The Study On Hydrochemistry Characteristic In The Process Of Precipitation In The Larix Gmelini Forests In Da Xingan Mountains

Da Xingan Mountains region zonal forest and the most representative of the forest ecosystems of the northern part of the zonal plant communities. In this thesis, as the study area the MOHE Forest Ecosystem Research Station, as the research object, Larix gmelinii, Larix gmelinii redistribution of rainfall under the forest ecosystem and interaction between rainfall throughfall stemflow water chemistry characteristics of comparative analysis, the purpose is to understand the the Larix gmelinii redistribution of rainfall distribution process water chemistry changes its laws. The main results are as follows:(1) Study period rainfall pH value between changes in the4.39-6.37range, the volume-weighted average of5.33, the variation of performance decreases gradually decreasing rainfall; conductivity between6.0-26.0μs/cm changethe rainfall weighted averages6.0μs/cm the greater the changes show the pH the smaller the value of the conductivity. The measured rainfall weighted average concentrations of major anions and cations in descending order:Ca2+> Na+>NO3-N> SO42> NH4+—N>K+> Mg2+> Cl-, According to the trend seen lower rainfall greater the ion concentration.(2) The Larix gmelinii throughfall pH value greater than atmospheric rainfall increased the pH value in the5.18-7.09range, the pH value of the volume-weighted average of6.47, compared with the rainfall, increased by1.14pH valueunits, with a median of6.56, an increase of1.1pH units than rainfall. Conductivity between2.0-26.0μ.s/cm in the the measured penetration rain samples, the volume-weighted average for29.0μs/cm, the the throughfall conductivity median32.0μs/cm, relative to atmospheric rainfall than3times. Penetrating rain to Ca2+concentration highest, NH4+content was the lowest. Penetrating rain weighted average concentrations of major ions rainfall in descending order as follows::Ca2+> K+> SO42-> Na+> Mg2+> NO3-N> Cl-> NH4+—。Compared with the rainfall, Ca2+, K+, Na+, Mg2+, Cl-ion concentration has increased of SO42-, NO3N, NH4+—N ion concentration decreased. Fe, Zn and Mn in the same trend as penetrating rain weighted average of the average rainfall. Compared with rainfall rainfall has greatly improved. Penetrate rain, Na+, NO3N and NH4+-N, the total net input is negative, indicating that some of these elements are retained absorbed or leaves in the canopy. Na+net importer of penetration of rain each month are negative, indicating more nutrient ions in the process of plant growth. The the penetrating rain CT, Mg2, K+total net input are positive.(3) Larix gmelinii stemflow pH values between4.02-6.71changes in the pH value of the volume-weighted average of4.48, the stemflow gas rainfall show the acidification phenomenon; stemflow sample conductivity54.0-190.0μscm between rainfall weighted average142.0μs/cm. Weighted average concentrations of major ions in addition to the NO3—Nand NH4+—Nwere higher than rainfall, may be due to bark accept good place to atmospheric deposition. Stemflow variation of other ions NH4+and NO3emerged as the downward trend similar to the late rains.