This seems to be another tax gimmick (is not everything about the income tax a tax gimmick?), that can be used by owners of agricultural land. It’s called a “legacy nutrient deduction,” and if I understand it correctly, when you buy farmland, your purchase includes the fertilizer resident in the soil. Over time, the quality or quantity of fertilizer degrades, so you can deduct the loss in value. It’s not exactly “land” as Henry George envisioned it*, and it does open some opportunities for clever and affluent folks. Who otherwise might be engaged in productive tasks.
I do wonder whether, if glyphosate leeches out of the soil, that might increase its value and perhaps should be taxed.
*Or maybe it is. “Your land itself is not quite so good. You have been cropping it, and by and by it will need manure.”