退耕还林类型对黑土表层土壤活性有机碳分布特征的影响1）

摘要

以东北黑土区退耕还林地落叶松（ Larix gmelini）林、樟子松（ Pinus sylvestris var．mongolica）林、水曲柳（Fraxinus mandshurica）林、美青杨（Populus nigra var．italica×P．cathayan）林表层（0～10 cm）土壤为研究对象，测定土壤热水浸提有机碳、颗粒有机碳（粒径＞53μm）、易氧化有机碳、土壤碳库管理指数等指标，分析不同退耕还林地表层土壤活性有机碳组分的差异。结果表明：退耕还林地土壤活性有机碳组分，以颗粒有机碳质量分数及其占土壤总有机碳的比例最大，变化范围分别为6．88～12．66 g· kg－1、17．40％～27．47％，其次为易氧化有机碳，热水浸提有机碳最低；与撂荒地相比，4种退耕还林地均显著提高了土壤热水浸提有机碳、颗粒有机碳、易氧化有机碳质量分数以及各组分活性有机碳的分配比例。落叶松林、樟子松林、水曲柳林、美青杨林土壤碳库管理指数，比撂荒地分别提高了19．48％、18．62％、48．86％、51．97％。退耕还林对黑土土壤活性有机碳质量分数、土壤碳库管理指数具有显著的促进作用，且表现出阔叶林的促进效果明显优于针叶林。%We studied the indicators representing soil labile organic carbon from topsoil ( 0-10 cm ) of converting cultivated lands into forestlands in typical black soil region by measuring , calculation and analyzing hot-water extractable carbon , particulate organic carbon , readily oxidizable carbon , soil carbon pool management index , and other indices .Four conver-ted forestlands including Larix gmelini, Fraxinus mandshurica, Pinus sylvestris var.mongolica, and Populus nigra var.ital-ica×P.cathayan plantations were selected as test objects , and the abandon land was as the comparison .The concentration of soil particulate organic carbon and the percentage ratios of soil organic carbon were higher than other labile organic car -bon, ranging in 6.88-12.66 g· kg-1 and 17.40%-27.47%, respectively, and followed with readily oxidizable carbon , hot-water extractable carbon .Different reafforestation lands improved the concentration of soil hot-water extractable carbon , particulate organic carbon and readily oxidizable carbon and the percentage ratios of soil organic carbon .Soil carbon pool management indexes of Larix gmelini, Fraxinus mandshurica, Pinus sylvestris var.monglo ica, and Populus nigra var. itali-ca×P.caht ayanplantations were increased by 19.48%, 18.62%, 48.86%and 51.97%, respectively, compared with aban-doned land .Our results indicated that reafforestation had great potential to improve activity of soil labile organic carbon and carbon pool management index in typical black soil region , and the broadleaf forest was better .