noun
General term for soil or earth, often used in agricultural or geological contexts.
この地域の壌土は野菜作りに適している。
The soil in this region is suitable for growing vegetables.
noun
loam; loamy soil
Specifically refers to loam, a fertile soil with a balanced mixture of sand, silt, and clay. In Japanese soil classification, it indicates a clay content of 25–37.5%.
壌土は水はけと保水性のバランスが良い。
Loam has a good balance of drainage and water retention.
粘土 is clay or clay soil, with a much higher clay content than 壌土.
Compound of 壌 (jō, 'soil, earth') and 土 (do, 'soil, ground'). The reading is on'yomi. The specific sense of 'loam' is a technical usage in soil science.