Department of Animal Sciences, Xizang Agriculture and Animal Husbandry College, Linzhi, 860000, China; Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences (CAS), Beijing, 100101, China; University of Chinese Academy of Sciences (UCAS), Beijing, 100049, China.
Department of Animal Sciences, Xizang Agriculture and Animal Husbandry College, Linzhi, 860000, China.
J Environ Manage. 2022 Aug 1;315:115145. doi: 10.1016/j.jenvman.2022.115145. Epub 2022 May 4.
Climate change and human activities have seriously degraded alpine grassland, potentially affecting soil particle size distribution (PSD) and further influencing the nutrient levels and erodibility of soil. Predicting the fertility and erodibility of alpine soil using multifractal dimensions of soil PSD could be used to enhance the management and restoration of degraded alpine grasslands. In the present study, we evaluated three types of alpine grasslands: alpine meadow (AM), alpine steppe (AS), and alpine desert steppe (ADS). Fencing and grazing management measures were conducted at sites containing each grassland type. Then, we analyzed the PSDs, erodibility, and other properties of soil in the 0-20 cm soil layer. Multifractal characterization of soil PSD was calculated using the fractal scale theory. The findings showed that grassland type significantly impacted soil nutrients and the multifractal dimensions of soil PSDs, whereas management measures affected soil erodibility significantly. The proportion of finer particles decreased as follows: AM > AS > ADS. Compared to grazing, fencing enhanced clay content and reduced the proportion of coarser particles under all three grassland types. AM had higher organic carbon and nitrogen levels than AS and ADS. Multifractal dimensions were highest for AM, with ADS having higher erodibility than AM and AS. Multifractal dimensions (except for correlation dimension) also had significantly positive relationships with soil organic carbon and available nutrient content and soil erodibility, but had significantly negative correlations with soil pH, bulk density, and electrical conductivity. Thus, the multifractal dimensions of soil PSDs could be used to characterize the erodibility and fertility characteristics of soil in alpine regions, providing a reference for assessing vegetation restoration measures in the Northern Tibet Plateau.
气候变化和人类活动严重退化了高山草原，可能影响土壤颗粒大小分布（PSD），并进一步影响土壤养分水平和土壤侵蚀性。利用土壤 PSD 的多重分形维数预测高山土壤的肥力和侵蚀性，可以用于增强退化高山草原的管理和恢复。本研究评估了三种高山草原类型：高山草甸（AM）、高山草原（AS）和高山荒漠草原（ADS）。在包含每种草原类型的地点进行了围栏和放牧管理措施。然后，我们分析了 0-20 cm 土壤层中的 PSD、侵蚀性和其他土壤特性。利用分形标度理论计算了土壤 PSD 的多重分形特征。研究结果表明，草原类型显著影响土壤养分和土壤 PSD 的多重分形维数，而管理措施显著影响土壤侵蚀性。较细颗粒的比例如下降低：AM>AS>ADS。与放牧相比，围栏在三种草原类型下均增加了粘粒含量并降低了较粗颗粒的比例。AM 的有机碳和氮含量高于 AS 和 ADS。AM 的多重分形维数最高，ADS 的侵蚀性高于 AM 和 AS。多重分形维数（除相关维数外）与土壤有机碳和有效养分含量以及土壤侵蚀性呈显著正相关，与土壤 pH、容重和电导率呈显著负相关。因此，土壤 PSD 的多重分形维数可以用来描述高山地区土壤的侵蚀性和肥力特征，为评估西藏高原北部植被恢复措施提供参考。
