柳江流域岩溶草丛群落生物量和碳储量的初步研究

根据柳江流域草丛群落类型、高度及其分布面积选择平均高度>1.5m、0.5~1m和<0.5m的高、中、低3种高度的代表性草丛,通过收获法研究了其群落生物量,并对其碳储量进行了初步估算。研究结果表明:(1)五节芒(Miscanthusflorid-ulus)、毛秆野古草(Arundinellahirta)和假俭草(Eremochloaophiuroides)草丛群落的生物量分别为8609.68g/m2、1022.61g/m2和821.63g/m2,生物量与高度呈正相关,但随群落高度增加,地上生物量增加迅速,地下生物量增长平缓;(2)随群落高度增加,生物量迅速向地上部分聚集,低矮的假俭草群落地下生物量与地上生物量的比值为1.91,高度中等的毛秆野古草群落为1.32,但高度大的五节芒群落仅为0.21,地下/地上生物量比值与群落高度呈负相关,其中毛秆野古草与五节芒群落的地下生物量和地上生物量可以用幂函数很好的拟合(R2>0.79,P<0.01),因此二者可以依据地上生物量便捷的估算其地下生物量,但假俭草地下和地上生物量的关系模型不理想;(3)地下生物量以幂函数关系随深度递减(R2>0.95,P<0.01),主要集中分布在0~20cm土层,可达根系生物量的80%以上,40cm以下土层中根系很少;(4)柳江流域岩溶区草丛植被的碳储量达9.51TgC。 

Preliminary study on the biomass and the carbon storage in karst grassland in Liujiang Basin, Guangxi

Grassland is one of the largest terrestrial ecosystem types and plays an important role in the global carbon cycle.Studies on biomass of karst grassland are rare that making the estimation on carbon storage inaccuracy because of lack of data.According to the average height and distribution areas,three representative karst grassland types in Liujiang Basin are chosen to estimate community biomass by harvest method.The results show that（1） total biomass of Miscanthus floridulus,Arundinella hirta and Eremochloa ophiuroides is 8 609.68 g·m2,1 022.61 g/m2 and 821.63 g/m2 respectively.Biomass and height are positively correlated,while above-ground biomass increases faster than the below-ground one;（2） the ratio of below-ground biomass to above-ground biomass varies from 0.21 for Miscanthus floridulus to 1.91 for Eremochloa ophiuroides,and shows a negatively correlation with community height.The relation of below-ground biomass（y） and above-ground biomass（x） is well fit with power functions of y=1.735 2x0.906 2 for Arundinella hirta and y=5.3076x0.446 6 for Miscanthus floridulus（R2〉 0.79,P〈0.01）.Above-ground biomass accumulates rapidly with the increase of community height;（3） below-ground biomass decrease with depth and is well fit with power function model（R2〉 0.95,P〈0.01）.Most of below-ground biomass distributes in 0~20 cm soil layers;（4） the carbon storage of grassland in Liujiang Basin is calculated as 9.51 TgC.