The interrelationship between the cultivation of crops and soil‐strength dynamics

Summary

This field study on reclaimed lignite-strip-mine soil in eastern Germany investigated how two perennial crops with different water-uptake capacities—lucerne and wild rye—alter soil water dynamics and consequently soil penetration resistance over a 22-month period. Lucerne, with higher dewatering capacity, created water tensions exceeding the permanent wilting point for up to 20 weeks, leading to predicted penetration resistance >15 MPa and exceeding accepted root-growth thresholds; wild rye maintained lower water tensions and penetration resistance throughout. The findings demonstrate that plant water extraction during growth cycles directly modifies soil mechanical strength, with potential implications for root development and soil workability in both agricultural and restored-soil contexts.

Regional applicability

The study was conducted in Germany on reclaimed post-mining soil, so direct applicability to UK farming soils may be limited. However, the mechanisms of crop-induced soil water depletion and resulting increases in penetration resistance are relevant to UK arable and grassland soils, particularly in drier seasons or where high-transpiration crops (e.g. alfalfa) are grown. UK practitioners should consider analogous effects in contrasting crop types and soil types, though local rainfall patterns and soil composition would require site-specific assessment.

Key measures

Soil water content, water tension (hPa), penetration resistance (MPa), permanent wilting point, water retention characteristics

Outcomes reported

The study measured soil water content, water tension, and penetration resistance under lucerne and wild rye crops over 22 months on restored lignite-strip-mine soil. It assessed whether differential crop dewatering capacity affects soil strength and exceeds critical root-growth thresholds.

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