牦牛放牧率对小嵩草高寒草甸地上、地下生物量的影响初析  

Effects of Yak Stocking Rates on Aboveground and Belowground Biomass on Kobrecia parvaAlpine Meadows

作　　者：董全民[1] 李青云[2] 马玉寿[2] 施建军[2] 

机构地区：[1]青海省畜牧鲁医科学院 [2]青海省畜牧兽医科学院,西宁810003

出　　处：《四川草原》2004年第2期20-27,共8页Journal of Sichuan Grassland

基　　金：青海省"九五"攻关项目(编号96-N-112)。

摘　　要：牦牛放牧率对小嵩草高寒草甸地上、地下生物量有显著的影响。莎草、禾草地上生物量和总地上生物量在不同放牧率之间差异显著(P<0.05),且随着放牧率的降低,禾草和莎草的比例增加,可食杂草和毒杂草比例下降;两季草场优良牧草生物量组成的年度变化与放牧率均呈负相关(P<0.01),与杂类草均呈正相关(P<0.01)。地上生物量的绝对生长率1999年在7月份达到最大,1998年冷季草场各放牧处理的绝对生长率在8月份达到最大,暖季草场对照和轻牧在7月份最大,而中轻和重牧在8月份最大。各土壤层地下生物量随放牧率增大呈明显下降趋势;暖季草场各放牧处理0～10 cm地下生物量占0～30 cm总地下生物量的88.04％～89.37％,10～20 cm占7.14％～9.34％,20～30 cm占2.25％～3.5％;冷季草场各放牧处理0～10 cm地下生物量占0～30 cm总地下生物量的88.01％～91.14％,10～20 cm占5.44％～8.04％,20～30 cm占3.42％～3.94％。地上生物量、各土壤层的地下生物量(包括活根和死根)与放牧率之间呈负相关,其线性回归方程为y=a-bx(b>0)。地下与地上生物量呈正相关,其线性回归方程为y=a+bx(b>0).Stocking rates of yaks had obvious effects on aboveground and belowground biomass on the Ko-brecia parva alpine meadows. There were significant differences between biomass of grasses and sedges, total biomass and different stocking rates(P < 0.05), and ratio of sedges and grasses decreased, ratio of palatable weeds and toxic weeds increased with the rise of stocking rates. The yearly changes of biomass composition for desirable herbage were negatively correlated with stocking rates (P < 0.01), and the yearly changes of biomass composition for weeds were positovely correlated with stocking rates (P<0.01). The absolute growth ratio of aboveground biomass reached to the maximum in July in 1999, butin 1998, itreachedtothemaximumincold-season pastureland in August, and as for warm-season pastureland, it reached to the maximum for control and light grazing in July, in August for moderate and heavy grazing. There was an obviously decreasing trend on the belowground biomass of every soil stratum with the increase of stocking rates. Belowground biomass of 0-10cm, 10-20cm and 20-30cm amounted to 88.04-89.37%, 7.14-9.34% and 2.25-3.5% of 0-30cm total belowground biomass respectively in warm-season pastureland, and 88.01-91.14%, 5.44-8.04% and 3.42-3.94% in cold-season pastureland respectively. There were negative correlation relationships between aboveground biomass, belowground biomass for different soil stratums and stocking rates, and their linear regression equation as follows: y=a-bx (b>0). There was a positive correlation relationship between aboveground biomass and belowground biomass, with the regression equation as follows: Y=a+bx (b>0).

关 键 词：牦牛 放牧率 小嵩草 高寒草甸 地上生物量 地下生物量 草地畜牧业 可持续发展 

分 类 号：S812.8[农业科学—草业科学]