Would it be possible to add a crop, such as Crimson Clover (https://en.wikipedia.org/wiki/Trifolium_incarnatum) or Hairy Vetch (https://en.wikipedia.org/wiki/Vicia_villosa) that serves no real purpose other than boost nearby crops, and have drops that can only be used for compost?

https://en.wikipedia.org/wiki/Green_manure

Interesting. I do like the idea of adding a bit of permaculture/veganic/stock-free concepts into the mod.