A quantitative study of the influence of soil organic carbon and pore characteristics on the stability of aggregates of the karst peak-cluster depression area in Southwest China

• Published in: Journal of soils and sediments Vol. 23; no. 1; pp. 312 - 330
• Main Authors: Wei, Hui, Deng, Yusong, Huang, Juan, He, Ling, Tang, Qiuyue, Xiao, Yan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2023; Springer Nature B.V
• Subjects: Aggregates; Agricultural production; Agriculture; Agrochemicals; Carbon; Clusters; Cohesive soils; Cultivated lands; Cultivation; Desertification; Earth and Environmental Science; Ecological effects; Environment; Environmental Physics; Fertilizers; Fruit cultivation; Human impact; Karst; Land use; Mechanical failure; Mineral fertilizers; Multivariate statistical analysis; Organic carbon; Organic soils; Particulate organic carbon; Plantations; Pores; Porosity; Quantitative research; Sec 3 • Remediation and Management of Contaminated or Degraded Lands • Research Article; Slaking; Soil; Soil aggregates; Soil improvement; Soil porosity; Soil properties; Soil Science & Conservation; Soil stability; Soil structure; Soil texture; Soils; Stability; Stability analysis; Storage; Structural stability; Texture; China; Computed tomography (CT) scan; Aggregate pore; Aggregate stability; The peak-cluster depression area; Soil organic carbon
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-022-03318-5

Purpose Rock desertification is the most serious ecological problem in karst areas and can easily cause soil structure instability. The aim of this work was to analyze the influences of organic carbon, carbon components and pore structural differences on the stability of aggregates in rocky desertification areas. Materials and methods Soil samples were collected from the karst peak-cluster depression area in Southwest China. Soil aggregate stability was determined by the Le Bissonnais (LB) method. The relationship between variables was analyzed via the structural equation model (SEM). Results and discussion There were significant differences in the stability of aggregates among different land uses in the study area: secondary forest (SF) > coppice forest (CF) > plantation forest (PF) > citrus plantation (CP) > cultivated land (CL). The main crushing mechanisms of aggregates were slaking and mechanical failure. Aggregate pores were mainly < 30 μm storage pores, with pore throat diameters concentrated in the 0–20 μm range, which was associated with the cohesive soil texture of the study area. The pore connectivity of aggregates was better in SF and CF, followed by PF, while CP and CL had lower colloidal material contents, isolated pore structure and poor connectivity due to the heavy application of inorganic fertilizers and influences from human disturbances. Conclusions SEM analysis showed that SOC and POC determined aggregate stability, mainly by directly or indirectly influencing aggregate porosity and the number of storage pores. The POC was the main variable in organic carbon composition to determine the pore characteristics and stability of aggregates. To meet the bidirectional demand of production and improvement of soil structure, it is necessary to rationally distribute fertilizer and reduce disturbance frequency in agricultural production land.