韩少杰　王恩姮　罗松　陈祥伟

(东北林业大学，哈尔滨，150040)



植被恢复对典型黑土表层土壤压缩性和承载能力的影响1)

韩少杰王恩姮罗松陈祥伟

(东北林业大学，哈尔滨，150040)

以恢复年限分别为14、36、50 a的落叶松人工林及相邻耕地表层土壤(0～10 cm)为研究对象，采用快速固结试验法，对土壤孔隙比、压缩指数、先期固结压力等指标进行测试，分析植被恢复对典型黑土表层土壤压缩性、承载能力的影响。结果表明：土壤孔隙比、压缩指数、先期固结压力，均随恢复年限的增加而增加，压缩指数、先期固结压力变化范围分别为0.231～0.399、4.2～100.0 kPa。落叶松林地土壤压缩指数、先期固结压力，均显著高于耕地土壤(p<0.05)；随植被恢复年限的增加，典型黑土表层土壤压缩性、承载能力逐渐提高，耕性有所增强。土壤力学性质指标与理化性质之间，表现出显著的相关性(p<0.05)；压缩指数与土壤黏粒比例、有机质质量分数之间关系更为紧密(p<0.01)；先期固结压力与土壤黏粒比例呈极显著负相关(p<0.01)。植被恢复导致土壤有机质质量分数的增加；土壤密度和黏粒比例的降低，是黑土表层土壤压缩性增加、土壤承载能力增强的重要原因。

植被恢复；黑土；土壤；土壤压缩性；土壤承载能力

To explore the changes of black soil’s compressibility and load support capacity in the restoration process, we took the topsoil (0-10 cm) in typical black soil region with vegetation restoration of 14, 36 and 50 years and the nearby farmland as test objects. We used fast oedometer test to measure and calculate soil mechanical parameters, soil void ratio, the compression index and the pre-compression stress. The soil void ratio, compression index, and pre-compression stress were increased with the increasing year of vegetation restoration. The values of compression index and pre-compression stress were varied in 0.231-0.399, 4.2-100.00 kPa, respectively. The compression index and pre-compression stress of soils at different age larch plantations were significantly higher than those of tillage soil (p<0.05), that is, the compression index, pre-compression stress and the tilth of soil were increased with the increasing of recovery years. The soil bulk density, clay proportion decreased and the mass fraction of organic matter were increased with the increasing of recovery years, and good linear regressions were between bulk density, clay proportion, the contents of organic matter and soil mechanical properties. Bulk density had a negative influence on compression index (p<0.05), the correlation between the contents of organic matter, clay proportion and compression index were closer (p<0.01). Clay proportion also had a negative influence on pre-compression stress (p<0.01). Therefore, degree of soil compaction decrease, soil compressibility and load support capacity were increased with the increasing of recovery years. The conceivable reasons for increasing the soil compressibility and load support capacity were the decrease of soil bulk density, clay proportion and the increase of the content of organic matter due to the vegetation recovery.

从土壤力学角度出发，探究压实过程中土壤性质的变化备受国内外学者关注[1-3]。通过土力学中固结试验得到的土壤压缩曲线，常用来表征土壤的压实行为；由压缩曲线进一步得到的土壤压缩指数和先期固结压力，则被广泛应用于评价土壤的压实敏感性和压实风险[4]。由于土壤压缩指数反映了土壤压缩性的大小，所以压缩性的大小与土壤耕性呈正相关[5]；先期固结压力又反映了土壤面对外界压力时的抵抗能力[6-7]；因此，土壤压缩指数、先期固结压力，可以反映出土壤承载能力的大小和耕性的优劣。

作为我国重要的商品粮生产基地，东北黑土区广泛采用机械化耕作。机械化作业，一方面，推进了农业集约化进程，提高了农业生产效率；……