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应用生态学报 ›› 2020, Vol. 31 ›› Issue (10): 3404-3412.doi: 10.13287/j.1001-9332.202010.025

• 研究论文 • 上一篇    下一篇

黄土高原生物结皮覆盖对风沙土和黄绵土溶质运移的影响

王芳芳1,2, 肖波1,2,3*, 孙福海1,2, 李胜龙1,2   

  1. 1中国农业大学土地科学与技术学院, 北京 100193;
    2农业农村部华北耕地保育重点实验室, 北京 100193;
    3中国科学院水土保持研究所黄土高原土地侵蚀与旱地农业重点实验室, 陕西杨凌 712100
  • 收稿日期:2020-04-13 接受日期:2020-08-10 出版日期:2020-10-15 发布日期:2021-04-15
  • 通讯作者: * E-mail: xiaobo@cau.edu.cn
  • 作者简介:王芳芳, 女, 1997年生, 硕士研究生。主要从事土壤物理与水土保持研究。E-mail: 18735429262@163.com
  • 基金资助:
    国家自然科学基金项目(41671221)和中国科学院“西部引进人才”项目(2019)资助

Effects of biological soil crusts on solute transport characteristics of sandy and loessal soils on the Loess Plateau, China

WANG Fang-fang1,2, XIAO Bo1,2,3*, SUN Fu-hai1,2, LI Sheng-long1,2   

  1. 1College of Land Science and Technology, China Agricultural University, Beijing 100193, China;
    2Key Laboratory of Arable Land Conservation in North China, Ministry of Agriculture and Rural Affairs, Beijing 100193, China;
    3State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling 712100, Shaanxi, China
  • Received:2020-04-13 Accepted:2020-08-10 Online:2020-10-15 Published:2021-04-15
  • Contact: * E-mail: xiaobo@cau.edu.cn
  • Supported by:
    National Natural Science Foundation of China (41671221) and the “Light of West China” Program of the Chinese Academy of Sciences (2019).

摘要: 干旱和半干旱地区生物结皮的普遍发育显著改变了表层土壤的结构与养分富集特征,但其对土壤养分迁移和淋失的影响目前尚不明确。本研究针对黄土高原风沙土和黄绵土上发育的藓类生物结皮,以Ca2+和Cl-为示踪离子开展溶质穿透试验,对有无生物结皮层及其覆盖下不同深度土壤的溶质运移特征进行了研究。结果表明: 在0~5 cm土层,生物结皮覆盖延缓了风沙土和黄绵土的溶质穿透过程,其Cl-的穿透时间比无结皮延长了3.83(风沙土)和2.09倍(黄绵土),而Ca2+则分别延长了2.50和2.73倍。生物结皮覆盖条件下,表层0~5 cm土壤溶质完全穿透所对应的孔隙体积数比下层5~10 cm土壤更高,且其穿透历时更长;其中,Cl-的穿透时间分别增加了67.3%(风沙土)和51.8%(黄绵土),Ca2+的穿透时间分别增加了8.0%和33.7%。生物结皮覆盖降低了土壤孔隙水流速(37.5%~70.2%);除风沙土的5~10 cm土层外,生物结皮使溶质弥散系数提高了1.73~6.29倍,使溶质弥散度提高了2.77~20.95倍。置换液完全穿透土壤后,风沙土和黄绵土的生物结皮层Ca2+含量显著高于无结皮,其分别比无结皮高4.14和2.58倍。研究证实,生物结皮覆盖能够提高表层土壤对养分的吸附与固持能力,从而减少土壤表聚养分的深层渗漏和流失,对干旱和半干旱地区退化土壤的肥力提升与植被恢复具有重要意义。

关键词: 穿透曲线, CDE方程, 风沙土, 黄绵土, 吸附作用

Abstract: Biological soil crusts (BSCs) greatly change surface soil structure and nutrient enrichment processes in arid and semiarid regions. However, their impacts on solute transport characteristics and nutrient loss are still not clear. In this study, the solute (Cl- and Ca2+) transport experiments were conducted on soils covered by moss-dominated BSCs and uncrusted soil on sandy and loessal soils on the Loess Plateau, respectively. We analyzed the solute transport characteristics of the BSCs covered soil and uncrusted soil in different soil depths (0-5 cm and 5-10 cm). The BSCs mulching generated delay effects on the solute breakthrough process of 0-5 cm soils. The breakthrough time of Cl- in the BSCs covered soil was 3.83 (sandy soil) and 2.09 times (loessal soil) longer than that in the uncrusted soil. The breakthrough time of Ca2+ in the BSCs covered soil was 2.50 and 2.73 times longer than that in the uncrusted soil. Due to the strong influence of BSCs mulching, the pore volume number of the complete solute breakthrough at 0-5 cm depth was higher than that at 5-10 cm depth in the BSCs covered soils. The breakthrough time of Cl- at 0-5 cm depth was increased by 67.3% (sandy soil) and 51.8% (loessal soil) by the BSCs as compared with that at 5-10 cm depth. The breakthrough time of Ca2+ at 0-5 cm depth was increased by 8.0% and 33.7% by the BSCs. The BSCs reduced soil pore water flow velocity by 37.5%-70.2% compared with the uncrusted soil. Except for the sandy soil at 5-10 cm depth, the BSCs increased the solute dispersion coefficient by 1.73-6.29 times and the degree of dispersion by 2.77-20.95 times compared with the uncrusted soils. After the complete breakthrough of solute, the content of Ca2+ in the BSCs layer (0-2 cm) was 4.14 and 2.58 times higher than that in the uncrusted sandy and loessal soils, respectively. In conclusion, our results indicated that BSCs could reduce the deep percolation and loss of nutrients accumulated in surface soil through improving their solute adsorption and retention abilities, which is of great significance for the improvement of soil fertility and vegetation restoration on degraded land in arid and semiarid regions.

Key words: breakthrough curve, CDE equation, sandy soil, loessal soil, adsorption