Soil aggregate stability is significant obstacle to sustainable agriculture, and biochar is an effective way of improving the stability. However, it is still not clear which specific organic carbon components play a significant role in the stability of aggregates and the action of soil internal forces. The present study investigated the effects of biochar application on soil aggregate stability through analyzing the responses of soil active carbon fraction and electrochemical properties, soil internal forces, and soil aggregate stability to biochar application. The paper is well written with clear logic. Some comments should be considered before accepting publication.

1. The references cited in the MS are relatively dated. It is recommended that the authors incorporate more recently published relevant literature to strengthen the timeliness of the review.

2.  It is recommended that the detailed calculations pertaining to the electrochemical performance and soil internal forces be provided in the Supporting Information.

3. Soil electrochemical properties under biochar treatment for 365 days？

4. The data in Table 5 should be used the same order of magnitude.

5. Fig. 9, the differences between a and b, c and d?

This manuscript investigates the effects of maize straw biochar and wheat straw biochar on soil aggregate stability by linking active organic carbon fractions, soil surface electrochemical properties, soil internal forces, and aggregate breakdown behavior. The study provides valuable insights into the mechanisms underlying biochar-induced soil structural improvement. The combination of organic carbon fraction analysis and quantitative evaluation of soil internal forces represents a meaningful contribution to the field of soil physics and soil amendment research. However, several issues regarding methodological clarification, mechanistic interpretation, and presentation should be addressed to further improve the manuscript. Therefore, I recommend minor revision before publication.

1. The calculation of internal soil forces is a key innovation of this study. Specific details regarding this theoretical calculation should be provided.
2. The authors used Na⁺-saturated soil samples to quantify aggregate stability and internal forces. Please discuss how this treatment may differ from natural soil conditions and how it affects the interpretation of the results.
3. This paper emphasizes that biochar enhances aggregate stability by strengthening van der Waals forces and weakening electrostatic repulsions. However, the role of hydration repulsions appears to be rarely mentioned. Please explain why hydration repulsions are neglected.
4. Since soil electrolyte concentration varies substantially under different irrigation, salinity, and climate conditions, the authors should clarify how the laboratory electrolyte gradient relates to realistic soil environments.
5. Natural soils typically contain a variety of exchangeable cations and a complex electrolyte composition. The limitations of the experimental design in this study should be discussed in greater detail, and future research directions involving mixed electrolyte systems or field validation should be proposed.