沈子雅, 程金花, 管凝, 曾合州, 秦建淼, 赵梦圆. 模拟降雨条件下灌草配置对坡面侵蚀泥沙颗粒分布的影响[J]. 农业工程学报, 2022, 38(11): 125-133. DOI: 10.11975/j.issn.1002-6819.2022.11.014
    引用本文: 沈子雅, 程金花, 管凝, 曾合州, 秦建淼, 赵梦圆. 模拟降雨条件下灌草配置对坡面侵蚀泥沙颗粒分布的影响[J]. 农业工程学报, 2022, 38(11): 125-133. DOI: 10.11975/j.issn.1002-6819.2022.11.014
    Shen Ziya, Cheng Jinhua, Guan Ning, Zeng Hezhou, Qin Jianmiao, Zhao Mengyuan. Effects of shrub-herb arrangements on the distribution of sediment particles eroded from slopes under simulated rainfall conditions[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(11): 125-133. DOI: 10.11975/j.issn.1002-6819.2022.11.014
    Citation: Shen Ziya, Cheng Jinhua, Guan Ning, Zeng Hezhou, Qin Jianmiao, Zhao Mengyuan. Effects of shrub-herb arrangements on the distribution of sediment particles eroded from slopes under simulated rainfall conditions[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2022, 38(11): 125-133. DOI: 10.11975/j.issn.1002-6819.2022.11.014

    模拟降雨条件下灌草配置对坡面侵蚀泥沙颗粒分布的影响

    Effects of shrub-herb arrangements on the distribution of sediment particles eroded from slopes under simulated rainfall conditions

    • 摘要: 为探究不同灌草配置方式对侵蚀泥沙颗粒的分布特征的影响,以种植胡枝子(Lespedeza bicolor Turcz.)及紫花苜蓿(Medicago sativa L.)的灌草褐土坡面为研究对象,分别进行降雨强度为30、60、90 mm/h的室内模拟降雨试验。设计3种灌草覆盖度(灌草覆盖度比例分别为1:2(Ⅰ)、2∶1(Ⅱ)、1∶1(Ⅲ))及3种灌草空间配置方式(灌木位于坡上(US)、坡中(MS)、坡下(LS)),以裸坡作为对照组,分析降雨条件下灌草不同覆盖度及空间配置交互作用下侵蚀泥沙颗粒分布特征。结果表明:1)粉粒是侵蚀泥沙中的主要颗粒组成,均值为73%。随着降雨强度的增大,侵蚀泥沙逐渐粗化。90 mm/h雨强条件下,不同灌草配置方式下的粉粒含量值中Ⅱ-LS配置最大(84.8%),Ⅲ-US最小(40.4%)。2)平均重量直径变化范围为0.023~0.078 mm,分形维数变化范围为2.184~2.740。分形维数和富集率大小规律与平均重量直径相反,细颗粒富集率均大于1。平均重量直径和分形维数的大小主要取决于粗颗粒(极细砂、细砂、中砂)的含量。3)灌草覆盖度和空间配置交互作用对泥沙颗粒分选的作用并不显著(P>0.05)。灌木位于坡下且灌木覆盖度50%、草本覆盖度25%时(即Ⅱ-LS),对坡面径流泥沙起到较好的水土保持效果。该研究可为华北土石褐土区水土保持措施布设提供理论参考与技术依据。

       

      Abstract: This study aims to explore the effect of different distribution modes of shrubs and herbs on the distribution characteristics of eroded sediment particles. The research object was selected as the slope with the cinnamon soil planted with shrubs (Lespedeza bicolor Turcz.) and herbs (Medicago sativa L.). The indoor simulation rainfall experiments were performed on the cinnamon soil slopes, with three types of rainfall intensity: 30, 60, and 90 mm/h, three types of vegetation coverage as the ratios of shrubs and herbs: 1:2 (denoted as Ⅰ), 2:1 (denoted as Ⅱ) and 1:1 (denoted as Ⅲ), and three types of vegetation patterns as the shrub locations: an up-slope (denoted as US), a middle-slope (denoted as MS), and a low-slope (denoted as LS). The experimental data of bare slope was used as the control group. A systematic analysis was made to determine the distribution characteristics of eroded sediment, and the interaction between the vegetation coverage and vegetation patterns under rainfall conditions. The results showed that: 1) The silt was the main particle composition of the eroded sediment on the slope, with a mean value of 73% under the various distribution of shrubs and herbs. The eroded sediment gradually coarsened with the increase in the rainfall intensity. Specifically, the maximum content of silt particles of 84.8% was found on the slope with the LS shrubs and the Ⅱ vegetation cover under the 90 mm/h rainfall intensity. Conversely, the minimum content of silt particles of 40.4% was on the slope with the US shrubs and the Ⅲ vegetation cover. 2) There was a significant effect of shrubs and herbs distribution on the Mean Weight Diameter (MWD), Fractal Dimension (D), and Enrichment Ratio (ER). The MWD varied from 0.023 to 0.078 mm, and the D varied from 2.184 to 2.740 in different distributions of shrubs and herbs. The size trends of D and ER were opposite to the MWD. Furthermore, the MWD and D values depended mainly on the content of coarse particles, including very fine, fine, and medium sand. Meanwhile, the fine particles (clay and silt) were enriched in the eroded sediment, whereas, the large particles (fine and very fine sand) were not easily lost on the slope. 3) The shrubs and herbs on the slope presented a relative impact on the fine-grained eroded sediment. The vegetation also greatly contributed to the sediment particles for a strong sorting action. However, there was no significant effect of the interaction of shrubs and herbs coverage and pattern on the sorting of sediment particles. The best effect of soil and water conservation on the slope runoff sediment was achieved, when the shrubs were located at the bottom of the slope, the fraction of coverage of shrubs was 50%, and the fraction of coverage of herbs was 25% (i.e., II-LS). This finding can provide a promising theoretical reference and a technical basis for the implementation of soil and water conservation measures in the earth-rock mountainous areas with cinnamon soil.

       

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