植物群落生物量和有机碳对高寒草甸土地利用变化的响应

在中国科学院海北高寒草甸生态系统定位站地区,选择高寒矮嵩草草甸及其开垦后形成的农田和一年生人工草地作为研究对象,研究了高寒草甸不同土地利用方式下生物量和植物-土壤系统固定的有机碳量的变化.结果表明:3种土地利用方式相比较,地上生物量由高到低依次为人工草地＞农田＞高寒草甸(P＜0.01),分别为11.83、9.78和4.36 t/hm2;3种土地利用方式下地下生物量剖面分布均呈倒金字塔形,0～40 cm地下生物量为高寒草甸＞人工草地＞农田(P＜0.01),分别为15.74、5.61和1.24 t/hm2.随着高寒草甸土地利用方式改变,植物群落碳素固定量也随之减小,其序列由高到低依次为:高寒草甸＞人工草地＞农田(P＜0.05),其值分别为7.63、6.81和4.51 t/hm2.

Effect of different land use on the biomass and organic carbon of plant communities in alpine meadow

As one of the major ecosystems in the Tibetan Plateau,alpine meadow has been playing an important role in ecological equilibrium.With the population growth,alpine meadow has been cultivated to meet the demands for foods and benefits.In order to study the effect of land use change on the biomass and amounts of fixed-carbon of vegetation,alpine meadow(Kobresia humilis),the croplands and artificial grasslands formed by cultivating alpine meadow were selected in the Haibei research station,Chinese Academy of Science.The results indicated that the aboveground biomass rates varied among alpine meadow,croplands and artificial grasslands with an order of artificial grassland>croplands>alpine meadow(P<0.01),respectively,the rate was 11.83,9.78,4.36 t/hm2.The vertical distribution of belowground biomass displayed reverse pyramidal models in alpine meadow,croplands and artificial grasslands respectively.In 0~40 cm soil depth,the belowground biomass ranged with an order alpine meadow>artificial grassland>croplands(P<0.01),the rate was 15.74,5.61,1.24 t/hm2.With the change of alpine meadow land use,the amounts of fixed-carbon of vegetation varied with the rank of alpine meadow>artificial grassland>croplands(P<0.05),respectively,the rate was 7.63,6.81,4.51 t/hm2.