noun
leaf mold; humus; mulch
Decomposed leaves and organic matter used as a soil conditioner or mulch in gardening and agriculture.
庭の土に腐葉土を混ぜて、花壇を作りました。
I mixed leaf mold into the garden soil and made a flower bed.
腐葉土でマルチング
Mulching with leaf mold makes it harder for weeds to grow.
腐植土 is a more technical term for humus-rich soil, often used in soil science; 腐葉土 is the common gardening term.
Compound of 腐 (ふ, 'rot, decay'), 葉 (よう, 'leaf'), and 土 (ど, 'soil'). The reading ふようど reflects a sound change from ふ + よう + ど.