Simulating the composition of the in situ soil solution by the model EXPRESO: Application to a reclaimed marsh soil of SW Spain irrigated with saline water
The drained and irrigated marshes in south-west Spain are formed on soils of alluvial origin from the ancient Guadalquivir river estuary. The reclaimed area near Lebrija, called Sector B-XII (about 15,000ha), has been under cultivation since 1978. Some years, however, water supply for irrigation is limited due to drought periods. The scarcity of good quality water during the drought period 1993-1995 imposed on farmers the necessity to irrigate with river water, which at this location is saline due to tidal flow. The objective of this work was to determine the composition of the in situ soil solution and exchange complex of the reclaimed soil, of a plot near Lebrija, using the EXPRESO model. One of the irrigations, during the growing season of cotton crop in 1997, was with saline water (EC=22.7dSm-1). The soil samples (0-0.3m and 0.3-0.6m depths) used in this work were obtained during 1997 in a farm plot of 12.5ha (250m×500m) situated in an area of marshes on the left bank of the Guadalquivir river, near Lebrija (south-west Spain) [Agric. Water Manage 48 (2001) 133]. The chemical composition of the saturated paste extracts was determined in the laboratory. The electrical conductivity of the saturated paste extract (ECsp) 1 day after irrigation with saline water, for both sampling depths, showed an increase in comparison with the value of the samples taken just before irrigation. One month later, the ECsp reached a similar value to that before irrigation with saline water, due to the three irrigations with fresh water. The in situ soil solution characteristics, simulated by EXPRESO, showed higher values of the different parameters than those of the saturated paste, but with similar trends. ECsp, at 0-0.3m depth, after irrigation with saline water ranged between 7.87 and 8.15dSm-1, and in situ values simulated by EXPRESO ranged between 15.1 and 22.4dSm-1. This means that under field conditions the EC can be up to three times the ECsp. The ESP showed a similar trend to that of the EC. Simulation by EXPRESO of the soil solution and exchange complex composition at the in situ soil water content gives a more comprehensive picture of the soil salinity than the saturated paste extract.
| Main Authors: | , , , |
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| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Elsevier
2004
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| Online Access: | http://hdl.handle.net/10261/60454 http://dx.doi.org/10.13039/501100007273 http://dx.doi.org/10.13039/501100011011 |
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| Summary: | The drained and irrigated marshes in south-west Spain are formed on soils of alluvial origin from the ancient Guadalquivir river estuary. The reclaimed area near Lebrija, called Sector B-XII (about 15,000ha), has been under cultivation since 1978. Some years, however, water supply for irrigation is limited due to drought periods. The scarcity of good quality water during the drought period 1993-1995 imposed on farmers the necessity to irrigate with river water, which at this location is saline due to tidal flow. The objective of this work was to determine the composition of the in situ soil solution and exchange complex of the reclaimed soil, of a plot near Lebrija, using the EXPRESO model. One of the irrigations, during the growing season of cotton crop in 1997, was with saline water (EC=22.7dSm-1). The soil samples (0-0.3m and 0.3-0.6m depths) used in this work were obtained during 1997 in a farm plot of 12.5ha (250m×500m) situated in an area of marshes on the left bank of the Guadalquivir river, near Lebrija (south-west Spain) [Agric. Water Manage 48 (2001) 133]. The chemical composition of the saturated paste extracts was determined in the laboratory. The electrical conductivity of the saturated paste extract (ECsp) 1 day after irrigation with saline water, for both sampling depths, showed an increase in comparison with the value of the samples taken just before irrigation. One month later, the ECsp reached a similar value to that before irrigation with saline water, due to the three irrigations with fresh water. The in situ soil solution characteristics, simulated by EXPRESO, showed higher values of the different parameters than those of the saturated paste, but with similar trends. ECsp, at 0-0.3m depth, after irrigation with saline water ranged between 7.87 and 8.15dSm-1, and in situ values simulated by EXPRESO ranged between 15.1 and 22.4dSm-1. This means that under field conditions the EC can be up to three times the ECsp. The ESP showed a similar trend to that of the EC. Simulation by EXPRESO of the soil solution and exchange complex composition at the in situ soil water content gives a more comprehensive picture of the soil salinity than the saturated paste extract. |
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