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土壤养分异质性是竹林-阔叶林界面(bamboo and broad-leaved forest interface,以下简称竹阔界面)的重要特征,细根生长、周转和分解影响土壤养分供应能力,但其在竹阔界面养分异质性形成中的贡献尚不清楚。该文选取竹阔界面两侧的毛竹(Phyllostachys pubescens)林和常绿阔叶林为研究对象,开展土壤养分(C、N、P)含量、细根生物量及周转、细根分解及养分回归等指标的对比研究。结果表明:(1)竹阔界面两侧毛竹林和常绿阔叶林土壤养分差异明显,毛竹林0-60cm土壤有机碳(SOC)和土壤总氮(STN)含量分别为20.51和0.53g·kg-1,常绿阔叶林0-60cm土壤有机碳(SOC)和土壤总氮(STN)含量分别为13.42和0.26g·kg-1,前者比后者分别高出34.53%和50.35%,但毛竹林土壤全磷(STP)含量低于常绿阔叶林25.54%;(2)竹阔界面两侧细根生物量、养分密度及养分回归量差异明显,毛竹林细根生物量高达1201.60g·m-2,是常绿阔叶林的5.86倍;养分密度分别为591.42g C·m-2、5.44g N·m-2、0.25g P·m-2,分别是常绿阔叶林的6.12倍、3.77倍和3.11倍;年均养分回归量分别为278.54g C·m-2·a-1、2.36g N·m-2·a-1、0.11g P·m-2·a-1,是常绿阔叶林的6.93倍、4.29倍和3.67倍;(3)细根对界面两侧土壤SOC、STN异质性形成的年均潜在贡献分别为76.79%和28.33%,但对STP异质性形成起减缓作用,贡献率为6.17%。这些结果说明毛竹扩张可以改变常绿阔叶林土壤的养分状况,且细根对不同养分的异质性形成贡献不一致,是土壤SOC、STN异质性形成的重要原因。
Soil nutrient heterogeneity is an important characteristic of the bamboo-broadleaf forest interface (hereinafter referred to as “broad-leaved forest interface”). Fine root growth, turnover and decomposition affect soil nutrient supply capacity. However, The contribution of nutrient heterogeneity formation is not clear. In this paper, Phyllostachys pubescens and evergreen broad-leaved forests on both sides of the bamboo-broad interface were selected to study the effects of soil nutrients (C, N, P), fine root biomass and turnover, fine root decomposition and nutrient return Comparison of other indicators. The results showed that: (1) There was significant difference in soil nutrient contents between Phyllostachys pubescens forest and evergreen broad-leaved forest on both sides of the bamboo-broad interface. The contents of soil organic carbon (SOC) and total nitrogen (STN) of 0-60cm in Moso bamboo forest were 20.51 and 0.53g kg-1. The contents of soil organic carbon (SOC) and total nitrogen (STN) in the 0-60cm layer of evergreen broadleaved forest were 13.42 and 0.26g · kg-1, respectively, the former were 34.53% and 50.35% However, the total phosphorus (STP) content of Phyllostachys pubescens forest was lower than that of evergreen broad-leaved forest by 25.54%. (2) The differences of fine root biomass, nutrient density and nutrient accumulation on both sides of bamboo- g · m-2, which is 5.86 times of the evergreen broad-leaved forest. The nutrient densities were 591.42g C · m-2, 5.44g N · m-2, 0.25g P · m-2, 6.12 times, 3.77 times and 3.11 times higher than that of forest. The average annual nutrient regains were 278.54g C · m-2 · a-1,2.36g N · m-2 · a-1 and 0.11g P · m-2 · a-1, which is 6.93 times, 4.29 times and 3.67 times higher than that of evergreen broad-leaved forest; (3) The average annual potential contribution of fine root to soil SOC and STN heterogeneity is 76.79% and 28.33% But formed a mitigating effect on the formation of STP heterogeneity, with a contribution rate of 6.17%. These results indicate that the bamboo expansion can change the nutrient status of the evergreen broad-leaved forest soils, and the contribution of fine roots to the heterogeneity of different nutrients is inconsistent, which is the important reason for the formation of soil SOC and STN heterogeneity.