基于高寒草地放牧系统次级生产力的优化放牧强度研究

Study on Optimal Grazing Intensity Based on the Secondary Productivity of Alpine Grassland Grazing System

依据小嵩草(Kobresia parva)高寒草甸和垂穗披碱草(Elymus nutans)/星星草(Puccinellia tenuflora)高寒混播人工草地牦牛放牧系统、紫花针茅(Stipa purpurea)高寒草原藏系绵羊放牧系统中草地次级生产力(家畜增重)的试验数据,构建了放牧家畜个体增重与放牧强度之间的模型:y=a-bX(b>0),以此为基础确定了单位面积草地次级生产力(家畜增重)与放牧强度之间的数学模型:y=aX—bX^2(b>O);计算出各放牧系统最大生产力放牧强度:高寒草甸冷季和暖季草场分别是1.68头·hm^-2和2.52头·hm^-2,高寒人工草地牧草生长季为7.23头·hm^-2,高寒草原冷季、暖季和全年连续放牧草场分别是4,33,6.45,2.36只·hm^-2。

According to the experimental data of grassland secondary productivity in Kobrecia parva alpine meadow and Elymus nutans/Puccinellia tenuflora alpine mixture sowing cultivated grassland yak grazing system as well as Stipa purpurea alpine steppe Tibetan sheep grazing system,naive model between grazing animal live-weight gain and grazing intensity Y=a-bX （b〉0）was built,and mathematical model between the grassland secondary productivity （animal live-weight gain） of unit area and grazing intensity Y=aX-bX2 （b〉0）was made certain based on naive model Y=a-bX（b〉0）.And then the maximal productivity grazing intensities （optimal grazing intensity） of tested grazing systems were calculated.The optimal grazing intensities of growing season in alpine cultivated grassland,cool-and warm-season pastures in alpine meadow were 7.23 yaks · hm-2,1.68 yaks · hm-2 and 2.52 yaks · hm 2,respectively.The optimal grazing intensities of cool-season pasture,warm-season pasture and whole year grazing pasture in alpine steppe were 4.33,6.45 and 2.36 sheeps · hm-2,respectively.