桂西北喀斯特山区4种森林表土土壤有机碳含量及其养分分布特征

The distribution of organic carbon and soil nutrients under four forest types in karst mountain areas of northwest Guangxi, China

研究桂西北喀斯特山区4种森林植被类型表层(0~20 cm)土壤有机碳含量和土壤养分特征,与国内喀斯特土壤有机碳的研究成果进行比较分析,为该区域天然林管护、植被恢复和生态重建提供参考。4种森林植被类型表土SOC含量表现为:常绿阔叶林(151.31 g/kg)>常绿落叶阔叶林(145.33 g/kg)>针阔叶混交林(90.61g/kg)>灌草丛(86.92 g/kg);其中,常绿阔叶林、常绿落叶阔叶林与针阔叶混交林表层SOC含量差异不显著(P>0.05),而与灌草丛之间差异显著(P<0.05)。土壤SOC含量与速效N、速效K和全N呈显著或极显著正相关,表明土壤氮素积累与土壤有机碳的输入关系密切。表土SOC含量明显高于该研究区域内耕地(19.36g/kg)、退耕还草(15.31 g/kg)和退耕还林地(18.89 g/kg)以及受干扰林地(46.14 g/kg)等不同土地利用类型,也高于贵州开阳和贵州关岭等地区森林植被类型,与云南曲靖不同森林群落土壤SOC含量也存在一定的差异。

This paper studied the variation characteristics of surface layer soil organic carbon （SOC） content and soil nutrient, comparative analysis of soil organic carbon under different vegetation types in Karst mountain areas, provided reference for the protection, vegetation restoration and ecological construction to the natural forest. The results showed that the average SOC content of the topsoil are characterized by evergreen broad-leaved forest （151.31 g/kg） 〉 evergreen deciduous broad-leaved forest （145.33 g/kg） 〉 coniferous and broadleaved mixed forest （90.61 g/kg） 〉 shrub-grassland （86.92 g/kg）, But statistically there was no significant difference between the four forest types, were significantly correlated with SOC of Shrub-grassland. The content of soil organic carbon and total N, total P, available N, available K showed significant or extremely significant positive correlation, interpretation there was closely related to soil nitrogen accumulation and soil SOC input. In this study, the content of SOC under different forest types was significantly higher than the cultivated land （19.36 g/kg）, replacing cropland with pasture （15.31 g/kg）, conversion of cropland to forest （18.89 g/kg） and the disturbed forest（46.14 g/kg） in Karst mountains area, there were existed some differences among the content of SOC with other places forest types.