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草业学报 ›› 2024, Vol. 33 ›› Issue (10): 1-13.DOI: 10.11686/cyxb2023446

• 研究论文 •    

黄土高原典型草本植物根系分布特征及其对土壤理化性质的影响研究

刘芳(), 王佩佩, 曹玉莹, 刘俊娥, 周正朝()   

  1. 陕西师范大学地理科学与旅游学院,陕西 西安 710119
  • 收稿日期:2023-11-21 修回日期:2024-01-12 出版日期:2024-10-20 发布日期:2024-07-15
  • 通讯作者: 周正朝
  • 作者简介:Corresponding author. E-mail: zczhou@snnu.edu.cn
    刘芳(1999-),女,河南郑州人,在读硕士。E-mail: fliu@snnu.edu.cn
  • 基金资助:
    国家自然科学基金面上项目(42277320);陕西省杰出青年科学基金项目(2023-JC-JQ-27)

Root distribution characteristics of typical herbaceous plants and their effects on soil physicochemical properties on the Loess Plateau

Fang LIU(), Pei-pei WANG, Yu-ying CAO, Jun-e LIU, Zheng-chao ZHOU()   

  1. School of Geography and Tourism,Shaanxi Normal University,Xi’an 710119,China
  • Received:2023-11-21 Revised:2024-01-12 Online:2024-10-20 Published:2024-07-15
  • Contact: Zheng-chao ZHOU

摘要:

为控制黄土高原严重的水土流失,我国实施了大规模的植被恢复,生态环境得到改善。阐明植被恢复过程中不同根系类型对土壤性质的影响差异,有利于完善黄土高原植被恢复优选模式的系统性研究,为黄土高原后续生态恢复提供参考。本研究选取黄土高原自然恢复优势种长芒草(须根系)和铁杆蒿(直根系)为研究对象,以退耕一年的裸地为对照,测定根系特征与土壤理化性质,分析不同直径下根系分布规律及其与土壤理化性质的关系。结果表明:1)长芒草和铁杆蒿根系特征差异显著,须根系长芒草极细根(直径,D<0.5 mm)根长密度(RLD)和根表面积密度(RSAD)占比较高,分别为94.73%和90.20%。直根系铁杆蒿主根优势明显,表现出较高的根质量密度(RMD)、平均直径(RD)和根体积密度(RVD)。其中,铁杆蒿粗根RLD(16.28%)和RSAD(32.85%)的占比明显高于长芒草。2)与裸地相比,长芒草与铁杆蒿显著改善土壤结构,提高土壤稳定性。长芒草与铁杆蒿根系主要聚集在0~20 cm土层,对表层土壤的理化性质影响最大。其中,铁杆蒿群落土壤团聚体稳定性和土壤持水性最高,土壤团聚体平均重量直径(2.04 mm)、毛管持水量(24.69%)及饱和含水量(34.93%)分别是裸地的4.33、1.36和1.31倍。长芒草群落土壤有机质含量(7.23 g·kg-1)最高。3)植物根系特征显著影响土壤性质,细根RLD与RSAD对土壤理化性质的影响最显著。细根RLD和RSAD与土壤容重显著负相关(P<0.05),与土壤孔隙度显著正相关(P<0.05),极细根(D<0.5 mm)与有机质含量极显著正相关(P<0.01)。主成分分析结果显示,长芒草与铁杆蒿改善土壤性质的差异主要体现在土壤团聚体平均重量直径(MWD)、有机质含量(SOM)和土壤含水量(SWC)。

关键词: 黄土高原, 植物群落, 根系特征, 土壤理化性质

Abstract:

Extensive vegetation restoration has been implemented to control serious soil erosion on the Loess Plateau, China, and the ecological environment has improved. Understanding the beneficial effects of plant roots on soil properties will be helpful for further systematic research aimed at optimizing vegetation restoration on the Loess Plateau, and will provide a scientific reference for subsequent ecological restoration in this area. In this study, we focused on Stipa bungeana and Artemisia gmelinii growing naturally on the Loess Plateau. Land that had been abandoned for 1 year served as the control. The root characteristics of the two plant species and soil physicochemical properties were determined, the distribution of roots in different size classes and its relationship with the soil physicochemical properties were analyzed. The results showed that: 1) There were significant differences in root characteristics between S. bungeana and A. gmelinii. Compared with A. gmeliniiS. bungeana had higher root length density (RLD) and root surface area density (RSAD). In addition, the proportion of very fine roots (diameter, D<0.5 mm) was higher in S. bungeana (94.73%) than in A. gmelinii (90.20%). Compared with S. bungeanaA. gmelinii had an obvious taproot advantage, with a higher root mass density, mean diameter, and root volume density. The proportions of coarse roots RLD (16.28%) and RSAD (32.85%) were significantly higher in A. gmelinii than in S. bungeana. 2) Compared with bare land, the plots with S. bungeana and A. gmelinii showed significantly better soil structure and stability. The roots of S. bungeana and A. gmelinii were concentrated in the 0-20 cm soil horizon, which had the greatest influence on the physicochemical properties of the topsoil. The soil aggregate stability and soil water retention were highest in the plots containing A. gmelinii, and the mean weight diameter (MWD) (2.04 mm), capillary water capacity (24.69%), and saturated water content (34.93%) of soil in those plots were 4.33-times, 1.36-times, and 1.31-times higher than their respective values in soil in bare land. The soil organic matter (SOM) content (7.23 g·kg-1) was highest in the plots containing S. bungeana. 3) The plant root characteristics significantly affected soil properties. The RLD and RSAD of fine roots had the most significant effect on soil physicochemical properties, and were significantly negatively correlated (P<0.05) with soil bulk density and positively correlated with soil porosity (P<0.05). The proportion of very fine roots (D<0.5 mm) was significantly positively correlated (P<0.01) with SOM content. The results of principal component analysis showed that the MWD, SOM content, and soil water content were the soil properties showing the largest differences between plots containing S. bungeana and those containing A. gmelinii.

Key words: Loess Plateau, plant community, root traits, soil physicochemical properties