峡谷型喀斯特不同生态系统土壤养分及其生态化学计量特征

结合野外调查与室内分析,对峡谷型喀斯特水田(ST)、旱地(HD)、草地(CD)、灌丛(GC)、人工林(RGL)、次生林(CSL)6类生态系统进行研究,探讨不同生态系统土壤养分及其生态化学计量特征。结果表明:(1)除全钾含量外,6类生态系统土壤养分含量均随土层增加而减少,土壤pH与之相反;(2)与全球不同生态系统土壤的平均水平相比,峡谷型喀斯特不同生态系统的碳氮比、碳磷比、碳钾比、磷钾比和氮磷比均较低;(3)不同生态系统土壤养分含量差异显著,不同生态系统的化学计量差异也显著,土壤肥力的总体趋势为次生林人工林水田旱地灌丛草地。不同发展阶段、不同生态系统土壤养分的限制因子不同,应制定不同的管理和施肥措施,促进峡谷型喀斯特乃至整个西南喀斯特区域植被的迅速恢复和生态重建。

Soil Nutrients and Ecological Stoichiometry Characteristics under Different Ecosystems in Karst Canyon Region

To explore soil nutrients and their ecological stoichiometry characteristics under six ecosystems including farmland (ST), dry land (HD), grassland (CD), shrubbery (GC), plantation (RGL) and secondary forest (CSL)), were studied in karst canyon region by a combination of field investigation and laboratory analysis. The results showed that: (1) soil nutrient content under six ecosystems had a decreasing trend with soil depth except total potassium (TK), while the verse was true for soil pH. (2) Compared with the global soil average level, the ratios of carbon to nitrogen, carbon to phosphorus, carbon to potassium, phosphorus to potassium, and nitrogen to phosphorus ratio in six ecosystems were low in the karst canyon region. (3) Both soil nutrients contents and stoichiometry significantly differed among six ecosystems and soil fertility presented in the order of secondary forest > plantation > farmland> dry land > shrubbery > grassland. The main influencing factors varied at different developing stages and under different ecosystems; thus, respective management and fertilization measures should be adopted to promote vegetation restoration and rapid ecological reconstruction in the karst canyon region and even the whole southwest karst area of China.