| The classification of soil humic epipedon and the content of organic carbon are important markers to judge the soil fertility status and also an important indicator of soil classification.The content of organic carbon in the soil is great significance to the global carbon cycle,which has an important effect on global temperature change and greenhouse effect.Based on the study on the formation and mechanism of the surface of organic carbon and soil humus,seven provinces(cities and districts)in Heilongjiang,Jilin,Liaoning,Hebei,Inner Mongolia,Beijing and Tianjin were selected as the study area.The results showed by GIS,SPSS and Microsoft Excel,and the soil samples were collected 200 profiles,787 samples.from the soil samples at different climate(precipitation and temperature).Every profile collect the samples the same as genetic horizon,the soil physical and chemical properties of the soil samples were analyzed.Based on the criteria of soil diagnosis and diagnostic characteristics in the Chinese Soil System Classification Retrieval(3rd Edition),the characteristics of humus diagnosis and humus were determined,and the diagnosis of humus Layer and its corresponding laws,with a view to the soil survey classification and soil type to determine the theoretical basis.The results are as follows:(1)In the 200 profiles surveyed,according to the classification of the humus surface category in the "Chinese soil system classification search",the number of the surface area of the Mollic epipedon was 109,accounting for 54.5%of the total;91 for the Ochric epipedon,according for 45.5%of the total.There are 69 profiles Rh ? 0.4,to meet the Isohumic property,accounting for 63.3%of the Mollic epipedon,The maximum content of organic carbon was 60.79 g/kg and the minimum was 6.04 g/kg,with an average value of 19.67 g/kg.In the Ochric epipedon,the maximum organic carbon content is 45.54 g/kg,the minimum is 1.94 g/kg,and the average is 11.07 g/kg.(2)The distribution of the Mollic epipedon is affected by climatic factors(annual precipitation and annual average temperature).The profile of the Mollic epipedon of the survey is mainly distributed in Huolin Golfer Hohhot Town-West Wuzhumuqin Banner Jiren Gollet Town-Ulan Bora Gacha-Tuoketuo County East Area,87.2%of the sections have an average annual precipitation of>350 mm a From the south to the north of the temperature zone are Mollic epipedon surface distribution.(3)The distribution of the Umbric epipedon is less affected by climatic factors.The surveyed section with a Umbric epipedon is mainly distributed in the Branch right front flag Soren town-Daqing Du Meng Tai Kang town-Liuhe County-Han Zhang Xiang to the south,the average annual temperature above 0 ?,of which 85%of the Umbric epipedon distribution above 4 ?;Umbric epipedon distribution is not precipitation Influence,in a variety of precipitation within the distribution.(4)The geographical distribution of Isohumic epipedon is closely related to climatic factors.The surveyed sections with Isohumic properties are mainly distributed in Auluerqinqin-Taipusi Bauhokang Town-Zhangbei County east,Guyuan-Fengning-Changtu-Binxian-north of north,86%of the soil where the average annual rainfall>350 mm.There are more than 90%of the distribution of soil temperature range of 0?8 ?,(5)There was a significant correlation between soil surface and soil total carbon storage,and the annual average temperature and annual mean precipitation were significantly correlated with annual mean temperature.The relationship between surface carbon storage and annual mean temperature and annual precipitation can be characterized by the following equation:Z = 2.69*In(x)+ 33.6e-0.012y-43.57,where "Z" is the surface carbon storage,"x" is the annual precipitation,"y" is the annual average temperature(N = 200,r = 0.6079,P<0.01).The relationship between carbon storage and annual mean temperature and precipitation in 1 m can be expressed by the binary primary equation:Z = 13.93 + 0.0095x-1.03(N = 200,r =0.4905,P<0.01),where"Z" is the carbon storage in the section 1 m,others the same as above. |
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