effects of dairy cow weight on selected soil physical properties indicative of compaction

The effect of treading by dairy cows of three different weights on soil physical properties was investigated under different soil moisture deficit (SMD) treatments in the south of Ireland. SMD was used as a readily predicable surrogate for volumetric water content. Animal treading in grassland ecosystems is known to affect soil and vegetation properties, which can influence agricultural system productivity. Treading action can result in reduced soil water infiltration and increased runoff. In Ireland short winter housing and early spring turnout are key elements of low cost grass based production. However, there is potential for soil damage as a consequence of animal treading during early spring and late autumn. This study shows that SMD is the main factor affecting changes in bulk density (BD), soil shear strength, penetration resistance (PR) and total porosity. At high SMD (dry), soil was less sensitive to trampling damage than at low SMD (wet). At SMD 0 mm, BD increased by 6.1% post trampling, whereas it only increased by 3.1, 4.0 and 0.5% at SMD 11, 14, and 29 mm, respectively. Average soil BD was 2.3% greater immediately post trampling, and 4.6% greater in the hoof marks. PR was significantly greater following trampling by the heavy weight cow compared with the light or medium weight cow. There was no significant effect of cow weight on soil water content or soil BD. The results indicate that forecasted SMD can be used as a management input for rotational grazing systems to protect soil quality.