bulk density values varied across soils showing the expected trends with increasing soil water content (Figure 1). Reference [26] explained this behavior where bulk density increased until peak critical values were attained and then decreased with further increases in soil water content. Variation occurred among the soils in both the shape and position of the relationship. Piarco showed responses in the lower moisture range, with a moisture content >15% resulting in reduced bulk density. The bulk density values for Piarco and Chagaramus was always higher and lower respectively, than the other soils regardless of moisture content. This finding is in agreement with other works on similar soils [26]. These authors observed that the clay soils had
greater aggregate stability than the sandy soils. They also inferred that lower bulk densities are associated with a higher degree of aggregation in soils with high clay and organic matter contents. They explained that the relative amount of organic material acts to dilute the soil mineral matter effectively lowering density and reducing aggregate slaking and buffering the effects of compaction. Minimal variation of bulk density with water content was observed for Chagaramus.