noun
organic fertilizer
Refers to fertilizer derived from natural organic matter, as opposed to chemical fertilizers.
この農場では有機質肥料だけを使っている。
This farm uses only organic fertilizer.
化学肥料 is chemical fertilizer, while 有機質肥料 is organic fertilizer.
Compound of 有機 (organic), 質 (quality/matter), and 肥料 (fertilizer).