Right, it was interesting how they said that the reason for the shift was because the plant would deplete the soil of nutrients. I have no idea if they're correct or not, though I do see some gardening things that say if you grow it, it does need regular fertilizer, which would follow (others call it low-maintenance, though, so who knows). Some types of soil depletion can be fairly easily mitigated by crop rotation or fertilizing or growing/plowing under a cover crop for a season to replenish the soil. Without knowing what it is depleting, though, or how a farmer in that region deals with that, it's hard to guess what the long-term effects are or if they go away over time.

There do appear to be various species!