soil; soil quality
Refers to the nature or properties of soil, especially in civil engineering, agriculture, or geology. Often used in compound terms like 土質調査 (soil investigation) or 土質改良 (soil improvement).
The soil quality in this area is suitable for agriculture.
We conducted a soil investigation before construction.
soil mechanics
Compound of 土 (soil) and 質 (quality, nature). The reading is on'yomi, suggesting a Sino-Japanese technical term.