The vagueness of the first statement (being under the protection) works fine, because it is up to everyone in game exactly what that means and how it applies, while the super specificness of the second one in describing a game action "cast Bless Crops" rather than something equally general like "The local priestess will ensure Ernalda's blessing are upon their lands" where the exact nature of this could be worked out in game.
It might be an artifact from before the Bless Crops/Pregnancy rules were clarified, but even then, it is uncertain whether it would work. How many hides belong to the village the priestess and her assistant are responsible for? Ten? A hundred? The number of runepoints becomes unfeasible fast, even with assistants.
One way of dealing with this which I don't think is explicitly against the rules (correct me if I am wrong) would be to have the local priestess lead the blessing of the fields, just as is described in many more local volumes (the fertility stones in sun county etc) and cast the Bless Crop spell in cooperation with the owner of the fields. The Priestess (or one of her assistants) hold the knowledge, but the rune points are supplied by the people who will actually be working the fields. Just like many people can help with enchanting items and other larger ceremonies. I feel that way, the rules could stand as written, without the priestess having to lock up her own rune points. And the family members could sacrifice a rune point per hide, which would not be too heavy a burden if spread among several people.
I like this. I think that the priestess should be out blessing every field, and support the ritual to make it solid aka Bless Crops cast by the Initiate.