Douaik, A., M. Van Meirvenne, and T. Tóth. 2006. Temporal stability of spatial patterns 
of soil salinity determined from laboratory and field electrical conductivity. Arid Land 
Research and Management. 20: 1-13. 

We elaborated a procedure for the assessment of the temporal stability of soil salinity and 
the optimalization of the sampling effort. Soil electrical conductivity data obtained from 
field electrode probes and laboratory analysis were compared and analyzed to check the 
temporal stability of salinity patterns. Therefore sampling of 20 locations at different 
depths was repeated 19 times over a period from November 1994 to June 2001. Both 
determination methods showed a strong temporal stability. The Spearman rank 
correlation confirmed the persistence of the ranking of the different locations. 
Additionally, using the technique of relative differences, we were able to identify three 
classes: (1) the low saline locations, (2) locations which are representative of the average 
field soil salinity, and (3) the high saline locations. The latter included the least time 
stable locations while the first class contained the most time stable ones. The low saline 
locations were identified as belonging to the zones of waterlogging and/or salt leaching, 
the high saline locations belonged exclusively to the zone of salt accumulation, while 
locations representative of the average soil salinity belonged to all three possible zones. 
We investigated also how precise the selected locations representating the average soil 
salinity can estimate this average. We found that using only two locations from the 20 
available, the average (2 dS/m) was adequately estimated with a difference smaller than 
0.3 dS/m. This representativity was also checked by splitting the measurements into two 
temporal subsamples. We found for both subsamples that the same locations were 
representative of the average soil salinity as when all measurement dates were 
considered.