Note: This page is no longer being maintained and is kept for archival purposes only.
For current information see our main page.
GWI Kurtz-Fernhout Software
Developers of custom software and educational simulations.
Home ... News ... Products ... Download ... Order ... Support ... Consulting ... Company
Garden with Insight
Product area
Help System
Quick start

Garden with Insight v1.0 Help: Soil patch next day functions: automatically irrigate if necessary

At this point in the soil next-day function, after water has entered the soil from rainfall and filtered through the soil, after some water has evaporated out, and after the water table has had its effect on the soil water, automatic irrigation occurs.

These conditions can prevent auto irrigation:

gif/20000000.gif the auto irrigation option is turned off
gif/20000000.gif there was rainfall or snowmelt today (any amount)
gif/20000000.gif the soil was watered using a tool since the last day of simulation (any amount)
gif/20000000.gif the number of days that occurred since the last auto irrigation is less than a parameter (which prevents too-frequent watering)
gif/20000000.gif the total amount of irrigation water applied to this soil patch for the year exceeds a maximum parameter

If none of these conditions are met, automatic irrigation is triggered if the worst (smallest) water stress factor for all plants in the soil patch is less than a parameter. Since the plants have not yet calculated their actual transpiration or water stress, yesterday's water stress values are used to decide if auto irrigation is needed. Note that auto irrigation never occurs when there are no plants in the soil patch.

The actual amount of water applied in auto irrigation is the smallest of:

gif/20000000.gif the amount of water needed to bring all the soil layers to field capacity if the aspect "Ignore soil water content when irrigating" is "no"
gif/20000000.gif the maximum amount of water to apply in one irrigation application (a parameter) if the aspect "Ignore soil water content when irrigating" is "yes"
gif/20000000.gif the maximum amount of auto irrigation allowed for the year (for a soil patch) minus what has already been applied this year

If the calculated amount of water is lower than the minimum amount of irrigation water allowed in any application (a parameter), no application is made. The amount of auto irrigation water is added to the soil patch during the percolation function.

calculation of soil evaporation, water table depth, rainfall, snowmelt, watering using a tool, water stress factor, percolation
EPIC Auto Operations
Model contents

Home ... News ... Products ... Download ... Order ... Support ... Consulting ... Company
Updated: May 4, 1998. Questions/comments on site to
Copyright © 1998 Paul D. Fernhout & Cynthia F. Kurtz.