Livestock products from grass contributed €24 billion to the Irish economy in 2011. Mismanagement due to pressure to intensify production results in soil quality deterioration and reduced productivity. This study assessed soil C content (0–10 cm) over a range of land use management from 20 arable crop farms and 20 grassland farms in Ireland. Visual Evaluation of Soil Structure (VESS) was used to score (Sq) each field. The average Sq score was 2.15 for arable land and 2.24 for grassland, with no significant difference between land uses. However, fields under minimum tillage had a significant lower Sq (better soil structure) than fields under conventional tillage. Under grassland management, an increase of Sq (decrease in soil structural quality) with intensification of management was found (R² = 0.7). The soil C ranged from 15 to 53 g C kg⁻¹ soil under tillage management and from 37 to 104 g C kg⁻¹ soil under grassland. It indicates a greater capacity of C storage under grassland. There was a negative correlation between Sq and soil C both under arable and grassland (lower C content with decreased quality). The results indicated that soil management was largely sustainable in term of soil structure (Sq score), but if management intensity increases, many farms could decrease their soil quality.