Evapotranspiration forecasting irrigation control system

A system for efficiently controlling irrigation, including:

• (a) means for receiving evapotranspiration data characteristics of an irrigation site;
• (b) means for receiving forecast meteorological data, including expected precipitation, for the irrigation site based on current meteorological conditions;
• (c) means for forecasting an ETo value, ETo', from the forecast meteorological data;
• (d) means for calculating a current soil moisture depletion value Cd.sub.t for the irrigation site as proportional to a previous soil moisture depletion value Cd.sub.t-1 for the irrigation site plus a daily depletion value Dd that depends upon the evapotranspiration data characteristics of the irrigation site, less an effective expected precipitation value, Peff, determined from the forecast meteorological data;
• (e) means for electronically computing a watering schedule based upon at least the current soil moisture depletion value Cd.sub.t ;
• and
• (f) communication means for applying the computed schedule to at least one irrigation control system to control at least one irrigation valve coupled to such control system in accordance with such schedule, wherein the computed schedule controls when and how much to irrigate through each irrigation valve.

A system for efficiently controlling irrigation, including:

• (a) at least one irrigation control system coupled to at least one irrigation valve;
• (a) means for receiving evapotranspiration data characteristics of an irrigation site;
• (b) means for receiving forecast meteorological data, including expected precipitation, for the irrigation site based on current meteorological conditions;
• (c) means for forecasting an ETo value, ETo', from the forecast meteorological data;
• (d) means for calculating a current soil moisture depletion value Cd.sub.t for the irrigation site as proportional to a previous soil moisture depletion value Cd.sub.t-1 for the irrigation site plus a daily depletion value Dd that depends upon the evapotranspiration data characteristics of the irrigation site, less an effective expected precipitation value, Peff, determined from the forecast meteorological data;
• (e) means for electronically computing a watering schedule based upon at least the current soil moisture depletion value Cd.sub.t ;
• and
• (c) communication means for applying the computed schedule to at least one irrigation control system to control at least one irrigation valve in accordance with such schedule, wherein the computed schedule controls when and how much to irrigate through each irrigation valve.

A computer program, residing on a computer-readable medium, for efficiently controlling an irrigation system, the computer program comprising instructions for causing a computer to:

• (a) receive evapotranspiration data characteristics of an irrigation site
• (b) receive forecast meteorological data, including expected precipitation, for the irrigation site based on current meteorological conditions;
• (c) forecast an ETo value, ETo', from the forecast meteorological data;
• (d) calculate a current soil moisture depletion value Cd.sub.t for the irrigation site as proportional to a previous soil moisture depletion value Cd.sub.t-1 for the irrigation site plus a daily depletion value Dd that depends upon the evapotranspiration data characteristics of the irrigation site, less an effective expected precipitation value, Peff, determined from the forecast meteorological data;
• (e) compute a watering schedule based upon at least the current soil moisture depletion value Cd.sub.t, the computed watering schedule defining when and how much to irrigate through each irrigation valve of at least one irrigation control system.