Soil salinity related to physical soil characteristics and irrigation management in four Mediterranean irrigation districts

25 Pag., 6 Tabl., 1 Fig. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774Irrigated agriculture is threatened by soil salinity in numerous arid and semiarid areas of the Mediterranean basin. The objective of this work was to quantify soil salinity through electromagnetic induction (EMI) techniques and relate it to the physical characteristics and irrigation management of four Mediterranean irrigation districts located in Morocco, Spain, Tunisia and Turkey. The volume and salinity of the main water inputs (irrigation and precipitation) and outputs (crop evapotranspiration and drainage) were measured or estimated in each district. Soil salinity (ECe) maps were obtained through electromagnetic induction surveys (ECa readings) and district-specific ECa–ECe calibrations. Gravimetric soil water content (WC) and soil saturation percentage (SP) were also measured in the soil calibration samples. The ECa–ECe calibration equations were highly significant (P 0.1) with WC, and was only significantly correlated (P Morocco (2.2 dS m−1) > Spain (1.4 dS m−1) > Turkey (0.45 dS m−1). Soil salinity was mainly affected by irrigation water salinity and irrigation efficiency. Drainage water salinity at the exit of each district was mostly affected by soil salinity and irrigation efficiency, with values very high in Tunisia (9.0 dS m−1), high in Spain (4.6 dS m−1), moderate in Morocco (estimated at 2.6 dS m−1), and low in Turkey (1.4 dS m−1). Salt loads in drainage waters, calculated from their salinity (ECdw) and volume (Q), were highest in Tunisia (very high Q and very high ECdw), intermediate in Turkey (extremely high Q and low ECdw) and lowest in Spain (very low Q and high ECdw) (there were no Q data for Morocco). Reduction of these high drainage volumes through sound irrigation management would be the most efficient way to control the off-site salt-pollution caused by these Mediterranean irrigation districts.This study was supported by the European Commission research project INCO-CT-2005-015031.Peer reviewe

Comparison of Geonics EM38 and Dualem 1S electromagnetic induction sensors for the measurement of salinity and other soil properties

17 Pags., 3 Tabls., 3 Figs. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1475-2743The electromagnetic induction (EMI) Geonics EM38 (G-EM38) and Dualem 1S (D-1S) sensors are used frequently for assessment of soil salinity and other soil characteristics in irrigated agriculture. We compared these two sensors to determine whether they could be used interchangeably for the measurement of apparent soil electrical conductivity (ECa) in horizontal (ECa-h) and vertical (ECa-v) coil receiver modes. Readings were taken at 201 locations identified in three irrigation districts in both modes, and statistical comparisons were made on the raw data and from maps of a 2-ha irrigated field made using 1680 horizontal mode readings. Both sensors gave the same ECa-v readings (mean G-EM38 and D-1S difference = 0), whereas the ECa-h readings were slightly greater with the Geonics EM38 than with the Dualem D-1S (mean difference = 0.075 and 0.05 dS/m for the 201 and 1680 observations, respectively). The degree of coincidence between both sensors for soil profile ECa classification was acceptable: 82% for normal profiles (i.e. ECa-h/ECa-v 1.1). In practical terms, Geonics EM38 and Dualem 1S sensors could be used interchangeably with similar or very close results.This study was partially supported by the European Commission (Qualiwater project INCO-CT-2005-015031) and by an INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Spain) doctoral fellowship given to V. Urdanoz.Peer reviewe

Sensores electromagnéticos móviles georreferenciados y aplicaciones para la determinación de la salinidad

