土壤
tǔrǎng · HSK 7
soil
🌱 土壤 = 土 earth/dirt + 壤 loose loam; both halves mean ground, doubled up for soil
土 (tǔ) is the everyday word for earth or dirt, and 壤 (rǎng) means loose, fertile loam. Stacking two soil-words makes 土壤, the specific term for cultivated soil. The 土 radical sits on the left of 壤 too, marking it as earth-related.
土 — pictograph of a mound of earth on the ground
土 is a pictograph showing a lump or mound of soil resting on the ground line. In oracle bone script it depicted an earthen heap, sometimes interpreted as an altar to the earth god. The meaning has remained stable: earth, soil, or ground.