High clay can by itself be quite problematic, especially reclaimed soil from sea and river deltas (so called polders) here in the Netherlands. These lands are v

High clay can by itself be quite problematic, especially reclaimed soil from sea and river deltas (so called polders) here in the Netherlands. These lands are very dense clay to begin with, rich with nutrients but not great for root growth and holding water. Sand is added for the former, and groubd water level is managed to max 1m underground for the latter. Nowadays with long stretches of dry weather (> 2 weeks no rain) this is becoming a huge problem as traditionally the issue always was drainage, ie getting rid of the water as fast as possible. There's an interesting read about a polder in English here, especially the mechanical soil improvement section is worthwhile: https://www.canonnoordoostpolder.nl/en/land/cultivation https://www.canonnoordoostpolder.nl/en/land/cultivation