Verifiable Water Use Inventory Using ICT …
9
The citrus fruit plantation (Navelina variety) is located in the Guadalquivir valley,
an area with greater availability of resources (about 600 mm of average annual
rainfall), but with a high percentage of its cultivated area dedicated to irrigated crops
(28.92% of total national irrigation) [37]. The high demand for irrigation water in
this basin means that the irrigation allocations made by the water authorities must be
lower than the water requirements of the crops. It is very frequent for the application
of deficit irrigation strategies to make efficient use of the available water.
The average of the average reference evapotranspiration during the orange tree
irrigation campaign is 3.65 mm per day. The soil of the farm has a sandy loam texture.
The distance between the crop lines is 5.5 m and the distance between the trees is
4 m. The plantation is irrigated from a hydrant of the primary irrigation network of
the irrigation district to which the farm belongs. The farm’s irrigation network is
organized in sectors in which each tree line is irrigated with two irrigation branches,
with self-compensating emitters of 2.8 L/h and a separation between them of 1 m.
The mean annual production of the studied orchard is 15 t/ha while being mainly
exported to German fresh produce markets.
2.2 Use of ICTs to Measure and Optimize Water Use
Soil moisture sensors and water meters have been installed to monitor crop water
use. The capacitive moisture sensors of type FDR (Frequency Domain Reflectometry)
were used to monitor and measure changes in soil volumetric water content (VWC).
To ensure that the soil water monitoring devices record variations in soil moisture
due to crop absorption, they should be placed in the layer with the largest volume of
crop roots. The depth of the roots depends on the crop, its state of development, type
of soil, presence of tillage sole, among other factors. After an in situ examination of
the soil and root systems of each crop, sensors were installed at 3 levels in increasing
order of depth: surface layer, zone with the highest concentration of roots and the
depth at which only a small fraction of the roots reach, where high moisture contents
would indicate water leakage by percolation and therefore inefficient use of irrigation
water.
Water meters record the total volume that has circulated through the pipe in which
they were located since their installation. Metering is done by an electronic sensor that
emits a pulse with each rotation of a piece moved by the flow of water. The volume
of water recorded can be displayed on the meter’s analog dial and is then transmitted
in digital format to the data server, with the same frequency as soil moisture content
records are sent. Both elements are connected to a data logger with General Packet
Radio Service (GPRS) communication that records and transmits in real-time data
measured by sensors to a remote server. To consult and use the data provided by water
meters and soil moisture sensors, it is accessed through an Application Programming
Interface (API).
9
The citrus fruit plantation (Navelina variety) is located in the Guadalquivir valley,
an area with greater availability of resources (about 600 mm of average annual
rainfall), but with a high percentage of its cultivated area dedicated to irrigated crops
(28.92% of total national irrigation) [37]. The high demand for irrigation water in
this basin means that the irrigation allocations made by the water authorities must be
lower than the water requirements of the crops. It is very frequent for the application
of deficit irrigation strategies to make efficient use of the available water.
The average of the average reference evapotranspiration during the orange tree
irrigation campaign is 3.65 mm per day. The soil of the farm has a sandy loam texture.
The distance between the crop lines is 5.5 m and the distance between the trees is
4 m. The plantation is irrigated from a hydrant of the primary irrigation network of
the irrigation district to which the farm belongs. The farm’s irrigation network is
organized in sectors in which each tree line is irrigated with two irrigation branches,
with self-compensating emitters of 2.8 L/h and a separation between them of 1 m.
The mean annual production of the studied orchard is 15 t/ha while being mainly
exported to German fresh produce markets.
2.2 Use of ICTs to Measure and Optimize Water Use
Soil moisture sensors and water meters have been installed to monitor crop water
use. The capacitive moisture sensors of type FDR (Frequency Domain Reflectometry)
were used to monitor and measure changes in soil volumetric water content (VWC).
To ensure that the soil water monitoring devices record variations in soil moisture
due to crop absorption, they should be placed in the layer with the largest volume of
crop roots. The depth of the roots depends on the crop, its state of development, type
of soil, presence of tillage sole, among other factors. After an in situ examination of
the soil and root systems of each crop, sensors were installed at 3 levels in increasing
order of depth: surface layer, zone with the highest concentration of roots and the
depth at which only a small fraction of the roots reach, where high moisture contents
would indicate water leakage by percolation and therefore inefficient use of irrigation
water.
Water meters record the total volume that has circulated through the pipe in which
they were located since their installation. Metering is done by an electronic sensor that
emits a pulse with each rotation of a piece moved by the flow of water. The volume
of water recorded can be displayed on the meter’s analog dial and is then transmitted
in digital format to the data server, with the same frequency as soil moisture content
records are sent. Both elements are connected to a data logger with General Packet
Radio Service (GPRS) communication that records and transmits in real-time data
measured by sensors to a remote server. To consult and use the data provided by water
meters and soil moisture sensors, it is accessed through an Application Programming
Interface (API).