Soil Physicochemical Properties and Dynamic Changes of Understory Plant Diversity at Different Growth and Development Stages of Eucalyptus urophylla×Eucalyptus grandis Plantation
[Objective]To study the growth status,soil physical and chemical properties and understory plant diversity of Eucalyptus urophylla×Eucalyptus grandis pulpwood plantation of different age groups in southern Yunnan for providing theoretical basis for sustainable management of eucalyptus pulpwood plant-ation.[Method]In this study,106 plots of red soil or red soil developed from coarse-grained crystalline rocks,muddy rocks,and carbonate rocks,with similar site conditions at an altitude of 1 400～1 700 meters,belonging to 5 different age groups.The differences in growth indicators,soil factors,and plant diversity in-dices among different age groups were analyzed through variance,multiple comparisons,and redundancy analysis.Correlation analysis was also used to reveal the correlation between them.[Result]The height,DBH and living wood growing stock of E.urophylla×E.grandis plantation in different age groups in-creased with the growth of the stand.The growth rate was faster in the middle-aged forest,but slowed down in the mature forest(7-8a).There were significant differences in soil porosity and soil moisture con-tent among different age groups,and the overall trend showed an increase and then a decrease with the growth of the stand,reaching the highest value in the near mature forest.There were significant differ-ences in soil total nitrogen among different age groups,and the growth of tree height,diameter at breast height,and stand volume were significantly correlated with total nitrogen.The richness index and even-ness index of herbaceous and total shrubland under the Eucalyptus urophylla forest were positively correl-ated with soil organic matter and available zinc.The richness index of shrubs was positively correlated with soil moisture,available nitrogen,and available copper.The Shannon Wiener index of herbs and shrubs was positively correlated with soil total nitrogen,while it was significantly negatively correlated with soil bulk density and pH value.The evenness index of shrub Pielou was positively correlated with soil total po-tassium.Among them,soil organic matter had the greatest impact on the understory vegetation diversity of Eucalyptus urophyllus,with the variance accounting for 18.3%(F=13.21,P<0.05).[Conclusion]There is a competitive relationship between the growth of young E.urophylla×E.grandis plantation and herbaceous plants.The influence of plant diversity on soil structure and physical properties is greater than that of chemical properties.At near maturity,the total shrub and shrub biodiversity reaches the maximum,which reveals that the eucalyptus plantation ecosystem enters self-restoring succession after near maturity.
万方数据
维普
