Salinity in a Humid, Coastal Region: Examples From the Netherlands.

In coastal regions of the Netherlands various aspects of salinity were recognized and dealt with throughout history: causes of salinization and sodification, soil structure deterioration, crop salt tolerance/intolerance, and soil and crop management. Originally, experience of water managers and farmers formed the basis. Since 1850, first chemical analysis and physico-chemical concepts, later also flow and transport processes and plant physiology, were used to transform traditional opinions into scientific understanding. In the 20th century, salinization and sodification arose from natural floods (1906, 1916, 1953) and strategic wartime inundation (1940, 1944/45), and in the context of creation of the Flevopolders. J.M. van Bemmelen (1830-1911) pioneered diagnosis of salinity, while D.J. Hissink (1874-1956) understood sodicity and promoted application gypsum. These early studies were amplified, respectively, by A.J. Zuur and by W.H. van der Molen and G.H. Bolt.
In the period 1925-1940, TU Delft physicist J.M. Burgers (1895-1981) and his followers set the stage for studying seepage from saline open water into lower lying land and the description of diffusion and convection of salts into and out of lake bottoms. Eventually this led to analysis of density-stratified flows, including stability/instability of such flows. Some recent results in this area obtained in cooperation with colleagues at TU Eindhoven and Wageningen U will be discussed.
In the 1990s Bram de Vos used HYDRUS-2D, developed by Rien van Genuchten et al at the US Salinity Laboratory (USSL), to analyze the temporal Cl-fluctuations in tile drainage water arizing from the subsoil in the Noordoostpolder, reclaimed in 1942 from the IJsselmeer. The USSL has also inspired studies of salt tolerance and intolerance: in the aftermath of WWII inundations in Zeeland, in water and nutrient management in greenhouse horticulture, and in recent exploratory studies of saline agriculture.