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

reduce standing dead for decomposition to flat residue
Each day a small portion of the standing dead biomass in all of the plants in each soil patch decays into flat residue in the top soil layer of the soil patch. This simulates the falling of dead leaves and stems from plants as well as the eroding of nutrients from dead plant parts with the action of rain. The amount of material removed from the standing dead plant matter depends on the amount of rainfall, snowmelt and irrigation (automatic and using tools) today, though a very tiny proportion (0.1 percent) will decay even with no rain. The decomposition is accompanied by movement of N and P in the standing dead biomass into fresh organic N and P in the top soil layer flat residue.

reduce mulch residue for decomposition to flat residue
In the same way that standing dead biomass decays into flat residue, residue in the mulch layer decays into flat residue in the top soil layer each day. Mulch flat residue accumulates from plants that were pulled, harvested, or reseeded. The amount of mulch residue decaying into flat residue is determined by today's rainfall, though a small proportion (one percent) will decay without rain. Some of the fresh organic N and P in the mulch moves into the top soil layer flat residue along with the decaying plant matter.

reduce flat residue for mineralization to organic matter and labile N and P
Flat residue in each soil layer decomposes into organic matter at a rate determined by the decay rate constant, which is calculated when mineralization of fresh organic N and P are calculated. Remember that fresh organic N and P is found in the flat residue. Since only 20% of the material lost from the flat residue during mineralization is added to the organic matter, 80% of the flat residue decay is lost to the atmosphere through gases such as methane.

reduce organic matter for mineralization to labile N and P
After mineralization of active organic N and P are calculated, an amount of organic matter is subtracted which is proportional to the amount of active organic N lost from the organic matter. It seems a bit like the tail wagging the dog to calculate the movement of nitrogen before the movement of carbon, but it amounts to the same thing.

add to organic matter for mineralization from flat residue
Remember that mineralization of fresh organic N and P result from the action of soil microbes on the flat residue. For that reason that only 80% of the material produced during fresh organic N and P mineralization is transferred to the nitrate or labile P pools. The remaining 20% is added to the organic N and P compartments in the organic matter as the remains of the dead microbes. A corresponding addition to the organic matter compartment is made here to represent the addition of soil microbes to the organic matter.

calculation of rainfall, snowmelt, auto irrigation, watering using a tool, carbon cycling, movement of fresh organic N with decomposition, movement of fresh organic P with decomposition, mineralization of active organic N, mineralization of organic P, fresh organic N mineralization, fresh organic P mineralization
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Updated: March 10, 1999. Questions/comments on site to webmaster@kurtz-fernhout.com.
Copyright © 1998, 1999 Paul D. Fernhout & Cynthia F. Kurtz.