Cattle treading effects on sediment loss and water infiltration

To quantify effects of forage canopy properties, soil surface relief, and h ill slope on the hydrologic properties of the soil in a New Zealand hill la nd pasture, duplicate plots (15 x 3 m) with 3 canopy heights (6, 20, and 47 mm) were trodden with 0, 4, or 8 mature cows for 40 min on a moderate (15- 18 degrees) slope (Trial 1), and similar plots with the low and high canopy heights were trodden by 8 mature cows for 40 min on gentle (8-14 degrees), moderate (15-18 degrees), or moderately steep (20-25 degrees) slopes (Tria l 2). Pre- and post-treading measurements included canopy heights; bare soi l proportions: soil moisture contents; hoof prints and skids; roughness coe fficients. surface water detention storage volumes, and soil clump volumes with a 38-pin contometer; and water infiltration and sediment loss by rainf all simulation. In Trial 1, increasing canopy height resulted in lower (P < 0.01) proportions of bare ground, roughness coefficients, soil clump volum es, and sediment losses. Increasing treading damage resulted in higher (P < 0.05) post-treading roughness coefficients, proportions of bare ground, ho of print and skid densities, surface water detention volumes, and soil clum p volumes. In Trial 2, soil hydrologic properties did not differ between ca nopy height or hill slope treatments. In the two trials, water infiltration rate was significantly related to the roughness coefficient (r(2) = 0.31) and the number of hoof prints (r(2) = 0.26), Results imply that a 20-mm can opy height of the forage species common on a New Zealand hill land pasture is adequate to minimize the effects of a short-term treading event on soil water infiltration rate and sediment loss.