Summary of the Article:

1. Physical Crop Characteristics:
   - Leaf area index (L) is calculated based on specific leaf area and leaf carbon.
   - Stem area index (S) is a fraction of L, varying by crop type.
   - Crop heights at the top and bottom of the canopy are calculated using a formula.

2. Interactive Fertilization:
   - CLM simulates fertilization by adding nitrogen directly to the soil mineral nitrogen pool.
   - Fertilizer is prescribed based on crop functional types and varies spatially and temporally.
   - Fertilizer is applied slowly during the leaf emergence phase to minimize nitrogen loss.

3. Biological Nitrogen Fixation for Soybeans:
   - Soybean nitrogen fixation is calculated using the fixation and uptake of nitrogen module.
   - All soybeans are treated as nitrogen fixers, unlike natural vegetation.

4. Latitudinal Variation in Base Growth Temperature:
   - For spring wheat and sugarcane, the calculation of growing degree days (GDD) allows for latitudinal variation in base temperature.
   - This can slow GDD accumulation and extend the growing season in regions within 30°S to 30°N.

5. Separate Reproductive Pool:
   - Crops have a separate reproductive carbon and nitrogen pool, which helps determine crop performance through yield calculations.
   - During the grain fill stage, carbon and nitrogen allocation to the reproductive pool increases as allocation to other pools declines.

6. Tillage:
   - Tillage is represented as an enhancement of the decomposition rate coefficient.