Summary of the article on CLM5.0:

### Key Developments in CLM5.0

- CLM5.0 builds on the progress made in CLM4.5, with major updates to soil and plant hydrology, snow density, river modeling, carbon and nitrogen cycling, and crop modeling.
- The focus was on more mechanistic treatment of key processes and comprehensive representation of land use and land-cover change.
- Users can switch between different parameterizations via namelist control.

### Hydrology and Snow Updates
- Introduction of a dry surface layer-based soil evaporation resistance parameterization and a revised canopy interception parameterization.
- Spatially varying soil thickness, ranging from 0.4 to 8.5 meters, replaces the unconfined aquifer parameterization.
- Increased soil layer resolution, especially in the top 3 meters, to better represent the active layer in permafrost regions.
- Updates to the fresh snow density parameterization and increased maximum snow layers and amount to allow for firn formation.
- Integration of the CISM2 ice sheet model for Greenland, with two-way feedbacks between CLM and CISM.

### Plant Physiology and Nutrient Dynamics
- Introduction of a plant hydraulic stress routine to model water transport through vegetation.
- Replacement of the Ball-Berry stomatal conductance model with the Medlyn model.
- Implementation of the Fixation and Update of Nitrogen (FUN) model for plant nutrient dynamics, including flexible plant C:N ratios.
- Incorporation of the Leaf Use of Nitrogen for Assimilation (LUNA) model for photosynthetic capacity optimization.

### Land Use and Management
- Expansion of the crop model to include rice, sugarcane, tropical corn and soybean, and perennial bioenergy crops.
- Updates to fertilization rates, irrigation triggers, and crop phenology.
- Introduction of mass-based wood harvest and a more sophisticated building energy model.

### Other Improvements
- Transition to a more modular, object-oriented software structure with increased user configurability.
- Retention of older parameterizations under namelist switches for compatibility and user flexibility.
- Addition of multiple vertical soil layer structures with the ability to add more.