10 Pag., 2 Tabl., 4 Fig.[EN] Soil salinity is a major threat in irrigated agriculture because of its negative on-site (decreased productivity) and off-site (salinization of irrigation return flows) effects. The delineation of the spatial variability of soil salinity is best suited using non-invasive geophysical measurements of the apparent soil electrical conductivity (ECa) using mobile GPS-based systems. Two simple and cost-effective Mobile Georeferenced Electromagnetic Sensors (MGES) developed in Aragón and Navarra (Spain) are described. These devices involve electromagnetic instruments towed by all terrain vehicles and combined with GPS units and data acquisition systems that collect both ECa readings and GPS coordinates. Two applications of the MGES aimed at delineating ECa maps for (i) selecting the most suitable crops in a 43-ha saline site (Hondo de Espartosa) and (ii) correlating ECa with drainage water salinity to ascertain the salinity-source areas in a new 715 ha irrigated basin (Barranco de Lerma) were examined. These examples demonstrate the MGES surveying capacities for management of salt-affected agricultural areas.[ES] La salinidad del suelo es una importante amenaza para la agricultura de regadío debido a sus efectos negativos internos (descenso de la productividad) y externos (salinización de los flujos de retorno del riego). El procedimiento más adecuado para delinear la variabilidad espacial de la salinidad edáfica es mediante la medida geofísica de la conductividad eléctrica aparente del suelo (ECa) efectuada con sistemas móviles georreferenciados. En este trabajo se describen dos Sensores Electromagnéticos Móviles Georreferenciados (MGES) sencillos y económicos desarrollados en Aragón y Navarra (España). Estos equipos incluyen instrumentos electromagnéticos arrastrados por un vehículo todo terreno, combinados con una unidad de GPS y un sistema de adquisición de datos que recopila las lecturas de ECa y las coordenadas geográficas. Se presentan dos aplicaciones del MGES en las que se levantan mapas de ECa para (i) seleccionar los cultivos más apropiados en un regadío salino de 43 ha (Hondo de Espartosa) y (ii) correlacionar la ECa con la salinidad de las aguas de drenaje para identificar las áreas-fuente mas importantes de salinidad en una nueva cuenca de regadío de 715 ha (Barranco de Lerma). Estos ejemplos demuestran las capacidades de análisis del MGES para el manejo de áreas agrícolas afectadas por salinidad.The work developed at Navarra was financially supported by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria and the Fondo Europeo de Desarrollo Regional (INIA and FEDER; RTA04-041-C2-1 and I05-021-P04-01) and by the Department of Agriculture of the Government of Navarre (Spain). The work developed at Zaragoza was financially supported by the Government of Aragon (PM107/2006) and the European Commission (INCOCT-2005-015031). We also acknowledge the INIA doctoral fellowships given to V. Urdanoz and V. Ochoa.Peer reviewe

Pre- and Post-Irrigation Mapping of Soil Salinity with Electromagnetic Induction Techniques and Relationships with Drainage Water Salinity

9 Pag., 5 Tabl., 6 Fig.Irrigated agriculture may impair negative “on-site” (i.e., soil salinization) and “off-site” (i.e., salts exported in irrigation return flows) effects. The aim of this study was to assess these effects, and the relationships between soil- and drainage-water salinity in a basin before and after the development of irrigation. Soil salinity (ECe) was estimated through electromagnetic induction (EMI) techniques (ECa) and the corresponding calibration equations, and drainage water salinity (ECdw) was measured in the outlets of 22 watersheds delineated within a 505-ha study area before (Year 2006) and after (Year 2008) irrigation development. Apparent soil EC was about 50% higher in 2008 than in 2006 due to increasing soil water contents, but estimated ECe was about 15% lower in 2008 than in 2006 due to salt leaching induced by irrigation. Drainage water EC increased by one order of magnitude from the upper (ECdw = 0.4 dS m−1) to the lower (ECdw = 4.5 dS m−1) reaches of the drainage network. The mean ECdw of the 22 watershed drainage outlets increased from pre-irrigation 2006 (2.4 dS m−1) to post-irrigation 2007 (3.1 dS m−1) and 2008 (2.7 dS m−1) years. Drainage water EC significantly depended (P < 0.001) on surface-weighted EC (ECe*) of each watershed, but the linear regressions were different in 2006 and 2008. The transformation from dryland to irrigation led to the leaching of salts and its export in the irrigation return flows. A compromise needs to be attained in the study area to achieve the beneficial “on-site” leaching of salts while minimizing the detrimental “off-site” export of salts.This study was partially supported by the European Commission (INCO-CT-2005-015031) and by an INIA (Instituto Nacional de Investigación y Tecnologia Agraria y Alimentaria, Spain) doctoral fellowship given to V. Urdanoz.Peer reviewe

Highlighting twenty years of salinity research in Spain’s Ebro River Basin

1 .pdf (35 Pags.) copia de presentación original de los autores.• Terrestrial EM vehicles are excellent tools for soil salinity mapping and establishment of relationships with hydrology and water quality. • Soil and water salinity is and will continue to be an increasing problem in the ERB. • Our irrigation waters are of good quality for crops. Thus, high irrigation efficiencies are attainable in order to minimize salt loading in IRF. • Our irrigation waters may impair losses in the structural stability of sensitive (silt) soils. Ranking by measuring IR with gypsum-saturated, distilled and canal irrigation waters.• TLS and DIS are excellent tools for appraisal of salinity tolerance of crops under field conditions. • Strategies to reduce leaf salt absorption in saline sprinkler irrigation: - 3-min pre-wetting and 3-min post-washing with fresh water is a recommended strategy in barley and corn. - Nocturnal irrigations did not have any beneficial effect over diurnal irrigations in alfalfa and corn.Peer reviewe

Sistemas piloto de vigilancia de la salinidad edáfica en la Cuenca media del Ebro (CME)

