黄土高原不同退耕年限刺槐林地土壤侵蚀阻力

发布时间：2018-02-25 21:19

本文关键词： 侵蚀试验土壤黄土高原退耕还林土壤分离能力细沟可蚀性临界剪切力　出处：《农业工程学报》2017年10期 　论文类型：期刊论文

【摘要】：为了明确黄土高原植被恢复后不断蓄积的枯落物对土壤分离过程的影响,论文选取10、15、20、30、40a退耕年限刺槐林样地及对照样地,采集180个土壤样品用于土壤分离试验,在6组侵蚀动力条件下进行变坡水槽冲刷试验,结果表明:随着退耕年限的增大,刺槐林土壤结构趋于稳定且疏松多孔,40年刺槐林地与对照样地相比:容重降低12.9%、总孔隙度增加10.1%、毛管孔隙度增加62.4%,土壤有机质含量增加97.9%、水稳性团聚体增加112.3%。土壤分离能力均值随着林龄呈指数函数递减(R~2=0.82、P0.05)。在退耕0~40年范围内,在0~15 a内土壤分离能力下降迅速,对照、10 a刺槐林地、15年刺槐林地之间的土壤分离能力差异显著(P0.05),退耕15 a以后土壤分离能力趋于稳定。40 a林龄刺槐林细沟可蚀性比对照的细沟可蚀性降低86.3%,临界剪切力提高10.1%。土壤临界剪切力变化范围在4.15~4.78 Pa之间。细沟可蚀性的变化趋势与土壤分离能力变化趋势相似,相比临界剪切力的变化,细沟可蚀性的变化更能反映土壤分离能力的变化情况。
[Abstract]:In order to understand the effect of litter accumulation after vegetation restoration on soil separation process, 180 soil samples were collected for soil separation test in this paper. Under the condition of 6 groups of erosion dynamics, the flume scour test with variable slope was carried out. The results showed that: with the increase of the years of returning farmland, The soil structure of Robinia pseudoacacia forest tended to be stable and porous. Compared with the same plot, the bulk density of Robinia pseudoacacia forest in 40 years was decreased by 12.9, the total porosity increased by 10.1, the capillary porosity increased by 62.4%, the content of soil organic matter increased by 97.9, and the water stable aggregate increased by 112.3cm. The mean value of soil separation ability decreased with the forest age as an exponential function. The ability of soil separation decreased rapidly within 15 years. The soil separation ability of Robinia pseudoacacia forest for 15 years was significantly different from that of the control plantation for 10 years (P0.05N). After 15 years of returning to farmland, the soil separation ability tended to be stable. 40 years old Robinia pseudoacacia forest had a lower erodibility of 86.3% than that of the control, and the critical value was lower than that of the control. The critical shear stress of soil varies from 4.15 to 4.78 Pa. The change trend of erodibility of rill is similar to that of soil separation ability. Compared with the change of critical shear stress, the change of rill erodibility can better reflect the change of soil separation ability.
【作者单位】：中国科学院水利部水土保持研究所/黄土高原土壤侵蚀与旱地农业国家重点实验室;中国科学院生态环境研究中心/城市与区域生态国家重点实验室;北京师范大学地理学与遥感科学学院;西北农林科技大学水土保持研究所/黄土高原土壤侵蚀与旱地农业国家重点实验室;
【基金】：中国科学院“百人计划” 国家自然科学基金(41530858,41271287)
【分类号】：S714.7

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