| In order to reveal the typical black soil of the carbon and nitrogen nutrients of the time and space evolutive characteristics in Shuangcheng district,this study is based on typical black soil of Yongsheng town,Linjiang township,Nongfengmanzuxibozu town,Lequnmanzu township,Xinxing street,Xingfu street,Shuangcheng town,Shengfeng town,Lianxing town,Dongguan town,zhoujia street,Lanleng street,Dancheng town in Shuangcheng district were taken as the research object,using classical statistics method and ArcGIS software,typical black soil's organic carbon and total nitrogen of the spatiotemporal distribution characteristics were analyzed systematacially with 13 townships and streets in Shuangcheng district in 2002 and 2019.The main research results are as follows:(1)In 2002,the organic carbon content of the typical black soil in Shuangcheng district was 8.21?35.96 g·kg-1,with an average of 16.22 g·kg-1,total nitrogen content was 1.43?2.41 g·kg-1,average content was 1.84 g·kg-1,according to classification standard for soil nutrient content in the second national soil census,the average content of organic carbon was the medium level,the average of total nitrogen was rich levels,organic carbon and total nitrogen all belong to medium level variation.The highest average content of soil organic carbon in Lianxing town was 21.24 g·kg-1,the variable coefficient was 30.56%,and the content ranged from 15.4 to 19.52 g·kg-1.The average of soil organic carbon content in Lanleng Street was 12.18 g·kg-1,the variable coefficient was 16.83%,and the content of soil organic carbon was 8.21?14.25 g·kg-1.The average content of organic carbon in other towns and streets of Shuangcheng district was in the middle reaches,ranging from 13.95 to 19.64 g·kg-1,and the content of organic carbon ranging from 12.33 to 35.96 g·kg-1.The highest average content of soil total nitrogen in Yongsheng town was 2.06 g·kg-1,the variable coefficient was1.46%,and the soil content of total nitrogen ranged from 1.88 to 2.41 g·kg-1.The average soil content of total nitrogen in Dongguan town was 1.62 g·kg-1,the variable coefficient was 7.4%,and the soil content of total nitrogen ranged from 1.43 g·kg-1 to1.75 g·kg-1.The average contents of total nitrogen in other towns and streets in Shuangcheng district were in the middle reaches,ranging from 1.73 g·kg-1 to 2.03 g·kg-1,and the soil content of total nitrogen ranged from 1.43 g·kg-1 to 2.06 g·kg-1.(2)In 2019,the organic carbon content of the typical black soil in Shuangcheng district was 9.86?38.52 g·kg-1,with an average of 17.74 g·kg-1,the content of total nitrogen nutrient was 1.03?2.32 g·kg-1,with an average of 1.67 g·kg-1,according to classification standard for soil nutrient content in the second national soil census,the average content of organic carbon was rich level,the average content of total nitrogen was rich level,organic carbon and total nitrogen all belong to medium level variation;The average content of soil organic carbon in Lianxing town was 22.25 g·kg-1,the variable coefficient was 16.27%,and the soil content of total nitrogen ranged from16.66 g·kg-1 to 24.37 g·kg-1.The average soil organic carbon content of Lanleng Street was 12.51 g·kg-1,the variable coefficient was 14.39%,and the soil organic carbon content ranged from 9.86 g·kg-1 to 15.61 g·kg-1.The average content of the soil organic carbon in other towns and streets of Shuangcheng district was in the middle reaches,ranging from 14.85 g·kg-1 to 21.81 g·kg-1,and the soil content of organic carbon ranged from 12.28 g·kg-1 to 38.52 g·kg-1.The highest average soil total nitrogen content in Lianxing town was 1.97 g·kg-1,the variable coefficient was 4.06%,and the soil total nitrogen content ranged from 1.53 g·kg-1 to 1.94 g·kg-1.The average soil total nitrogen content of Lanleng Street was 1.28 g·kg-1,the variable coefficient was 14.06%,and the soil total nitrogen content ranged from 1.03 g·kg-1 to 1.41 g·kg-1.The average content of total nitrogen in other towns and streets of Shuangcheng district was in the middle reaches,ranging from 1.47 g·kg-1 to 1.82 g·kg-1,and the soil content of total nitrogen ranged from 1.25 g·kg-1 to 1.94 g·kg-1.(3)During the 17 years from 2002 to 2019,the average content of soil organic carbon with typical black soil in Shuangcheng district showed an increasing trend with an average increase of 9.37%,while the average content of total nitrogen showed a decreasing trend with an average decrease of 9.24%,the variable coefficient of organic carbon decreased by 2.46%,and the variable coefficient of total nitrogen increased by3.01%,both of which were weak variations.From the point of view of spatial distribution,the average content of organic carbon in Nongfengmanzuxibozu Town increased by 16.7%,the average content of organic carbon in Lanleng Street increased by 2.7%,and the average content of organic carbon in other towns and streets varied from 3.09 to 14.55%.The average content of total nitrogen in Lanleng district decreased by 28.89%,and the average content of total nitrogen in Dongguan town increased by0.62%.The average content of organic carbon in other towns and streets varied from1.11 to 18.13%.Through this study,it was found that the typical black soil of carbon and nitrogen nutrients in Shuangcheng district were unbalanced,and the spatial and temporal variability of carbon and nitrogen nutrients was large,which was mainly due to the influence of fertilization and the enhancement of human intervention. |
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