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Garden with Insight v1.0 Help: The next-day and end-year functions


The simulation proceeds by carrying out some calculations on a set of data for every simulated day. The calculations are grouped into sets of instructions called functions. In brief, the simulation runs like this:

 
garden next-day function 
  weather next-day function 
    (for each soil patch) soil patch next-day function 
      (for each plant in the soil patch) plant next-day function 

In this section of the help system is a brief description of each of the functions, or sets of instructions, called by the next-day functions. You might find that reading through these descriptions in order works best, because later functions sometimes refer to things that were calculated in earlier functions. To read through the functions in order, either keep returning to this page (using the Back button) or use the arrow buttons to move through the functions.

Note that this description of the models is not complete, but a quick run-through. If you don't understand these explanations, see the explanations from EPIC for more information and look in any soil science, agronomy, or botany textbook.

garden next-day function 
  weather next-day function 
    interpolate long-term daily means from monthly means 
    calculate today's mean for maximum temperature, radiation, relative humidity 
    generate today's precipitation (if any) 
    generate today's minimum and maximum temperature 
    generate today's solar radiation 
    generate today's relative humidity 
    generate today's mean wind speed 
    generate today's wind direction 
  (for each soil patch) soil patch next-day function 
    add organic matter from pulled plants to mulch 
    calculate today's soil cover index 
    calculate today's albedo 
    calculate today's soil temperature for each layer 
    calculate today's wind erosion 
    if the mean temperature is above freezing, 
      melt some snow 
      calculate today's runoff and water erosion from rainfall 
    if the mean temperature is below freezing 
      add to the amount of snow on the soil patch 
    calculate the amount of nitrate that entered the soil in rainfall 
    calculate the amount of nitrate that entered the soil in irrigation water 
    calculate percolation and lateral flow 
    calculate potential soil evaporation 
    (for each plant in the soil patch) 
      calculate potential plant transpiration 
    calculate actual soil evaporation 
    recalculate water table depth 
    automatically irrigate if necessary 
    calculate runoff and water erosion from irrigation water 
    do nutrient cycling 
    (for each plant in the soil patch) 
    plant next-day function before water and nutrient allocation function 
      [if annual plant and one year old, die (if dead, leave next-day function) 
      accumulate vernalization units  
      if a seed, check to see if germination is complete 
        (if still a seed, leave next-day function) 
      accumulate heat units and calculate heat unit index 
      if perennial, check to see if should be dormant 
      calculate general temperature growth constraint 
      calculate leaf area index 
      calculate height and root depth 
      calculate damage from frost and short day length 
      figure if have died from frost (if dead, leave next-day function) 
      if not dormant or too cold, calculate root growth constraints for layers] 
    (back to soil patch)  
    allocate water to plants 
    (for each plant in the soil patch) 
    plant next-day function between water and nutrient allocation function 
      [if a seed, or dead, or dormant, or it is too cold, leave 
      if optimal water uptake chosen, change water use to optimal 
      calculate aeration growth constraint 
      calculate potential biomass increase (new growth)] 
    (back to soil patch)  
    allocate nutrients to plants 
    (for each plant in the soil patch) 
    plant next-day function after water and nutrient allocation function 
      [if a seed or dead, leave 
      if not too cold to grow and not dormant, 
        calculate general growth constraint 
        decide if should move to next stage of growth 
        figure actual increase in biomass 
        allocate new biomass among shoots, roots, fruits 
        decay fruits if old 
      if not too cold to grow (even if dormant), 
        reduce biomass if water-stressed and senescent 
     do drawing portion of next-day function 
        if just emerging from a seed, make first internode and leaves 
        if have just started reproduction, tell all plant parts to switch over 
        add new and remove lost biomass from plant parts 
        (for each drawing plant part) next-day function 
          meristem next day 
          internode next day 
          leaf next day 
          inflorescence next day 
          flower/fruit next day] 
    (back to soil patch)  
    automatically fertilize if necessary 
    calculate how much nutrient was lost in eroded soil 
    settle the soil if it rained 
    figure the nitrate carried up to the top of the soil during evaporation 
    remove eroded soil from the soil profile

End-year functions

Garden end year function 
  Weather end year function 
    calculate long-term adjustment factors 
  (for each soil patch) soil patch end year function 
    change pH for effect of fertilizations during year 
    attempt to auto-control pH 

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Updated: May 4, 1998. Questions/comments on site to webmaster@kurtz-fernhout.com.
Copyright © 1998 Paul D. Fernhout & Cynthia F. Kurtz.