那拉提山地草甸合理放牧强度研究

Study on Reasonable Grazing Intensity in Nalati Mountain Meadow Steppe

【目的】明确山地草甸毒害草蔓延现状下的合理载畜量,研究不同放牧强度下草地植被特征、毒害草白喉乌头种群的变化规律。【方法】采用野外调查取样的方法,在那拉提山地草甸测定不同放牧强度(轻牧13.5只羊/hm^2,中牧20.3只羊/hm^2,重牧26.3只羊/hm^2,极牧33.0只羊/hm^2)下绵羊增重量、白喉乌头的种群特征以及草场质量指数状况。【结果】(1)随着放牧强度的增加,可食牧草的生物量、高度、盖度均呈逐渐下降的变化趋势,放牧区可食牧草生物量和草场质量指数比对照区极显著降低了32.2%~70.2%、23.6%~65.7%(P<0.01);(2)白喉乌头重要值随放牧强度的增加呈逐渐下降的变化趋势,且放牧区极显著高于对照的51.5%~114.7%(P<0.01);(3)放牧强度与单位绵羊增重、可食牧草生物量、草场质量指数呈显著(P<0.05)或极显著负相关系(P<0.01),但与白喉乌头重要值呈极显著正相关关系(P<0.01)。【结论】在毒草增生的山地草甸合理的放牧强度为20.0只羊/hm^2。

【Objective】To make clear the rational carrying capacity of poisonous grass in mountain meadow and study the characteristics of grassland vegetation and population of Aconitum leucostomum under different grazing intensities.【Method】The mountain meadow of Nalati was taken as the research object,and the unit weight gain of sheep,the characteristics of population of A.leucostomum and index of grassland quality under different grazing intensities(lightly grazing 13.5 sheep/hm 2,moderately grazing 20.3 sheep/hm 2,heavily grazing 26.3 sheep/hm 2,extremely grazing 33.0 sheep/hm 2)were studied.【Result】(1)With the increase of grazing intensity,the biomass,height and coverage of edible forage grass gradually decreased,and the biomass of edible forage grass and the quality index of grassland in grazing plots were significantly reduced by 32.2%-70.2%,23.6%-65.7%(P<0.01)compared CK plot.(2)The important value of A.leucostomum gradually decreased with the increase of grazing intensity,and the grazing plots was significantly higher than that(51.5%-114.7%)of the CK plot(P<0.01).(3)There was a significant(P<0.05)or very significant(P<0.01)negative correlation relationship between grazing intensity and unit weight gain of sheep,biomass of edible forage grass,index of grassland quality,but there was a significant positive correlation between the grazing intensity and the important value of A.leucostomum(P<0.01).【Conclusion】Considering the economic and ecological benefits,the reasonable grazing intensity of herbaceous meadow was 20.0 sheep/hm 2.