Nutrients simulated - Carbon (C), Nitrogen (N), and Phosphorus (P)

Algorithms from existing models - CENTURY & EPIC

Simulations performed on daily basis and can be continued in excess of 100 years

CARBON (C) COMPONENT

Carbon pools: (a) Residue - structural & metabolic; (b) humus - active, slow, & passive.

Carbon processes:

• aboveground and below ground litter input,
• litter decomposition and conversion to humus,
• C loss to respiration,
• particulate C movement with surface runoff and sediment, and
• dissolved organic C movement with runoff (surface & subsurface)

NITROGEN (N) COMPONENT

Nitrogen pools: (a) Residue - structural & metabolic; (b) humus - active, slow, & passive; (c) ammonium & nitrate.

Nitrogen processes:

• aboveground and below ground litter N input,
• N mineralization & immobilization,
• nitrification,
• denitrification,
• plant uptake,
• adsorption /desorption and movement of ammonium with sediment, and
• movement of dissolved forms of N (organic, ammonium, & nitrate) with runoff (surface & subsurface)

PHOSPHORUS (P) COMPONENT

Phosphorus pools: (a) Residue - structural & metabolic; (b) humus - active, slow, & passive; (c) inorganic - labile, active, & stable.

Phosphorus processes:

• aboveground and below ground litter P input,
• P mineralization & immobilization,
• plant uptake,
• stabilization/release reactions between organic and inorganic P pools,
• adsorption /desorption and movement of labile P with sediment, and
• movement of dissolved forms of P with runoff (surface & subsurface)