基于划区轮牧理论的祁连山北麓牧区动态草畜平衡研究

Forage-livestock dynamic balance of pasturing area based on rotational grazing theory in northern slope of Qilian Mountains

为了恢复和保护祁连山北麓草地生态系统,建设生态畜牧业,该文以肃南县祁连山北麓牧区为研究对象,基于划区轮牧理论模拟不同降水情景下轮牧区理论载畜量并分析现状牧区草畜平衡状况,分析理论载畜量下轮牧牧区产草需草过程,进行牧区动态草畜平衡分析,并与传统方法和基于关键场理论方法进行对比。结果表明:肃南县祁连山北麓牧区降水量极大地影响着牧区理论载畜量,宜将平水年理论载畜量100.9万标准羊单位作为今后牧区畜牧业管理的主要参考指标;2015年牧区同时存在牲畜超载和欠载并且冷暖草场理论载畜量差异较大,应在后期发展中注重调整当前的畜牧业发展结构和合理配置冷暖草地资源。通过3种方法的草畜平衡动态对比分析,基于划区轮牧理论方法不仅能保证不同轮牧区的草畜动态平衡,且能保持饲草的高效利用,在轮牧区草畜平衡分析计算中具有一定的优越性。

Overgrazing is an important reason for grassland ecological destruction in Qilian Mountains.In order to resumes and protects grassland ecosystem and constructs ecological animal husbandry in the northern slope of Qilian Mountains.In this paper,we selected the northern slope of Qilian Mountains in Sunan County as the study area,simulated the proper stocking capacity for livestock from different precipitation scenarios in grassland and analyzed the present forage-livestock balance status based on rotational grazing theory,researched the process of pasture production and demand with the proper stocking capacity in rotational pasturing area,carried out the dynamic forage-livestock balance analysis,and compared the result with the key pasture theory method and traditional method.The result showed that the change of precipitation greatly influences the proper stocking capacity for livestock of pasturing area in the northern slope of Qilian Mountains in Sunan County,the proper stocking capacity for livestock was 1.303 million sheep unit,1.009 million sheep unit,and 65.1 million sheep unit in high,normal,and low flow years,respectively.In analysis of the proper stocking capacity for livestock calculated by three methods in different precipitation,we found that the result calculated by the traditional grassland-livestock balance method was the largest,and the result calculated by the grassland and livestock balance method based on key pasture theory was the lowest.This is because the traditional grassland-livestock balance method does not consider the relationship between the process of grassland production and demand of livestock in pastoral areas,the traditional grassland-livestock balance method does not consider the dynamic change of livestock number in the process of grassland demand of livestock.Therefore,we proposed that the proper stocking capacity for livestock in the normal flow year was 1.009 million sheep unit as the main reference indexes of animal husbandry management in the future.There were both existence overgrazing and under load problem in pasturing area in 2015,and the proper stocking capacity for livestock in cold season meadow was obviously different in warm,it should be adjusted to the current development of animal husbandry structure and rational allocation of cold and warm season meadow in the future.The proper stocking capacity for livestock calculated by the traditional grassland-livestock balance method would deplete the available forage in cold season meadow in March,which would lead to overgrazing.The proper stocking capacity for livestock calculated by the grassland and livestock balance method based on key pasture theory can ensure the dynamic balance of the grassland resources and livestock in the whole pasture area,but it produced a lot of waste of forage in the whole pasture.By contrast the results with the other two methods,the rotational grazing theory method not only can ensure the dynamic forage-livestock balance in different rotational pastoral areas,but also can maintain the efficient utilization of forage,and it showed that the rotational grazing theory method had certain superiority in analysis of forage-livestock balance in the rotational pastoral area.The results can provide a scientific basis for the restoration and protection of grassland ecology in Qilian Mountains and the development of ecological animal husbandry in Sunan County.