不同土地利用方式下三江平原东北部土壤有机碳和全氮分布规律

利用在全国采集的1400个典型农田剖面数据(其中在此研究区域有53个剖面),系统分析了不同土地利用方式下三江平原东北部土壤有机C和全N的分布规律。三江平原东北部典型农田0～20cm土壤有机C和全N的平均含量是22.7g/kg和1.84g/kg,20～100cm平均含量为13.0g/kg和1.08g/kg,不同土壤类型和种植作物下土壤有机C和全N分布没有显著性差异(p0.05)。与第二次土壤普查时三江平原东北部典型剖面土壤有机C和全N数据进行比较发现,0～20cm有机C和全N含量呈现下降趋势,而20～100cm呈现增加趋势。

Distributions of soil organic carbon and total nitrogen under different land uses in northeast of Sanjiang Plain

Sanjiang Plain is the biggest wetland in China, however through about 50-year development, the wetland area reduced to 959 000hm2 while the cultivated area increased to 5 569 000 hm2 in 2005, which caused obvious influences on the distributious of soil organic carbon and total nitrogen. So using the data of 1 400 typical profiles (53 representative profiles in Sanjiang Plain), we analyze the distributions of soil organic carbon and total nitrogen under different land uses in the northeast of Sanjiang Plain. The mean contents of soil organic carbon and total nitrogen at 0-20cm and 20-100cm soil depths of typical cropland are 22.7g/kg, 1.84g/kg and 13.0g/kg, 1.08g/kg respectively, however, the distributions of soil organic carbon and total nitrogon at 0-20cm and 20-100cm soil depths under different soil types and crops do not show significant differences (p>0.05). Compared with the corresponding data collected in the 2nd soil survey in 1980s, both soil organic carbon and total nitrogen show the declining tendency at 0-20cm soil depths and the increasing tendency at 20-100cm soil depth.