A GIS-based decision tool for reducing salinization risks in olive orchards

Abstract

This work was aimed at implementing a GIS based on an open-source software able to help in decision making in irrigation water management with a view of avoiding the excessive accumulation of salts in soils for olive tree production in South Spain (province of Jaen). The proposed model provides graphical and geostatistical analysis that can be easily performed by using different mathematical algorithms available in the gvSIG software. Leaching and mixing of water from different origin were taken into account in the model as strategies to decrease salinization risk in soil.Overall, electrical conductivity, and consequently leaching requirements, were higher for surface water than for groundwater. A relative crop yield of 90% can be achieved in 23% of the area irrigated with surface water, meanwhile with groundwater a 90% of relative yield can be achieved in 36.7% of the irrigated area with leaching fraction (LF) above 10%. The implemented GIS-tool based on open source gvSIG software was able to assess water leaching requirements in order to prevent the salinization risk of soils in olive orchards in the province of Jaen. Where LF was so high to be feasible, the GIS-based tool can recommend different mixing ratios for surface and underground water in order to decrease recommended LF thus making irrigation sustainable. The model was able to facilitate data analysis and processing, allowing the visualization of the spatial distribution and offering all the functionality of handling geographic data, which will be used in the planning and decision making. The proposed GIS-based tool is also able to provide fast map recalculation after an update of database, thus allowing one to adapt decisions to fast changes in water properties.