임간초지 (林間草地) 개발에 관한 연구 10 . 임간초지에서 방목강도 (放牧强度) 가 목초생산성과 품질 및 초지이용율에 미치는 영향 = Studies on the Grassland Development in the Forest 10 . Effect of grazing intensity on production and quality of grasses , and pasture utilization on woodland pasture

다국어 초록 (Multilingual Abstract)

A field experiment was conducted to determine the effects of grazing intensity on the grass production, grass quality, pasture utilization and botanical composition on woodland pasture. the experimental field faced south direction with 30% of shade(ca. 70% of full sunlight). The three levels of grazing intensity(low, optimum and high) used were set by the number of cows per hectar, which was adjusted according to the grass production. The low and high level of grazing intensity was 50% and 150% of optimum intensity. Optimum grazing density in spring was between 160 and 220 AU, while those of summer and autumn were 120 AU ha^-l d^-1, respectively. Higher regrowth yield were observed in the plot of optimum and low grazing intensity, compared with high intensity(p $lt;0.05). In spring, daily grass production was more vigorous(more than 2 times) than that in summer and autumn. The percentage of pasture utilization was remarkably high in high grazing intensity (85.8%), followed by optimum(75.8%) and low intensity(56.8%). However, the percentage of pasture grasses after final grazing in low, optimum and high grazing intensity was 87%, 81% and 69%, respectively. Nitrate nitrogen(NO₃-N) concentration of grasses was significantly higher in high grazing intensity than those of low and optimum intensity. NO₃-N in summer and autumn were remarkably higher than in spring season. But water soluble carbohydrate contents was not affected by grazing intensity. It may be concluded based on the results of present experiment that it is desirable to maintain optimum grazing intensity during grazing season for good regrowth and quality of grasses, pasture utilization and persistence on woodland pasture.