Abstract:In order to explore the effects of electrolytes on the stability of soil aggregates in karst areas, limestone soils under three land-use types (citrus groves, eucalyptus plantations and sloping cultivated land) from Mashan County, Nanning, Guangxi, were selected as research objects to analyze the stability and fragmentation process of soil aggregates at various concentrations of (0, 0.05, 0.10, 0.20, 0.50, 1.00 mol/L) electrolyte (NaCl, KCl, MgCl2) solutions. The results showed that: 1) The stability of the aggregates decreased as the concentration of the electrolyte solution increased. The particle size distribution of the aggregates decreased in the range of 3 ~ 5 mm and increased in the range of<0.25 mm. The stability of the aggregates decreased slowly after the electrolyte concentration>0.10 mol/L. The influences of different electrolytes on the stability of aggregates were: NaCl>KCl>MgCl2. 2) Most of soil aggregates in the fragmentation experiment were fragmented within the first minute, and the rate of aggregate breaking in electrolyte solutions was significantly faster than in pure water. 3) The study of the "Dynamic Stability Index of Aggregates", based on MWD values, showed that the dynamic stability of soil aggregates when disturbed by electrolytes was higher or lower in the following order for different land types: citrus groves, eucalyptus forests and sloping arable land. In summary, electrolytes significantly affected the stability of karst soil aggregates, and the stability of soil aggregates gradually was decreased with the increase of electrolytes concentration. The results of the study can provide a theoretical basis for soil erosion control in karst areas.