黄土丘陵区林草退耕年限对土壤团聚体特征的影响

发布时间：2018-02-12 13:23

本文关键词： 退耕年限土壤水稳性团聚体平均质量直径分形维数　出处：《环境科学学报》2017年04期 　论文类型：期刊论文

【摘要】：随着国家退耕还林还草战略的实施、植被覆盖的变化,林、草地植被恢复进程中土壤团聚体特征的变化受到广泛关注.本研究以黄土丘陵区西部的官山林场退耕后栽植的刺槐林地、撂荒草地为对象,选取退耕年限为10、25 a的林、草地,采用湿筛法测定各样地0~30 cm土壤的水稳性团聚体组成,比较退耕还林、还草和退耕年限(10、25 a)对土壤水稳性团聚体平均质量直径(MWD)和分形维数(D)的影响.结果表明:退耕10 a的林地0~30 cm土层水稳性大团聚体含量(R0.25)、MWD和D分别为57.60%、1.91 mm和2.73;退耕25 a的林地分别为60.17%、1.88 mm和2.74;退耕10 a的草地分别为59.89%、1.82 mm和2.74;退耕25 a的草地分别为72.69%、2.71 mm和2.61.进一步分析证明,随着退耕年限的增加,土壤团聚性增强;但林草地的变化存在差异:恢复10 a阶段,土壤团聚性林地尚优于草地,25 a后草地优于林地.各样地土壤的SOC含量与R0.25呈显著正相关关系(p0.01),与D呈显著负相关关系(p0.05).退耕类型和退耕年限对土壤团聚性有显著影响.
[Abstract]:With the implementation of the national strategy of returning cropland to forest and grassland, the change of vegetation cover, forest, The change of soil aggregate characteristics in the process of grassland vegetation restoration was widely concerned. In this study, Robinia pseudoacacia forest land planted in Guanshan Forest Farm in the west of Loess Hilly region, abandoned grassland was taken as the object, and the forest and grassland with a conversion period of 1025 years were selected. The composition of water-stable aggregates in 30 cm soil of different plots was determined by wet sieve method, and the conversion of cultivated land to forest was compared. The results showed that the average mass diameter (MWD) and fractal dimension (D) of soil water stable aggregates were 57.60 mm and 2.73 respectively in 0 ~ 30 cm soil layer of forest land for 10 years. The forest land for 25 years was 60.17mm and 2.74, the grassland for 10 years was 59.89 1.82 mm and 2.74, and the grassland for 25 years was 72.692.71 mm and 2.61, respectively. Soil agglomeration increased with the increase of returning years, but the change of forest and grassland was different: the stage of restoration was 10 years. Soil agglomeration forest land was better than grassland forest land after 25 years. The SOC content of soil in various plots was significantly positively correlated with R0.25 and negatively correlated with D, and the type of returning cultivated land and the years of returning farmland had significant effects on soil agglomeration.
【作者单位】：西北农林科技大学水土保持研究所;
【基金】：国家自然科学基金(No.41471439,41271526) 中国科学院国际交流项目(No.2013T2Z0027)~~
【分类号】：S714;S812

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