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Garden with Insight v1.0 Help: Basic group

Minimum temperature today: The lowest temperature today, corresponding to the 'low' on the weather forecast. Hourly temperatures are not simulated, but this would normally probably represent the temperature sometime during the night.

Maximum temperature today: The highest temperature today, corresponding to the 'high' on the weather forecast. Hourly temperatures are not simulated, but this would normally probably represent the temperature sometime during the day.

Precipitation (rain or snow) today: The amount of rainfall or snowfall today. Once a day is determined to be a 'wet day' using probabilities, the amount of rain or snow is selected from a skewed normal distribution around the mean daily precipitation for this month.

Radiation today: The amount of solar radiation actually falling on the soil and plants today, after adjustment for cloud cover.

Relative humidity today: The simulated relative humidity today, which is the ratio of actual vapor pressure to saturated vapor pressure, or how much of the 'room' the air has for water vapor is actually occupied by water vapor. Important in evapotranspiration.

Wind speed today: The average simulated wind speed today. Wind speed is simulated using a modified exponential equation with the long-term monthly average wind speed interpolated (smoothed) for this day of the year and using a parameter to modify the equation.

Snow water content for patch: The total amount of water in this soil patch, including all soil layers.

Temperature today by layer: Temperature at the vertical center of each soil layer today. As you move down the soil profile, soil temperature becomes more and more buffered from changes in air temperature because soil water heats up and cools down more slowly than air.

Water content by layer: Amount of water in each soil layer. Compare this to the wilting point (amount in the soil when most plants permanently wilt), the field capacity (amount the soil holds after draining), and the porosity (greatest amount the soil can possibly hold).

Porosity by layer: Porosity, or percent pore space, is the percent of the total soil volume not taken up by soil solids -- sand, silt, clay, rocks and organic matter and therefore available to be taken up by water and air. Important in all soil water calculations.

N as nitrate by layer: Nitrogen as nitrate (NO3-) ions, which are readily available to plant roots. Increased by mineralization from fresh organic and active humus N and nitrification from ammonia; decreased by plant uptake, denitrification to ammonia, and loss in eroded soil.

P as labile by layer: Phosphorus as phosphate ions in solution and available to plants. Increased by mineralization of fresh organic and humus P; decreased by plant uptake, loss in eroded soil, equilibrium flow to active mineral P, and leaching by percolation and lateral flow.

Mulch residue: The amount of dead plant residue on the surface of this soil patch. Mulch comes from dead plants and soil amendments such as straw, and moves into flat residue in the top soil layer with rainfall. Mulch is dug into the soil when the soil is mixed.

Flat residue by layer: Flat residue is dead plant matter mixed in with each soil layer (as opposed to standing dead residue, which is dead plants that are still standing). 'Fresh organic' N and P are found in the flat residue and in soil microbes.

Organic matter by layer: The amount of stable organic matter (humus) in each soil layer. In order of increasing decomposition, the organic components in the soil layers go: plant standing dead residue, soil flat residue, soil organic matter, soil minerals in solution.

Plant age in days: The age of this plant in days. Age affects a few life-history stage changes (such as the start of vernalization after six months), but for most events the heat unit index is used.

Days seed has been germinating: The number of days this plant has been germinating and in the seed state.

Plant life history stage: This plant's development stage. The stages are: seed (germination), vegetative period (heat unit index exceeds 0.2), floral induction (enough photothermal units accumulated), floral initiation (enough thermal units accumulated), reproduction.

Plant is dead: If 'yes', this plant is completely dead, meaning no part of its biomass (dry weight) is considered to be alive. If 'no', at least some part of the plant is alive. Because plants are modular it is difficult to say exactly when a plant is dead.

Total live biomass including root: The total live biomass (dry weight) in this plant, not including standing dead biomass.

P in live plant biomass: The total amount of elemental phosphorus in the living parts of the plant.

N in live plant biomass: The total amount of elemental nitrogen in the living parts of the plant.
Heat unit index: The heat units (accumulated temperature over a minimum) accumulated for this plant divided by the heat units it is expected to accumulate in a normal growing season. Affected by minimum growth temperature and climate.
Leaf area index (LAI) today: The leaf area index (LAI) today. Leaf area index is the ratio of the total area of all the plant's leaves to the ground area covered by the leaves. LAI is important in determining the amount of new photosynthate (new biomass) made during photosynthesis.

N uptake today: The amount of nitrate N actually taken up by this plant today, considering root biomass distribution over the soil layers, water uptake (which limits nutrient uptake), and competition between plants in the same soil patch.

P uptake today: The amount of labile P actually taken up by this plant today, considering root biomass distribution over the soil layers, water uptake (which limits nutrient uptake), and competition between plants in the same soil patch.

Water use today: The amount of water taken from the soil by this plant today by soil layer. Depends on root biomass distribution in the soil layers, transpiration, and competition with other plants in the same soil patch.

Combined growth constraint today: A factor from zero to one for the combined constraint on above-ground plant growth. Equal to the lowest (worst) of the above-ground growth constraints: temperature, aeration (waterlogging), water, N stress, or P stress. Multiplied by new biomass.

Combined constraint on root growth today: A factor from zero to one for the combined constraint on root growth (separate for each soil layer). Equal to the lowest (worst) of the root growth constraints: temperature, aluminum toxicity, and soil strength. Reduces root biomass and water uptake.

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Updated: May 4, 1998. Questions/comments on site to webmaster@kurtz-fernhout.com.
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