Monitoring electrical conductivity for improving irrigation scheduling
Objective: Providing guidelines and protocols for optimising irrigation scheduling in rice systems where salinity is a constraint
|Scale: Plot||Site: Irrigation scheme on the Lower Guadalquivir Bank, Southern Spain|
|Partners involved: CSIC, Tepro||Other stakeholders: Farmers, water users’ associations and private sector|
The Innovation HUB team identified irrigation water salinity as one the main threats for rice in the Guadalquivir marshes. In order to explore potential tools to deal with this constraint, electrical conductivity sensors were selected to be co-evaluated on the field.
Sensors of electrical conductivity (EC) of the irrigation water are installed at the inlet and outlet of several paddy fields. Farmers, farm and water users’ association managers and researchers, have learn together about the daily variation of EC. Innovations at two levels have been introduced:
- At the scheme level: establishing EC thresholds at the pumping station reduces the salinity in the paddy fields significantly. The constraint is that daily pumping is limited. There is room to optimize the pumping schedule minimizing EC and maximizing the volume of water. This is the innovation adopted by the scheme water managers.
- At farm level: manual operation of field inlet gates closing the gate when salinity increases and opening the gate when it decreases. The constraints are: a) labour requirements, although gate automation is a solution to be consider; b) capacity of the collective distribution system.
From left to right: The graph shows the variation of EC at the inlet and outlet of the paddy filed located at the right side of the canal in the picture below the graph. The sinusoidal variation of EC is consistent; the picture in the middle shows the inlet gate and the transmitter of EC data collected by a pressure transducer submerged in the canal water. In the figure on the right, a screenshot of the app displaying EC data at the inlet of a pilot field.
The innovation process has been continuous and informal. The EC sensors were installed by an irrigation advisory company. Farmers and farm managers discussed the data collected with researchers, thus operation solutions that could control salinity levels were envisaged. These solutions were shared with the irrigation scheme managers. Meanwhile, the installation of the water salinity sensors and the transmission of the data were adjusted for robustness. Data may be consulted on-line through a commercial app.
The innovation has attracted the attention of all stakeholders. Managers of the water users associations are already using EC as a pumping control variable. A large group of farmers is exploring how to automate their gates, although the irrigation scheduling EC criterion has already been assimilated.