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应用生态学报 ›› 2022, Vol. 33 ›› Issue (7): 1843-1852.doi: 10.13287/j.1001-9332.202207.013

• 生物土壤结皮专栏 • 上一篇    下一篇

物理结皮和生物结皮的斥水特征及其对水分入渗的影响

钟香艳1, 石辉1,2*, 李旋1, 赵一键1   

  1. 1西安建筑科技大学环境与市政工程学院/西北水资源与环境生态教育部重点实验室, 西安 710055;
    2陕西省土地整治重点实验室, 西安 714103
  • 收稿日期:2022-03-21 接受日期:2022-05-06 出版日期:2022-07-15 发布日期:2023-01-15
  • 通讯作者: *E-mail: shihui@xauat.edu.cn
  • 作者简介:钟香艳, 女, 1997年生, 硕士研究生。主要从事环境土壤研究。E-mail: 1336140714@qq.com
  • 基金资助:
    国家自然科学基金项目(41771309)和陕西省土地整治重点实验室开放基金项目(2019-JC16)资助。

Water repellent characteristics of physical and biological crusts and their effects on water infiltration

ZHONG Xiang-yan1, SHI Hui1,2*, LI Xuan1, ZHAO Yi-jian1   

  1. 1School of Environmental and Municipal Enginee-ring, Xi’an University of Architecture and Technology/Northwest China Key Laboratory of Water Resources and Environmental Ecology, Ministry of Education, Xi’an 710055, China;
    2Shaanxi Key Laboratory of Land Reclamation Engineering, Xi’an 714103, China
  • Received:2022-03-21 Accepted:2022-05-06 Online:2022-07-15 Published:2023-01-15

摘要: 土壤结皮是一种常见的自然现象,但由于结皮形成机制的不同,会产生不同的亲水性和斥水性,从而影响土壤的水力学特征与水文循环。本研究利用水滴穿透时间法测定了野外不同植被下物理结皮和生物结皮的斥水特征,利用扫描电镜观测了结皮的表面形态,并用微型入渗装置测定了结皮及其对照土壤的入渗特征。结果表明: 1)物理结皮的平均水滴穿透时间(WDPT)为3.3 s,对照为0.9 s,表现为亲水性;生物结皮的平均WDPT介于20.9~140.9 s,是无结皮的2.8~19倍,其中君迁子和刺槐林下的生物结皮平均WDPT分别为134.5和140.9 s。2)与对照相比,物理结皮累积入渗量、平均入渗速率和吸湿力分别降低了0~4.3%、3.5%~5.1%和27.2%~90.1%,生物结皮分别降低了0~25%、1.4%~28.2%和36.0%~84.9%。3)无论是否存在结皮,利用Philip模型拟合处理入渗数据均存在“曲棍球状”曲线;曲线上斥水性停止时间(WRCT)之前,点源微入渗以水平方向上的扩散为主,WRCT点以后以垂直方向上的入渗为主,土壤结皮的形成延长了该转折点的形成时间。综上,物理结皮是无机矿质颗粒堵塞了表层土壤,不影响斥水性的变化;生物结皮表现为斥水性有机物对土壤结构的影响,增强了其斥水性。物理结皮和生物结皮均会降低土壤的累积入渗量和平均入渗速率,但物理结皮主要影响土壤的吸湿力,对稳定入渗速率影响不大;生物结皮不仅降低了土壤吸湿力,还增加了稳定入渗速率。

关键词: 物理结皮, 生物结皮, 土壤斥水性, 入渗特征, “曲棍球状”曲线

Abstract: Soil crust is a normal natural phenomenon with different water hydrophilicity and repellency due to different formation mechanism, thus affecting soil hydraulic characteristics and hydrological cycle. In this study, we measured water repellent characteristics of physical and biological crusts under different vegetations in the field using water drop penetration time (WDPT). The surface morphology of crusts was observed using scanning electron microscopy, and the infiltration characteristics of crusts and their non-crust soils (control) was evaluated with micro-infiltration device. The results showed that: 1) The average WDPT of physical crusts and the control soils was 3.3 s and 0.9 s, respectively, indicating that both were hydrophilic. The average WDPT of biological crusts ranged from 20.9 s to 140.9 s, which was 2.8 to 19 times that of control, and that under Diospyros lotus and Robinia pseudoacacia was 134.5 s and 140.9 s, respectively. 2) Compared with the control, the cumulative infiltration amount, average infiltration rate and moisture absorption force of physical crusts decreased by 0-4.3%, 3.5%-5.1%, and 27.2%-90.1%, respectively, while those of biological crusts decreased by 0-25%, 1.4%-28.2% and 36.0%-84.9%, respectively. 3) Regardless of the presence of crusts or not, there were “hockey-stick-like” curves by using Philip model to fit infiltration data. Before the WRCT point in the “hockey-stick-like” curve, the point source infiltration was mainly horizontal diffusion. After the WRCT point, the infiltration was mainly vertical diffusion. The presence of soil crust prolonged the formation time of the turning point. In all, physical crusts formed by inorganic mineral particles blocking the surface soil did not affect water repellency, while biological crusts that reflected the effects of hydrophobic organic compounds on soil structure enhanced its water repellency. Both physical crusts and biological crusts decreased the cumulative infiltration amount and average infiltration rate of soil. Compared with the control, physical crusts mainly affected soil hygroscopicity, but with limited effects on the steady infiltration rate. Biological crust decreased soil hygroscopicity and increased steady infiltration rate.

Key words: physical crust, biological crust, soil water repellency, infiltration characteristic, “hockey-stick-like” curve