不同造林模式下火烧迹地的土壤修复效果及植物多样性变化

Effects of Soil Remediation and Changes of Plant Diversity in Burned Areas Under Different Afforestation Patterns

以威海仙姑顶中度火烧迹地人工更新后的麻栎-樱花-刺槐混交林(MYC)、麻栎-黑松-五角枫混交林(MHW)、麻栎-黑松-黄栌混交林(MHH)和麻栎-黑松-臭椿混交林(MHC)为研究对象,对4种不同造林模式进行土壤的定量分析和物种多样性调查,以自然更新林地(CK)作为对照,对比分析不同造林模式对火烧迹地土壤修复效果以及林下植被更新状况。结果表明:(1)MHH在0-40 cm土层内土壤容重最小,土壤通气性能最佳,土壤持水状况最好,MHC次之,MYC最差,但均与CK存在显著差异(P<0.05);(2)MHH在0-40 cm土层内土壤有机碳、碳氮比(C/N)、全磷、全钾、速效钾含量均为最高,MHC在0-40 cm土层内全氮、速效磷含量最高,MYC和MHW的土壤有机碳、碳氮比(C/N)、全磷、全钾与CK无显著差异(P>0.05);(3)MHH的Margalef指数、Shannon-Wiener指数、Simpson指数以及Pielou指数均处于较高水平;(4)综合分析后得出,MHH对中度火烧迹地土壤修复效果最佳,林下植被更新速度最快,MHC次之。MYC和MHW对火烧迹地土壤物理性质改良明显,但在土壤养分和林下植物更新方面并无明显作用。

Taking Quercus acutissima-Cerasus-Robinia pseudoacacia mixed forest(MYC), Quercus acutissima-Pinus thunbergii-Acer mono mixed forest(MHW), Quercus acutissima-Pinus thunbergii-Cotinus coggygria mixed forest(MHH), and Quercus acutissima-Pinus thunbergii-Ailanthus altissima mixed forest(MHC) grown in the burned area of Weihai as research object, soil properties and species diversity were surveyed under four different afforestation patterns with naturally updated woodland(CK) as the control. The effects of different afforestation modes on soil remediation and the status of subforest vegetation renewal were analyzed. The results showed that:(1) MHH had the lowest soil bulk density in 0-40 cm soil layer, the best soil aeration performance, and the best soil water retention. MHC was the second and MYC the worst. All of these three were different significantly from CK(P < 0.05);(2) The soil organic carbon, carbon nitrogen ratio(C/N), total phosphorus, total potassium and available potassium contents in MHH were the highest in 0-40 cm soil layer. MHC had the highest total nitrogen and available phosphorus contents in 0-40 cm soil layer. There was no significant difference in soil organic carbon, carbon/nitrogen ratio(C/N), total phosphorus, total potassium and CK between MYC and MHW(P < 0.05).(3) MHH’s Margalef index, Shannon-Wiener index, Simpson index and Pielou index were relatively higher;(4) After comprehensive analysis, it could be concluded that MHH had the best soil remediation effect on moderately burned land, and the regeneration rate of understory vegetation was the fastest, followed by MHC. MYC and MHW could improve soil physical properties obviously, but had no obvious effect on soil nutrients and understory plant regeneration.