Assessing Soil Compaction on Forest Inventory and Analysis Phase 3 Field Plots Using a Pocket Penetrometer

摘要

Soil compaction is an important indicator of soil quality, yet few practical methods are available to quantitatively measure this variable. Although an assessment of the areal extent of soil compaction is included as part of the soil indicator portion of the Forest Inventory & Analysis (FIA) program, no quantitative measurement of the degree of soil compaction is made. We tested a small, lightweight pocket penetrometer that measures soil compression strength as a simple, quantitative measure of the degree of compaction of mineral soils under forested conditions. Soil compression strengths were significantly higher in compacted trails and areas than in adjacent undisturbed locations. In contrast, no significant difference in soil compression strength was found between rutted trails and adjacent undisturbed areas. A protocol is suggested for further pilot testing of this device as part of the soil indicator assessment. The main disadvantage of this device is that many of the compacted soils had compression strengths higher than the maximum measurable value of 4.5 tons/ft(sup 2). Despite this limitation, this device can rapidly and easily distinguish between compacted and uncompacted areas in the field. Time previously spent by field crews trying to identify qualitative evidences of compaction can instead be used to provide a quantitative measure of the degree of compaction, which would strengthen the analysis and interpretation of the soil quality indicator.