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采用土壤分析筛分离处理和室内萌发试验,对桂西北喀斯特退化生态系统不同植被类型土壤种子粒径进行了研究。结果表明,在0～15cm的土层中,草地土壤种子库密度为1955粒m-2,灌丛次之,为1850粒m-2,次生林地最少,仅有665粒m-2;垂直剖面上,草地和灌丛土壤种子集中分布在0～2cm土层,而次生林地种子主要分布于5cm以下;草地可萌发种子总量的99%集中于>0.25mm粒径,灌丛与次生林地主要集中在>0.25mm和≤0.177mm粒径;透过0.177～0.25mm的土壤萌发种子数量很少,3类样地分别仅为0.5%、1.4%和2.2%。因此,喀斯特地区退化生态系统草地土壤种子分离的最小孔径确定为0.25mm,灌丛和次生林地透过0.177～0.25mm筛孔的土壤可不进行萌发试验。
Using soil analysis sieve separation and indoor germination test, the soil seed size of different vegetation types in the degraded karst ecosystem of northwestern Guangxi Province was studied. The results showed that in 0 ~ 15 cm soil layer, the density of seed bank in the grassland was 1955 m-2, followed by shrubs, 1850 m-2, with the least secondary forest land, with only 665 m-2; vertical section The seeds of upper, grassland and shrub soil were concentrated in 0 ~ 2cm soil layer, while the seeds of secondary forest land mainly distributed below 5cm. 99% of the total germinable seeds concentrated in> 0.25mm diameter of shrubs and secondary forest Concentrations> 0.25mm and ≤0.177mm particle size; 0.177 ~ 0.25mm through the soil germination seeds few, three samples were only 0.5%, 1.4% and 2.2%. Therefore, the minimum pore size of soil seed separation in degenerated grassland was determined to be 0.25 mm in the karst area, and no germination test was conducted in the shrubs and secondary forests through 0.177-0.25 mm sieve.