noun
Refers to the dark organic material in soil formed by the decomposition of plant and animal matter. Used in gardening, agriculture, and soil science contexts.
腐植土は植物の成長に欠かせない。
Humus is essential for plant growth.
この畑の腐植土はとても豊かだ。
The humus in this field is very rich.
腐葉土 is leaf mold made from decomposed leaves, a type of organic matter that contributes to humus formation; 腐植土 is the more general term for humus.
Compound of 腐 (ふ, 'decay') + 植 (しょく, 'plant') + 土 (ど, 'soil'), literally 'decayed plant soil'. The reading is on'yomi.