In this manuscript, the authors describe how they implemented an algorithm for pasture burning date into the LPJmL dynamic global vegetation model (DGVM). This sort of development is really important—ranchers in many parts of the world exert a strong influence on the frequency and timing of fire in grasslands, which can make a big difference on ecosystem dynamics. Most DGVMs have no such representation of fire management practices, especially an endogenous one (as opposed to one prescribed from input files). While it seems that other data limitations prevent this feature from being commonly used in general LPJmL runs, this capability is an important first step.

The authors do not just describe the technical capability, however. They also use the updated model to assess the separate and joint impacts of management fire and grazing on ecosystem carbon and nitrogen. The results show that both processes are important to represent in DGVMs.

I’m very happy to see a manuscript like this. The paper is mostly written well, and the figures are mostly good, with interpretations mostly well-supported. However, I have a major methodological concern along with a number of smaller questions and suggestions.

See attachment for details.

This manuscript presents a timely and relevant study that integrates a pasture-burning date algorithm into the LPJmL5 dynamic global vegetation model to assess the coupled impacts of fire and grazing on ecosystem carbon and nitrogen cycling in Brazilian grasslands. Using Chalumeau algorithm for climate-driven, management-based fire timing represents a valuable methodological advancement, particularly in regions where human land use plays a dominant role in shaping fire regimes. The paper is well-motivated, generally well-written that emphasize the interplay between grazing pressure, burning frequency, and biogeochemical feedback.

However, the study also has important limitations that should be more clearly acknowledged. Chief among these is the absence of any experimental or observational data used for model calibration or validation, despite the strong claims made about nitrogen and C: N dynamics. Additionally, several key biogeochemical processes—such as nitrogen recycling via manure and biological nitrogen fixation—are either under-described or not quantitatively supported. Such issues do not undermine the value of the study as a modelling exploration. However, they must be addressed more explicitly. Please see my detailed comments in the attached.