Kommentar zu Wajikra 25:4

יהיה לארץ [A SABBATH OF STRICT REST] SHALL BE UNTO THE LAND [or SOIL] — unto the fields and vineyards.

שבת שבתון יהיה לארץ. You have to refrain totally from working the land, including preparatory work mentioned in detail by our sages in Avodah Zarah 50.

For the fields. Because if not [for this limitation], even making a hole in the earth [for non-agricultural purposes] would be forbidden. Therefore, Rashi explains: “For the fields and vineyards.” His proof for this is that it is written, “You shall not plant your field and you shall not prune your vineyard,” indicating that only fields and vineyards are forbidden, whereas making a hole is permitted. You might ask: Why does Rashi not explain this above where it says “The land shall be at rest”? The answer is: [If he said it there] you might object, how does he know that? Perhaps even digging the earth is forbidden? Here, however, it is explicitly written a “field” and a “vineyard.”