A lasting injury is done by ploughing land too wet.
—S.L. DANA, 1842
We’ve already discussed the benefits of cover crops, rotations, reduced tillage, and organic matter additions for improving soil structure. However, these practices still may not prevent compacted soils unless specific steps are taken to reduce the impact of heavy loads from field equipment and inappropriately timed field operations.
The causes of compaction were discussed in chapter 6, and in this chapter we’ll discuss strategies to prevent and lessen soil compaction. The first step is to decide whether compaction is a problem and which type is affecting your soils. The symptoms, as well as remedies and preventive measures, are summarized in table 15.1.
TABLE 15.1: Types of Compaction and Their Remedies | |||
|---|---|---|---|
| Compaction Type | Indications | Remedies/Prevention | |
| Surface Crusting | Breakdown of surface aggregates and sealing of surface Poor Seedling Emergence Accelerated runoff and erosion | Reduce tillage intensity Leave residues on the surface Add organic matter Grow cover crops | |
| Plow layer | Deep wheel tracks Prolonged saturation or standing water Poor root growth Hard to dig and resistant to penetrometer Cloddy after tillage | Plow with moldboard or chisel plow, but reduce secondary tillage Do primary tillage before winter (if no erosion danger exists) Use zone builders Increase organic matter additions Use cover crops or rotation crops that can break up compact soils Use better load distribution Use controlled traffic Don’t travel on soils that are wet Improve soil drainage | |
| Subsoil | Roots can’t penetrate subsoil Resistant to penetrometer at greater depths | Don’t travel on soils that are wet Improve soil drainage Till deeply with a subsoiler or zone builder Use cover crops or rotation crops that penetrate compact subsoils Use better load distribution Use controlled traffic Don’t use wheels in open furrows | |