SOIL PHYSICAL-PROPERTIES AS INFLUENCED BY INDUCED COMPACTION UNDER LABORATORY AND FIELD CONDITIONS

Soil compaction changes the ability of soil to hold water, decreases i nfiltration rate and saturated hydraulic conductivity, and increases p enetration resistance. The compaction characteristics of a clay loam w ere studied under various compaction loads and antecedent soil water c ontents. Soil water content had a more pronounced effect than load. Th e penetration resistance varied with water content, whereas saturated hydraulic conductivity decreased with increase in the bulk density. Th e compaction effects were more pronounced in the surface 0.1 m, but we re negligible at 0. 1-0. 2 m depth when compaction was employed at ava ilable water levels up to 40%. The narrow range of suitable soil moist ure for tillage operations requires the use of appropriate practices t o reduce spatial variability in surface soil moisture.