At the same time herds cause wide-scale land degradation, with about 20 percent of pastures considered as degraded through overgrazing, compaction and erosion.
畜群同时造成大范围土地退化，其中20%的牧场因过度放牧、土壤板结和侵蚀而退化。
2
Both degree of compaction and percent air voids designed in bituminous mixtures have key influence on compaction.