Research On Water Purification And Regulation In Larix Gmelinii Plantation At The Greater Xingan Mountains

Forest ecosystem plays an important role in purifying water quality.The study on the purification function of forest to water quality is of great significance for the further study on water conservation and hydrologic law of forest ecosystem.The multi-level canopy structure redistributes the atmospheric rainfall,which changes its chemical composition greatly.This study is to utilize modern cool larch ecological system as the research object,through the regular of atmospheric rainfall,through the rain,trunk stem flow,stream water in the shed and woodland soil sampling and determination of p H,acid radical ion,metal ions,analyzed the atmospheric rainfall into sing-an larch ecosystem at different levels after the change of the chemical composition,Sing-an larch ecosystem was studied to purify function of water quality,the results for understanding Xingan larch ecosystem rainfall redistribution in the process of its chemical composition,reveals the change rule of water conservation forest ecosystem function and prevent downstream water quality pollution to provide theoretical basis and data support,the results show that:1.The average p H of atmospheric rainfall in the rainy season is 8.61.The maximum p H is 8.96.PH values were all higher than 8.0 during the study period.The change trend of p H value of rainfall after passing through forest canopy,tree trunk and soil layer indicated that forest canopy,tree trunk,soil layer and stream all had regulation effect on p H value of rainfall.After analyzing the selected chemical components,it was found that SO₄^2-PO₄^3-and NO^3-determined the p H value.2.The mass concentrations of NO^3-NO^2-SO₄^2-PO₄^3-Cu Zn Fe Mn and Cr in atmospheric rainfall during the study period were 0.20±0.30mg·L^-1,0.00±0.08mg·L^-1,0.00±0.01mg·L^-1,3.84±25.47mg·L^-1,0.02±0.04mg·L^-1,0.30±0.44mg·L^-1,0.02±0.08mg·L^-1,0.17±0.27mg·L^-1,0.02mg·L^-1.3.The canopy has adsorption effect on NO^3-NO^2-Zn Mn and Cr in atmospheric rainfall,especially strong adsorption effect on NO^3-,Zn and Cr.The average mass concentration of SO₄^2-PO₄^3-Fe and Cu in penetrating rain increased in different degrees.The trunk adsorbed Zn and Mn in atmospheric rainfall,but released other components in different degrees.Soil litter and microbial decomposition released organic and inorganic matter in the tissue,resulting in the increase of the average mass concentration of SO₄^2-Cu Fe.The particles and colloids in the soil adsorbed NO^3-NO^2-PO₄^3-Zn Mn and Cr,leading to the decreasing trend of mass concentration.4.The pollutants carried by atmospheric rainfall in Larix gmelinii Plantation had a good interception effect,and the regulation ability of three levels was canopy>soil>trunk.5.There were positive correlations between NO^3-and SO₄^2-,NO^3-and Cu,NO^2-and Zn,NO^2-and Cr,Cu and Fe,Zn and Mn,Zn and Cr,Zn and p H.Meanwhile,NO^3-SO₄^2-Cr Fe and PO₄^3-are the main influencing factors that can make water change.