Soil Compaction

Compaction happens when axle loads exceed the soil's bearing capacity, especially on wet soils. A fully loaded grain cart or slurry tanker can apply 10–15 tons per axle; at field capacity moisture, that pressure propagates 50–60 cm deep and can form a dense plow pan just below tillage depth. Once bulk density exceeds ~1.6 g/cm³ for loams or 1.8 g/cm³ for sands, roots physically cannot penetrate and must detour around the compacted layer, shrinking their effective exploration volume. USDA NRCS research documents 10–25% yield reductions in compacted corn and soybean fields, with losses exceeding 50% on severely compacted headlands.

Diagnosis relies on three tools: a penetrometer (readings above 300 psi / 2 MPa indicate root-limiting compaction), visual root inspection (horizontal, flattened, or J-rooted growth signals a dense layer), and infiltration tests (healthy soils absorb 25–50 mm/hour; compacted soils under 10 mm/hour). Pennsylvania State University Extension recommends mapping compaction by zone rather than assuming uniform damage across a field.

Prevention beats remediation. Controlled traffic farming confines wheel tracks to permanent lanes covering only 10–15% of the field, protecting the remaining 85%. Staying off fields above 80% field capacity, reducing tire pressure to 1 bar or lower with IF/VF tires, and maintaining living roots through cover crops all reduce compaction risk. When damage is already done, deep ripping with a subsoiler (40–50 cm deep, performed when soil is dry) combined with a fibrous-rooted cover crop like tillage radish is the most cost-effective recovery path. WiseYield logs field operations and flags high-risk passes when soil moisture sensors indicate wet conditions.