Problems of shrinkage and soil improvement and the reallocation of this canal- rich horticultural area lacking normal roads led to this soil survey. Geologically, the region consists mainly of marine sediments. After deposition of the Old Marine clays and sands, the West Frisian Marine Clay (I and II) was deposited (1900-1200 B.C.). A recession followed and peat grew on some sites. Inversion of this landscape and lake-filling gave West Friesland its final shape and settlement became possible (1200 A.D.). Since then horticulture has developed gradually. Typical for this area are numerous man-made soils, constructed with humus-rich mud from the canals. The evaluation of the soils was carried out by studying of soil moisture (pF curves). It was concluded that there was more relation between moisture content at pF 4.2 and lutum content than between field capacity (pF 2.0) and lutum content. Future shrinkage after drainage was calculated from bulk densities. Vegetational and settlement history were reconstructed. A special study on the unusual relation between the low-lying position of West- Friesland and former sea levels showed that it was due to compaction of older sediments and possibly greater tidal ranges during the West Frisian Marine Clay sedimentation.
|Qualification||Doctor of Philosophy|
|Award date||22 May 1963|
|Place of Publication||Wageningen|
|Publication status||Published - 1963|
- soil science
- soil surveys