Fertilizer
From Captain of Industry Wiki
Fertilizer is a crafted liquid product used to restore Fertility in the Farm, Irrigated Farm, Greenhouse, and Greenhouse II. Along with the growing of
Green Manure, it is the only method of restoring Fertility levels.
In the mid-game, Fertilizer I is generally produced using the the Ammonia byproduct from Sour Water stripping and Nitrogen from the Air Seperator. It can be enhanced by adding Limestone and Sulfur to
Fertilizer II. Alternatively,
Fertilizer (Organic) can be sustainably produced through green methods using Compost.