Effect of cattle and sheep treading on surface configuration of a sedimentary hill soil

Pastures with a 6-year history of grazing by cattle (cattle pasture) and sh eep (sheep pasture) were used to measure the erects on soil disturbance of a single severe grazing/treading event by sheep (S), one by cattle (C-1), o r 2 events within 3 weeks by cattle (C-2). Treatments were stocked at 35 50 0 kg LW0.9 /ha (= 200 cattle/ha) for 48 h when the soil was wetter than the plastic limit. A control plot (untrodden, U) was grazed only lightly by sh eep to control pasture cover while causing minimal observable surface damag e. Change in surface contour, random roughness, soil surface damage, and pa sture cover were determined with a "contometer'. The construction and use o f the contometer to measure change in microtopography and to describe the s oil surface and vegetative state by grazing is described. Disturbance was c alculated as the change in height (mm) of soil level at fixed positions alo ng transects within treatment plots. Both sheep and cattle pastures were affected similarly (P > 0.05) in relati on to absolute and net disturbance of soils. Averaged across both pasture t ypes, very little absolute surface soil disturbance was measured on S, wher eas cattle-treading caused significant upward and downward movement of soil . Mean (+/- s.d.) absolute surface disturbance (sum of upward and downward movement on a transect) was greater by cattle (C-1, 11.2+/-8.1; C-2, 9.9+/- 5.0 mm) than by sheep (5.1+/-1.8 mm) (P < 0.01) after the single treading a nd 9.0+/-4.1 mm for C-2 after the second treading. Net disturbance (average of upward and downward movement on a transect) was 1.9+/-4.0, 1.8+/-4.0, a nd 3.0+/-1.8 mm for C-1, C-2,and S (P>0.05), respectively, after the first treading and 4.1+/-3.7 mm for C-2 after the second treading. Cumulative net disturbance resulting from C-2 on sheep pasture was greater than on cattle pasture (P < 0.05), especially after the first treading, suggesting sheep pasture was more susceptible to compaction than the previously damaged catt le pasture. Random roughness and percentage of surface soil penetrated by h ooves, based on observation, was greater following cattle than sheep treadi ng. Random roughness tended to increase more (P < 0.07) following treading of sheep than of cattle pastures, which were already rougher. It was concluded that the erect on soil surface configuration of severe sho rt-term treading events on wet soils was greater by cattle than by sheep st ocked at the same metabolic liveweight per hectare and that this occurred i rrespective of the previous grazing history. Although absolute disturbance in each of the 2 cattle treadings in C-2 was similar, net disturbance (comp action) on sheep pasture was more than twice that on cattle pasture (P < 0. 05).