TITLE:
Surface Hardness as an Indicator of Soil Strength of Agricultural Soils
AUTHORS:
Gaius D. Eudoxie, Dennison Phillips, Raymond Springer
KEYWORDS:
Clegg Impact Tester; Surface Hardness; Penetration Resistance; Moisture-Density Relationship
JOURNAL NAME:
Open Journal of Soil Science,
Vol.2 No.4,
December
31,
2012
ABSTRACT: Soil strength is an important quality
of agricultural soils prone to traffic. Surface hardness (SH) measured by the
Clegg Impact Tester (CIT) was evaluated as an indicator for assessing soil
strength. Proctor tests were performed on a diverse range of soils to examine
the relationships between bulk density (BD), penetration resistance (PR), SH
and water content. All three indices showed typical response curves with
increasing water content, with notable differences among the soils. Maximum dry
bulk density (MDBD), peak penetration resistance (PPR) and peak surface
hardness (PSH) showed values of 1.98 Mg m-3, 8.2 MPa and 248 Cmax
for Piarco, River Estate and Piarco respectively. Corresponding critical
moisture contents (CMC) were much greater for MDBD compared to PPR and PSH. SH
showed a significant positive correlation with PR, but not BD. Further divulgence
into the relationships between SH and other soil properties as well as crop
response will facilitate greater use of the CIT.