The oracle bone form is a lump of earth sitting on a baseline — a clod, or an altar mound raised from the soil. The horizontal at the bottom is the ground itself; everything above it is the earth you can pick up. It became the radical in almost every character about ground, walls and places: 地 (ground), 场 (field), 城 (city wall).
土地 is land, and 本土 is one's native soil. 土 also carries a wry modern sense: calling something 土 means unfashionable, countrified — the opposite of 洋 (foreign, imported). The old five elements name it 土 as the steady middle, the one the other four turn around.
A mound of EARTH pressed onto the ground line. Two strokes of soil, one of ground.
土 and 士 (scholar) differ only in which horizontal is longer. In 土 the bottom stroke is longer; in 士 the top one is.