甘肃马鹿冬季放牧践踏作用及其对土壤理化性质影响的评价

确定了草地上路径的密度，宽度，深度和土壤容重等5项放牧家畜践踏作用的观测指标，用该5个指标构建了2个践踏综合指数，定量了甘肃马鹿冬季季放牧的相对践踏强度，其可信度和可行性较高，定义了放牧践踏强度，根据冬季牧场载畜量和践踏综合指数确定了甘肃马鹿的绝对践踏强度和放牧强度。草地生长季土壤水分随践踏增强而减少，对放牧践踏的敏感性随着生长季推移逐渐降低。0－40cm土层全氮和速效氮含量，以及0－20cm土层速效磷，全盐和有机质含量，随践踏强度增加而减少，0－20cm土层全磷呈逐渐增多趋势，0－40cm土层水分和速效氮含量对践踏的敏感性随土层加深而上升，0－30cm土层全氮含量对家畜践踏的敏感性高于0－10cm土层，0－10cm土层速效磷含量对践踏的敏感性高于10－20cm土层。土壤子系统对放牧践踏作用的耐受性表现为土壤理化性状之间相互关系的稳定性，冬季牧场践踏强度梯度上，土壤质量综合指数的变化存在拐点，对应着草地从稍形过牧到明显过牧和短花针茅在群落中的次优势种地位。

Evaluation on trampling of grazed Gansu wapiti (Cervus elaphus kansuensis Po cock) and its effects on soil property in winter grazing land

Animal trampling plays more important role than defoliation and excrement in gra ssland, but there were few studies on trampling and no quantitative index of tra mpling intensity available. Five characteristics of the path trampled by grazed Gansu wapiti in winter grazing land were quantitatively identified as the measur ing indices of trampling intensity. Density, width and depth of path and soil bu lk density in path decreased, and number of plant in path increased as grazing p ressure reduced. Soil bulk...