Spatial distribution of dung patches under sheep grazing

Abstract

Abstract The spatial distribution of dung patches from sheep grazing pasture on a West Coast gley podzol near Greymouth was measured over four grazings in 2 years. During June four sheep stocking densities were used (900, 1200, 1500, and 1800 sheep/ha per day) with and without nitrogen (N) at 900 and 1800 sheep/ha per day. In an additional treatment, sheep were grazed for 4 days at 1800 su/ha per day on one area instead of 1 day on one-quarter of the area as for the other treatments. In October these grazings were repeated on pasture regrowth from the June grazings, but at one-third of the June stocking densities (300, 400, 500, and 600 sheep/ha per day). The spatial distribution of dung was best described by the negative binomial function. The Poisson Index which measures the aggregation of the dung patches showed that there was significantly more aggregation at the lowest stocking density than at the higher stocking densities. At the highest stocking density, grazing for 4 days resulted in more clumping...