## 3 Background Information
### IRRINOV(r) Method  
This subsection presents the IRRINOV(r) (All versions of the IRRINOV(r) method are available at [[http://www.irrinov.arvalisinstitutduvvegetal.fr/irrinov.asp](http://www.irrinov.arvalisinstitutduvvegetal.fr/irrinov.asp)]([http://www.irrinov.arvalisinstitutduvvegetal.fr/irrinov.asp](http://www.irrinov.arvalisinstitutduvvegetal.fr/irrinov.asp))) method. This method, developed by Arvalis and its partners, proposes a guide to make irrigation decisions based on measurements of soil moisture sensors and pluviometers oriented to farmers. The method aims at answering the following questions: (1) When should irrigation be started, or when should watering devices be installed on the plot? (2) When should we start each watering cycle (\"Watering cycle\" is the action of an irrigation system performing a watering activity on all the plots engaged in the system. \"Watering cycle duration\" is the number of days between two consecutive waterings of the same plot)? (3) When should irrigation be stopped, or when should farmers withdraw the watering devices? A set of decision tables and recommendations are provided by IRRINOV(r) method to allow farmers to manage their irrigation system on a single plot. Numerous variants of the method are proposed depending on the soil, plot and crop types. This work uses the IRRINOV(r) method for the region Midi-Pyrenee, which is dedicated to maize crop plants on clay-limestone soil [13] and includes the following measuring equipment:  
* One IRRINOV(r) measuring station composed of six Watermark ([[https://www.irrometer.com/sensors.html#wm](https://www.irrometer.com/sensors.html#wm)]([https://www.irrometer.com/sensors.html#wm](https://www.irrometer.com/sensors.html#wm))) probes that measure the soil water tension (tensiometer). Three Watermark probes should be placed at 30 cm depth in the soil, and the other three should be placed at 60 cm depth in the soil. Figure 2 illustrates the prototype of the IRRINOV(r) station. * One mobile pluviometer that measures the amount of water received by the crop during a watering. * One weather station with a pluviometer to measure the quantity of water received by the crop during a rainfall. More information about IRRINOV(r) method is available at [12]. The goal of this section is to illustrate the processing defined un previous section. The IRRINOV(r) method specifies the time needed to install the devices on the plot. The IRRINOV(r) station and the mobile pluviometer should be placed in the plot when the crop reaches growth stage V2 (V2, V7, R1, and R5 are the code names of maize growth stages defined in [14]. They are respectively named \"7 leaf\", \"10 leaf\", \"silking\" and \"dent stage with 50% moisture\" in the Arvalis growth stage classification.). The measurements can start two or three days after installation. The Watermark probes are typically read once a week, but during dry weather, farmers can check the probes more frequently, for example, one observation per day. Irrigation should stop when the crop reaches the growth stage R5 hg45. Please note that state R5 is defined in [14]; however, the state R5 hg45 is defined in this project. This state means that the crops have moisture dents equivalent to 45%. The IRRINOV(r) method specifies the constraints to validate the measurements of Watermark probes. Those treatments are part of the acquisition phase. If the difference between the probe measurements is above 30 cbar, then one of the probes is malfunctioning, and the farmer should visit the field to correct the probe installation. The value read on a Watermark probe must be multiplied by the correction coefficient, which is specific for each batch of probes. For example,  
Figure 2: Prototype of the IRRINOV® station. probes from 2013 have a correction coefficient equal to 1.0. In this paper, we call the former value a raw data value. The latter value after this process is the measurement value.