Copia .pdf en a-3 del orginal (1 Póster, con 1 Tabl, Figs.). Presentado en las XXVIII Reunión de la Sociedad Española de la Ciencia del Suelo (Barcelona, 4-7 septiembre 2011).La salinidad edáfica es un serio problema de la agricultura de regadío que reduce la calidad del suelo, el rendimiento de las cosechas y la gama de cultivos. Su prevención y mitigación requiere el establecimiento de inventarios y sistemas de vigilancia. La monitorización periódica de áreas salinas es esencial para el desarrollo de estrategias de manejo y recuperación. Este trabajo presenta una propuesta de sistema piloto de vigilancia de la salinidad edáfica en zonas de regadío de la cuenca media del Ebro. Los objetivos específicos son (1) seleccionar áreas a monitorizar (RedSAL) y (2) definir los aspectos más relevantes del sistema de vigilancia. El estudio se ha realizado en Navarra (13 municipios de la zona media, con 70.000 ha, un 25% de ellas en proceso de transformación en regadío entre 2008-2011), y en Aragón (3.400 ha de regadío en Huesca). En Navarra, la selección de RedSALs se ha realizado mediante el cruce de (a) mapas de áreas con riesgo de presentar salinidad primaria (establecido a partir del modelo digital del terreno y capas adicionales), (b) mapas de áreas afectadas por salinidad (E 1:25.000) y (c) mapas de zonas a transformar en regadío en el sistema Itoiz-Canal de Navarra. Se preseleccionaron 32 zonas, se visitaron en campo y finalmente se han seleccionado 9 RedSALs con una superficie de 267 ha. En Aragón, a partir del mapa de áreas afectadas por salinidad (E 1:25.000) y un conocimiento detallado de la zona de estudio, se han seleccionado 5 RedSALs, 4 a modernizar en el futuro (paso de riego por inundación a presión) y 1 ya modernizada, con una superficie total de 85 ha. Se han analizado los aspectos más relevantes del sistema de vigilancia (metodologías, frecuencia de monitorización, entregables, etc.), y se ha establecido el protocolo para elaborar mapas de salinidad a partir de lecturas tomadas con sensores electromagnéticos móviles georreferenciados (SEMG). En 2010 y 2011 se han elaborado mapas de salinidad con dichos equipos en las RedSALs seleccionadas (en el caso de Navarra, antes o en el momento de su transformación en regadío), que suponen la referencia para el establecimiento de tendencias en el espacio y tiempo mediante su monitorización periódica (cada 5 años en principio). Este seguimiento permitirá seleccionar los cultivos más apropiados y analizar el impacto ambiental de la transformación (Navarra) o modernización (Aragón) del regadío.Peer reviewe

Soil salinity related to physical soil characteristics and irrigation management in four Mediterranean irrigation districts

25 Pag., 6 Tabl., 1 Fig. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774Irrigated agriculture is threatened by soil salinity in numerous arid and semiarid areas of the Mediterranean basin. The objective of this work was to quantify soil salinity through electromagnetic induction (EMI) techniques and relate it to the physical characteristics and irrigation management of four Mediterranean irrigation districts located in Morocco, Spain, Tunisia and Turkey. The volume and salinity of the main water inputs (irrigation and precipitation) and outputs (crop evapotranspiration and drainage) were measured or estimated in each district. Soil salinity (ECe) maps were obtained through electromagnetic induction surveys (ECa readings) and district-specific ECa–ECe calibrations. Gravimetric soil water content (WC) and soil saturation percentage (SP) were also measured in the soil calibration samples. The ECa–ECe calibration equations were highly significant (P 0.1) with WC, and was only significantly correlated (P Morocco (2.2 dS m−1) > Spain (1.4 dS m−1) > Turkey (0.45 dS m−1). Soil salinity was mainly affected by irrigation water salinity and irrigation efficiency. Drainage water salinity at the exit of each district was mostly affected by soil salinity and irrigation efficiency, with values very high in Tunisia (9.0 dS m−1), high in Spain (4.6 dS m−1), moderate in Morocco (estimated at 2.6 dS m−1), and low in Turkey (1.4 dS m−1). Salt loads in drainage waters, calculated from their salinity (ECdw) and volume (Q), were highest in Tunisia (very high Q and very high ECdw), intermediate in Turkey (extremely high Q and low ECdw) and lowest in Spain (very low Q and high ECdw) (there were no Q data for Morocco). Reduction of these high drainage volumes through sound irrigation management would be the most efficient way to control the off-site salt-pollution caused by these Mediterranean irrigation districts.This study was supported by the European Commission research project INCO-CT-2005-015031.Peer reviewe

Mobile and georeferenced electromagnetic sensors and applications for salinity assessment

