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Bulk density is a measure of soil compaction, which may affect water holding capacity, infiltration, and nutrient availability (Doran and Jones, 1996).
How to operationalize the metric
Method of data collection and data needed to compute the method:
Measuring bulk density requires soil water content that is at normal field capacity. Field capacity is the soil moisture or water content held in the soil after drainage of excess water. Soil to be used for analysis should not be very dry and a small deviation from field capacity will not bias the results (Anderson and Ingram, 1993; Doran and Jones, 1996).
Procedure for measuring bulk density for non-stony soils:
- Remove 1-2 cm of surface soil from the spot where samples will be taken and level the spot.
- Drive a 5cm diameter thin sheet-metal tube of known weight (B) and volume (V) 5cm into the soil surface.
- Excavate the soil from around the tube and cut the soil beneath the tube bottom.
- Trim excess soil from the tube ends.
- Dry at 105ºC for 2 day, and weigh (C)
Unit of analysis:
The unit of analysis of bulk density is g/cm3. To calculate bulk density from the above measurements (Anderson and Ingram, 1993):
(Excerpted from Anderson and Ingram, 1993, pp. 95)
Limitations regarding estimating and interpreting: