, physical properties and crop yield in Oxisol and Alfisol.
The expression of the current bulk density as a percentage of some reference state or of maximum bulk density is referred as 'degree of compactness' or 'relative compaction', and has been useful when characterising the soil compaction and crop response in different soil types (Carter 1990; Hakansson 1990; Lipiecera/.
The normalisation of the bulk density denotes the 'degree of compactness' or 'relative compaction' of the soil (DC) and is defined as:
Under standardised conditions this relationship is measured using the Proctor test, and varies with texture and other properties, so other concepts (Carter 1990; Lipiec and Hakansson 2000) including relative compaction and degree of compactness are discussed below.
However, the concept of relative compaction is closely related to macroporosity and crop yield (Carter 1990; Lindstrom and Voorhees 1994).
A specialized sheepsfoot roller compacted the treated section of the road to a minimum of 95 percent relative compaction
. A smooth drum roller completed the compaction, and the final grade was accomplished by trimming with a blade.
The field core soil BD values and maxBD values (from the compaction test) were used to obtain the relative compaction (RC):
Correlation coefficients between pairs of soil properties of compaction for 0-0.20m depth (P<0.01) TOC, total organic carbon; POC, particulate organic carbon; ROC, resistant organic carbon; BD, bulk density; PR, penetration resistance; WC, water content; maxBD, maximum bulk density; CWC, critic water content; RC, relative compaction; SI, structural instability Sand Clay Silt TOC POC ROC Clay -0.7980 1 Silt -0.9638 0.6085 1 TOC -0.6695 1 POC 0.7376 1 ROC -0.7598 0.7670 0.7897 1 BD 0.5509 0.5743 0.6552 0.5949 PR WC 0.5656 maxBD 0.7928 -0.7765 -0.6502 -0.6302 CWC -0.7582 0.7060 0.5065 0.6546 RC -0.5603 0.5314 SI BD PR WC maxBD CWC RC Clay Silt TOC POC ROC BD 1 PR 1 WC 0.5447 -0.7862 1 maxBD 0.5137 1 CWC 0.6517 1 RC -0.8101 0.5391 1 SI Fig.
To reach a specified density of 95 percent relative compaction
, the initial rolling must be completed before the temperature of the fresh mat drops below 290 [degrees] F.