Garden with Insight v1.0 Help: Soil patch next day functions: do nutrient cycling

Nutrient cycling in the soil patch includes cycling of nitrogen, phosphorus and carbon (decomposition). We will explain one at a time here.

Nitrogen

The nitrogen compartments in this simulation are:

nitrate (NO3-) anions in the soil solution
ammonium (NH4+) cations in the soil solution and adsorbed to micelles
fresh organic N in flat residue (dead plant matter) and live microbial biomass
active organic N loosely bound in organic matter
stable organic N tightly bound in organic matter

Daily nitrogen cycling functions, in the order they are carried out, are:

calculate equilibrium flow between active and stable N in organic matter
calculate nitrate entering soil from rainfall, snowmelt and irrigation
for the top soil layer, calculate nitrate lost in runoff, lateral flow, and percolation
for lower soil layers, calculate nitrate lost in percolation and lateral flow
calculate nitrification (ammonia to nitrate)
calculate volatilization (ammonia lost)
calculate mineralization of active organic N in organic matter
calculate mineralization of fresh organic N
transfer organic N with decomposing organic matter
calculate denitrification (nitrate to ammonia)

Phosphorus

The phosphorus compartments are:

labile phosphorus (available to plants) -- mostly as H2PO4- and HPO42- (but separate forms are not kept track of)
fresh organic P in flat residue and live microbial biomass
organic P in organic matter -- the loosely/tightly bound distinction is not made here
active mineral P loosely bound in mineral particles
stable mineral P tightly bound in mineral particles

Daily phosphorus cycling functions, in the order they are carried out, are:

calculate equilbrium flow between labile P and active mineral P
calculate equilbrium flow between active and stable mineral P
in the first soil layer, calculate labile P loss in runoff and percolation
in lower soil layers, calculate labile P loss in percolation
calculate mineralization of organic P in organic matter
calculate mineralization of fresh organic P
transfer organic P with decomposing organic matter

Carbon

The carbon compartments, in increasing order of decomposition, are:

standing dead plant matter, in individual plants
mulch on the soil patch surface, from plants pulled up or harvested
flat residue in each soil layer
organic matter (humus) in each soil layer

Daily carbon cycling functions are listed and described in a separate carbon cycling section.

Model contents