Patent ID: 8924031

Claim:
A method for managing the irrigation of plants comprising: a) mapping a geographical area subject to irrigation into two or more target control areas; b) determining a diel progression of a plant canopy temperature change, T s , for each of said control areas comprising: 1) measuring and recording a predawn canopy temperature, T e , of plants in the vicinity of said control areas; 2) measuring and recording a mean canopy temperature, T rmt,t , of plants in each of said control areas over a time interval, τ, during a daylight time, t+nτ, where n is an integer greater than or equal to 0; 3) measuring and recording over each said time interval, τ, during the course of a day, a mean reference canopy temperature, T ref , for plants of the same species grown under well-watered conditions in a reference area in the vicinity of said geographical area wherein the value of T ref which is measured coincident with the time as said T rmt,t for any control area is measured, is T ref,t ; and 4) determining the diel progression of the canopy temperature change, T s , for each of said control areas at each said time, t+nτ; c) determining a water stress index value, WSI, for each of said control areas at each said time, t+nτ; d) comparing each of said WSI values for each of said control areas to a threshold water stress index value, WSI e — psp , wherein said WSI e — psp is specific for said plant in said geographic area, and 1) for each of said WSI which is greater than or equal to said WSI e — psp , adding a unit to a WSI register to provide an integrated WSI, WSI e — i orWSI e — t , for each said control area; e) comparing said WSI e — i or WSI e — t for each of said control areas to an encoded set-point value, WSI e — ip , for a predetermined time period, and generating an irrigation signal for irrigation, or automatically initiating irrigation, of any control area wherein said integrated WSI is greater than or equal to said WSI e — ip .