Changes in soil salinity in the habitats of five halophytes after 20Â years

Long-term soil salinity data are required to properly manage saline habitats. This study presents easy procedures for comparing soil salinity profiles, which were used to assess four saline wetlands in NE Spain. Soil salinity measurements at sites where different halophytes were dominant were recorded throughout the year in 1979-1980 and 1999-2000, with additional measurements in 1985. Electrical conductivity of saturation extracts (ECe) and the concentrations of major ions were measured in four hundred soil samples. To confirm the consistency of the quality of the lab measurements, we used saturation percentage (SP) statistics and the relationships between ECe and both the cationic and the anionic concentrations in the extracts (R2 > 97%), and the relationship with the EC of the extracts at a soil-to-water ratio of 1:5 by weight (EC 1:5). The ECe of the soil samples ranged from 4 to 114 dS m− 1, and the averages in the four wetlands (AN, PC, AL, and AG) were 38.6, 10.1, 22.3, and 68.5 dS m− 1, respectively. The median of the sodium adsorption ratio [SAR, (meq L− 1)0.5] in the samples was 69, 126, 64, and 28, respectively. At AN, the maximum average ECe in the upper 100 cm of the soil was 35.0 dS m− 1 for Artemisia herba-alba and 75.2 dS m− 1 for Suaeda vera; at PC, the maximum value was 19.3 dS m− 1 for Puccinellia festuciformis; and, at AL, it was 30.3 dS m− 1 for Salicornia ramosissima and 44.6 dS m− 1 for S. vera. At AG, the maximum average ECe was 69.2 for S. vera, and 85.2 dS m− 1 for Arthrocnemum macrostachyum. The ECe and SAR remained stable between the two sampling periods in three of the wetlands but, in AL, which was converted into a paddy, ECe was reduced from ~ 40 dS m− 1 to ~ 2 dS m− 1 and SAR was reduced from > 77 to ~ 2. The presence of saline non-sodic and saline-sodic soils at nearby wetlands reflects the pedodiversity of the area.