Plant Flora And Physicochemical Properties Of Soil Of Peat Swamp In Xiaoxing'an Mountains

There are varieties of extensive swamps existing in Xiaoxing'an Mountains, including forest-swamp, shrub-swamp, marsh, moss-swamp and so on. These kinds of wetlands effect significantly on regulating peak, storing precipitation, conserving soil and water as well as improving microclimate. Peat swamp as the representative wetland of Xiaoxing'an Mountain was studied, in order to research on the flora, vegetation type, physical and chemical properties, especially on the content of organic carbon, and to analyze the relativity, so that the scientific foundation could be provided.The main results are as followed:(1)Seed plants of peat swamp in Xiaoxing'an Mountains contained 63 families,184 genera and 339 species, including 1 family,4 genera,4 species of gymnosperms and 67 families,193 genera,358 species of angiosperms, which account for 49.22% of total families, 24.83% of total genera and 12.93% of total species of Northeastern China. The families of seed plants could be divided into 4 distribution types and 4 forma; genera 12 distribution types and 9 forma; species 15 distribution types and 18 subtypes. The geographical elements of families, genera and species in this study area mainly belong to temperate zone.(2)The soil bulk density of the five typical swamp soil varied from 0.06 g-cm-3 to 0.74 g-cm-3. The capillary porosity changed between 49.54%-59.95%, non-capillary porosity 31.69%?12.75%, among which the capillary porosity of Pseudocuraica marsh was the largest, both the non-capillary porosity and general porosity of Larix gmelinii-Ledum-Sphagnum wetland were the largest. The soil maximum moisture capacity, capillary water capacity, and the minimum moisture capacity of Larix gmelinii-Ledum-Sphagnum wetland were 1586.57%,1007.71%and 882.70%, respectively.(3)The PH of these 5 swamps were completely lower than 6.0. Among which Larix gmelinii-Ledum-Sphagnum wetland had the largest organic matter content with each soil layer larger than 800 g.kg-1. The average total N content varied from 3.41 g.kg-1 to 13.78g.kg-1 the average hydrolysis N content changed between 60?1100 g.kg-1, the total P content changed between 0.47-1.26g.kg-1, the available P content represented that the one of surface was larger than the lower, and decreased with the layer deeper, in addition that the available P content was higher than 30mg.kg-1(4)The order of the average SOC content was:Larix gmelinii-Ledum-Sphagnum wetland> Pseudocuraica marsh> Betula ovalifolia-Vaccinium-Carex> Carex swamp>Betula platyphylla-Betula ovalifolia-Deyeuxia angustifolia> contrast area, with the SOC content of Larix gmelinii-Sphagnum wetland was 477.69g.kg-1, which was 16.06 times higher than the contrast area. The average carbon density was in a order of:Pseudocuraica marsh> Betula ovalifolia-Vaccinium-Carex> Carex swamp> Betula platyphylla-Betula ovalifolia-Deyeuxia angustifolia> Larix gmelinii-Ledum-Sphagnum wetland> the contrast area. The carbon density of the Pseudocuraica marsh was the highest (83.19kg.m-3), while that of Larix gmelinii-Ledum-Sphagnum wetland was relatively low (48.03kg.m-3), and they were 3.15 and 2.03 times that of the contrast area respectively. The carbon content of the 0-40cm soil layer was ranked as follow. Pseudocuraica marsh> Betula ovalifolia-Vaccinium-Carex> Carex swamp> Betula platyphylla-Betula ovalifolia-Deyeuxia angustifolia> Larix gmelinii-Ledum-Sphagnum wetland> the contrast area. While that of the Pseudocuraica marsh was up to 33.6 thousand t.km'2, and that of the Larix gmelinii-Ledum-Sphagnum wetland was 12.7 t.km-2 thousand.(5) The SOC content of these 5 swamp were in a significant negative correlation with soil bulk density(r=-0.879, P=0.0000), and the fitting results were exponential relationship (R2=0.851). It is in a significant positive correlation with non-capillary porosity(r=0.628, P=0.011). Besides, the SOC were highly significantly related with total N, hydrolysis N content and available P (r=0.901, r=0.891, r=0.825), and were significantly correlated with full P (r=0.690). The SOC content of these 5 kinds of wetland soil were in a power function relationship with soil total N (R2=0.912), and in a linear relationship with both the hydrolysis N and available P (R2=0.843, R2=0.68).