The poem sets two ways of seeing a piece of land against each other. One is the language of a contract, where a field is a parcel with boundaries and a value. The other is everything that actually lives there, which the contract has no way of counting. The phrase "without any reckoning" carries that gap: the living things aren't just overlooked, they fall outside the system of measuring altogether.
The second stanza is more cryptic. "Poor as the shale" suggests thin, unforgiving ground, and the odd pairing with "the business of visions" makes me think of two kinds of worth that don't fit the ledger: a barren-looking landscape, and imagination or spiritual seeing. The speaker doesn't state a feeling outright, but the tone is quiet and a little wry, with a gentle sympathy for what goes unvalued. The mood is spare and contemplative, like standing in an empty field and noticing how much the paperwork leaves out.