Verifiable Water Use Inventory Using ICT …
15
recorder by NAE. If the gross precipitation of the day is lower than the soil storage
capacity, the total gross precipitation can be stored, so ER is equal to P. In the opposite
situation, when ER will reach the value the soil moisture content corresponding field
capacity conditions so, ER will be 0. Industrial cultivation conditions are usually
achieved in flat fields, so the occurrence of runoff is not considered in the daily basis
calculation in Eq. 8. In this case, the water not used by the plant is lost by percolation
and evaporation.
The aggregated value of ER n throughout the irrigation season represents the crop
green water use in the water footprint inventory (see Sect. 2.3). To perform the 7-day
watering schedule, it is necessary to make ER n predictions using the same Eq. (9)
but in this case, evapotranspiration (ET Cn) is calculated using ET 0 predictions and
rainfall forecast.
The coefficients f CE , f Pte and f Rs in equation (8) are correction factors for greenhouse crops as a function of the electrical conductivity of irrigation water, the slope
of the greenhouse roof and whitening, respectively [16]. For outdoor crops, the value
of these factors is 1.
In water-scarce region, crop water irrigation needs are usually much higher than
the water allowances assigned by the water authorities. In these circumstances, the
application of deficit irrigation strategies is recommended. They are included in Eq.
(8) by the daily irrigation deficit coefficient IDC n that varies in accordance with
irrigation strategies selected:
• Full Irrigation Requirements (FIR): Irrigation events (duration and water depth)
are designed to fully satisfy crop irrigation needs with an IDC equal to 1 in Eq.
(8).
• Sustained Deficit Irrigation (SDI): Only a fixed fraction of crop irrigation needs
is satisfied throughout the irrigation season. In this case, IDC equals this fraction
being a constant value during the irrigation season.
• Regulated Deficit Irrigation (RDI): A variable fraction of crop irrigation requirements is applied throughout the irrigation season, according to the crop cycle,
avoiding or reducing as much as possible the water stress in its most sensitive
crop stages: flowering and fruit set [24]. Thus, IDC depends on the crop development stage being equal to the variable fraction of crop irrigation needs to be
satisfied during the irrigation season,
Regardless of the chosen irrigation strategy, the sum of IN n must be less than the
crop water allowance (IWA) for the irrigation campaign. Thus, IDC of the selected
strategy is combined with the average fortnightly ETC (historical) to distribute the
water allowance according to the crop irrigation needs. Therefore, every fortnight is
assigned a fortnightly IWA. The occurrence or not of rainfall together with deviations
of ETC from the historical average will condition whether the total amount of water
available for each half of the month is used or not.
Any deviation from the established limit will be recorded by the irrigation meter,
therefore, at the end of each fortnight, the remaining allocation, if any, will be
distributed proportionally to the needs of the remaining months of the irrigation
season, readjusting the established limits every 15 days.
15
recorder by NAE. If the gross precipitation of the day is lower than the soil storage
capacity, the total gross precipitation can be stored, so ER is equal to P. In the opposite
situation, when ER will reach the value the soil moisture content corresponding field
capacity conditions so, ER will be 0. Industrial cultivation conditions are usually
achieved in flat fields, so the occurrence of runoff is not considered in the daily basis
calculation in Eq. 8. In this case, the water not used by the plant is lost by percolation
and evaporation.
The aggregated value of ER n throughout the irrigation season represents the crop
green water use in the water footprint inventory (see Sect. 2.3). To perform the 7-day
watering schedule, it is necessary to make ER n predictions using the same Eq. (9)
but in this case, evapotranspiration (ET Cn) is calculated using ET 0 predictions and
rainfall forecast.
The coefficients f CE , f Pte and f Rs in equation (8) are correction factors for greenhouse crops as a function of the electrical conductivity of irrigation water, the slope
of the greenhouse roof and whitening, respectively [16]. For outdoor crops, the value
of these factors is 1.
In water-scarce region, crop water irrigation needs are usually much higher than
the water allowances assigned by the water authorities. In these circumstances, the
application of deficit irrigation strategies is recommended. They are included in Eq.
(8) by the daily irrigation deficit coefficient IDC n that varies in accordance with
irrigation strategies selected:
• Full Irrigation Requirements (FIR): Irrigation events (duration and water depth)
are designed to fully satisfy crop irrigation needs with an IDC equal to 1 in Eq.
(8).
• Sustained Deficit Irrigation (SDI): Only a fixed fraction of crop irrigation needs
is satisfied throughout the irrigation season. In this case, IDC equals this fraction
being a constant value during the irrigation season.
• Regulated Deficit Irrigation (RDI): A variable fraction of crop irrigation requirements is applied throughout the irrigation season, according to the crop cycle,
avoiding or reducing as much as possible the water stress in its most sensitive
crop stages: flowering and fruit set [24]. Thus, IDC depends on the crop development stage being equal to the variable fraction of crop irrigation needs to be
satisfied during the irrigation season,
Regardless of the chosen irrigation strategy, the sum of IN n must be less than the
crop water allowance (IWA) for the irrigation campaign. Thus, IDC of the selected
strategy is combined with the average fortnightly ETC (historical) to distribute the
water allowance according to the crop irrigation needs. Therefore, every fortnight is
assigned a fortnightly IWA. The occurrence or not of rainfall together with deviations
of ETC from the historical average will condition whether the total amount of water
available for each half of the month is used or not.
Any deviation from the established limit will be recorded by the irrigation meter,
therefore, at the end of each fortnight, the remaining allocation, if any, will be
distributed proportionally to the needs of the remaining months of the irrigation
season, readjusting the established limits every 15 days.