草地载畜量研究进展:参数和计算方法

doi:10.11686/cyxb20140438

摘要/Abstract

摘要： 根据生长季末草地产量,利用草地利用率等校正系数校正,除以家畜牧草需求量,是草地载畜量最基本的计算方法。但在草地产量及其测定时间跨度、草地利用率和家畜折算系数等参数的确定上存在争议。基于放牧压力或家畜采食量需求的家畜单位用于不同畜种的折算,牛单位和羊单位是常采用的家畜单位,但家畜单位主要依据家畜活体重量确定,对家畜代谢体重,以及混群放牧中因家畜食性差异造成的采食重叠考虑不足;草地利用率是放牧管理的重要参数,主要根据放牧经验和试验方法确定,实际应用中通常遵循“采食一半、保留一半”的经验法则,但在不同草地类型、地形差异、水源距离等因素影响下,草地利用率并不确定,其估计和测定方法也存在争议。此外,不同草地利用率下的草地载畜量差异很大。本文结合国内外研究进展,综述了草地载畜量估算中草地产量、草地利用率、家畜单位等参数的概念、确定方法和应用上的争议,总结草地载畜量的计算方法及校正因子,以期为草地放牧管理决策提供参考。

Abstract: The traditional technique for determining grassland carrying capacity (CC) is to calculate the total amount of forage at the end of the growing season,multiply this by a correction factor,and then divide by the average yearly feed requirements of a livestock unit. But there has been no consensus on the correction factors and time span. For convenience of management,ananimal unit (AU) is defined,based on the grazing pressure on grassland or grass consumption of certain specific animals,as the standard so other animals can be converted into animal units by comparing the same items. Currently,the most widely used animal units are animal unit (cow unit) and sheep unit (SU). But the AU is often defined on a live body weight (LBW) basis,which does not distinguish between physiological stages that may affect forage intake. What’s more,some forage species are not preferred by some kinds of livestock,and some ranges are better suited to one kind of livestock than to another; Animal units for different animal species should be adjusted based on the average dietary overlaps of these animal species on a specific type of range for calculating pasture-specific substitution ratios. It is important for pastoralist to be aware of use levels,residual vegetation and other grazing impacts during the period of use as well as utilization at the end of the growing season. Various methods were developed to estimate proper utilization rates,which can fall into two categories:estimation and measurement. The rule-of-thumb takes half-leave,half-use has been a standard in the range management profession for years. But forage output fluctuates considerably between years in response to changing climatic conditions and the concept of utilization rates means how it should be used in pasture management and has led to some confusion because a variety of ways in calculating pasture utilization rates are often not clearly defined. Furthermore,the choice of a proper use value has a profound effect on the estimate of CC. Based on research progress,the concept,measurement method and application dispute of parameters such as grassland output,proper utilization rate,livestock substitute rate et al. for CC calculation are summarized. The calculation method and adjustment factors for CC are also summarized to provide reference for grazing management decisions.

中图分类号:

S812

徐敏云，高立杰，李运起. 草地载畜量研究进展:参数和计算方法[J]. 草业学报, 2014, 23(4): 311-321.

XU Min-yun,GAO Li-jie,LI Yun-qi. A review on grassland carrying capacity (Ⅱ): Parameters and calculation methods[J]. Acta Prataculturae Sinica, 2014, 23(4): 311-321.

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