中文摘要：

基于对践踏强度评定中存在问题的分析，提出践踏强度是在特定的放牧方式（自由放牧或轮牧）下，单一种或组合种畜群单位时间内（通常指1个放牧季内）对单位草地面积所施加的践踏重力或践踏面积，它应有3种表示方法：重力表示法、面积表示法和频率表示法。首次提出了践踏单位和践踏当量概念，以明确践踏强度的计算标准和折算标准。具体是指在放牧季中，一头体重40k的滩羊每蹄践踏1次所施加于草地的践踏称为1个践踏单位——羊践踏，促进了践踏强度单位表示方法的统一化。引入的践踏当量概念，使得不同类别、不同年龄的家畜个体对草地的践踏量，均可通过践踏当量换算为统一单位——羊践踏，是制定出合理而简明的践踏强度指标计算公式的依据，有助于使当前不统一的践踏强度表示方法规范化。从纷繁复杂的影响践踏强度的众多因素中提炼出践踏次数或行走步数作为变量指标，把家畜的放牧行为及其时间分配模式归结到践踏次数中去。为计算单一种群或混合群践踏强度指标奠定了计算基础。在相同的放牧强度下，通过对虚拟的3个单一种群和1个混合畜群践踏强度的计算比较表明，如果忽略畜种在践踏次数上的差异，牛群和马群的践踏强度分别是羊群的5．6和4．7倍，混合群的践踏强度是羊群的4．8倍。而在此种情况下，用放牧强度或用单位面积草地上家畜体重与放牧时间的乘积表示的践踏强度均相等，因此有理由认为用放牧强度或用单位面积草地上家畜体重与放牧时间的乘积表示单一种群或混合畜群的践踏强度均是不准确的。

英文摘要：

After analysis of the problem of evaluating trampling intensity （TI）, TI is defined in this paper as trampling area or trampling pressure of grazing single or multiple livestock per hectare during a unit time under free or rotational grazing. It has three methods of expression, trampling pressure method, trampling area method, trampling frequency method. The trampling unit and trampling equivalent unit （TEU） are put forward for the first time in order to define the calculating standard and conversion standard of TI. A comparison of TI of three single livestock and multiple livestock at the same grazing intensity indicated that, if the difference of trampling pass is ignored, the TI of cattle, horse and mixed cattle and horse are 5.6, 4.7 and 4.8 times respectively that of sheep. But if TI is expressed as grazing intensity or livestock weight per pasture × grazing time it is equal to that of sheep, so we think these comparisons under single livestock and multiple livestock are inaccurate. Application of these conceptions for trampling studies will increase the comparability of results.