The Influence Factors Of The Soil Carbon Storage In Typical Agricultural Area Of North China

Soil organic carbon is an important part of soil carbon pool,which is affected by many factors.Based on the date of Multi-purpose Regional Geochemical Survey and the Second National Soil Survey,this paper study the top soil carbon distribution and changes and the effect of surface soil carbon source/sink caused by climate change,landuse change,soil erosion and other aspects in northeastern China and north China from 1980 to 2000.The results indicated:1)The reserve of surface soil(0-20cm)organic carbon in North China is 716.31 Tg,the dry farm land surface organic carbon storage is 571.37 Tg,which is the lagest organic carbon pool,account for 79.79% of the total surface organic pool in the study area;The reserve of surface soil organic carbon in northeastern China is 877.91 Tg,the dry farm land also is the largest organic carbon pool in northeastern China,the value is 472.67 Tg,The second is forest,the reserve of surface soil organic carbons is 115 Tg,which account for 13.01% of the total surface organic pool in the study area,The reserves of paddy field is 93.88 Tg,accounting for 10.70% of the total surface organic pool in the study area;2)The temperature of North China rised 1.24 degrees centigrade,and the rainfall reduced 74.6mm in past 20 years,that make the reserve of surface organic carbon increased 2.03Tg;The temperature of northeastern China rised 1.58 degrees centigrade,and the rainfall reduced 86.78 mm in past 20 years,that make the reserve of surface organic carbon decreased 142.68Tg;3)The aggregate effect of the landuse changes results in an effect of soil carbon source of 2.74 Tg in North China,the dry farm land change to urban land has become the largest carbon source in study area,the organic carbon loss about 2.06 Tg,accounting for about half of the total carbon source;The aggregate effect of the landuse changes results in an effect of soil carbon source of 21.14 Tg in northeastern China,the forest change to dry farm land has become the largest carbon source in study area,the organic carbon loss about 15.57 Tg,accounting for about one-third of the total carbon source.Paddy field change to dry farm land,marsh change to dry land and grassland change to dry farm land also are comparatively large carbon source.4)Effect of soil erosion on organic carbon is mainly distributed in the Yongding River Basin and the middle reaches of the Yellow River in North China,through the analysis,the effect of erosion factors on dry land is most obvious,due to the soil erosion,soil organic carbon loss amounted to-10.57Tg;Soil erosion has no effect on the surface soil organic carbon in northeastern China.