| The upper-middle reaches of the Yangtze River has a complex terrain and its soil erosion is severe, the ecological problem has attracted the attention of the world, its forest plays an important role in maintaining regional ecological security. At the same time, the regional forest also plays an important role in the carbon cycle.This paper used C-FIX model, using the daily mean value of meteorological data (temperature, solar radiation),remote sensing data(NDVI), the DEM to obtain the vegetation primary productivity NPP of regional scale in the upper-middle reaches of the Yangtze River on2001and2010, which compared with the results of CAS A simulation model, and analyzed its distribution pattern. Using the soil type method to estimate and analyze the upper soil layer (0-30cm) and lower (30-100cm) organic carbon storage and its spatial distribution. The results are as follows:(1)Using methods like IDW, BRF, OK, and SK to get a interpolation to each month of daily temperature datas and total radiation datas, which froms the upper-middle Yangtze River and its surrounding provinces’s207temperature meteorological stations and46radiation-meteorological stations. The results show that, the ordinary Kriging (OK) is best, and considering the factors of DEM in interpolating datas of temperature. Interpolating not only considers the meteorological stations of upper reaches of the Yangtze River basin, but also takes the surrounding provinces into the interpolation process, which will ensure the reliability of near point interpolation.(2)Until2010, in the forest ecosystem of upper-middle reaches of the Yangtze River,total NPP is1052.71Tg/yr and soil organic carbon content is545.49×108t, NPP and soil organic carbon accounted for54%ang59%,respectively.NPP is612.32gC/m2/yr on unit area, the upper and lower soil organic carbon density is42.40kg/m2,2.75kg/m2, which is far higher than the national average level.(3)The region of NPP, soil carbon and its distribution in the upper-middle Yangtze basin are mainly influenced by the comprehensive factors like climate, vegetation and soil type.they have significantly geographical differences. The general trend is the NPP of warm and moist middle region is greater than the cold upstream desert area, the highest per unit area of NPP appeared in the Yunnan-Guizhou Plateau, the lowest in Qinghai in southeast of Qinghai-Tibet Plateau and high-cold area of desert land; soil carbon density is highest in the northeast of Qinghai-Tibet Plateau and the southeastern mountains, the lowest in Sichuan basin. They are mattered with vegetation productivity and decomposition rate of soil organic, controlled by climate. At the same time, farming, stand age, forest harvesting also has effect on soil carbon.(4)From the point of view of the NPP seasonal distribution, mean value of NPP in spring and winter was significantly lower than that in the summer and autumn, in which NPP is the highest in summer.5-9month is the accumulation of the month NPP, accounted for68.4%of the total. This period is most suitable for vegetation growing because of the high temperatures, rainfall, water and heat conditions.From the point of view of the relationship between NPP and the terrain, the higher the altitude and slope, NPP smaller.In the plain area.The largest NPP appears in the height less than500meters and the slope less than5℃. The slope has little effect on NPP.(5)From2001-2010, the absolute change in the amount of NPP analysis, in2001the forest coverage rate34.08%,37.17%in2010, the forest coverage rate increased by0.03%, correspondingly, NPP increased13.06Tg. Yunnan-Guizhou Plateau, the largest increase in the Poyang Lake area of NPP; while along the Jialing Jiang Zhimin Tuo NPP largest decline. Overall, the Yangtze River NPP increase was greater than the upstream arehaas.(6)0-30cm soil organic carbon is greater than the30-100cm layer. The deeper the soil, soil carbon is smaller.And the lower layer of soil organic carbon content is much lower than the upper soil. In the0-30cm layer, the highest soil carbon appears in Qinghai Plateau and its west zone, the lowest in the Sichuan Basin, Yunnan-Guizhou Plateau and other regions. While the distribution of soil organic carbon in30-100cm layer is opposite to the upper.(7)In all vegetations, removing grass, arable land and non-forest land, in the six kinds of woodland types of NPP, NPP total is forest> shrub> evergreen coniferous forest> deciduous forest> Evergreen broadleaf forest> deciduous coniferous forest; vegetation NPP average is deciduous broad-leaved forest> evergreen broad-leaved forest> forest> evergreen coniferous forest> deciduous coniferous forest> shrub. For the different soil types, total NPP is red> purple soil> yellow-brown sugar> yellow> Alpine soil> paddy soil> brown. NPP average is brown soil> yellow> yellow-brown sugar> gray brown soil> red> gray brown soil> calcareous soil> purple soil> Cinnamon> yellow cinnamon soil, the fertility of brown soil is best(8)In all vegetation types, removing grass, arable land and non-forest land, in the six kinds of woodland types of soil organic carbon, Total organic carbon is forest> shrub> deciduous broad-leaved forest> evergreen coniferous forest> evergreen broad-leaved forest> deciduous coniferous forest. On the0-30cm layer, soil organic carbon density is evergreen coniferous forest> coniferous deciduous forest> shrub forest> forest> evergreen broad-leaved forest> deciduous coniferous forest. On the30-100cm layer, soil organic carbon density is evergreen broadleaf forest> deciduous coniferous forest> forest> deciduous broad-leaved forest> evergreen coniferous forest> shrub. The upper soil organic carbon is red> Alpine soil> yellow brown soil> yellow> yellow brown soil, sub-soil organic carbon is purple soil> red> yellow> paddy soil> yellow brown. |
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