Topography and Pasture Management in the Mountainous Slopeland. : 1. The distribution of bare area and cattle dung.

Abstract

Experiments were carried out to determine the topographic effects on the distribution of cattle tracks, bare area and cattle dung with special attention to the inclination and the slope types ; such as a convex, linear and concave slope in the pasture in 1992 and 1993. The experimental site was located in the 2.2 ha sloping pasture on southern footslops of a volcanic mountain "Asama" at about 1,200 m above sea level, and the range of inclination was 8.5-23.2°, the value of mean was 13.6°. Dominant species in the pasture was Kentucky bluegrass (Poa pratensis L.). 12-13 heads of cow and the same numbers of calf were rotationally grazed in the experimental paddock and another one. Total period of occupation was about 95 days/year from April to November, and carrying capacity was 500 AUD/ha in the experimental paddock. Data were obtained through the 113 grid cells of 10 m×10 m in the experimental site excepting the under trees. The grazing behavior of cattle was affected by the inclination of pasture. Cattle tracks bare of vegetation cover were formed on steep slopes of inclination over 12°, which resulted in the increment of percentage of bare area at the site more than inclination 12° with the exception of the strong concave slope site. The percentage of area occupied by the fresh dung pats was much higher at the gentle sloping site than at the steep one except for the strong concave slope site, because grazing cattle mainly rested on the gentle sloping site and after excreted there. There was no difference of dung pats distribution between the experimental years.