La salinidad del suelo es una importante amenaza para la agricultura de regadío debido a sus efectos negativos internos (descenso de la productividad) y externos (salinización de los flujos de retorno del riego). El procedimiento más adecuado para delinear la variabilidad espacial de la salinidad edáfica es mediante la medida geofísica de la conductividad eléctrica aparente del suelo (ECa) efectuada con sistemas móviles georreferenciados. En este trabajo se describen dos Sensores Electromagnéticos Móviles Georreferenciados (MGES) sencillos y económicos desarrollados en Aragón y Navarra (España). Estos equipos incluyen instrumentos electromagnéticos arrastrados por un vehículo todo terreno, combinados con una unidad de GPS y un sistema de adquisición de datos que recopila las lecturas de ECa y las coordenadas geográficas. Se presentan dos aplicaciones del MGES en las que se levantan mapas de ECa para (i) seleccionar los cultivos más apropiados en un regadío salino de 43 ha (Hondo de Espartosa) y (ii) correlacionar la ECa con la salinidad de las aguas de drenaje para identificar las áreas-fuente mas importantes de salinidad en una nueva cuenca de regadío de 715 ha (Barranco de Lerma). Estos ejemplos demuestran las capacidades de análisis del MGES para el manejo de áreas agrícolas afectadas por salinidad.Soil salinity is a major threat in irrigated agriculture because of its negative on-site (decreased productivity) and off-site (salinization of irrigation return flows) effects. The delineation of the spatial variability of soil salinity is best suited using non-invasive geophysical measurements of the apparent soil electrical conductivity (ECa) using mobile GPS-based systems. Two simple and cost-effective Mobile Georeferenced Electromagnetic Sensors (MGES) developed in Aragón and Navarra (Spain) are described. These devices involve electromagnetic instruments towed by all terrain vehicles and combined with GPS units and data acquisition systems that collect both ECa readings and GPS coordinates. Two applications of the MGES aimed at delineating ECa maps for (i) selecting the most suitable crops in a 43-ha saline site (Hondo de Espartosa) and (ii) correlating ECa with drainage water salinity to ascertain the salinity-source areas in a new 715 ha irrigated basin (Barranco de Lerma) were examined. These examples demonstrate the MGES surveying capacities for management of salt-affected agricultural areas

Soil salinity related to physical soil characteristics and irrigation management in four Mediterranean irrigation districts

Irrigated agriculture is threatened by soil salinity in numerous arid and semiarid areas of the Mediterranean basin. The objective of this work was to quantify soil salinity through electromagnetic induction (EMI) techniques and relate it to the physical characteristics and irrigation management of four Mediterranean irrigation districts located in Morocco, Spain, Tunisia and Turkey. The volume and salinity of the main water inputs (irrigation and precipitation) and outputs (crop evapotranspiration and drainage) were measured or estimated in each district. Soil salinity (ECe) maps were obtained through electromagnetic induction surveys (ECa readings) and district-specific ECa-ECe calibrations. Gravimetric soil water content (WC) and soil saturation percentage (SP) were also measured in the soil calibration samples. The ECa-ECe calibration equations were highly significant (P&lt;0.001) in all districts. ECa was not significantly correlated (P&gt;0.1) with WC, and was only significantly correlated (P&lt;0.1) with soil texture (estimated by SP) in Spain. Hence, ECa mainly depended upon ECe, so that the maps developed could be used effectively to assess soil salinity and its spatial variability. The surface-weighted average ECe values were low to moderate, and ranked the districts in the order: Tunisia (3.4dSm-1)&gt;Morocco (2.2dSm-1)&gt;Spain (1.4dSm-1)&gt;Turkey (0.45dSm-1). Soil salinity was mainly affected by irrigation water salinity and irrigation efficiency. Drainage water salinity at the exit of each district was mostly affected by soil salinity and irrigation efficiency, with values very high in Tunisia (9.0dSm-1), high in Spain (4.6dSm-1), moderate in Morocco (estimated at 2.6dSm-1), and low in Turkey (1.4dSm-1). Salt loads in drainage waters, calculated from their salinity (ECdw) and volume (Q), were highest in Tunisia (very high Q and very high ECdw), intermediate in Turkey (extremely high Q and low ECdw) and lowest in Spain (very low Q and high ECdw) (there were no Q data for Morocco). Reduction of these high drainage volumes through sound irrigation management would be the most efficient way to control the off-site salt-pollution caused by these Mediterranean irrigation districts. © 2011 Elsevier B.V.INCO-CT-2005-015031This study was supported by the European Commission research project INCO-CT-2005-015031 . The authors gratefully acknowledge the assistance of the technicians and students that actively participated in this work