The Clegg Impact Tester was shown to be useful in assessing soil strength but not compaction on a range of agricultural soils. Similar responses to increasing water content after compaction was observed for surface hardness, compared to bulk density and penetration resistance. Peak values and their associated critical moisture contents varied among soils and indices, with clay mineralogy and organic matter content having the most influential role.Surface hardness showed greater responsiveness to moisture content. Further correlation of this instrument to growth indices would provide needed information to improve its applicability to agricultural soil management.