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    李露, 曹伟, 赵鹏志, 王恩姮. 黑土区坡耕地与坡林地表土团聚体有机碳库差异[J]. 北京林业大学学报, 2016, 38(12): 46-53. DOI: 10.13332/j.1000-1522.20160078
    引用本文: 李露, 曹伟, 赵鹏志, 王恩姮. 黑土区坡耕地与坡林地表土团聚体有机碳库差异[J]. 北京林业大学学报, 2016, 38(12): 46-53. DOI: 10.13332/j.1000-1522.20160078
    LI Lu, CAO Wei, ZHAO Peng-zhi, WANG En-heng.. Differences of soil organic carbon storage in surface soil aggregates between sloping farmland and sloping forestland in black soil region.[J]. Journal of Beijing Forestry University, 2016, 38(12): 46-53. DOI: 10.13332/j.1000-1522.20160078
    Citation: LI Lu, CAO Wei, ZHAO Peng-zhi, WANG En-heng.. Differences of soil organic carbon storage in surface soil aggregates between sloping farmland and sloping forestland in black soil region.[J]. Journal of Beijing Forestry University, 2016, 38(12): 46-53. DOI: 10.13332/j.1000-1522.20160078

    黑土区坡耕地与坡林地表土团聚体有机碳库差异

    Differences of soil organic carbon storage in surface soil aggregates between sloping farmland and sloping forestland in black soil region.

    • 摘要: 以东北黑土区典型坡耕地(玉米)和坡林地(退耕还落叶松林和樟子松林)表层土壤为研究对象,分别在坡上、坡中上、坡中、坡中下、坡下5个坡位设置取样点采集非原状土,风干后将土壤筛分为2~5 mm、1~2 mm、0.5~1 cm、0.25~0.5 mm、0.25 mm 5个粒级团聚体,分别计算每个粒级土壤风干团聚体所占比例,测定各粒级土壤风干团聚体有机碳含量,并以此为基础计算土壤团聚体有机碳贮量。通过对比不同坡位、各粒级风干团聚体组成及其有机碳含量与贮量变化规律,探明黑土区不同土地利用方式下坡地土壤团聚体有机碳库对不同侵蚀类型的响应特征。结果表明:坡耕地土壤团聚体迁移、沉积过程不同于坡林地,耕地土壤2 mm团聚体的组成比例显著高于2种林地,并在坡下达到最高值(70.30%);有机碳含量均随团聚体粒级减小逐渐增加,樟子松林地内各粒级有机碳含量(25.57~142.60 g/kg)显著高于耕地(22.58~30.06 g/kg)和退耕还落叶松林地(21.58~66.53 g/kg);坡林地土壤团聚体有机碳贮量由坡上至坡下逐渐增加,相同坡位处土壤团聚体有机碳贮量均为樟子松林地退耕还落叶松林地耕地。研究结果证实了黑土区耕作侵蚀的存在及其对土壤团聚体、团聚体有机碳库分布的影响,同时印证了退耕还林是减缓坡地黑土耕作侵蚀、提升有机碳库的长效途径。

       

      Abstract: A typical sloping field in the black soil region of northeastern China was selected to analyze characteristics of soil aggregate composition and soil organic carbon of different size fractions under three different soil surface conditions, namely, sloping farmland, sloping forestland of larch (Larix gmelinii) converted from cultivated land, and sloping forestland of Mongolian pine (Pinus sylvestris var. mongolica). The sampling sites were situated at upper slope, upper to middle slope, middle slope, middle to lower slope, and lower slope positions. After air drying, the soil samples were sieved to 2-5 mm, 1-2 mm, 0.5-1 mm, 0.25-0.5 mm and 0.25 mm size classes and then their proportions were calculated. Soil organic carbon content was measured by vario TOC instrument manufactured by Elementar Company, and then the soil organic carbon storage of each aggregate size class and total aggregates was calculated. Results showed that: the transportation and deposition processes of soil aggregates in farmland were different from those in forestland mainly because of tillage effects. Compared with forestland, the proportion of soil aggregates 2 mm in farmland was significantly higher, especially in the lower slope position with a proportion of 70.30%. For all three types of sloping lands, soil organic carbon content of aggregates increased with their diameter decreasing. The most pronounced difference of soil organic carbon content was found in Mongolian pine forestland (25.57-142.60 g/kg), which remained highest in all positions compared with sloping farmland (22.58-30.06 g/kg) and sloping larch forestland (21.58-66.53 g/kg). Soil organic carbon storage showed a trend of increasing from upper to lower slope position in forestland; in the same slope position, it was the highest in the Mongolian pine forestland, followed by larch forestland, and sloping farmland in the last place. The results confirm the existence of tillage erosion in sloping land of this area as well as its effects on the redistribution of soil organic carbon. It also suggests that converting cultivated land to forest plays an important role as a type of measure to reverse ecological destruction and maintain higher productivity of black soil in the long run.

       

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