| Abstract: | Soil compaction was assessed in terms of soil strength as measured with a penetrometer. Penetrometer resistance was measured on virgin soil and on the same soil after one and after five passes of a 7,610 kg tractor. Also, comparative studies were made of strength profiles of soils in arable fields and in adjacent areas of virgin soil. The strength of virgin soil was increased by wheel traffic and agricultural operations in all cases. The increase in soil strength was significant down to 0.3 m, which is considerably greater than the normal depth of tillage in the area (0.05 m). Reduction in the coefficient of variation of penetrometer strengths after the passage of wheels was taken as evidence for associated losses of soil structure. Virgin soils provide important reference sites for assessing the impact of agriculture in an area. |
