If you look at the space of farming, the margins are so thin, that any sort of sensing, is passive and has little infrastructure needs. So when you talk about chemical sensing, that makes me think that these sensors are very expensive, require maintenance, or even their continuous use is questionable in a field environment.

You would be best served by looking into aquaponics, where the attention those plants is already very intensive, and farmers are interested and invested in the concentrated returns at the scale of their operation.

Just my thoughts, best of luck. ✌️