IDL – SALTFREE PROJECT
Soil salinity affects an estimated 1 million hectares in the European Union, mainly in the Mediterranean countries, and is a major cause of desertification. Soil salinization limits agricultural productivity and can ultimately cause desertification and abandonment of the land. Salinization can also affect the quality of both ground and surface water resources, degrade infrastructures, and decrease biodiversity.
The aim of this project is to develop a framework to evaluate the salinization risk in irrigated production systems in the Mediterranean basin and to propose management practices to prevent or correct salinization mechanisms. The project includes defining case-study production systems and measurement of the pedosphere with geophysical methods (electromagnetic induction) during at least two periods of the irrigation cycle and during two consecutive years. It also includes numerical modeling of the production systems and simulation under scenarios such as climate change and variability in the quality of the irrigation water.
The project consortium is formed by five partners from four countries around the Mediterranean- Egypt, Italy, Portugal, and Tunisia. It is planned that four of the partners (IDL, ISAFOM, PSU, and INRGREF), perform geophysical measurements in local irrigation areas. Three of the partners work with modeling and simulation (IDL, INIAV, and PSU). Partners will combine knowledge on soil science, agricultural practices, geophysical measurement, geophysical data processing, and numerical modeling in order to achieve the expected results.
Salinization of soil and water can occur due to different phenomena. In irrigated agricultural areas soil salinization can occur because of:
• accumulation of salts added by irrigation water and fertilization in the root zone due to insufficient leaching;
• rise of the water table due to increase of water input to the soil which brings the salts to the root zone by capillarity;
• high evapotranspiration that brings up to the root zone salts accumulated under it;
In order to study the salinization risk it is important to understand which, if any of the mechanisms described above, can occur in a determined production system. If we can foreseen the occurrence of these mechanisms or detect their existence we can develop preventive or corrective measures, respectively.
Also, our hypothesis is that by studying plots with varying soil types, soil and water table depths, evapotranspiration, irrigation and fertilization practices, we can model these production systems and estimate its outcomes under different scenarios including different soils, agronomic practices, irrigation management, climate change, and variation in the quality of the irrigation water. The result would be a framework for estimating the salinization risk than can be used in other Mediterranean irrigated areas. This would be an unprecedented achievement with a potentially high impact on preservation of soil and water, combined with maximization of agricultural productivity in Mediterranean countries..
WP1 Standardization of state-of-the-art methods for the geophysical surveys
Harmonization of the methods is fundamental because the experimental work in irrigated sites defined in WP2 will be carried out in four different countries and by five different teams and results have to be comparable. Therefore it is necessary the collaboration between partners with knowledge and experience in geophysical methods in order to define the state-of-art methodologies to be used in the surveys and that will also be published in a manual for agricultural researchers and technicians worldwide.
The work package includes the following tasks:
1.1 Defining parameters of the geophysical measurements;
1.2 Defining methods for determination of the location of soil samples;
1.3 Defining the soil properties to be determined in the measurement sites;
1.4 Calibration of geophysical measurements.
WP2 Geophysical surveys
This WP consists of the geophysical surveys and will be carried out by four partners in four different countries. In each country at least two experimental sites will be chosen, with varying soil types, irrigation and fertilization managements in order to achieve some level of representatively of production systems around the Mediterranean. It is planned that measurements are performed during at least two periods of the irrigation cycle and during two consecutive years, in order to analyze the temporal variability of the salinity. The number of field campaigns per year is determined by regional climatic conditions and irrigation cycles.
The WP 2 includes the following tasks:
2.1 Definition of plots in production systems with varying parameters: soil type, irrigation and fertilization management;
2.2 Collection of data and information relative to soils, irrigation, climate, agricultural practices, and irrigation water quality;
2.3 Geophysical surveys and soil sampling. The geophysical surveys will be carried out in every experimental site with EM sensors which all partners in the consortium have access. Soil sampling and analysis will also be carried out simultaneously with geophysical survey.
2.4 Inversion of geophysical data for 2-D and 3-D mapping.
WP3 Correlation of geophysical data to soil samples and spatiotemporal salinity mapping
This WP includes the determination in the laboratory of the soil’s physical properties and analysis of the correlation of geophysical data to soil’s salinity.
3.1 Determination of soil’s physical properties (i.e. particle size distribution, bulk density, and soil hydraulic properties), and main soil variables (i.e. water content, electrical conductivity of the soil saturation extract, cation exchange capacity, sodium adsorption ratio), influencing the geophysical measurements.
3.2 Statistical analysis of soil properties influencing the geophysical measurements.
3.3. Converting geophysical models to salinity maps.
WP4 Modeling of water and salts transport
This WP consists in the numerical modelling of the production systems and simulation under scenarios such as varying crops, agronomical and irrigation management, climate change, and variability in the quality of the irrigation water.
4.1 Modelling water and salt transport with field data;
4.2 Simulation of salinization risk under different scenarios.
WP5 Interpretation and framework for salinity risk
Salinization can occur as a result of different mechanisms, as described in our scientific hypothesis.
The geophysical surveys in WP2 will allow identifying if any of these mechanisms is present, then it is necessary to evaluate if they can result in salinization or, if not present at all, if they are likely to develop under specific conditions. This WP includes the analysis of the results of WP2, 3, and 4 and delivers the framework for salinity prediction in Mediterranean irrigated production systems. It includes the following tasks:
5.1 Identify relationships between properties such as soil type, evapotranspiration, irrigation and soil management and the dynamics of water and salts in the soil and the salinization risk;
5.2 Framework for prediction of salinity risk in irrigated areas.
Saltfree Project kickoff meeting