Soil organic carbon content and soil structure quality of clayey cropland soils: A large‐scale study in the Swiss Jura region

Summary

This large-scale field study across the Swiss Jura region examined whether the commonly recommended SOC:clay ratio threshold of 1:10 remains achievable in clayey soils (16–52% clay content). Contrary to expectations, the authors found that the relationship between SOC and clay content held across the clay range studied, and that reaching acceptable SOC:clay ratios was not constrained by high clay content. The findings suggest that soil texture determines potential SOC content, whilst farming practices determine the actual SOC:clay ratio achieved, regardless of clay content.

UK applicability

UK clayey soils face similar structure degradation challenges as those in the Swiss Jura region and operate under comparable temperate cropping systems. These findings could inform UK soil carbon recommendations and farm management guidance, suggesting that current SOC:clay ratio thresholds may be applicable to UK clay soils without requiring significantly modified targets based on texture alone.

Key measures

Soil organic carbon (SOC) content; soil structure quality assessed via CoreVESS method; gravimetric air content; gravimetric water content; bulk density at −100 hPa; soil structure degradation index; clay content (16–52% range)

Outcomes reported

The study measured soil organic carbon (SOC) content, soil structure quality (via CoreVESS method), gravimetric air and water content, bulk density, and soil structure degradation index across 96 fields in the Swiss Jura region with clay contents ranging from 16% to 52%. The research evaluated the relationship between SOC content, clay content, and physical soil properties under similar cropping practices.

Topic tags