Abstract
This study was conducted to investigate the effects of the amount of cattle dung pat on the duration of dung patch existence. Fresh dung pats weighing 0.25, 0.5, 1.0 and 2.0 kg were artificially deposited on an Italian ryegrass (Lolium multiflorum Lam.) pasture, where it was thereafter rotationally grazed by Japanese Black cows. Control (no dung deposition) was set for comparison. The sward height was measured at three places (0-10, 10-30 and 30-50 cm) apart from the center of the dung pat, and changes over days in the dung patch areas were examined during dung patch existence. In all the dung treatments, the sward in the 0-10 or 10-30 cm place was taller than that in the 30-50 cm place around 35 days after the dung deposition, so that it was judged the dung patch was formed. The dung patch sward was taller in the places closer to the dung pat, and tallest on the 63rd day after the deposition. The duration of dung patch existence was evaluated at 2, 3, 4 and 6 months for 0.25, 0.5, 1.0 and 2.0kg treatments, respectively. In addition, it was suggested that the duration of dung patch existence was affected by weather, especially rainfall.
