a Breakthrough Virtue (particularly if integrating Babylonian or Canaanite secrets and probably risking Infernalism).