A field investigation on the tilled layer soil in Nanjing region revealed two distinctive types of soil structures: machinery-till related and biological related structures. The former was featured with relatively large-scale disintegrated soil clods，having a negative effect on corn root development, the later was characterized with the presence of bio-channels. The spatial topological relations among soil particles, encompassing different scales from primary soil particles to relatively large-scale soil clods as a result from tillage operations, were defined as soil macro-structures. Soil macro-structure brought forward a scope that was not to be coped with agricultural or chemical approaches. Soil tillage affects soil macro-structure, which further affects soil biological performances in different scales.