为了研究黑土区不同土地使用类型团聚体氮库及其分布，以东北黑土区坡耕地、退耕还落叶松林地、樟子松人工林地土壤作为研究对象，结合不同坡位，对不同粒径团聚体内氮质量分数及总储量进行对比分析，结果表明：坡耕地以＞2 mm粒径土壤团聚体为主，达到50％以上，樟子松人工林地、退耕还落叶松林地以＜2 mm粒径土壤团聚体为主；各土地利用类型＜0．5 mm粒径的土壤团聚体含氮质量分数均较高，但储量较低，坡下和坡中下的储量高于其他坡位；坡耕地各径级团聚体氮质量分数及总储量均为最低，总体氮库由小到大表现为坡耕地、退耕还落叶松林地、樟子松林地。坡耕地团聚体及氮库的再分布印证了耕作侵蚀的存在，退耕还林能够有效恢复黑土区氮库、维持碳氮平衡。%Aiming to understand the distribution pattern of nitrogen pool of sloping lands in the black soil region of Northeast Chi -na, sloping farm land, larch forest land converted from farm land , and Pinus sylvestris forested land were selected to ana-lyze characteristics of nitrogen content and storage of different aggregate sizes and slope positions for the quality assessment of black soil .The farm land was mainly composed of aggregates bigger than 2 mm, reaching more than 50%.On the contra-ry, larch forested land and P.sylvestris forested land were composed of aggregate smaller than 2 mm.Nitrogen content with-in <0.5 mm aggregates was higher for all three lands comparing to aggregates with bigger size , while nitrogen storage was lower because of its lower composition percent , and nitrogen storage in middle-down and down slope position was relatively higher.Nitrogen content and storage of sloping farm land was the lowest , with ascending order of farm land , larch forested land, and P.sylvestris forested land.The results confirmed the existence of tillage erosion in this region , and converting cultivated land into forest could be an effective way to regenerate soil nitrogen pool and maintain carbon -nitrogen balance of black soils .
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